Chemistry of Oxaziridines. 15. Asymmetric Oxidations Using 3-Substituted 1,2-Benzisothiazole 1,1-Dioxide Oxides

Article abstract of DOI:10.1021/jo00002a056

The synthesis and asymmetric oxidations of chiral nonracemic 3-substituted 1,2-benzisothiazole 1,1-dioxide oxides (6) are described.These new N-sulfonyloxaziridines are prepared by oxidation of the corresponding enantiomerically pure sulfonimines 5.These reagents oxidize sulfides to sulfoxides (11-52percent ee), epoxidize nonfunctionalized alkenes (17-61percent ee), and oxidize enolates to α-hydroxy carbonyl compounds (11-81percent ee).Epoxidation of (-)-(S)-limonene with (+)-(2R,3S)-6a, a double asymmetric synthesis, affords a 93:7 cis/trans mixture of limonene oxides.Evaluation ofpossible transition-state structures suggests that the molecular recognition is primarily determined by steric factors.These reagents are less effective than N-sulfonyloxaziridines 1-3 in their asymmetric oxidations because they lack well-defined regions that are topologically dissimilar near the active site.