1 - Science of Synthesis: Knowledge Updates 2015/1 [Seite 1]
2 - Title Page [Seite Title Page]
- 7 [Seite 7]
3 - Imprint [Seite 8]
4 - Preface [Seite 9]
5 - Abstracts [Seite 11]
6 - Overview [Seite 17]
7 - Table of Contents [Seite 19]
8 - 4.4.4.8 Silyl Hydrides (Update 2015) [Seite 29]
8.1 - 4.4.4.8.1 Synthesis of Silyl Hydrides [Seite 30]
8.1.1 - 4.4.4.8.1.1 Method 1: From Inorganic Silanes [Seite 30]
8.1.2 - 4.4.4.8.1.2 Method 2: From Alkyl- or Arylsilanes [Seite 32]
8.1.3 - 4.4.4.8.1.3 Method 3: From Silyl Halides [Seite 36]
8.1.4 - 4.4.4.8.1.4 Method 4: From Silyl Ethers [Seite 38]
8.1.5 - 4.4.4.8.1.5 Method 5: From Other Silyl Hydrides by Monohalogenation or Deuterium Exchange [Seite 41]
8.2 - 4.4.4.8.2 Applications of Silyl Hydrides in Organic Synthesis [Seite 44]
8.2.1 - 4.4.4.8.2.1 Method 1: Hydrosilylation of Alkenes, Alkynes, and Related Compounds [Seite 44]
8.2.2 - 4.4.4.8.2.2 Method 2: Silyl Hydrides as Reducing Agents [Seite 58]
8.2.3 - 4.4.4.8.2.3 Method 3: Dehydrogenative Silylation [Seite 71]
9 - 4.4.34.35 Vinylsilanes (Update 2015) [Seite 87]
9.1 - 4.4.34.35.1 Vinylmetal Addition to Silane Electrophiles [Seite 88]
9.1.1 - 4.4.34.35.1.1 Method 1: Addition to Chlorosilanes [Seite 88]
9.1.2 - 4.4.34.35.1.2 Method 2: Addition to Cyclic Siloxanes [Seite 91]
9.2 - 4.4.34.35.2 Hydrosilylation of Alkynes [Seite 93]
9.2.1 - 4.4.34.35.2.1 Method 1: Transition-Metal-Catalyzed b-Hydrosilylation of Terminal Alkynes To Give e-Vinylsilanes [Seite 93]
9.2.1.1 - 4.4.34.35.2.1.1 Variation 1: PlatinumCatalysis [Seite 93]
9.2.1.2 - 4.4.34.35.2.1.2 Variation 2: Rhodium Catalysis [Seite 98]
9.2.1.3 - 4.4.34.35.2.1.3 Variation 3: Palladium Catalysis [Seite 101]
9.2.1.4 - 4.4.34.35.2.1.4 Variation 4: Iridium Catalysis [Seite 101]
9.2.2 - 4.4.34.35.2.2 Method 2: Transition-Metal-Catalyzed b-Hydrosilylation of Terminal Alkynes To GiveZ- [Seite 102]
9.2.2.1 - 4.4.34.35.2.2.1 Variation 1: RutheniumCatalysis [Seite 102]
9.2.2.2 - 4.4.34.35.2.2.2 Variation 2: Rhodium Catalysis [Seite 103]
9.2.2.3 - 4.4.34.35.2.2.3 Variation 3: Iridium Catalysis [Seite 104]
9.2.3 - 4.4.34.35.2.3 Method 3: Transition-Metal-Catalyzed a-Hydrosilylation of Terminal Alkynes [Seite 105]
9.2.3.1 - 4.4.34.35.2.3.1 Variation 1: Ruthenium Catalysis [Seite 105]
9.2.3.2 - 4.4.34.35.2.3.2 Variation 2: Platinum Catalysis [Seite 107]
9.2.4 - 4.4.34.35.2.4 Method 4: Transition-Metal-Catalyzed syn Hydrosilylation of Internal Alkynes [Seite 108]
9.2.4.1 - 4.4.34.35.2.4.1 Variation 1: Platinum Catalysis [Seite 108]
9.2.4.2 - 4.4.34.35.2.4.2 Variation 2: Palladium Catalysis [Seite 111]
9.2.5 - 4.4.34.35.2.5 Method 5: Transition-Metal-Catalyzed anti Hydrosilylation of Internal Alkynes [Seite 112]
9.2.6 - 4.4.34.35.2.6 Method 6: Lewis Acid Catalyzed Hydrosilylation [Seite 114]
9.2.7 - 4.4.34.35.2.7 Method 7: Radical Hydrosilylation [Seite 115]
9.3 - 4.4.34.35.3 Silylmetalation of Alkynes [Seite 115]
9.3.1 - 4.4.34.35.3.1 Method 1: Silylcupration [Seite 116]
9.3.1.1 - 4.4.34.35.3.1.1 Variation 1: Silylcupration Using Silyllithium Reagents [Seite 116]
9.3.1.2 - 4.4.34.35.3.1.2 Variation 2: Silylcupration Using Silylboronic Ester Reagents [Seite 117]
9.3.2 - 4.4.34.35.3.2 Method 2: Copper-Catalyzed Silylmetalation [Seite 122]
9.3.3 - 4.4.34.35.3.3 Method 3: Silylzincation [Seite 123]
9.3.4 - 4.4.34.35.3.4 Method 4: Silylrhodation [Seite 123]
9.4 - 4.4.34.35.4 Addition to Alkynylsilanes [Seite 125]
9.4.1 - 4.4.34.35.4.1 Method 1: Hydrogenation [Seite 126]
9.4.2 - 4.4.34.35.4.2 Method 2: Hydrometalation [Seite 126]
9.4.2.1 - 4.4.34.35.4.2.1 Variation 1: Hydrometalation Followed by Protodemetalation [Seite 126]
9.4.2.2 - 4.4.34.35.4.2.2 Variation 2: Hydrometalation Followed by Halogenation [Seite 128]
9.4.2.3 - 4.4.34.35.4.2.3 Variation 3: Hydrometalation Followed by Alkylation [Seite 129]
9.4.3 - 4.4.34.35.4.3 Method 3: Carbometalation [Seite 132]
9.5 - 4.4.34.35.5 Intermolecular Coupling of Alkynylsilanes [Seite 132]
9.5.1 - 4.4.34.35.5.1 Method 1: Ruthenium-Catalyzed Alder-Ene Reaction [Seite 132]
9.5.2 - 4.4.34.35.5.2 Method 2: Reductive Coupling [Seite 136]
9.5.3 - 4.4.34.35.5.3 Method 3: Enyne Cross Metathesis [Seite 140]
9.6 - 4.4.34.35.6 Ring-Closing Metathesis of a-Substituted Vinylsilanes [Seite 141]
9.7 - 4.4.34.35.7 Dehydrogenative Silylation of Alkenes [Seite 143]
9.7.1 - 4.4.34.35.7.1 Method 1: Reaction with Silanes [Seite 143]
9.7.2 - 4.4.34.35.7.2 Method 2: Reaction with Halosilanes or Silyl Trifluoromethanesulfonates [Seite 144]
9.7.3 - 4.4.34.35.7.3 Method 3: Transfer Silylation [Seite 146]
9.7.4 - 4.4.34.35.7.4 Method 4: Reaction with Siletanes [Seite 146]
9.8 - 4.4.34.35.8 Carbometalation of Vinylsilanes [Seite 147]
9.8.1 - 4.4.34.35.8.1 Method 1: Heck Reaction with Aryl Halides [Seite 147]
9.8.2 - 4.4.34.35.8.2 Method 2: Heck-Type Reaction with Benzonitriles [Seite 149]
9.8.3 - 4.4.34.35.8.3 Method 3: Iron-Catalyzed Oxidative Arylation [Seite 150]
9.9 - 4.4.34.35.9 Addition to Carbonyl Compounds [Seite 150]
9.9.1 - 4.4.34.35.9.1 Method 1: Reaction with (Dihalomethyl)silane Reagents [Seite 150]
9.9.2 - 4.4.34.35.9.2 Method 2: Reaction with DisilylmethyllithiumReagents [Seite 151]
9.9.3 - 4.4.34.35.9.3 Method 3: Reaction with (Halomethyl)silane Reagents [Seite 152]
9.9.4 - 4.4.34.35.9.4 Method 4: Reaction with (a-Silylallyl)borane Reagents [Seite 154]
9.10 - 4.4.34.35.10 Rearrangements [Seite 155]
9.10.1 - 4.4.34.35.10.1 Method 1: Gold-Catalyzed Rearrangement of Allyl(alkynyl)silanes [Seite 156]
9.10.2 - 4.4.34.35.10.2 Method 2: Rearrangement of (a-Hydroxypropargyl)silanes [Seite 157]
9.10.3 - 4.4.34.35.10.3 Method 3: Rearrangement of Silyl Allenoates [Seite 158]
9.11 - 4.4.34.35.11 Synthesis of Cyclic Vinylsilanes [Seite 159]
9.11.1 - 4.4.34.35.11.1 Method 1: Intramolecular Hydrosilylation of Alkynes [Seite 159]
9.11.1.1 - 4.4.34.35.11.1.1 Variation 1: Metal-Catalyzed syn-exo Hydrosilylation [Seite 159]
9.11.1.2 - 4.4.34.35.11.1.2 Variation 2: Metal-Catalyzed anti-exo Hydrosilylation [Seite 160]
9.11.1.3 - 4.4.34.35.11.1.3 Variation 3: Metal-Catalyzed endo-Hydrosilylation [Seite 161]
9.11.1.4 - 4.4.34.35.11.1.4 Variation 4: Base-Promoted Hydrosilylation [Seite 163]
9.11.2 - 4.4.34.35.11.2 Method 2: Cyclization of Vinylsilanes [Seite 164]
9.11.2.1 - 4.4.34.35.11.2.1 Variation 1: By Ring-Closing Metathesis with Terminal Vinylsilanes [Seite 165]
9.11.2.2 - 4.4.34.35.11.2.2 Variation 2: By Silylvinylation [Seite 166]
9.11.3 - 4.4.34.35.11.3 Method 3: Cyclization of Alkynylsilanes [Seite 167]
9.11.3.1 - 4.4.34.35.11.3.1 Variation 1: By Ring-Closing Enyne Metathesis [Seite 167]
9.11.3.2 - 4.4.34.35.11.3.2 Variation 2: By Reductive Coupling of Alkynylsilanes [Seite 168]
9.11.3.3 - 4.4.34.35.11.3.3 Variation 3: By Gold-Catalyzed Cyclization [Seite 169]
9.11.3.4 - 4.4.34.35.11.3.4 Variation 4: By Semihydrogenation [Seite 170]
9.11.4 - 4.4.34.35.11.4 Method 4: Three-Component Coupling [Seite 172]
9.11.5 - 4.4.34.35.11.5 Method 5: Ring Contraction of Cyclic Vinylsilanes [Seite 173]
9.12 - 4.4.34.35.12 Synthesis from Acylsilanes [Seite 174]
9.13 - 4.4.34.35.13 Synthesis fromAllenes [Seite 176]
9.13.1 - 4.4.34.35.13.1 Method 1: Hydrosilylation [Seite 177]
9.13.2 - 4.4.34.35.13.2 Method 2: Silylmetalation [Seite 178]
10 - 31.1.2 Fluoroarenes (Update 2015) [Seite 187]
10.1 - 31.1.2.1 Synthesis of Fluoroarenes [Seite 188]
10.1.1 - 31.1.2.1.1 Synthesis by Substitution of Hydrogen [Seite 188]
10.1.1.1 - 31.1.2.1.1.1 Method 1: Reaction with Hydrogen Fluoride-Pyridine Complex [Seite 188]
10.1.1.2 - 31.1.2.1.1.2 Method 2: Reaction with Silver(II) Fluoride [Seite 189]
10.1.1.3 - 31.1.2.1.1.3 Method 3: Reaction with Fluorinating Agents Mediated by Transition-Metal Catalysts [Seite 190]
10.1.2 - 31.1.2.1.2 Synthesis by Substitution of Organometallic Groups [Seite 191]
10.1.2.1 - 31.1.2.1.2.1 Method 1: Substitution of Boronic Acids and Esters [Seite 192]
10.1.2.1.1 - 31.1.2.1.2.1.1 Variation 1: Reaction with Silver(I) Trifluoromethanesulfonate and Selectfluor [Seite 192]
10.1.2.1.2 - 31.1.2.1.2.1.2 Variation 2: Reaction with Acetyl Hypofluorite [Seite 193]
10.1.2.1.3 - 31.1.2.1.2.1.3 Variation 3: Palladium-Catalyzed Fluorodeboronation [Seite 193]
10.1.2.1.4 - 31.1.2.1.2.1.4 Variation 4: Copper-Catalyzed Fluorodeboronation [Seite 195]
10.1.3 - 31.1.2.1.3 Synthesis by Substitution of Halogens [Seite 195]
10.1.3.1 - 31.1.2.1.3.1 Method 1: Reaction with Anhydrous Tetrabutylammonium Fluoride [Seite 196]
10.1.3.2 - 31.1.2.1.3.2 Method 2: Reactions Catalyzed by Transition Metals [Seite 196]
10.1.3.2.1 - 31.1.2.1.3.2.1 Variation 1: Palladium-Catalyzed Reactions [Seite 196]
10.1.3.2.2 - 31.1.2.1.3.2.2 Variation 2: Copper-Catalyzed Reactions [Seite 197]
10.1.4 - 31.1.2.1.4 Synthesis by Substitution of Nitrogen [Seite 198]
10.1.5 - 31.1.2.1.5 Synthesis by Substitution of Oxygen [Seite 198]
10.1.5.1 - 31.1.2.1.5.1 Method 1: Palladium-Catalyzed Displacement of Trifluoromethanesulfonate by Cesium Fluoride [Seite 198]
10.1.5.2 - 31.1.2.1.5.2 Method 2: Deoxyfluorination Using PhenoFluor [Seite 200]
11 - 31.2.3 Chloroarenes (Update 2015) [Seite 203]
11.1 - 31.2.3.1 Synthesis of Chloroarenes [Seite 203]
11.1.1 - 31.2.3.1.1 Synthesis by Substitution [Seite 203]
11.1.1.1 - 31.2.3.1.1.1 Method 1: Electrophilic Chlorination [Seite 203]
11.1.1.1.1 - 31.2.3.1.1.1.1 Variation 1: Of Phenols and Anisoles [Seite 203]
11.1.1.1.2 - 31.2.3.1.1.1.2 Variation 2: Of Anilines, Acetanilides, and Related Compounds [Seite 206]
11.1.1.1.3 - 31.2.3.1.1.1.3 Variation 3: Of Benzene and Alkylbenzene Derivatives [Seite 207]
11.1.1.1.4 - 31.2.3.1.1.1.4 Variation 4: Of Electron-Deficient Benzene Derivatives [Seite 208]
11.1.1.2 - 31.2.3.1.1.2 Method 2: Substitution of Boron [Seite 209]
11.1.1.3 - 31.2.3.1.1.3 Method 3: Substitution of Bromine [Seite 210]
11.1.2 - 31.2.3.1.2 Synthesis by Addition-Elimination [Seite 212]
11.2 - 31.2.3.2 Applications of Chloroarenes in Organic Synthesis [Seite 212]
11.2.1 - 31.2.3.2.1 Method 1: Cross-Coupling Reactions [Seite 212]
11.2.1.1 - 31.2.3.2.1.1 Variation 1: Synthesis of Biaryls [Seite 212]
11.2.1.2 - 31.2.3.2.1.2 Variation 2: Synthesis of Arylalkenes [Seite 221]
11.2.1.3 - 31.2.3.2.1.3 Variation 3: Synthesis of Arylalkynes [Seite 225]
11.2.1.4 - 31.2.3.2.1.4 Variation 4: Synthesis of Arylalkanes [Seite 227]
11.2.1.5 - 31.2.3.2.1.5 Variation 5: Carbonylation and Cyanation Reactions [Seite 228]
11.2.1.6 - 31.2.3.2.1.6 Variation 6: Metal-Catalyzed Heterosubstitution Reactions [Seite 229]
12 - 31.3.3 Bromoarenes (Update 2015) [Seite 235]
12.1 - 31.3.3.1 Synthesis of Bromoarenes [Seite 235]
12.1.1 - 31.3.3.1.1 Synthesis by Substitution [Seite 235]
12.1.1.1 - 31.3.3.1.1.1 Method 1: Electrophilic Bromination [Seite 235]
12.1.1.1.1 - 31.3.3.1.1.1.1 Variation 1: Of Phenols and Anisoles [Seite 235]
12.1.1.1.2 - 31.3.3.1.1.1.2 Variation 2: Of Anilines, Acetanilides, and Related Compounds [Seite 240]
12.1.1.1.3 - 31.3.3.1.1.1.3 Variation 3: Of Benzene and Alkylbenzene Derivatives [Seite 242]
12.1.1.1.4 - 31.3.3.1.1.1.4 Variation 4: Of Electron-Deficient Benzene Derivatives [Seite 243]
12.1.1.1.5 - 31.3.3.1.1.1.5 Variation 5: Of Arylboronates [Seite 245]
12.1.1.2 - 31.3.3.1.1.2 Method 2: Synthesis from Organometallics [Seite 245]
12.1.1.2.1 - 31.3.3.1.1.2.1 Variation 1: From Arylboronates [Seite 245]
12.1.1.3 - 31.3.3.1.1.3 Method 3: Substitution of a Trifluoromethanesulfonate Group [Seite 246]
12.2 - 31.3.3.2 Applications of Bromoarenes in Organic Synthesis [Seite 247]
12.2.1 - 31.3.3.2.1 Method 1: Cross-Coupling Reactions [Seite 247]
12.2.1.1 - 31.3.3.2.1.1 Variation 1: Synthesis of Biaryls [Seite 247]
12.2.1.2 - 31.3.3.2.1.2 Variation 2: Synthesis of Arylalkenes [Seite 250]
12.2.1.3 - 31.3.3.2.1.3 Variation 3: Synthesis of Arylalkynes [Seite 251]
12.2.1.4 - 31.3.3.2.1.4 Variation 4: Synthesis of Arylalkanes [Seite 252]
12.2.1.5 - 31.3.3.2.1.5 Variation 5: Carbonylation and Cyanation Reactions [Seite 253]
12.2.1.6 - 31.3.3.2.1.6 Variation 6: Metal-Catalyzed Heterosubstitution Reactions [Seite 255]
12.2.1.7 - 31.3.3.2.1.7 Variation 7: Borylation Reactions [Seite 255]
12.2.1.8 - 31.3.3.2.1.8 Variation 8: Phosphonylation Reactions [Seite 256]
12.2.1.9 - 31.3.3.2.1.9 Variation 9: Transhalogenation Reactions [Seite 257]
12.2.2 - 31.3.3.2.2 Method 2: Hydrodebromination Reactions [Seite 257]
13 - 31.4.1.3 Hypervalent Iodoarenes and Aryliodonium Salts (Update 2015) [Seite 261]
13.1 - 31.4.1.3.1 Synthesis of Hypervalent Iodoarenes and Aryliodonium Salts [Seite 261]
13.1.1 - 31.4.1.3.1.1 Synthesis by Oxidative Addition to Iodoarenes [Seite 261]
13.1.1.1 - 31.4.1.3.1.1.1 Method 1: Iodylarenes by Oxidation of Iodoarenes [Seite 261]
13.1.1.1.1 - 31.4.1.3.1.1.1.1 Variation 1: Acyclic Iodylarenes [Seite 262]
13.1.1.1.2 - 31.4.1.3.1.1.1.2 Variation 2: Cyclic Iodylarenes [Seite 263]
13.1.1.1.3 - 31.4.1.3.1.1.1.3 Variation 3: Polymer-Supported Iodylarenes [Seite 264]
13.1.1.2 - 31.4.1.3.1.1.2 Method 2: (Difluoroiodo)arenes by Fluorination of Iodoarenes [Seite 264]
13.1.1.2.1 - 31.4.1.3.1.1.2.1 Variation 1: (Difluoroiodo)arenes by One-Pot Synthesis from Arenes [Seite 265]
13.1.1.3 - 31.4.1.3.1.1.3 Method 3: (Dichloroiodo)arenes by Chlorination of Iodoarenes [Seite 266]
13.1.1.4 - 31.4.1.3.1.1.4 Method 4: [Bis(acyloxy)iodo]arenes by Oxidation of Iodoarenes in the Presence of a Carboxylic Acid [Seite 268]
13.1.1.5 - 31.4.1.3.1.1.5 Method 5: Aryliodine(III) Sulfonates by Oxidation of Iodoarenes in the Presence of a Sulfonic Acid [Seite 269]
13.1.2 - 31.4.1.3.1.2 Synthesis by Ligand Exchange of Hypervalent Iodine Compounds [Seite 270]
13.1.2.1 - 31.4.1.3.1.2.1 Method 1: 1-Oxo-1-(tosyloxy)-1H-1l5-benzo[d][1,2]iodoxol-3-one from 2-Iodoxybenzoic Acid by Exchange with 4-Toluenesulfonic Acid [Seite 270]
13.1.2.2 - 31.4.1.3.1.2.2 Method 2: [Bis(acyloxy)iodo]arenes from Other [Bis(acyloxy)iodo]arenes by Exchange with Carboxylic Acids [Seite 271]
13.1.3 - 31.4.1.3.1.2.3 Method 3: Phenyliodine(III) Sulfate from (Diacetoxyiodo)benzene [Seite 272]
13.1.4 - 31.4.1.3.1.2.4 Method 4: Iodosylarenes by Hydrolysis of [Bis(acyloxy)iodo]arenes [Seite 272]
13.1.5 - 31.4.1.3.1.2.5 Method 5: Aryliodine(III) Amides from (Acyloxyiodo)arenes [Seite 273]
13.1.6 - 31.4.1.3.1.2.6 Method 6: Alkynyl(aryl)iodonium Salts from Hypervalent Iodoarenes [Seite 274]
13.1.6.1 - 31.4.1.3.1.2.6.1 Variation 1: Alkynyl(aryl)iodonium Tetrafluoroborates [Seite 274]
13.1.6.2 - 31.4.1.3.1.2.6.2 Variation 2: Alkynyl(aryl)iodonium Trifluoroacetates [Seite 275]
13.1.6.3 - 31.4.1.3.1.2.6.3 Variation 3: Alkynyl(aryl)iodonium Organosulfonates [Seite 276]
13.1.6.4 - 31.4.1.3.1.2.6.4 Variation 4: 1-Alkynylbenziodoxoles [Seite 277]
13.1.7 - 31.4.1.3.1.2.7 Method 7: Aryl- and Hetaryliodonium Salts from Hypervalent Iodoarenes [Seite 278]
13.1.7.1 - 31.4.1.3.1.2.7.1 Variation 1: Aryliodonium Tetrafluoroborates [Seite 278]
13.1.7.2 - 31.4.1.3.1.2.7.2 Variation 2: Aryl- and Hetaryliodonium Sulfonates [Seite 279]
13.1.7.3 - 31.4.1.3.1.2.7.3 Variation 3: Aryliodonium Halides [Seite 281]
13.1.7.4 - 31.4.1.3.1.2.7.4 Variation 4: 1-Arylbenziodoxoles [Seite 283]
13.1.8 - 31.4.1.3.1.2.8 Method 8: 1-(Trifluoromethyl)benziodoxoles by Trifluoromethylation of Other Benziodoxoles [Seite 284]
13.1.9 - 31.4.1.3.1.2.9 Method 9: Aryliodonium Ylides from (Diacetoxyiodo)arenes [Seite 285]
13.1.10 - 31.4.1.3.1.2.10 Method 10: Aryliodonium Imides from (Diacetoxyiodo)arenes [Seite 286]
13.2 - 31.4.1.3.2 Applications of Hypervalent Iodoarenes and Aryliodonium Salts in Organic Synthesis [Seite 287]
13.2.1 - 31.4.1.3.2.1 Preparation of Products with a New C-C Bond [Seite 288]
13.2.1.1 - 31.4.1.3.2.1.1 Method 1: Alkynylation Using 1-Alkynylbenziodoxoles [Seite 288]
13.2.1.2 - 31.4.1.3.2.1.2 Method 2: Arylation Using Diaryliodonium Salts [Seite 289]
13.2.1.3 - 31.4.1.3.2.1.3 Method 3: Trifluoromethylation Using (Trifluoromethyl)benziodoxoles [Seite 290]
13.2.1.4 - 31.4.1.3.2.1.4 Method 4: Reactions of Aryliodonium Ylides [Seite 291]
13.2.2 - 31.4.1.3.2.2 Preparation of Products with a New C-F Bond [Seite 293]
13.2.2.1 - 31.4.1.3.2.2.1 Method 1: a-Fluorination of Carbonyl Compounds [Seite 293]
13.2.2.2 - 31.4.1.3.2.2.2 Method 2: Fluorination of Aromatic Compounds [Seite 294]
13.2.3 - 31.4.1.3.2.3 Preparation of Products with a New C-Cl Bond [Seite 294]
13.2.3.1 - 31.4.1.3.2.3.1 Method 1: Chlorination of Unsaturated Compounds [Seite 294]
13.2.4 - 31.4.1.3.2.4 Preparation of Products with a New C-I Bond [Seite 295]
13.2.4.1 - 31.4.1.3.2.4.1 Method 1: Oxidative Iodination Using Hypervalent Iodoarenes [Seite 295]
13.2.5 - 31.4.1.3.2.5 Oxidations and Oxidative Rearrangements [Seite 296]
13.2.5.1 - 31.4.1.3.2.5.1 Reactions with Iodine(V) Reagents [Seite 296]
13.2.5.1.1 - 31.4.1.3.2.5.1.1 Method 1: Oxidations with Iodylarenes [Seite 296]
13.2.5.1.2 - 31.4.1.3.2.5.1.2 Method 2: Iodine(V)-Catalyzed Oxidations [Seite 297]
13.2.5.1.2.1 - 31.4.1.3.2.5.1.2.1 Variation 1: Catalytic Oxidation of Alcohols to Carbonyl Compounds [Seite 297]
13.2.5.1.2.2 - 31.4.1.3.2.5.1.2.2 Variation 2: Catalytic Oxidation at the Benzylic Position [Seite 298]
13.2.5.1.2.3 - 31.4.1.3.2.5.1.2.3 Variation 3: Catalytic Preparation of a,b-Unsaturated Carbonyl Compounds [Seite 298]
13.2.5.2 - 31.4.1.3.2.5.2 Reactions with Iodine(III) Reagents [Seite 299]
13.2.5.2.1 - 31.4.1.3.2.5.2.1 Method 1: 2,2,6,6-Tetramethylpiperidin-1-oxyl-Catalyzed Oxidation of Alcohols [Seite 299]
13.2.5.2.2 - 31.4.1.3.2.5.2.2 Method 2: Diacetoxylation of Alkenes [Seite 300]
13.2.5.2.3 - 31.4.1.3.2.5.2.3 Method 3: Oxidative Dearomatization of Phenols and Phenol Ethers [Seite 301]
13.2.5.2.3.1 - 31.4.1.3.2.5.2.3.1 Variation 1: Oxidation of 4-Substituted Phenols [Seite 301]
13.2.5.2.3.2 - 31.4.1.3.2.5.2.3.2 Variation 2: Oxidation of 2-Substituted Phenols [Seite 303]
13.2.5.2.4 - 31.4.1.3.2.5.2.4 Method 4: Iodine(III)-Catalyzed Oxidations [Seite 304]
13.2.5.2.4.1 - 31.4.1.3.2.5.2.4.1 Variation 1: Catalytic a-Functionalization of Carbonyl Compounds [Seite 304]
13.2.5.2.4.2 - 31.4.1.3.2.5.2.4.2 Variation 2: Catalytic Lactonization Reactions [Seite 305]
13.2.5.2.4.3 - 31.4.1.3.2.5.2.4.3 Variation 3: Catalytic Stereoselective Diacetoxylation of Alkenes [Seite 305]
13.2.5.2.4.4 - 31.4.1.3.2.5.2.4.4 Variation 4: Catalytic Oxidative Cleavage of Alkenes and Alkynes [Seite 306]
13.2.5.2.4.5 - 31.4.1.3.2.5.2.4.5 Variation 5: Catalytic Spirocyclization of Aromatic Substrates [Seite 306]
13.2.6 - 31.4.1.3.2.6 Preparation of Products with a New C-N Bond [Seite 308]
13.2.6.1 - 31.4.1.3.2.6.1 Method 1: Azidations with Iodine(III) Reagents [Seite 308]
13.2.6.2 - 31.4.1.3.2.6.2 Method 2: Aminations with Iodine(III) Reagents [Seite 308]
13.2.6.3 - 31.4.1.3.2.6.3 Method 3: Reactions of Aryliodonium Imides [Seite 310]
13.2.6.3.1 - 31.4.1.3.2.6.3.1 Variation 1: C-H Amidation [Seite 310]
13.2.6.3.2 - 31.4.1.3.2.6.3.2 Variation 2: Aziridination of Alkenes [Seite 311]
13.2.7 - 31.4.1.3.2.7 Oxidations at Nitrogen [Seite 311]
13.2.7.1 - 31.4.1.3.2.7.1 Method 1: Hypervalent Iodoarenes as Reagents for Hofmann Rearrangement [Seite 311]
13.2.7.1.1 - 31.4.1.3.2.7.1.1 Variation 1: Hypervalent Iodine Catalyzed Hofmann Rearrangement [Seite 312]
13.2.7.2 - 31.4.1.3.2.7.2 Method 2: Hypervalent Iodoarenes as Reagents for Generation of Nitrile Oxides from Oximes [Seite 313]
13.2.7.2.1 - 31.4.1.3.2.7.2.1 Variation 1: Synthesis of Dihydroisoxazoles via Hypervalent Iodine Catalyzed Generation of Nitrile Oxides [Seite 314]
14 - 31.41.3 Arylphosphine Oxides and Heteroatom Derivatives (Update 2015) [Seite 319]
14.1 - 31.41.3.1 Arylphosphine Oxides [Seite 319]
14.1.1 - 31.41.3.1.1 Synthesis of Arylphosphine Oxides [Seite 319]
14.1.1.1 - 31.41.3.1.1.1 Method 1: Oxidation of Phosphines and Derivatives [Seite 319]
14.1.1.1.1 - 31.41.3.1.1.1.1 Variation 1: Oxidation with Dioxygen or Air [Seite 320]
14.1.1.1.2 - 31.41.3.1.1.1.2 Variation 2: Catalytic Oxidation [Seite 320]
14.1.1.1.3 - 31.41.3.1.1.1.3 Variation 3: Oxidation with Peroxides [Seite 323]
14.1.1.1.4 - 31.41.3.1.1.1.4 Variation 4: Photooxidation [Seite 325]
14.1.1.1.5 - 31.41.3.1.1.1.5 Variation 5: Oxidation with Miscellaneous Oxidants [Seite 325]
14.1.1.1.6 - 31.41.3.1.1.1.6 Variation 6: Oxidation of Chalcogen Phosphine Derivatives and Phosphine-Boranes [Seite 328]
14.1.1.2 - 31.41.3.1.1.2 Method 2: Addition of Secondary Phosphine Oxides to Unsaturated Bonds [Seite 329]
14.1.1.2.1 - 31.41.3.1.1.2.1 Variation 1: Addition to Unsaturated Carbon-Carbon Bonds [Seite 329]
14.1.1.2.2 - 31.41.3.1.1.2.2 Variation 2: Addition to Imines [Seite 331]
14.1.1.2.3 - 31.41.3.1.1.2.3 Variation 3: Addition to Carbonyl Compounds [Seite 334]
14.1.1.2.4 - 31.41.3.1.1.2.4 Variation 4: Conjugate Addition to Activated Alkenes [Seite 337]
14.1.1.3 - 31.41.3.1.1.3 Method 3: Nucleophilic Substitution at the Phosphorus Atom [Seite 341]
14.1.1.3.1 - 31.41.3.1.1.3.1 Variation 1: P-X Bond Cleavage (X = Halogen) [Seite 341]
14.1.1.3.2 - 31.41.3.1.1.3.2 Variation 2: P-O Bond Cleavage [Seite 347]
14.1.1.3.3 - 31.41.3.1.1.3.3 Variation 3: P-C Bond Cleavage [Seite 349]
14.1.1.3.4 - 31.41.3.1.1.3.4 Variation 4: Hydrolysis of Phosphonium Salts [Seite 351]
14.1.1.3.5 - 31.41.3.1.1.3.5 Variation 5: Electrophilic Aromatic Substitution [Seite 355]
14.1.1.4 - 31.41.3.1.1.4 Method 4: Nucleophilic Substitutionwith Phosphorus Nucleophiles [Seite 355]
14.1.1.4.1 - 31.41.3.1.1.4.1 Variation 1: Michaelis-Becker Reactions [Seite 355]
14.1.1.4.2 - 31.41.3.1.1.4.2 Variation 2: Michaelis-Arbuzov Reactions [Seite 357]
14.1.1.5 - 31.41.3.1.1.5 Method 5: Transition-Metal-Mediated P-C Bond Formation [Seite 360]
14.1.1.5.1 - 31.41.3.1.1.5.1 Variation 1: Copper-Mediated Reactions [Seite 361]
14.1.1.5.2 - 31.41.3.1.1.5.2 Variation 2: Nickel-Mediated Reactions [Seite 363]
14.1.1.5.3 - 31.41.3.1.1.5.3 Variation 3: Palladium-Mediated Reactions [Seite 366]
14.1.1.5.4 - 31.41.3.1.1.5.4 Variation 4: Other Metal-Mediated Reactions [Seite 371]
14.1.1.6 - 31.41.3.1.1.6 Method 6: Other Reactions [Seite 373]
14.1.1.6.1 - 31.41.3.1.1.6.1 Variation 1: Phosphinylation of Ortho Esters [Seite 373]
14.1.1.6.2 - 31.41.3.1.1.6.2 Variation 2: Manganese(III)-Mediated Free-Radical Phosphinylation [Seite 374]
14.1.1.6.3 - 31.41.3.1.1.6.3 Variation 3: Palladium-Catalyzed Intramolecular Dehydrogenative Cyclization [Seite 375]
14.1.1.6.4 - 31.41.3.1.1.6.4 Variation 4: Reaction of Elemental Phosphorus [Seite 376]
14.1.1.6.5 - 31.41.3.1.1.6.5 Variation 5: The Wittig Reaction [Seite 376]
14.1.1.6.6 - 31.41.3.1.1.6.6 Variation 6: The Appel Reaction [Seite 377]
14.1.1.6.7 - 31.41.3.1.1.6.7 Variation 7: The Mitsunobu Reaction [Seite 378]
14.1.1.7 - 31.41.3.1.1.7 Method 7: Modification of Phosphine Oxides without Substitution at Phosphorus [Seite 379]
14.1.1.7.1 - 31.41.3.1.1.7.1 Variation 1: Monoreduction of Bisphosphine Dioxides [Seite 379]
14.1.1.7.2 - 31.41.3.1.1.7.2 Variation 2: Deprotonation Directed by the P=O Group [Seite 380]
14.1.1.7.3 - 31.41.3.1.1.7.3 Variation 3: Nucleophilic Aromatic Substitution Promoted by the P=O Group [Seite 382]
14.1.1.7.4 - 31.41.3.1.1.7.4 Variation 4: Alkene Metathesis [Seite 384]
14.1.1.7.5 - 31.41.3.1.1.7.5 Variation 5: Cycloaddition Reactions [Seite 385]
14.1.1.7.6 - 31.41.3.1.1.7.6 Variation 6: Annulation Reactions [Seite 388]
14.1.1.7.7 - 31.41.3.1.1.7.7 Variation 7: Cross-Coupling Reactions [Seite 389]
14.1.2 - 31.41.3.1.2 Applications of Arylphosphine Oxides in Organic Synthesis [Seite 392]
14.2 - 31.41.3.2 Arylphosphine Sulfides [Seite 392]
14.2.1 - 31.41.3.2.1 Synthesis of Arylphosphine Sulfides [Seite 392]
14.2.1.1 - 31.41.3.2.1.1 Method 1: Sulfuration of Phosphines [Seite 392]
14.2.1.1.1 - 31.41.3.2.1.1.1 Variation 1: Using Elemental Sulfur [Seite 392]
14.2.1.1.2 - 31.41.3.2.1.1.2 Variation 2: Using Polysulfide Reagents [Seite 393]
14.2.1.1.3 - 31.41.3.2.1.1.3 Variation 3: Using Other Sulfur Sources [Seite 396]
14.2.1.1.4 - 31.41.3.2.1.1.4 Variation 4: Via Sulfuration of Phosphine-Borane Species [Seite 397]
14.2.1.1.5 - 31.41.3.2.1.1.5 Variation 5: Via Sulfuration of Other Chalcogen Phosphine Derivatives [Seite 397]
14.2.1.2 - 31.41.3.2.1.2 Method 2: Addition of Secondary Phosphine Sulfides to Unsaturated Bonds [Seite 399]
14.2.1.2.1 - 31.41.3.2.1.2.1 Variation 1: Addition to Carbonyl Compounds [Seite 399]
14.2.1.2.2 - 31.41.3.2.1.2.2 Variation 2: Addition to Alkenes [Seite 400]
14.2.1.2.3 - 31.41.3.2.1.2.3 Variation 3: Conjugate Addition to Activated Alkenes [Seite 402]
14.2.1.3 - 31.41.3.2.1.3 Method 3: Nucleophilic Substitutionwith Phosphorus [Seite 403]
14.2.1.3.1 - 31.41.3.2.1.3.1 Variation 1: Transition-Metal-Mediated Substitution [Seite 404]
14.2.1.3.2 - 31.41.3.2.1.3.2 Variation 2: Thio-Michaelis-Arbuzov Reactions [Seite 405]
14.2.1.4 - 31.41.3.2.1.4 Method 4: Nucleophilic Substitution at the Phosphorus Atom [Seite 406]
14.2.1.4.1 - 31.41.3.2.1.4.1 Variation 1: P-X Bond Cleavage (X = Halogen) [Seite 407]
14.2.1.4.2 - 31.41.3.2.1.4.2 Variation 2: P-S Bond Cleavage [Seite 408]
14.2.1.4.3 - 31.41.3.2.1.4.3 Variation 3: P-C Bond Cleavage [Seite 409]
14.2.1.4.4 - 31.41.3.2.1.4.4 Variation 4: P-O Bond Cleavage [Seite 410]
14.2.1.4.5 - 31.41.3.2.1.4.5 Variation 5: Solvolysis of Phosphorus(V) Compounds [Seite 410]
14.2.1.5 - 31.41.3.2.1.5 Method 5: Other Reactions [Seite 411]
14.2.1.5.1 - 31.41.3.2.1.5.1 Variation 1: Reaction of Sulfides with Elemental Phosphorus [Seite 411]
14.2.1.5.2 - 31.41.3.2.1.5.2 Variation 2: Cycloaddition of Strained Cyclic Phosphine Sulfides with Dienes [Seite 411]
14.2.1.5.3 - 31.41.3.2.1.5.3 Variation 3: Wittig Reaction with Thiocarbonyl Compounds [Seite 412]
14.2.1.5.4 - 31.41.3.2.1.5.4 Variation 4: Reaction of Ylides with Elemental Sulfur and with Thiiranes [Seite 412]
14.2.1.5.5 - 31.41.3.2.1.5.5 Variation 5: Cycloaddition of (Alkylsulfanyl)(chloro)phosphines [Seite 413]
14.2.1.5.6 - 31.41.3.2.1.5.6 Variation 6: Reaction of Butadienylphosphine Sulfides [Seite 414]
14.2.1.6 - 31.41.3.2.1.6 Method 6: Modification of Phosphine Sulfides without Substitution at Phosphorus [Seite 414]
14.2.1.6.1 - 31.41.3.2.1.6.1 Variation 1: a- and ortho-Deprotonation [Seite 415]
14.2.1.6.2 - 31.41.3.2.1.6.2 Variation 2: Cycloaddition Reactions [Seite 415]
14.2.1.6.3 - 31.41.3.2.1.6.3 Variation 3: Annulation Reactions [Seite 418]
14.2.2 - 31.41.3.2.2 Applications of Arylphosphine Sulfides in Organic Synthesis [Seite 418]
14.3 - 31.41.3.3 Arylphosphine Selenides [Seite 418]
14.3.1 - 31.41.3.3.1 Synthesis of Arylphosphine Selenides [Seite 419]
14.3.1.1 - 31.41.3.3.1.1 Method 1: Selenation of Free Phosphines with Elemental Selenium [Seite 419]
14.3.1.2 - 31.41.3.3.1.2 Method 2: Other Methods [Seite 420]
14.3.2 - 31.41.3.3.2 Applications of Arylphosphine Selenides in Organic Synthesis [Seite 421]
14.4 - 31.41.3.4 Aryl(imino)phosphoranes [Seite 421]
14.4.1 - 31.41.3.4.1 Synthesis of Aryl(imino)phosphoranes [Seite 421]
14.4.1.1 - 31.41.3.4.1.1 Method 1: The Staudinger Reaction of Free Phosphines and Azides [Seite 421]
14.4.1.2 - 31.41.3.4.1.2 Method 2: Synthesis via Aminophosphonium Salts [Seite 423]
14.4.2 - 31.41.3.4.2 Applications of Aryl(imino)phosphoranes in Organic Synthesis [Seite 424]
15 - 35.2.5.1.9 Synthesis by Addition across C=C Bonds (Update 2015) [Seite 441]
15.1 - 35.2.5.1.9.1 Method 1: Hydroxy- and Alkoxybromination of Alkenes [Seite 441]
15.2 - 35.2.5.1.9.2 Method 2: Aminobromination of Alkenes [Seite 450]
15.3 - 35.2.5.1.9.3 Method 3: Azidobromination of Alkenes [Seite 456]
15.4 - 35.2.5.1.9.4 Method 4: Phosphobromination of Alkenes [Seite 457]
15.5 - 35.2.5.1.9.5 Method 5: Catalytic Enantioselective Syntheses [Seite 458]
15.5.1 - 35.2.5.1.9.5.1 Variation 1: Bromination of Alkenes [Seite 459]
15.5.2 - 35.2.5.1.9.5.2 Variation 2: Hydroxy- and Alkoxybromination of Alkenes [Seite 460]
15.5.3 - 35.2.5.1.9.5.3 Variation 3: Aminobromination of Alkenes [Seite 478]
16 - Author Index [Seite 491]
17 - Abbreviations [Seite 523]
4.4.4.8 Silyl Hydrides (Update 2015)
R. W. Clark and S. L. Wiskur
General Introduction
The product subclass discussed herein is previously discussed in Houben-Weyl, Vol. 13/5, pp 79-96; silyl hydrides and their application as reducing agents is included in Houben-Weyl, Vol. 13/5, pp 350-360. More detailed examples include asymmetric reductions (Houben-Weyl, Vol. E 21, pp 4067-4081), transition-metal-catalyzed hydrosilylations (Houben-Weyl, Vol. E 18, pp 685-742), and stereoselective hydrosilylations of alkenes and dienes (Houben-Weyl, Vol. E 21, pp 5733-5740). This section is limited in scope to silicon-based compounds containing at least one Si-H bond. Specifically, the subsequent section highlights recent scientific discoveries regarding the subclass since last reviewed in Science of Synthesis in 2001 (Section 4.4.4). The text that follows is not all inclusive, but rather seeks to highlight the most synthetically viable preparation methods for this class of compounds, including the preparation of chlorinated silyl hydrides and silyl hydrides that are stereogenic at silicon. The use of these silyl hydrides will also be explored. The application of silyl hydrides as reagents in other important synthetic processes is of particular interest; therefore, this update has a large focus on this. Progress in the field of hydrosilylation, reduction, and dehydrogenative silylation of carbonyl compounds, alkenes, alkynes, and other functional groups is discussed in the following sections.
SAFETY: Silane (SiH4) is an extremely pyrophoric gas which should be avoided where possible.[1] This reactive gas is also known to form via disproportionation from less reactive silyl precursors during the course of a reaction. An example of such a precursor is triethoxysilane; it is known to produce silane under an inert atmosphere when in the presence of a metal catalyst.[2] Large-scale reactions or an excess of silane in such reactions are known to create uncontrollable exothermic reactions leading to fires and explosions.[3] Great care should be exercised when silane or its precursors are handled. Cases that are discussed in subsequent sections where silane is possibly formed as a byproduct are clearly labeled as such.
Organosilanes (R1SiH3, R12SiH2, and R13SiH) are generally much less reactive than silane. These compounds become more stable to hydrolysis, oxidation, and other reactions as alkyl or aryl substitution at silicon increases. Alkyl- or arylsilanes possess many physical properties similar to alkanes: most are highly flammable liquids or gases with high thermal stabilities.[4] Notable differences to alkanes should be noted. Silanes, especially when monoalkylated, are sensitive to hydrolysis and should be stored under an inert atmosphere. These compounds should also be stored away from acids, bases, and fluorides as these conditions produce unwanted and flammable dihydrogen.[5]
As with most reagents, silanes should be handled with care to avoid inhalation, skin contact, and ingestion. Always use a fume hood when handling these volatile compounds. Because of the vast differences in reactivity of these compounds, a thorough knowledge of the particular silane to be utilized or synthesized is necessary.
4.4.4.8.1 Synthesis of Silyl Hydrides
4.4.4.8.1.1 Method 1: From Inorganic Silanes
Dialkyl- and diarylsilanes continue to be prepared from dichlorosilane and alkyl- or aryllithium or Grignard reagents.[6] However, the gaseous and explosive dichlorosilane can be made a more feasible reagent when used as an N,N,N´,N´-tetraethylethylenediamine complex [(teeda)H2SiCl2], which is prepared from N,N,N´,N´-tetraethylethylenediamine (teeda) and trichlorosilane.[7,8] This complex is a solid and is stable upon storage away from moisture and air.[9] Various silanes are prepared from this complex including secondary silanes and silacycles. As an example of a secondary silane, diphenylsilane can be synthesized in 75% yield by reacting [(teeda)H2SiCl2] with phenylmagnesium chloride in a 1:3 dichloromethane/tetrahydrofuran solution at room temperature.[7] When the reaction is attempted in tetrahydrofuran or diethyl ether, the secondary silanes are still obtained, but in moderate yields due to the formation of biphenyl as a major impurity.[9] Presumably, this decrease in reactivity is due to insolubility of the silyl chloride complex in tetrahydrofuran and diethyl ether. Reaction of diorganometallic biaryls with the [(teeda)H2SiCl2] complex at room temperature in a mixture of dichloromethane and tetrahydrofuran yields silacyclopentadienes (siloles, e.g., 1) in good yield (? Scheme 1). Siloles (five-membered rings containing silicon and a butadiene) such as 1 or 3 are of synthetic importance due to their direct applicability as monomers for functional materials[10] such as organic light-emitting diodes[11] and field-effect transistors.[12]
Scheme 1 Reaction of a Diorganometallic Biaryl with the N,N,N´,N´-Tetraethylethylenediamine Complex of Dichlorosilane[9]
Siloles can also be prepared in high-yielding reactions from zirconacyclopentadienes 2, but these reactions require the use of dichlorosilane as a silane source (? Scheme 2).[13] The reaction proceeds rapidly at room temperature in chloroform to produce siloles 3 in excellent yield. More sterically demanding dienes require longer reaction times to produce similar yields. Extending the reaction to include other inorganic silanes is not as successful. For example, no reaction occurs with tetrachlorosilane, and trichlorosilane yields a ternary mixture of siloles.
Scheme 2 Preparation of Siloles from Zirconacyclopentadienes[13]
R1 R2 Time Yield (%) Ref Et Et 5 min 92 [
13] TMS Me 24 h 97 [
13]
Tertiary triaryl- and trialkylsilanes, like secondary silanes, are historically prepared from trichlorosilane[14,15] and aryl or alkyl Grignard reagents.[16] The synthesis of triallylsilane is also amenable to this method. In cases where dilithiation of the aryl group is possible, the synthesis of triarylsilanes can be improved by isolation of the aryllithium salt after lithium-halogen exchange with butyllithium at room temperature in pentane (? Scheme 3).[17] The salt is purified by centrifugation and repeated washes with cold pentane. The purified salt is then reacted directly with trichlorosilane in pentane at room temperature to form the triarylsilanes (e.g., 4) in excellent yields. Note: Care must be taken when isolating the pyrophoric aryllithium salts.
Scheme 3 Improved Preparation of a Triarylsilane from Trichlorosilane[17]
3,7-Di-tert-butyl-5H-dibenzo[b,d]silole (1); Typical Procedure:[9]
CAUTION:
1,2-Dibromoethane is an eye, skin, and respiratory tract irritant and is aprobable human carcinogen.
A soln of 2,2´-dibromo-4,4´-di-tert-butylbiphenyl (2.01 g, 4.71 mmol) in THF (30 mL) containing 1,2-dibromoethane (0.4 mL) was added slowly to a suspension of Mg (0.567 g, 23.3 mmol) in THF (5 mL). The reaction was slightly exothermic and the addition took approximately 0.5 h. The mixture was then heated to reflux for 2 h, and cooled to rt. A slurry of [(teeda)H2SiCl2] (1.3 g, 4.72 mmol) in CH2Cl2 (8 mL) was prepared and cannulated into the Grignard soln, resulting in the formation of a clear soln. The mixture was stirred overnight, followed by solvent removal and the addition of Et2O (30 mL) and 0.2 M aq HCl (50 mL). The organic layer was separated and dried (MgSO4), and the solvent was removed. Kugelrohr distillation of the crude product resulted in the desired product in the first fraction (bp 150-190 °C/0.2 Torr). That fraction was dissolved in abs EtOH and cooled to -7 °C to yield the product as a white solid; yield: 0.269 g (19%).
Tris(4-bromophenyl)silane (4); Typical Procedure:[17]
To a stirred soln of 1-bromo-4-iodobenzene (6.5 g, 23 mmol) in pentane (65 mL) at rt, a 1.6 M soln of BuLi in hexanes (14.4 mL, 23 mmol) was added dropwise and allowed to react for 1 h, producing a precipitate. The soln was centrifuged for 5 min at 2400 rpm and the supernatant was removed via syringe. Pentane (70 mL) was added to the sediment and the suspension was stirred for 5 min. The suspension was centrifuged again and the supernatant was again removed via syringe. A soln of HSiCl3 (0.95 g, 7.0 mmol) in pentane (17.5 mL) was added to the soln of (4-bromophenyl)lithium in pentane (50 mL) at rt (CAUTION: exothermic reaction). The reaction was stirred at rt for 2 h. The suspension was then centrifuged and the supernatant removed via syringe. The solids were again stirred with pentane (70 mL) and centrifuged. The supernatants were combined and quenched with TMSCl (0.5 mL) and...
