Phosphine-catalyzed sequential (2+3)/(2+4) annulation of γ-vinyl allenoates: access to the synthesis of chromeno[4,3-b]pyrroles

A phosphine-catalyzed cascade (2+3)/(2+4) cyclization reaction of gamma-vinyl allenoates with aldimine esters has been developed to provide a series of chromeno[4,3-b]pyrrole derivatives that contain three contiguous stereogenic centers. The method gives a good yield, excellent chemoselectivity and diastereoselectivity under mild conditions.

Automated summary

A phosphine-catalyzed cascade (2+3)/(2+4) cyclization reaction has been developed for the synthesis of chromeno[4,3-b]pyrrole derivatives. This method provides good yield, excellent chemoselectivity and diastereoselectivity under mild conditions, resulting in compounds containing three contiguous stereogenic centers.