Recent Advances in C(sp³)–C(sp³) and C(sp³)–C(sp²) Bond Formation through Cathodic Reactions: Reductive and Convergent Paired Electrolyses

Abstract

The formation of C(sp 3 )−C(sp 3 ) and C(sp 3 )−C(sp 2 ) bonds is one of the major research goals of synthetic chemists. Electrochemistry is commonly considered to be an appealing means to drive redox reactions in a safe and sustainable fashion and has been utilized for C−C bond-forming reactions. Compared to anodic oxidative methods, which have been extensively explored, cathodic processes are much less investigated, whereas it can pave the way to alternative retrosynthetic disconnections of target molecules and to the discovery of new transformations. This review provides an overview on the recent achievements in the construction of C(sp 3 )−C(sp 3 ) and C(sp 3 )−C(sp 2 ) bonds via cathodic reactions since 2017. It includes electrochemical reductions and convergent paired electrolyses.

Direct Reductive Arylation of Imines with Electron-Deficient (Hetero) Arenes via Electrosynthesis to Access Benzylic Amines

“…Furthermore, this reaction utilizes cathodic reduction, which is less explored compared to the widely studied anodic oxidation. 15 Rovis's work mentioned above, which is the only report on the electrochemical reductive arylation of imines to date (Scheme 1Ab), 9 mainly focused on accessing primary amines, with some examples of accessing secondary amines. However, our work focused on accessing benzylic secondary amines.…”

“…The reaction features inexpensive electrodes, the wide range of substrates, good functional tolerance and mild conditions, providing a platform for arylation of imines with simple operation and high atomic economy. Furthermore, this reaction utilizes cathodic reduction, which is less explored compared to the widely studied anodic oxidation …”

Recent advances in photo- and electro-enabled radical silylation

“…Since the first electrochemical reduction of chlorosilanes reported by Hengge and Litscher in 1976, 64 organosilicon electrochemistry has offered an alternative to conventional chemical approaches for the synthesis of organosilanes. 21,65–67 In recent years, with the rapid iteration of organic electrochemistry, 68–79 organosilicon electrochemistry has emerged as a powerful and efficient synthetic approach for accessing organosilicon compounds in a sustainable manner, which continues to give impetus for the innovation of organosilicon chemistry.…”

Electrochemical formal homocoupling of sec-alcohols

“…Electroorganic chemistry has been recognized as an environmentally benign and powerful strategy to promote redox reactions using electricity as a traceless oxidant or reductant [24][25][26][27][28]. Electrochemical pinacol coupling would be a promising alternative to avoid the use of low-valent metal reductants.…”