An Enantioselective Synthesis of the Resorcylic Acid Lactone L-783,277 via Addition of an Acetylide Anion to a Tethered Weinreb Amide

Abstract

Treatment of the terminal acetylene 12, readily obtained from the previously reported acid 10, with LiHMDS resulted in a novel macrocyclization reaction to give the cycloalkyne 13. Subjection of compound 13 to hydrogenation under Lindlar-type conditions afforded the Z-configured enone 14 that could be converted into the resorcylic acid lactone 4 upon treatment with BCl 3 in CH 2 CL 2 at -78°C.