A novel and highly efficient esterification process using triphenylphosphine oxide with oxalyl chloride

Triphenylphosphine oxide (TPPO) and oxalyl chloride ((COCl)(2)) are used as novel and high-efficiency coupling reagents for the esterification of alcohols with carboxylic acids via the TPPO/(COCl)(2) system at room temperature for 1 h. The reaction represents the first TPPO-promoted esterification under mild and neutral conditions with excellent yields. Furthermore, we proposed a plausible mechanism with the help of P-31 NMR spectroscopy.