Application of chiral sulfinamides

Jacobus and Mislow have investigated the development of chiral sulfinamides as precursors to optically pure sulfoxides [22]. The reaction of benzenesulfinyl chloride and (5)-(+)-deoxyephedrine proceeded at low temperature (0°C) to yield 

Montanari s procedure allows access to both enantiomers of methyl p-tolyl sulfoxide. The sulfinamides (14) were, however, observed to racemize on exposure to light, but were reported to be optically stable in the dark. 

Recently, in a related approach by Evans, chiral oxazolidinones derived from (lR,25)-norephedrine and (5)-phenylalanine were employed to prepare novel, chiral sulfinyl transfer reagents (15) and (16), respectively [26]. 

These N-sulfinyloxazolidinone reagents can be synthesized either by sulfinylation of the metallated oxazolidinone or by sulfoxidation of the N-sulfenimide. The crystalline reagents (15) and (16) are readily purified from their respective minor epimers to high diastereoisomeric purity by chromatography and their reactivity toward nucleophiles is reported to be —100 times greater than that of menthyl sulfinate esters. 

The AA-sulfinyloxazolidinone reagents were found to be useful in the asymmetric synthesis of a-sulfinyl acetate (18), sulfinate esters (19) and sulfinamides (20). 

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