Catalytic diastereoselective sulfimidation of diaryl sulfides and application of chiral sulfimides to asymmetric allylic alkylation

The copper‐catalyzed diastereoselective imidation of diaryl sulfides bearing a chiral oxazolinyl moiety at the ortho‐position with [N‐(p‐toluenesulfonyl) imino]phenyliodinane (TsN=IPh) or Chloramine‐T trihydrate [TsN(Cl)Na·3H2O] was successfully carried out to give the corresponding optically active N‐tosylsulfimides in good yields. For example, the imidation of diphenyl sulfide bearing a methoxymethyl moiety at the 4‐position of the oxazoline ring with TsN(Cl)Na·3H2O in acetonitrile in the presence of 10 mol% Cu(OTf)2 at 25°C for 24 h affords the corresponding optically active N‐tosylsulfimide in 52% isolated yield with a high diastereoselectivity of 99%. Hydrolysis of the optically active N‐p‐tosylsulfimides converts them into the corresponding optically active sulfimides in high yields without loss of diastereoselectivity. These novel optically active sulfimides and N‐tosylsulfimides work as efficient chiral ligands for palladium(II)‐catalyzed allylic alkylation of 1,3‐diphenyl‐3‐acetoxy‐1‐propene with dimethyl malonate to give the corresponding alkylation product quantitatively and with a high stereoselectivity (up to 90% ee). Chirality 12:299–312, 2000. © 2000 Wiley‐Liss, Inc.