Properties and Reactions of Substituted 1,2‐Thiazetidine 1,1‐Dioxides: 3‐Acetoxy‐1,2‐thiazetidine 1,1‐Dioxide, Synthesis and Reactions with C‐Nucleophiles

Abstract

Abstract N ‐Silylated 3‐acetoxy‐1,2‐thiazetidine 1,1‐dioxide ( 5 ) is prepared from L ‐cystine. Reactions of 5 with silyl enol ethers yield C‐3‐substituted β‐sultams 6, 12 and 15 . Desilylation of 6 affords 7 , which undergoes photochemical cyclization to give the bicyclic β‐sultam 10 . In the course of such reactions, a portion of the C‐3‐substituted β‐sultam is consumed in a retro‐Michael‐type reaction, leading to the open‐chained sulfonamides 8 and 13 as side products. In the case of reactions between 5 and silyl enol ethers of cyclic ketones 16 , only such open‐chained products, 17 , are isolated. Reactions of 5 with substituted malonates yield the β‐sultams 19 and 20 . Structures and stereochemistry are elucidated by spectroscopic methods.