Catalytic Syntheses of N‐Heterocyclic Ynones and Ynediones by In Situ Activation of Carboxylic Acids with Oxalyl Chloride

Breaking the bottleneck: α-Keto carboxylic acids and N-heterocyclic carboxylic acids are activated in situ with oxalyl chloride then catalytically alkynylated to give ynediones and N-heterocyclic ynones efficiently in a one-pot fashion. 5-Acylpyrazoles and 2-phenylaminopyrimidines, potentially interesting for pharmaceutical applications, are readily synthesized in concise one-pot, three-component syntheses.