PROPERTIES AND REACTIONS OF SUBSTITUTED 1,2-THIAZETIDINE 1,1-DIOXIDES- SYNTHESIS OF 1,2-THIAZETIDINE-2,3-DIACETIC ACID-DERIVATIVES AND THEIR REARRANGEMENT TO 1,2-THIAZINAN-3-ONES

beta-Sultam-3-acetic acid ester 3 prepared from rac-S-benzyl-beta-homo cysteine is alkylated with bromoacetates yielding diacetates 9 which a re transformed into the phenylthio esters 11. The thiazinanone derivat ives 12 are obtained from 11 by rearrangement with lithium bis(trimeth ylsilyl)amide in excellent yields, and the syntheses of the derivative s 13, 14, and 15 are described. The stereochemistry of all products is elucidated by spectroscopic methods, and a reaction pathway is propos ed. It is supported by the synthesis of the isomeric beta-sultam-2,3-d iacetate 20, which does not rearrange to a thiazinanone derivative. So me side reactions are described.