Photoinduced Tandem Three-Component Coupling of Propanedinitrile, 2,5-Dimethylhexa-2,4-diene, and Cyanoarenes

摘要: A tandem three-component coupling photoreaction proceeds upon photoirradiation of MeCN/H2O solutions containing propanedinitrile (1, malononitrile), 2,5-dimethylhexa-2,4-diene (2), and polycyanoarenes in the presence phenanthrene carbonate, leading to selective α-monoalkylation 1. The reaction via photo-NOCAS (Nucleophile−Olefin Combination, Aromatic Substitution) type mechanism: nucleophilic attack anion 1 photogenerated 2•+ is followed by ipso-substitution on radical polycyanoarene. It advances under mild, safe, environmentally friendly conditions such as proceeding at ambient temperature without metals halogens, weak base. also represents a novel metal-free cross-coupling that leads polycyanoarene aryl–cyano bond cleavage. In addition, rare example introducing carbon nucleophile photoinduced electron transfer reaction, except cyanide ion.