Asymmetric Syntheses of (−)-ADMJ and (+)-ADANJ: 2‑Deoxy-2-amino Analogues of (−)-1-Deoxymannojirimycin and (+)-1-Deoxyallonojirimycin

The
asymmetric syntheses of (−)-ADMJ and (+)-ADANJ, the 2-deoxy-2-amino
analogues of (−)-1-deoxymannojirimycin and (+)-1-deoxyallonojirimycin,
are described herein. Methodology for the ring-closing iodoamination
of bishomoallylic amines followed by in situ ring-expansion (via intramolecular
ring-opening of the corresponding aziridinium intermediates with a
tethered carbamate moiety) to give oxazolidin-2-ones was initially
optimized on a model system. Subsequent application of this methodology
to two enantiopure bishomoallylic amines (which were produced via
aminohydroxylation of an α,β-unsaturated ester, partial
reduction, and reaction of the corresponding aldehyde with vinylmagnesium
bromide) also proceeded with concomitant N-debenzylation
to afford the corresponding diastereoisomerically pure (>99:1 dr)
oxazolidin-2-ones. Subsequent deprotection of these enantiopure templates
gave (−)-ADMJ and (+)-ADANJ as single diastereoisomers in 16%
and 24% overall yield, respectively.