Mannose differs from glucose in confguration at C-2. All hydroxyl groups are equatorial inb-D-glucopyranose; the hydroxyl at C-2 is axial in b-D-mannopyranose.(c)The conformational depiction ofb-L-mannopyranose begins in the same way as that ofb-D-mannopyranose.L-Mannose is the mirror image ofD-mannose.To rewrite the eclipsed conformation of L-mannose in a way that permits hemiacetal forma-tion between the carbonyl group and the C-5 hydroxyl, C-5 is rotated 120°in the clockwisesense.Translating the Haworth formula into a proper conformational depiction requires that a choicebe made between the two chair conformations shown.(d)The Fischer projection formula for L-ribose is the mirror image of that for D-ribose.CHOCH2OHHHHOHOHOHd-RiboseCHOCH2OHHOHOHOHHHl-RiboseEclipsed conformation of l-ribose isoriented properly for ring closure.
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This note was uploaded on 10/03/2011 for the course CHM 2210 taught by Professor Reynolds during the Fall '01 term at University of Florida.