Unsaturated Aryl and Heteroaryl N1-Tetrazoles from 1-Allyl-1H-tetrazole

Abstract Unsaturated aryl- and heteroaryl N1-substituted tetrazoles have been exceedingly difficult to access but are nonetheless highly attractive for the preparation of novel multifunctional spin crossover materials. The development of a Heck cross-coupling protocol, featuring good substrate tolerance for aromatic and heteroaromatic substrates overcoming this synthetic challenge is presented. The combination of aqueous THF, triethylamine, and PdCl 2 /P( o -tolyl) 3 gave fast reaction rates and good yields. Competition experiments with styrene evidenced a slight preference for reaction with 1-allyl-1 H -tetrazole.