Umpolung of the Reactivity of Carbonyl Compounds Through Sulfur-Containing Reagents

The synthetic usefulness of the umpolung of the reactivity of carbonyl compounds by reaction of sulfur-containing reagents is discussed. Firstly, hydrolysis and other reactions of S, S-acetals (mainly 1,3-dithianes) and vinyl sulfides are described. The second part is concerned with the reactions of other sulfur-containing reagents such as derivatives of vinyl sulfides, ketene S,S-acetals and derivatives, etc. Finally the applications of the methods to the syntheses of natural products are briefly mentioned. 1. Introduction 2. Hydrolysis of S,S-Acetal and Vinyl Sulfide Derivatives and other Desulfurization Reactions 2.1. Acidic Hydrolysis and Transacetalization 2.2. The Transition Metal-Induced Hydrolysis 2.3. Oxidative and Alkylative Hydrolysis of S,S-Acetals 2.4. Oxidative Solvolysis of Vinyl Sulfides and Ketene S, S-Acetals 2.5. Reductive Desulfurizations 3. Reactions of S,S-Acetal Derivatives (E¹-Type) 3.1. Metallated 1,3-Dithianes 3.2. Use of Metal Derivatives of S,S-Acetals other than 1,3-Dithianes 3.3. S,S-AcetalS-Oxides: Alkylation, Cycloalkylation, Arylation, Hydroxyalkylation, and Acylation Reactions 3.4. Reactions of Metallated S,S-Acetals with Heteroelectrophiles 3.5. Michael-Addition of S,S-Acetal Metal Derivatives 4. Miscellaneous Sulfur-Containing Reagents 4.1. Nucleophilic Acylations with Diheterosubstituted Anionic Reagents (XYRC^-) 4.2. Reactions of (RS)₃C^- -Reagents and of Thioformyl Anions with Electrophiles 4.3. Umpolung of Carbonyl Reactivity with α-Phenylsulfonyl Nucleophiles and with Sulfur-Substituted Cyclopropanes 5. The Use of Vinyl Sulfides and Ketene S,S-Acetal Derivatives (E¹-, N^2--, N⁴-Type Reactions) 5.1. Generation and E¹-Reactions of α-Lithiovinyl Sulfides 5.2. Derivatives of Ketene S, S-Acetals 5.3. Survey of Useful Transformations through Vinyl Sulfides and Ketene S, S-Acetals 6. Applications of Sulfur-Substituted Allylic Anions (E³-, E⁵-Type) 7. Natural Product Synthesis 7.1. 1,4-Diketone Synthesis: Access to Jasmonoids, Rethrolonoids, and Prostanoids 7.2. Use of 2-Lithio-1,3-dithianes in Carbohydrate Synthesis 7.3. Other Natural Product Syntheses