Nickel-Catalyzed Chemodivergent 1,1-Difunctionalization of Unactivated alpha-Olefins with Alkynyl Electrophiles and B(2)pin(2)

摘要

Divergent catalysis represents a powerful strategy for increasing molecular complexity and exploring catalytic modes in organic synthesis. Herein, we report, a nickel-catalyzed, chemodivergent 1,1-alkynylboration, and 1,1-dialkynylation of unactivated alpha-olefins. This study not only provides an efficient and modular protocol for the divergent synthesis of propargylic boronic esters and gem-dialkynylalkanes, but also achieves a controllable, single or double cross-coupling of Ni/B bimetallic intermediates. Mechanistic studies reveal that the diboron reagent (B-2 pin(2)) plays a significant role in the dialkynylation reaction, serving as both the reductant and transient assisting group. Notably, both reactions show high regioselectivities and good functional group tolerance. In addition, the synthetic value of the products has been demonstrated with several downstream transformations.