N‐Heterocyclic Carbene‐Catalyzed Oxidative Esterification Reaction of Aldehydes with Alkyl Halides under Aerobic Conditions

An efficient N‐heterocyclic carbene‐catalyzed oxidative esterification reaction of aldehydes with alkyl halides or alkyl 4‐methylbenzenesulfonate is reported. It was worth noting that (1) the configuration of alkyl halides or alkyl 4‐methylbenzenesulfonates was inverted completely, and (2) the presence of oxygen was crucial for this transformation. The reaction proceeded smoothly under mild conditions and various esters were afforded in moderate to good yields. In addition, we have developed an efficient tandem oxidation/esterification reaction of alcohols. This methodology provides a rare example of a reaction of the Breslow intermediate to sp 3 ‐carbon centered electrophiles.