Description:
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 31 P NMR spectroscopy.