Palladium-Catalyzed Direct Esterification via C-H Bond Activation of Aldehydes.

A concise and highly efficient synthesis method of direct esterification of aldehydes via Pd-catalyzed C-H bond activation of aldehyde group has been developed. The strategy avoids the preoxidation step of aldehyde or use of condensing agents in ester synthesis, which is not only applicable to various alcohols but also suitable for the esterification of phenolics which are usually difficult to be esterified. The methodology has the significant advantages of broad substrate scope, mild reaction conditions, and nonrequirement of additional oxidants.