Nickel-Catalyzed Reductive Borylation of Enaminones via C(sp 2 )-N Bond Cleavage.

The cleavage and transformation of alkenyl C(sp 2 )-N bonds is a significant synthetic challenge. Herein we described an unprecedented nickel-catalyzed reductive borylation of enaminones to synthesize β-ketone boronic esters. Notably, B 2 pin 2 played the dual role in this process, and water served as a hydrogen source, which was transferred to target products. The air-stable nickel catalyst was applied to the cleavage of alkenyl C(sp 2 )-N bonds, concomitant with the reductive process of the alkenyl boronic ester intermediates, on the basis of the mechanism study.