Snipping tool: Zn(OTf)2 is an efficient catalyst for selective cleavage of amides bearing a β‐hydroxyethyl group on the nitrogen atom. The mechanism involves an N,O‐acyl rearrangement and transesterification. This new catalytic system can be applied to sequence‐specific peptide bond scission at the amine side of a serine residue. Tf=trifluoromethanesulfonyl.
Transesterification of amino acid ester derivatives was developed using a tetranuclear zinc cluster, Zn4(OCOCF3)6O, as the catalyst. Because the reaction conditions were very mild, a variety of N-protective groups and functional groups on side chains were tolerated.