Coumarins represent an important class of heterocycles because of their prevalence in nature and their common presence as pharmaceutical structural motifs. However, their synthesis employs harsh conditions or requires a transition metal catalyst, limiting their scalability and sustainability. Herein we report an electrocatalytic synthetic method leading to coumarins using NHC·CS2 (NHC = N-heterocyclic carbene) species as organic mediators. Using this procedure, a variety of substituted coumarins were obtained in good yields, establishing this electrocatalytic strategy as an attractive synthetic alternative. Based on our observations, a reaction mechanism operating through a one-electron reduction and involving a radical intermediate is proposed.
Bru et al. (Wed,) studied this question.