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
PdCl2/P(o-tolyl)3 gave fast reaction rates and good yields. Competition experiments with styrene evidenced
a slight preference for reaction with 1-allyl-1H-tetrazole.
Key words
heterocycles - N1-substituted tetrazoles - Heck reaction - cross-coupling - C–C bond
formation - aqueous conditions - spin crossover