Synthesis of α,β-Unsaturated Diazoketones through the Use of <i>N</i> , <i>N</i> ′-Ditosylhydrazine

A scalable synthesis of α,β-unsaturated diazoketones has been developed through the reaction of 1-iodoenones with <i>N</i>,<i>N</i>'-ditosylhydrazine. 1-Chloroenones, accessible from aldehydes via a Wittig-type homologation, undergo in situ halide exchange and diazo transfer in a one-pot sequence that minimizes purification and enhances efficiency. This strategy offers practical access to α,β-unsaturated diazoketones, which serve as versatile intermediates for synthesis and reaction discovery. In addition, selective formation of dihydropyridazinones through a 1,4-addition pathway is described.