One-Pot Reaction of Carboxylic Acids and Ynol Ethers for The Synthesis of β-Keto Esters

An one-pot reaction of carboxylic acids and ynol ethers for the synthesis of β-keto esters has been developed. Under promotion of Ag2O, various carboxylic acids and ynol ethers could transform to α-acyloxy enol esters, which undergo a following DMAP-catalyzed rearrangement to deliver β-keto esters rapidly. This method provides a direct approach to β-keto esters from carboxylic acids without any preactivation. The protocol features mild reaction conditions, broad substrate scope, and the products could be transformed to an array of compounds.