2- Hydroxy-2-phenylethyl p-tolyl sulfoxide

No stereoselectivity was observed in the formation of a 1 1 diastereomeric mixture of 2-hydroxy-2-phenylethyl p-tolyl sulfoxide 145 from treatment of (R)-methyl p-tolyl sulfoxide 144 with lithium diethylamide . However, a considerable stereoselectivity was observed in the reaction of this carbanion with unsymmetrical, especially aromatic, ketones The carbanion derived from (R)-144 was found to add to N-benzylideneaniline stereoselectivity, affording only one diastereomer, i.e. (Rs,SJ-( + )-iV-phenyl-2-amino-2-phenyl p-tolyl sulfoxide, which upon treatment with Raney Ni afforded the corresponding optically pure amine . The reaction of the lithio-derivative of (-t-)-(S)-p-tolyl p-tolylthiomethyl sulfoxide 146 with benzaldehyde gave a mixture of 3 out of 4 possible isomers, i.e. (IS, 2S, 3R)-, (IS, 2R, 3R)- and (IS, 2S, 3S)-147 in a ratio of 55 30 15. Methylation of the diastereomeric mixture, reduction of the sulfinyl group and further hydrolysis gave (—)-(R)-2-methoxy-2-phenylacetaldehyde 148 in 70% e.e. This addition is considered to proceed through a six-membered cyclic transition state, formed by chelation with lithium, as shown below . ... 

Synthesis of optically active alcohols. For asymmetric synthesis of alcohols, the carbanion salt (2) is generated from optically active (R)-melhyl p-tolyl sulfoxide (1). The optically active carbanion reacts with bcnzaldehyde (3) to give a I I diastereomeric mixture of 2-hydroxy-2-phenylethyl p-tolyl sulfoxides (4a) and (4b) in 84% yield-These can be separated by silica gel chromatography and fractional crystallizations to give (4a, oq, -t- 91.7°. 17% yield) and (4b, at, + 202.8", 15.5% yield). Raney nickel desulfurization of (4a) and (4b) gives (S)-( )-l-phcnylcthanol (5a, — 42.6 ) and... 

CisHii,02S, Methyl 2,2-diphenylvinyl sulphone, 42B, 57 Ci5HisBrS02, (+)-1-Bromo-2-hydroxy-2-phenylethyl p-tolyl sulfoxide, 42B, 58... 

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