Switching the Spin State of Ni Catalysts Promotes Regiodivergent Reactions

Spin state, a variable factor at the electronic level, plays a significant role in determining the properties of metal complexes. However, the variability of the spin state has largely been regarded as a phenomenon to explain reaction mechanisms rather than as a chemical tool for controlling reaction selectivity. Herein, we report a nickel-catalyzed regiodivergent allylic substitution reaction of vinyl epoxides with styrylboronic acids, where the regiodivergence is directed by switching the spin state of the nickel catalysts. Linear and branched skipped diene alcohols were synthesized with broad substrate compatibility. Additionally, the enantioconvergent synthesis of branched products from racemic vinyl epoxides was achieved through dynamic kinetic asymmetric transformation. Mechanistic investigations confirmed the critical role of coordination modes with varying spin states of the nickel catalysts in achieving regiodivergence.