Cascade reaction of o -enoyl arylisocyanide and o -hydroxy aromatic aldimine: diastereoselective access to a polycyclic spirobenzoxazine chromeno[4,3- b ]pyrrole derivative.

A series of structurally unusual spirobenzoxazine chromeno[4,3- b ]pyrrole derivatives have been efficiently constructed in a single operation from readily available starting materials. This domino transformation forms successively three new rings and provides a fast and economic strategy with excellent diastereoselectivity.