The synthesis of multi-substituted benzazepine derivatives via Mn(III)-promoted oxidative annulation of isocyanides with boronic acids

Seven-membered nitrogen-containing heterocyclic rings are important cores of anti-cancer, anti-antimicrobial, anti-malaria and other drugs. Therefore, efficient and expedient strategies for the synthesis of azacycles are highly desirable. In the previous reports, precious metal catalysts and harsh reaction conditions were usually needed, which might prevent large-scale application. Here, we disclose a protocol with Mn(OAc) 3 ·2H 2 O as a mild one-electron oxidant promoting a radical process to construct indole-fused polysubstituted benzodiazepine skeleton derivatives. This protocol features a broad substrate scope, excellent functional group tolerance, and mild reaction conditions, affording the indole-fused seven-membered rings in good yields. Moreover, this synthetic protocol can be employed in gram-scale synthesis. Seven-membered nitrogen-containing heterocyclic rings are important cores of anti-cancer, anti-antimicrobial, anti-malaria and other drugs. Therefore, efficient and expedient strategies for the synthesis of azacycles are highly desirable. In the previous reports, precious metal catalysts and harsh reaction conditions were usually needed, which might prevent large-scale application. Here, we disclose a protocol with Mn(OAc) 3 ·2H 2 O as a mild one-electron oxidant promoting a radical process to construct indole fused polysubstituted benzodiazepine skeleton derivatives. This protocol features broad substrate scope, excellent functional group tolerance, and mild reaction conditions, affording the seven-membered rings in good yields. Moreover, this synthetic protocol can be employed in gram scale synthesis.