Enantio- and Diastereoselective Syntheses of Cyclic Cα-Tetrasubstituted α-Amino Acids and Their Use to Induce Stable Conformations in Short Peptides (Review)

Abstract

Cα-Tetrasubstituted α-amino acids are widely used to design and prepare peptides and peptide mimics with constrained conformations. Subcategories of these compounds are cyclic Cα-tetrasubstituted α-amino acids, in which both α-substituents are covalently connected. This survey presents recent advances in the synthesis and application of cyclic Cα-tetrasubstituted α-amino acids in a systematic order beginning with cyclopropane amino acids, continuing with four, five, six membered rings, and ring structures larger than six-membered. We discuss synthetic routes to the cyclic Cα-tetrasubstituted α-amino acids and their use as conformation determining elements in peptides.