Cp*Co(III)-Catalyzed γ-Selective C-H Allylation/Hydroamination Cascade for the Synthesis of Dihydroisoquinolines

A Cp*Co(III)-catalyzed γ-selective C-H allylation/hydroamination cascade toward the synthesis of 3,4-dihydroisoquinolines (DHIQs) has been successfully developed, starting from NH ketimines and allyl carbonates. Notably, highly efficient and γ-selective C-H allylations were accomplished using γ-substituted allyl reagents, thus overcoming the issues of poor α/γ selectivity and low reactivity of previous transition metal-catalyzed C-H allylations. The stereochemistry of allyl carbonates was a crucial factor, and synthesis of the DHIQs was achieved using (Z)-allyl carbonates.