Catalytic asymmetric constructions of nitrogen, boron and carbon continuous stereogenic centers.
Guan Zhang, Junyi Jia, Xuzhao Du, Bofan Feng, Kai Yang, Peiyuan Yu, Qiuling Song
Abstract
Open AccessPrecise construction of molecular chirality is a longstanding scientific challenge in synthetic chemistry. Although methods to enantioselectively assemble consecutive carbon stereocenters are abundant, courses to establish enriched continuous heteroatomic stereocenters have acquired less attention and remain a tremendous challenge. Of those atoms in main group elements, nitrogen and boron are the most intractable ones to control their chirality. The copper-catalyzed asymmetric insertion reaction is one of the most significant transformations to construct C-B bonds in organic synthesis. Herein, we report a protocol to synthesize troublesome continuous heteroatomic stereocenters from cyclic amine boranes and diazo compounds via asymmetric B-H insertion reaction. The protocol is compatible with a wide range of amine boranes and diazo compounds, exhibiting high diastereo- and enantioselectivities. Mechanistic studies reveal a meaningful kinetic resolution pathway involved in the transformation and DFT calculations elucidate the origins of stereoselectivity and diastereoselectivity.