Authors: Wengang Guo* (corresponding author), Ying Zhou, Hongling Xie, Xin Yue, Feng Jiang, Hai Huang, Zhengyu

 Han, and Jianwei Sun*

Abstract: While asymmetric insertion of metal carbenes into H–X (X = C, N, O, etc.) bonds has been well-established, asymmetric control over free carbenes is challenging due to the presence of strong background reactions and lack of any anchor for a catalyst interaction. Here we have achieved the first photo-induced metal-free asymmetric H–X bond insertion of this type. With visible light used as a promoter and a chiral phosphoric acid used as a catalyst, α-diazoesters and aryl amines underwent smooth N–H bond insertion to form enantioenriched α-aminoesters with high efficiency and good enantioselectivity under mild conditions. Key to the success was the use of DMSO as an additive, which served to rapidly capture the highly reactive free carbene intermediate to form a domesticated sulfoxonium ylide.

Congratulations to Dr. Guo and Ying Zhou!