Ring-Expansion of Thioacetal Ring via Bicyclosulfonium Ylide. Effect of Protic Nucleophile on Ylide Intermediate
作者:Takashi Mori、Yuichi Sawada、Akira Oku
DOI:10.1021/jo991775x
日期:2000.6.1
reaction of 2-(3-diazo-2-oxopropyl)-2-methyl-3-oxathiolane 9f in the absence of AcOH gave 4-oxa-7-thiocan-2-en-1-one 19 via a sulfonium ylideintermediate, whereas, in the presence of AcOH, an alternative regioisomer 20 was also formed competitively with 19 via an oxonium ylideintermediate.