Chemistry of Oxaziridines. 16. A Short, Highly Enantioselective Synthesis of the AB-Ring Segments of γ-Rhodomycinone and α-Citromycinone Using (+)-[(8,8-Dimethoxycamphoryl)sulfonyl]oxaziridine

Abstract

A highly efficient procedure for the preparation of rhodomycinone 1 AB synthons (-)-2a and (+)-2b in high enantiomeric purity (93-4% ee) and good yield is described. This method involves asymmetric oxidation of the lithium enolate of 2-ethyl-5,8-dimethoxy-1-tetralone (4) with (+)-[(8,8-dimethoxycamphoryl)sulfonyl]oxaziridine (5c), a new enantiomerically pure, aprotic oxidizing reagent. Lower stereoselectivities were observed with this reagent for the enantioselective oxidation of 2-substituted 1-tetralone enolates 8 lacking the 8-methoxy group. © 1991, American Chemical Society. All rights reserved.