Stereoselective Synthesis of α-Amino-H-phosphinic Acids and Derivatives

α-Amino- H -phosphinic acids and derivatives are an important group of compounds of synthetic and pharmacological interest, and particular attention has been dedicated toward their stereoselective synthesis in recent years. While some of these compounds show activity by themselves, they are also valuable starting materials in the synthesis of phosphinic bioisosteres of natural peptides, where the hydrolyzable bond is substituted by a phosphinic functionality that mimics the transition state of peptide hydrolysis, thus acting as efficient enzyme­ inhibitors in which the molecular stereochemistry is demonstrated to be critical. This review summarizes the latest developments on the asymmetric synthesis of acyclic and phosphacyclic α-amino- H -phosphinic acids and derivatives following an order according to the strategy used; in addition, some implications in medicinal chemistry are disclosed. 1 Introduction 2 Stereoselective Synthesis of Acyclic α-Amino- H -phosphinic Acids and Derivatives 2.1 Stereoselective C–P Bond Formation (Addition of Phosphorus Compounds to Imines) 2.1.1 Chiral Imine Compounds 2.2 Stereoselective C–P Bond Formation (One-Pot, Three-Component Reaction) 2.2.1 Chiral Amino Compounds 2.3 Stereoselective C–C Bond Formation 2.3.1 Diastereoselective Alkylations 2.4 Resolution Methodologies 2.5 Conversion from Chiral α-Aminophosphonates 3 Synthesis of Phosphacyclic α-Amino- H -phosphinates 3.1 1,4,2-Oxazaphosphacycles 4 Concluding Remarks