Total syntheses of (+)- and (−)-1-deoxynojirimycin (1,5-dideoxy-1,5-imino-d- and l-glucitol) and of (+)- and (−)-1-deoxyidonojirimycin (1,5-dideoxy-1,5-imino-d- and l-iditol) via furoisoxazoline-3-aldehydes

The isoxazoline obtained by 1,3-dipolar cycloaddition of 2,2-diethoxyacetonitrile N-oxide to furan was converted into enantiomerically pure (−)-(3aS,5S,6S,6aR)- and (+)-(3aR,5R,6R,6aS)-3a,5,6,6a-tetrahydro-5,6-isopropylidenedioxyfuro[2,3-d]isoxazole-3-carbaldehyde, (−)-5 and (+)-5, respectively, through resolution with (1S,2S)-1,2-diphenylethylenediamine. The aldehydes 5 are required as latent 1,5-iminohexitol moieties in cross-aldolizations towards imino-C-disaccharides. In order to establish absolute configurations of 5, and to probe the projected uses, (+)-5 was converted into (+)-1-deoxynojirimycin [(+)-1, 3 steps, 58%] and into (−)-1,5-dideoxy-1,5-imino-l-iditol [(−)-2, 4 steps, 40%] adopting stereoselective routes. Similarly, (−)-1,5-dideoxy-1,5-imino-l-glucitol ((−)-1) and (+)-1,5-dideoxy-1,5-imino-d-iditol ((+)-2) were obtained with the same ease.