Regio- and Stereoselective Synthesis of Functionalized Dihydropyridines, Pyridines, and 2H-Pyrans: Heck Coupling of Monocyclopropanated Heterocycles

A palladium-catalyzed coupling between aryl halides and monocyclopropanated pyrroles or furans has been developed, leading to valuable six-membered N- and O-heterocycles. As the key step, a selective cleavage of the non-activated endocyclic C-C bond of the 2-heterobicyclo-[3.1.0]hexane framework is achieved. The developed method offers access to highly functionalized piperidines, pyridines, and pyrans that are challenging to access by traditional methods.

Modular, flexible, and stereoselective synthesis of pyrroloquinolines: rapid assembly of complex heterocyclic scaffolds

A novel 1,2-dinucleophile engages two imines in a sequential vinylogous Mannich-Mannich-Pictet-Spengler process to generate complex hexahydropyrrolo[3,2-c]quinolines in a one-pot operation. This methodology provides a rapid, highly modular, and flexible access toward a wide range of products and forms four new σ-bonds and chiral centers each. The diastereoselectivity may be inverted by fine-tuning of reaction conditions and the electronic nature of the imines.