Short, stereoselective syntheses of 4,5,6-trihydroxylated norleucines: An approach to the synthesis of (+)-bulgecinine

Article abstract of DOI:10.1016/S0040-4039(00)60500-2

Reaction of the L-serine derived zinc reagent 1 with D-isopropylideneglyceryl chloride gave the 4-oxo amino acid 5, which was reduced with high diastereoselectivity to give the trans-lactone 7. Analogous reaction of the D-serine derived zinc reagent gave the the 4-oxo amino acid 6, which was reduced with high diastereoselectivity to give the cis-lactone 8. Conversion of 8 to 11, the enantiomer of the Box-protected analogue 10 of an intermediate in Fleet's synthesis of (-)-bulgecinine, was achieved in two steps.