A variety of (R)-phenylglycinol-derived oxazolopiperidone lactams 1-14 were converted to linear-chain enantiopure amino diols 15-26 by reduction with LiNH2BH3 in an unprecedented process involving the simultaneous reductive opening of the oxazolidine and lactam rings. Subsequent removal of the phenylethanol moiety gave enantiopure 5-amino-1-pentanols bearing substituents at the 2-, 3-, 4-, 2,2-, 2,3- 2,4- and 3,4-positions (28-36), which were isolated as their N-Boc derivatives.