Anionic inverse electron-demand 1,3-dipolar cycloaddition of nitrones with ynolates.: Facile stereoselective synthesis of 5-isoxazolidinones leading to β-amino acids

[GRAPHICS] The inverse electron-demand 1,3-dipolar cycloaddition of nitrones with ynolates, followed by quenching with t-BuOH, produced substituted 5-isoxazolidinones with good trans-selectivity. These products were easily converted into beta-amino acids.