3-(Aminomethyl)-2-(carboxymethyl)isoxazolidinyl nucleosides: building blocks for peptide nucleic acid analogues

The synthesis of orthogonally protected 3-(aminomethyl)-2-(carboxymethyl)isoxazolidinyl thymine, a convenient monomer for the preparation of novel isoxazolidinyl peptide nucleic acid analogues, has been achieved through enantioselective 1,3-dipolar cycloaddition between N-glycosyl nitrones and vinyl acetate.