A visible‐light‐induced reaction of cinnamic acid and diazoester is developed. In the presence of THF, this reaction provided chain elongated cinnamic acid esters via formation and ring opening of oxonium ylide with cinnamic acid. The same light‐induced reaction of cinnamic acid and diazoester in MeCN provided simple esters of cinnamic acid.
Kalita et al. (2026) studied this question.