DMAP‐Catalysed Sulfinylation of Diacetone‐<scp>D</scp>‐Glucose: Improved Method for the Synthesis of Enantiopure <i>tert</i>‐Butyl Sulfoxides and <i>tert</i>‐Butanesulfinamides

Abstract

Abstract An improved method for the tert ‐butanesulfinylation of diacetone glucose with tert ‐butanesulfinyl chloride is reported. The method is based on a beneficial effect of catalytic DMAP, which enhances both the rate of the reaction and the enantioselectivity of the process to give ( R S )‐diastereomer 2 R S with a 94 % de and in quantitative yield. ( R S )‐DAG sulfinate ester 2 R S is an excellent intermediate for the synthesis of enantiopure tert ‐butyl sulfoxides. Grignard agents and organolithium reagents can displace smoothly the diacetone glucose moiety to give synthetically relevant enantiopure sulfoxides, including highly functionalized derivatives, in high yields and with high enantioselectivities. ( R S )‐DAG sulfinate ester 2 R S is also an excellent N ‐sulfinylating agent; simple addition of LiHMDS (lithium hexamethyldisilazide) in THF gives ( S S )‐ tert ‐butanesulfinamide, and N ‐ tert ‐butanesulfinylimines are then formed in a two‐step one‐pot manner. N ‐Alkylated tert ‐butanesulfinamides are formed by the condensation of 2 R S with lithium amides.