Abstracts

2.7.10 Carbonyl Complexes of Chromium, Molybdenum, and Tungsten with σ-Bonded Ligands

E. Aguilar and L. A. López

This chapter is an update to the earlier Science of Synthesis contribution (Section 2.7.1) describing the chemistry of Fischer carbene complexes of chromium, molybdenum, and tungsten. The synthesis of acyclic, carbocyclic, and heterocyclic compounds is presented following an approach based on the nature of the starting carbene complex. Relevant mechanistic pathways are also discussed to allow a better understanding of the reactivity displayed.

Keywords: Fischer carbene complexes • Dötz benzannulation • Hegedus photochemistry • cyclopropanation • transmetalation • nonstabilized carbene complexes • chromium compounds • molybdenum compounds • tungsten compounds • heterocycles • carbocycles • metal migration

2.8.10 Organometallic Complexes of Vanadium

O. S. Shneider and A. M. Szpilman

This manuscript is an update to the earlier Science of Synthesis contribution describing methods for synthesis of organometallic complexes of vanadium. It summarizes previous methods and focuses on the literature published in the period 2000–2010.

Keywords: hydridovanadium complexes • vanadium • vanadium–alkene complexes • vanadium–alkyne complexes • vanadium–arene complexes • vanadium–carbene complexes • vanadocenes

3.4.8 Organometallic Complexes of Copper

B. H. Lipshutz and S. Ghorai

The topic of this update chapter is asymmetric copper hydride catalyzed transformations. Copper hydride complexes containing nonracemic ligands catalyze asymmetric 1,2- and 1,4-addition to a variety of unsymmetrical ketones and Michael acceptors.

Keywords: activated alkenes • asymmetric catalysis • asymmetric conjugate reduction • copper hydride • hydrosilylation • nonracemic ligands • unsymmetrical ketones

24.1.1.3 1,1-Dihaloallenes

K. Fuchibe and J. Ichikawa

This chapter is an update to Science of Synthesis Section 24.1.1. Syntheses and applications of 1,1-dihaloallenes reported between 2005 and 2013 are described. 1,1-Difluoroallenes are synthesized by elimination reactions of difluoroallylic compounds (formation of a second C=C bond in fluorinated alkenes) or by nucleophilic and electrophilic substitutions of difluoropropargylic compounds (rearrangement of the C≡C bonds in fluorinated alkynes). 1,1-Difluoroallenes are used for the syntheses of unsaturated fluorine-containing compounds, mainly by nucleophilic substitutions and additions at the positions α and/or γ to the fluorine substituents. Cycloadditions of tetrafluorobuta-1,2,3-triene are also described.

Keywords: allenes • alkenes • cumulenes • cycloaddition • domino reaction • electrophilic substitution • elimination • fluorine compounds • metalation • nucleophilic addition • nucleophilic substitution • propargylic compounds

24.1.16 1,1-Bis(heteroatom-functionalized) Allenes

C. Ibis

This chapter updates Science of Synthesis Sections 24.1.3, 24.1.10, 24.1.14, and 24.1.15. Mono-, bis-, tris-, and tetrakis(sulfanyl-substituted) butatrienes are obtained from alkyl-sulfanyl- or arylsulfanyl-substituted buta-1,3-dienes in the presence of base in petroleum ether at room temperature. The treatment of 1,1,4,4-tetrakis[4-(dimethylamino)pyridin-1-ium]-2,3-dichlorobuta-1,3-diene with thiolates in dimethyl sulfoxide leads to the formation of tetrakis(sulfanyl-substituted) butatrienes. Allenylphosphonates are synthesized by the reaction of aliphatic- or aromatic-substituted propargylic alcohols and chlorophosphites in the presence of triethylamine. The reaction of 1-bromo-1-silylallenes with butyl-lithium and then chlorodiphenylphosphine in tetrahydrofuran gives 1,1-bis(diphenyl-phosphino)allenes.

Keywords: butadienes • butatrienes • butenynes • elimination • allenylphosphonates • allenylphosphine oxides • silylallenes • diphenylphosphines • diphenylphosphine oxides • propargylic alcohols

24.2.11.3 1,1-Bis(organosulfanyl)alk-1-enes (Ketene S,S-Acetals)

Q. Liu

This chapter is an update to Science of Synthesis Section 24.2.11 describing methods for the synthesis of 1,1-bis(organosulfanyl)alk-1-enes (ketene S,S-acetals). It focuses on the literature published in the period 2000-2013 and gives several examples of the use of ketene S,S-acetals as versatile intermediates for organic synthesis.

Keywords: [5 + 1]-annulation reactions • [7 + 1]-annulation reactions • 1,1-bis(organosulfanyl)alk-1-enes • carbonyl condensation reactions • domino reactions • α-functionalization • substitution–cycloaromatization reactions

24.2.20 1,1-Bis(heteroatom-functionalized) Alk-1-enes (Update 1)

P. Beier

This chapter is an update to the earlier Science of Synthesis contributions describing 1-halo-alk-1-enes that bear an oxygen (Section 24.2.2), chalcogen (Section 24.2.3), nitrogen (Section 24.2.4), or phosphorus substituent (Section 24.2.5) at the 1-position. This review focuses on literature published in the period 2005–2013.

Keywords: alkenes • halo compounds • oxygen compounds • chalcogen compounds • nitrogen compounds • phosphorus compounds

24.2.21 1,1-Bis(heteroatom-functionalized) Alk-1-enes (Update 2)

M. H. Vilhelmsen

This chapter is an update to the existing Science of Synthesis contributions on the synthesis of ketene O,S-acetals (Section 24.2.7), ketene O,N-acetals (Section 24.2.9), and (1-alkoxyalk-1-enyl)phosphonates (enolphosphonates, Section 24.2.10). The reviewed synthetic methodologies are from literature published since 2005.

Keywords: (1-alkoxyalk-1-enyl)phosphonates • ketene O,S-acetals • ketene O,N-acetals • enolphosphonates • ring-opening reactions • carbohydrates • heterocycles

27.1.6 Sulfur Ylides

G. Mlostoń and H. Heimgartner

This chapter is an update to the earlier Science of Synthesis contribution describing methods for the in situ generation of thiocarbonyl ylides and Corey–Chaykovsky reagents (sulfonium and sulfoxonium methylides). Whereas thiocarbonyl ylides react as electron-rich 1,3-dipoles, Corey–Chaykovsky reagents act as methylene-transfer agents. The most relevant application of thiocarbonyl ylides relates to the synthesis of tetrahydrothiophene (thiolane) and 1,3-dithiolane derivatives, via [3 + 2]-cycloaddition reactions with electron-deficient C,C and C,S dipolarophiles, respectively. In the last decade, Corey–Chaykovsky reagents have been widely applied for cyclopropanation, epoxidation, and aziridination, as well as for diverse heterocyclization reactions. In all cases, asymmetric versions of the applied protocols are of great interest.

Keywords: aziridination • cyclopropanation • cycloaddition • five-membered rings • sulfur heterocycles • sulfides • sulfur ylides • thiiranes • thiones

27.4.3 Thioaldehyde and Thioketone S-Oxides and S-Imides (Sulfines and Derivatives)

G. Mlostoń and H. Heimgartner

This chapter is an update to the earlier Science of Synthesis contribution describing methods of synthesis and new applications for thiocarbonyl S-oxides (sulfines) and thiocarbonyl S-imides. In general, thiocarbonyl S-oxides are more stable and in many instances can be isolated. The in situ generated thiocarbonyl S-imides are efficient “sulfur-transfer agents” via the isomeric thiaziridines, formed as products of electrocyclic ring closure. Stable thiocarbonyl S-imides, derived from hexafluorothioacetone, are useful 1,3-dipoles and are applied in the preparation of fluorinated five-membered heterocycles.

Keywords: thiazolidines • cycloaddition • five-membered rings • oxidation • small-ring systems • thiones

27.26 Product Class 26: Thioaldehyde and Thioketone S-Sulfides (Thiosulfines)

G. Mlostoń and H. Heimgartner

This chapter is an overview of methods for the in situ generation and application of highly reactive thiocarbonyl S-sulfides. Typically, thiocarbonyl S-sulfides react as sulfur-rich 1,3-dipoles and trap both electron-deficient C,C-dipolarophiles and thiocarbonyl substrates, yielding the corresponding five-membered cycloadducts. In some instances, intermediate thiocarbonyl S-sulfides and/or their cyclic isomers (i.e., dithiiranes) act as sulfur-transfer agents leading to sulfur-rich heterocycles such as pentathiepanes and hexathiepanes.

Keywords: dipolar cycloaddition •...