When treated with Lewis acids, 2- or 3-vinyl- or -phenylsiloxyaminoacetals generated the corresponding imines or iminium ions which in turn underwent smooth intramolecular amidoalkylation to afford anti-1,2- or -1,3-aminoalcohol derivatives in very high chemical yields and excellent diastereomeric ratios. Applying the reaction, Z-allo-L-threonine and (±)-N-ethoxycarbonyl-anti-γ-hydroxynorvaline were successfully synthesized.
