Synthesis, Crystal Structure, and Conformation of Methyl 6‐Deoxy‐2,3‐O‐ isopropylidene‐α‐D‐manno‐heptofuranoside

Abstract Methyl 6-deoxy-2,3-O-isopropylidene-α- d -manno-heptofuranoside (9) has been synthesised from the acetyliron complex 2 by a sequence of reactions involving deprotonation of 2, its reaction with aldehyde 5, decomplexation, isolation of 7, and reduction to 9. Compound 9 crystallises in the orthorhombic system, space group P212121, with cell dimensions: a = 6.097(1), b = 7.942(1), c = 26.862(3) A. The intensity data were collected with a Syntex P21 diffractometer. The structure was solved by direct methods and refined by the full-matrix, least-squares procedure, resulting in R = 0.049. The furanoside and 2,3-O-isopropylidene rings are characterised by envelop conformations 5E and E3, respectively. Relatively strong intermolecular hydrogen bonss were observed in the crystal structure.