Convenient synthesis of .alpha.-heterosubstituted acyloxathianes
摘要:
In contrast to simple esters, alpha-alkoxy, alpha-alkylthio, and alpha-dimethylamino esters react with lithiooxathiane 1-Li in good yield to give the corresponding alpha-functionalized 2-acetylhexahydro-4,4,7-trimethyl-4H-1,3-benzoxathiin 2. In some cases, mixtures of diastereomers (2, 2') are obtained. The reaction has been extended to alpha-methoxy- and alpha-[(triisopropylsilyl)oxy]propanoyl and alpha-(methylthio)butanoyl homologs which have chiral centers at C(alpha).