Tertiary Alkyl Hantzsch Nitriles as a Redox-Neutral Platform for All-Carbon Quaternary Centers Construction via Bimolecular Homolytic Substitution (SH2)

Abstract The construction of quaternary carbon centers remains an important yet challenging goal in synthetic chemistry. Herein, we report a photochemical nickel-mediated coupling of tertiary 4-alkyl Hantzsch nitriles derived from alkyl aldehydes with redox-active esters of primary carboxylic acids to forge sterically congested C(sp3)–C(sp3) bonds via SH2 under redox-neutral conditions. Two reaction protocols were established: one operates under 390 nm irradiation, whereas the other employs blue-light irradiation in the presence of an exogenous photocatalyst. These operationally simple protocols exhibit excellent functional group tolerance and provide general access to all-carbon quaternary centers from a previously unexplored substrate combination.