Transformation of enantiomerically enriched propargyl esters 5 into dihydrofurans 6 with complete enantiospecificity is achieved by Ag(I)-catalyzed rearrangement and cyclization, and the sequence is successfully applied to the enantioselective synthesis of an antitumor protective and hypolipidemic antibiotic, (S)-(-)-ascofuranone.
SHIGEMASA, YOSHIHIRO;YASUI, MASARU;OHRAI, SHIN-ICHIRO;SASAKI, MAKOTO;SASH+, J. ORG. CHEM., 56,(1991) N, C. 910-912