Asymmetric [3+2] Photocycloaddition of β-Keto Esters and Vinyl Azides by Dual Photoredox/Nickel Catalysis

作者：Zhou, Xue-Song; Zhang, Zhihan; Qu, Wen-Yuan; Liu, Xiao-Peng; Xiao, Wen-Jing^*; Jiang, Min^*; Chen, Jia-Rong^*

来源：Journal of the American Chemical Society, 2023, 145(22): 12233-12243.

DOI：10.1021/jacs.3c02485

• VISIBLE-LIGHT
• CYCLOADDITIONS
• ENERGY

Photocatalytic[3 + 2] cycloadditions and control ofstereochemistryhave remained a substantial challenge, particularly in the contextof heterocycle synthesis; sporadic successful examples have involvedenantioselective [3 + 2] photocycloaddition between redox-active directgroup-containing cyclopropanes and alkenes for creation of cyclopentanes.Herein, we report a cooperative catalytic system comprising a chiralnickel Lewis acid catalyst and an organic photocatalyst fueled byvisible-light irradiation that allows for the hitherto elusive asymmetric[3 + 2] photocycloaddition of beta-keto esters with vinyl azidesunder redox-neutral conditions. This protocol enables highly enantioselectiveconstruction of polycyclic densely substituted 3,4-dihydro-2H-pyrrole heterocycles featuring two contiguous tetrasubstitutedcarbon stereocenters, including a useful chiral N,O-ketal motif that is not easily accessible withother catalytic methods. Mechanistic studies revealed that the overallreactivity relies on the seamless integration of dual roles of nickelcatalysts by the catalytic formation of the substrate/Ni complex,assisting both photoredox event and enantioselective radical addition.

• 单位
  杭州师范大学