α-Functionalization of 2-Vinylpyridines via a Chiral Phosphine Catalyzed Enantioselective Cross Rauhut-Currier Reaction.

Herein, 2-vinylpyridines as a new type of electron-poor system for the asymmetric cross Rauhut-Currier reaction are reported. 2-Vinylpyridines are chemo- and enantioselectively activated by a newly designed chiral phosphine catalyst. The new reaction provides a powerful synthetic tool for accessing structurally diverse, highly valued chiral pyridine building blocks in good yields and with high enantioselectivities. Preliminary mechanistic studies reveal that two NH protons in the catalyst are critical for the synergistic activation of the substrates and governing the stereoselectivity of this reaction.