Effects of bulky ligands and water in Pd-catalyzed oxidative carbonylation of phenol

The use of 2,2′-bioxazolyl ligands with bulky substituents at the 4,4′-position effectively accelerated the Pd-catalyzed oxidative carbonylation of phenol to produce diphenyl carbonate (DPC); the TONs of DPC were methyl < benzyl < iso-butyl < tert-butyl. The addition of molecular sieve 3A prevented CO2 formation, partly due to suppression of the reaction between CO and water.