GLYCOSYLIDENE CARBENES .8. CRYSTAL-STRUCTURE OF A CYCLIC, N-ACETYLALLOSAMINE-DERIVED ALKOXY-ALKYL-DIAZIRINE

The crystal structure of 2-acetamido-1,5-anhydro-1-azi-3-O-benzyl-4,6-O-benzylidene-1,2-dideoxy-D-allitol (6) is reported, and the structural parameters of the diazirine moiety are compared with those of other free diazirines for which structural information has been determined or calculated previously. Lengthening of the N=N bond and shortening of the C-N bonds can be observed as the substituents at the C-atom of the diazirine ring become more electronegative and/or stronger pi-electron donors. This is consistent with descriptions of the bonding nature of diazirines and similar observations made on substituted cyclopropanes.