Wittig Olefination of Lactones

摘要

The formation of carbon carbon double bonds from carbonyl compounds by the Wittig reaction and its variants, or Peterson olefination, has become an invaluable method in organic synthesis. However, enol ether formation from an ester by olefination hashardly been reported. Carbonyl groups of esters are much less reactive in the Wittig reaction than those of aldehydes or ketones. and only a few cases dealing with intramolecular reactions of this type have appeared. More recently the Tebbe methylenationof lactones and esters has been described. Several applications to the synthesis of C-methylene glycosides have been reported.