Synthesis of Cycloalkyl Substituted 7-Azaindoles via Photoredox Nickel Dual Catalytic Cross-Coupling in Batch and Continuous Flow

Abstract

An efficient photoredox/Ni dual catalytic C_sp²-C_sp³ cross-coupling protocol in a continuous-flow regime to synthesize a variety of regioisomeric cycloalkyl substituted 7-azaindoles has been developed. These transformations proceed efficiently under mild conditions (blue LED light irradiation at 30 °C over 40 min residence time in mixed solvent systems). Reactions are easy to perform and afford most of the desired 2-, 3-, 4-, 5-, and 6-cycloalkyl substituted 7-azaindoles in moderate-to-good yield.