Abstract Hydroxycinnamic acids such as p ‐coumaric, ferulic, sinapic and caffeic acids were protected as carbonates and activated as mixed carbonic anhydrides in water at RT by adding a base and isobutyl chloroformate. These anhydrides were used for amine and C ‐protected α‐amino acid acylation to give O ‐carbonate protected phenolic amides. Acylation of free α‐amino acids was performed in acetone‐water in high yields producing the O ‐carbonate protected N ‐hydroxycinnamoyl‐α‐amino acids. Pure derivatives were obtained in many cases directly by crystallization. Free phenolic compounds were rapidly obtained by carbonate deprotection with piperidine. The method offers a novel route for amide bond formation in water and the direct functionalization of hydroxycinnamic acid families with free α‐amino acids, providing a facile preparation of precious natural bioactive derivatives.