Total Synthesis of 1,5-Dideoxy-1,5-iminoalditols

Enantiomerically pure 1,5-dideoxy-I ,5-imino-D -glycero-D -allo-heptitol
(10) has been synthesized in ca. 9% overall yield by utilizing 2,3-O-isopropylidene-Dglyceraldehyde-
N-benzylimine (1) as a chiral source and 2-(trimethylsiloxy)furan
(2) as a homologative reactant. The opening move was the preparation of properly
protected seven-carbon butenolide 4. followed by diastereoselective anticisdihydroxylation
of the lactone double bond and furanose-to-azapyranose ring
expansion. This generated a piperidine intermediate 7, the stereochemistry of which
was secured by a single crystal X-ray analysis of its diacetate 9.