Asymmetric 1,3-Dipolar Cycloaddition of Cyclic Nitrones to Crotonic Acid Derivatives Bearing Chiral Auxiliaries. Synthesis of Optically Active β-Amino Acids, (+)-Sedridine, and (+)-Hygroline

All articles of this category Asymmetric 1,3-dipolar cycloaddition of cyclic nitrones with optically active crotonic acid derivatives bearing chiral auxiliaries in the presence of zinc iodide gives bicyclic isoxazolidines, which are precursors of ß-amino acids, highly stereoselectively. By using these reactions (+)-sedridine ( 4 ) and (+)-hygroline ( 5 ) can be synthesized readily.