Chiral VAPOL Imidodiphosphoric Acid-Catalyzed Asymmetric Vinylogous Mannich Reaction for the Synthesis of Butenolides
作者:Suoqin Zhang、Guangliang Zhang、Tianyun Zhou、Jigang Gao、Guofeng Liu、Xukai Guan、Dong An
DOI:10.1055/s-0037-1610232
日期:2018.9
Chiral butenolides were synthesized by the enantioselective vinylogousMannichreaction. Chiral (VAPOL)-type imidodiphosphoric acids are efficient catalysts for the asymmetricvinylogousMannich (AVM) reaction of aldimines and trimethylsiloxyfuran in toluene. Under the optimized conditions, a series of butenolides were obtained with high yields (up to 98%) and enantioselectivities (up to 97% ee) as
during the formation of iminesfrom aldehydes 1 and amines 2, is employed to promote the one-pot Mannich reaction of trimethylsilyloxyfuran 3a without addition of extra solvent or catalyst. This clean and quick reaction allows the obtention of a series of 5-substituted γ-butenolides 4 with good yields and modest diastereomeric ratio. A large panel of substituents is tolerated ranging fromaliphatic chains