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Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
Asymmetric [4+2] annulations to construct norcamphor scaffolds with 2-cyclopentenone via double amine-thiol catalysis
Qian-Qian Yang1, Wei Xiao, Wei Du
1Department of Medicinal Chemistry, West China School of Pharmacy, Sichuan University, Chengdu 610041, China. ycchen@scu.edu.cn.
Abstract:
An efficient double catalytic system, combining chiral amine and 2-mercaptobenzoic acid, is applied for α',β-regioselective [4+2] annulations of 2-cyclopentenone with a diversity of activated alkenes, constructing multifunctional chiral bicycle[2,2,1]heptane scaffolds in good to excellent yields and enantioselectivities. In comparison with the traditional cross-dienamine species between 2-cyclopentenone and chiral amine, the interrupted enamine intermediate containing a covalently linked thiol catalyst shows significantly improved reactivity.
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