Cerium(III)-catalyzed cascade cyclization: an efficient approach to functionalized pyrrolo[1,2-a]quinolines.

A general and practical route to the synthesis of multisubstituted pyrrolo[1,2-a]quinolines has been described from 2-alkylazaarenes and nitroolefins using cerium chloride as a catalyst via a tandem Michael addition, cyclization and aromatization. This protocol features readily available starting materials, operational simplicity and high regioselectivity to access multifunctionalized pyrrolo[1,2-a]quinolines with the formation of multiple C-C and C-N bonds in one pot. In addition, various substitution patterns and functional groups were found to be compatible under the optimized conditions, which was lacking in the existing procedures.