Practical access to spiroacetal enol ethers via nucleophilic dearomatization of 2-furylmethylenepalladium halides generated by Pd-catalyzed coupling of furfural tosylhydrazones with aryl halides.

Pd-catalyzed cross-coupling of furfural tosylhydrazones with aryl halides produces 2-furylmethylenepalladium halides, which can undergo intramolecular nucleophilic dearomatization to provide spiroacetal enol ethers. This is the first report on the formation of 2-furylmethylenepalladium halides from stable furfural hydrazones instead of from 2-furylmethyl halides, which are not readily accessible or are unstable.