The synthesis of the two diasteromeric meso forms of 4-amino-3,5-heptanediol (3R,4r,5S)-1a and (3S,4s,5R)-1b and the two pseudo C-2-symmetric enantiomers (3S,5S)-1c and (3R,5R)-ent-1c is described by stereocontrolled ethylmagnesium bromide or diethylzinc addition to diastereomeric alpha-amino-beta-hydroxy pentanal derivatives 9 and 13. These derivatives were prepared from (2S)-N,N-dibenzyl-O-TBS-serinal 2, that in turn were obtained from (L)-serine. (C) 1998 Elsevier Science Ltd. All rights reserved.