Phosphine-mediated enantioselective [1 + 4]-annulation of Morita-Baylis-Hillman carbonates with 2-enoylpyridines.

This work describes a phosphine-catalyzed asymmetric [1 + 4] annulation of Morita-Baylis-Hillman carbonates with 2-enoylpyridines for constructing the enantiomerically enriched 2,3-dihydrofuran motif. In the presence of (-)-1,2-bis[(2 R ,5 R )-2,5-dimethylphospholano]benzene, a series of Morita-Baylis-Hillman carbonates reacted with 2-enoylpyridines smoothly to afford a wide range of optically active 2,3-dihydrofurans featuring pyridine motifs in high yields with excellent asymmetric induction.