Dehydrative Condensation of Carboxylic Acids with Amines Promoted by HBF4/MS 5A

Abstract

AbstractThe direct dehydrative condensation of carboxylic acids with amines is one of the most straightforward methods for the synthesis of amides. We discovered that HBF4 effectively promotes the coupling of several N‐protected amino acids in the presence of molecular sieves (MS) 5A to afford the corresponding peptides in good to high yield. Interestingly, the recovered MS 5A could be reused as a catalyst even in the absence of additional HBF4 for the dehydrative condensation. This protocol is not limited to the synthesis of peptides, but generally works for the synthesis of amides from a variety of carboxylic acids and amines.