Arylboronate Ester Protected Amino Acids as Orthogonal Building Blocks for Fmoc Solid‐Phase Peptide Synthesis

Abstract

Three new arylboronate ester protected amino acids and their on‐resin deprotection methods have been developed. These useful building blocks were found to exhibit favorable chemical properties that are fully compatible with Fmoc strategy solid‐phase peptide synthesis. Furthermore, the formation of over‐oxidation side‐product methionine was minimized by using N‐methyl‐N‐phenylaniline N‐oxide as the oxidizing reagent. Effective application of the three new amino acids for the synthesis of different types of peptidomimetics has been demonstrated by high‐quality preparation of lipidated peptide MP‐196 C‐C8, on‐resin head‐to‐tail cyclization of desotamide B, and lactam bridging of hPTHrP‐(11–19) through a facile and metal‐free procedure by standard Fmoc solid‐phase peptide synthesis.