Acyl Iodide Synthesis from Carboxylic Acids Using a Novel Ph2P(O)H‐I2 Binary System and Its Application to Facile Preparation of Amides, Esters, and Thioesters.

Acyl iodides are expected to be excellent acylating agents due to the low bond dissociation energy of the carbon–iodine bond and the high capability of iodine as a leaving group. Unfortunately, the preparative methods for acyl iodides directly from carboxylic acids are rather limited. In this work, we found that a novel binary system combining I2 and diphenylphosphine oxide (Ph2P(O)H) provides a simple method for the preparation of acyl iodides from carboxylic acids. Furthermore, the subsequent one‐pot reaction with appropriate nucleophiles, such as amines, alcohols, and thiols, afforded the corresponding amides, esters, and thioesters, respectively, in good to excellent yields. [ABSTRACT FROM AUTHOR]