Divergent synthesis of pyrrolidone fused pyrimido[1,2-]indazole through selective trapping of an enone intermediate by 1-indazol-3-amine.

An oxidant-controlled divergent synthesis of a pyrrolidone fused pyrimido[1,2-]indazole skeleton was developed through selective cyclization of an generated enone intermediate and 1-indazol-3-amine. The one-pot, metal-free process formed three C-N bonds, one C-C bond, and a tetrasubstituted carbon stereocenter containing a hydroxyl group. This method not only allowed for the synthesis of over 60 new pyrrolidone fused pyrimido[1,2-]indazole derivatives, but was also compatible with the transformation of complex active molecules and the derivation of target products. Significantly, product 4q exhibited aggregation-induced emission (AIE) characteristics without any further modification.