Abstract: N, N-Dibenzyl-protected a-amino-aldehydes 1 undergo non-chelationcontrolled aldol additions of 1-phenoxy-1-trimethylsiloxyethylene 2 followed by p-lactone formation and dyotropic rearrangement, all three reactions being catalyzed by MgClZ. The products, 4- substituted 3-amino-r-lactones 3, are stereochemically pure (de and ee> 99%).
