Synthesis of 2,3,4,11b-Tetrahydro-1H-pyridazino[6,1-a]isoquinolines via the Three-Component Reaction of 2-Alkynylbenzaldehydes, a Sulfonohydrazide and Dimethyl Cyclopropane-1,1-dicarboxylate

Xingxin Yu, Guanyinsheng Qiu, Jianping Liu & Jie Wu
A three-component reaction of 2-alkynylbenzaldehydes, a sulfonohydrazide and dimethyl cyclopropane-1,1-dicarboxylate, co-catalyzed by silver(I) triflate and nickel(II) perchlorate hexahydrate, is described, which affords 2,3,4,11b-tetrahydro-1H-pyridazino[6,1-a]isoquinolines in moderate to good yields. A possible reaction pathway that proceeds via a tandem 6-endo-cyclization and [3+3] cycloaddition sequence is proposed.