Zinc- and Indium-Promoted Conjugate Addition-Cyclization Reactions of Ethenetricarboxylates with Propargylamines and Alcohol:Novel Methylenepyrrolidine and Methylenetetrahydrofuran Syntheses

摘要

A new zinc- and indium-promoted conjugate addition-cyclization reaction to afford nitrogen- and oxygen-containing five-membered heterocycles has been developed.Reaction of ethenetricarboxylates with propargylamines (1 equiv) in the presence of ZnBr_2 or InBr_3 afforded methylenepyrrolidines in high yields.The stoichiometric use of ZnBr_2 or InBr_3 at room temperature and the catalytic use of InBr_3- Et_3N at 80 deg C were effective.Reaction of ethenetricarboxylates with propargyl alcohol in the presence of ZnBr_2 or InBr_3 afforded methylenetetrahydrofurans.