Rhodium-Catalyzed Annulation of α-Imino Carbenes with α,β-Unsaturated Ketones: Construction of Multisubstituted 2,3-Dihydropyrrole/pyrrole Rings.

An efficient annulation of α-imino rhodium carbenes with α,β-unsaturated ketones has been developed to generate multisubstituted 2,3-dihydropyrrole derivatives. Using the optimized catalyst, this approach is compatible with both cyclic and normal linear α,β-unsaturated ketones. Further detosylation in the presence of base could produce multisubstituted pyrroles. The new method has the potential to enable the rapid construction of bioactive molecules containing pyrrole rings.