Syntheses of Isoxazoline-Based Amino Acids by Cycloaddition of Nitrile Oxides and Their Conversion into Highly Functionalized Bioactive Amino Acid Derivatives

Abstract

The present account illustrates the syntheses of isoxazoline-based amino acids by the cycloaddition of 1,3-dipolar nitrile oxides to the C–C double bond of unsaturated amino acid derivatives, with focus on the regio- and stereoselectivities of the transformations. Emphasis is also placed on the syntheses of highly functionalized amino acids by means of isoxazoline ring opening. The syntheses of various pharmacologically active compounds and their analogues via the above strategies are described. 1 Introduction 2 1,3-Dipolar Cycloadditions of Nitrile Oxides 3 Syntheses of Isoxazoline-Based Amino Acids 3.1 Syntheses of Isoxazoline α-Amino Acids 3.2 Syntheses of Isoxazoline γ-Amino Acids and Their Transformation into Bioactive Derivatives 3.3 Syntheses of Isoxazoline β-Amino Acids 3.3.1 Syntheses of Highly Functionalized Cyclic β-Amino Acids by 1,3-Dipolar Cycloaddition of Nitrile Oxides 4 Cycloaddition of Nitrile Oxides to Amino Acid Precursors 5 Summary and Outlook