Manganese-Catalyzed Intermolecular Oxidative Annulation of Alkynes with γ-Vinyl Aldehydes: An Entry to Bridged Carbocyclic Systems.

Manganese-catalyzed intermolecular oxidative annulation of alkynes with γ-vinyl aldehydes involving acylation and alkylation is described, thus providing a scenario for the divergent synthesis of bridged carbocyclic systems. By means of this manganese-catalyzed alkyne dicarbofunctionalization strategy, three chemical bonds, including two C-C bonds and one C-H bond, are formed via an aldehyde C(sp2)-H oxidative functionalization/[4 + 2] annulation/protonation cascade.