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.