Transesterification of Non‐Activated Esters Promoted by Small Molecules Mimicking the Active Site of Hydrolases

The synthesis of small molecules able to mimic the active site of hydrolytic enzymes has been largely pursued in recent decades. The high reaction rates and specificity shown by natural hydrolases present an attractive target, and yet the preparation of suitable small‐molecule mimics remains challenging, requiring activated substrates to achieve productive outcomes. Here we present small synthetic artificial enzymes which mimic the catalytic site and the oxyanion hole of chymotrypsin and N‐terminal hydrolases and are able to perform, for the first time, the transesterification of a non‐activated ester such as ethyl acetate with methanol under mild and neutral reaction conditions. A small artificial hydrolase that mimics the active centre of chymotrypsin and N‐terminal hydrolases is able to perform, for the first time, the transesterification of ethyl acetate with methanol under neutral conditions and at room temperature. This artificial enzyme also catalysed the transesterification of important neurotransmitter acetylcholine into methyl acetate and choline.