Synthesis of cyclopent-1-enecarbonitriles via a tandem Giese/HWE reaction initiated by visible light.

ABSTRACT

In the manuscript, a novel method for the preparation of cyclopent-1-enecarbonitriles via tandem Giese/HWE reaction initiated by visible light in the presence of fac-Ir(ppy)3 as a photocatyst has been described. The cascade reactivity combining radical and polar processes has proven applicable for a wide range of N-(acyloxy)phthalimides (which serve as precursors of the corresponding radicals) as well as diethyl (E)-(1-cyano-2-arylvinyl)phosphonates. The key parameters responsible for the success of the described strategy are visible light, 1 mol% of photoredox catalyst, base, anhydrous solvent and inert atmosphere. The reaction results in new sp3-sp3 and sp2-sp2 carbon-carbon bonds formation under mild conditions.