Synthesis of and NMR studies on the four diastereomeric 1-deoxy-d-ketohexoses

The four 1-deoxy-d-ketohexoses—1-deoxy-d-psicose, 1-deoxy-d-fructose, 1-deoxy-d-sorbose and 1-deoxy-d-tagatose—were synthesised by methyl lithium addition to suitably protected and readily available pentonolactones. The 1-deoxy-l-ketohexoses are available from the enantiomeric lactones. The NMR studies on aqueous solutions of each diastereomer show that the relative amounts of open chain ketones, α- and β-pyranoses, and α- and β-furanoses vary considerably; at least four different species are identifiable from each equilibrium.

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5-O-tert-Butyldimethylsilyl-2,3,-O-isopropylidene-d-ribono-1,4-lactoneC4H26O5SiEe = 100%[α]D23=-49.0 (c 1.2, CHCl3)Source of chirality:d-ribose as starting material

6-O-tert-Butyldimethylsilyl-1-deoxy-3,4-O-isopropylidene-d-psicofuranoseC15H30O5SiEe = 100%[α]D21=-13.1 (c 1.0, CHCl3)Source of chirality:d-ribose as starting material

1-Deoxy-3,4-O-isopropylidene-d-psicoseC9H16O5Ee = 100%[α]D21=-15.0 (c 1.1, CHCl3)Source of chirality:d-ribose as starting material

2-O-tert-Butyldimethylsilyl-3,4-O-isopropylidene-d-arabinono-1,5-lactoneC14H26O5SiEe = 100%[α]D21=-87.2 (c 1.0, CHCl3)Source of chirality:d-arabinose as starting material

3-O-tert-Butyldimethylsilyl-1-deoxy-4,5-O-isopropylidene-d-fructoseC15H30O5SiEe = 100%[α]D21=-61.3 (c 1.0, CHCl3)Source of chirality:d-arabinose as starting material

1-Deoxy-4,5-O-isopropylidene-d-fructoseC9H16O5Ee = 100%[α]D21=-102.2 (c 1.0, CHCl3)[α]D23=-137.9 (c 1.0, MeOH)Source of chirality: d-arabinose as starting material

5-O-tert-Butydimethylsilyl-2,3-O-isopropylidene-d-lyxono-1,4-lactoneC14H26O5SiEe = 100%[α]D21=+58.0 (c 1.0, CHCl3)Source of chirality: d-galactose as starting material

6-O-tert-Butydimethylsilyl-1-deoxy-3,4-O-isopropylidene-d-tagatofuranoseC15H30O5SiEe = 100%[α]D20=+5.0 (c 1.0, CHCl3)Source of chirality: d-galactose as starting material

1-Deoxy-3,4-O-isopropylidene-d-tagatoseC9H16O5Ee = 100%[α]D21=+21.0 (c 1.0, CHCl3)Source of chirality: d-galactose as starting material

1-Deoxy-d-psicoseC6H12O5Ee = 100%[α]D21=+1.0 (c 1.0, H2O)Source of chirality: d-ribose as starting material

1-Deoxy-d-fructoseC6H12O5Ee = 100%[α]D21=-80.5 (c 1.0, H2O)Source of chirality: d-arabinose as starting material

1-Deoxy-d-tagatoseC6H12O5Ee = 100%[α]D22=-13.0 (c 2.0, H2O)Source of chirality: d-galactose as starting material

2,3,5-Tri-O-benzyl-d-xylono-1,4-lactoneC26H26O5Ee = 100%[α]D20=89.0 (c 1.0, CHCl3)Source of chirality: d-xylose as starting material

3,4,6-Tri-O-benzyl-1-deoxy-d-sorbofuranoseC27H30O5Ee = 100%[α]D20=-11.0 (c 1.0, CHCl3)Source of chirality: d-xylose as starting material

1-Deoxy-d-sorboseC6H12O5Ee = 100%[α]D20=+49.0 (c 1.0, H2O)Source of chirality: d-xylose as starting material