Modular Synthesis of β-Amino Boronate Peptidomimetics.

Herein, we describe the synthesis of novel β-amino boronate peptidomimetics from amphoteric α-borylaldehydes in the Ugi multicomponent reaction. A mild deprotection method provided the free and stable boronic acid forms of the target molecules, which display notable stability toward protodeborylation. Despite the presence of Lewis acidic boron, there is no evidence for hydrolysis of the adjacent amide via a 5- or 6-membered ring intermediate. This methodology should facilitate the development of libraries of new boron-containing antibiotics and antifungal agents.