Efficient removal of protecting groups by a 'push-pull' mechanism. II. Deprotection of O-benzyltyrosine with a thioanisole-trifluoroacetic acid system without O-to-C rearrangements.

Abstract

A thioanisole-trifluoroacetic acid (TFA) system was found to deprotect Tyr (Bzl) quantitatively at 25°within 3 hr by a push-pull mechanism without O-to-C rearrangements. This new deblocking system did not completely deprotect Ser (Bzl) and Thr (Bzl), but deprotected Lys (Z) quantitatively.