Acyl anion equivalents: synthesis of ketones and enones from α-phenylthioalkylphosphine oxides

Abstract

The sulphenylated phosphine oxides Ph,P(0)*CH(SR2) R1, easily prepared from triphenylphosphine, diphenyl or dimethyl disulphide, and an alkyl halide, form anions which act as acyl anion equivalents. Reaction with aldehydes and ketones gives vinyl sulphides, which can be hydrolysed to carbonyl compounds. Reaction with a-phenylthioand cc-methoxy-aldehydes and ketones gives enone precursors. The scope and limitations of the method are described.CONVENTIOKAL ketone syntheses involve the addition of ponding to this approach. Recently a new family of a carbon nucleophile (Grignard reagent, enolate anion, ketone syntheses has been evolved using the same etc.) to a carbon electrophile (usually an acyl derivative), disconnection but with umpolung [equation (ii)] so the electrophilic carbon atom becoming the new carbonyl that the new carbonyl carbon atom is derived from the carbon*2 Equation (i) shows the disconnection 'Orre'-

Preparation and Reactivity of Chalcogenyl Phosphonates and Phosphane Oxides

“…In all examples, a high preference for the ( E / E ) isomers could be detected by 1 H and 13 C NMR spectroscopy, which is in accordance with these one‐step Horner–Wittig reactions of phosphane oxides, usually ( E ) selective 33. For example, in the synthesis of vinyl sulfides34 or vinyl fluorides,31 the diastereomeric ratio was 3:1 or lower. Pure ( E ) or ( Z ) alkenes would be accessible by the two‐step Horner–Wittig strategy 33.…”

Stereoselective Synthesis of (E)-Vinyl Sulfoxides by the Horner−Wittig Reaction

“…[11] The corresponding sulfides [17] were mono-oxidized using 1.1 equivalents of mCPBA [10] as the oxidizing agent [3g] at Ϫ20°C, leading to almost quantitative yields after workup (washing with thiosulfate, bicarbonate and saturated brine, followed by precipitation from ether). The products were sufficiently pure for use in the HornerϪWittig reaction.…”

Chemistry of Phosphorylated Formaldehyde Derivatives. Part I

“…Diphenyl(diphenylthiomethyl)phosphine oxide ( 126 ) [109] was previously obtained in similar manner in 75% yield from diphenyl(phenylthiomethyl)phosphine oxide ( 127 ) by its interaction with diphenyldisulfide (Scheme 33).…”

“…This method [107] and its variations [108,109,110] provide a possibility to synthesize linear dialkyl (dialkylthiomethyl)phosphonates 107 containing different substituents in the thioacetal group.…”