Catalytic Asymmetric Oxidation of tert-Butyl Disulfide. Synthesis of tert-Butanesulfinamides, tert-Butyl Sulfoxides, and tert-Butanesulfinimines

摘要: The first example of the catalytic asymmetric oxidation tert-butyl disulfide (1) is described. product, tert-butanethiosulfinate (2) obtained with 91% enantiomeric excess in yields ≥92% on scales as large 1 mol. application H2O2 stoichiometric oxidant presence 0.25 mol % VO(acac)2 and 0.26 a chiral Schiff base ligand, 6a, both convenient cost-effective. Thiosulfinate ester 2 chemically optically stable serves an excellent precursor to tert-butanesulfinyl compounds by stereospecific nucleophilic displacement thiolate. Addition LiNH2 liquid ammonia THF provides tert-butanesulfinamide (3; yield). A single recrystallization enantiomerically pure 3 71−75% overall yield from 1. Enantiomerically thiosulfinate also reacts readily stereospecifically Grignard reagents, organolithiums, lithium amides, imine salts provide pur...