Geometry‐Controlled Cycloaddition of C ‐Alkoxycarbonyl Nitrones: Synthetic Studies on Nonproteinogenic Amino Acids

Abstract

Nitrogen-containing compounds such as amino acids or alkaloids are of great importance as biologically active compounds. One of the best choices for the construction of such nitrogen-containing compounds would be cycloaddition of nitrones with alkenes, because these cycloadditions create carbon–carbon bonds and carbon–oxygen bonds in a single operation. This chapter independently investigates the methods to solve the stereochemical problem attributable to the geometrical equilibration. In contrast to intermolecular cycloaddition of nitrone, the regiochemical problem can be neglected and diastereoselectivity can also be dramatically improved in intramolecular cycloadditions of nitrones connected with olefin moieties by tethers of appropriate lengths. Tandem transesterification and intramolecular cycloaddition methodology was explored in this class of reactions. The chapter discusses systematic studies on diastereoselectivity in the tandem process, using acyclic secondary allyl alcohols. The 4-hydroxy-4-substituted glutamic acid moiety is the common substructure of several unusual, naturally occurring, biologically important amino acids.