American Chemical Society
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Achiral Cp*Rh(III)/Chiral Lewis Base Cooperative Catalysis for Enantioselective Cyclization via C–H Activation

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posted on 2022-04-11, 15:06 authored by Takumaru Kurihara, Masahiro Kojima, Tatsuhiko Yoshino, Shigeki Matsunaga
An enantioselective [4+3] cyclization via C­(sp2)–H activation with a cooperative catalytic system consisting of a Cp*Rh­(III) complex and a chiral Lewis base is described. An α,β-unsaturated acyl ammonium intermediate is generated from a chiral isochalcogenurea catalyst and an acyl fluoride reacts with a metallacycle generated from the Cp*Rh catalyst and a benzylamine derivative. This cooperative catalytic system gives a variety of benzolactams in good yields with excellent enantioselectivities (up to 99:1 er). The results demonstrated that chiral Lewis base catalysis is a powerful tool for controlling the enantioselectivity of transition metal-catalyzed C–H functionalizations.