A general, [1+4] approach to the synthesis of 3(5)-substituted pyrazoles from aldehydes

Article abstract of DOI:10.1016/S0040-4039(98)00472-9

A new, one-pot preparation of 3(5)-substituted-1H-pyrazole is described that employs Horner-Emmons reaction of aldehydes with dianion of novel phosphonate 1 and proceeds through cyclization of N-sodium salt of α,β- unsaturated tosylhydrazones 2.