An efficient approach to new dihydroxyquinolizidines

Using d-glyceraldehyde acetonide as a starting material, a four-step synthesis of enantiomerically pure 3,4-dihydroxyquinolizidines is described. The key steps of the synthesis consist of a Mitsunobu ring-closing reaction and the subsequent reduction of a pyridinium ring.

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(2S,3R)-3,4-O-Isopropylidene-1-(2′-pyridyl)-2,3,4-trihydroxy-butaneC12H16NO3[α]D20=+24 (c 1, CH2Cl2)Source of chirality: d-glyceraldehyde acetonideAbsolute configuration: (2S,3R)

(2R,3R)-3,4-O-Isopropylidene-1-(2′-pyridyl)-2,3,4-trihydroxy-butaneC12H16NO3[α]D20=-12 (c 1, CH2Cl2)Source of chirality: d-glyceraldehyde acetonideAbsolute configuration: (2R,3R)

(2R,3R)-2-Benzyloxy-3,4-O-isopropylidene-1-(2′-pyridyl)-2,3,4-trihydroxybutaneC19H22NO3[α]D20=+35 (c 1, CH2Cl2)Source of chirality: d-glyceraldehyde acetonideAbsolute configuration: (2R,3R)

(2S,3R,9aR)-Octahydro-1H-quinolizine-2,3-diolC9H17NO2[α]D20=-21 (c 0.52, CH3OH)Source of chirality: d-glyceraldehyde acetonideAbsolute configuration: (2S,3R,9aR)

(2S,3S)-2-O-Benzyl-3-hydroxy-3,4-dihydro-1H-quino-lizidinium tetrafluoroborateC16H18NO2BF4[α]D20=-16 (c 2.3, CH3OH)Source of chirality: d-glyceraldehyde acetonideAbsolute configuration: (2S,3S)

(2R,3R,9aS)-Octahydro-1H-quinolizin-2,3-diolC9H17NO2[α]D20=-6.5 (c 0.38, CH3OH)Source of chirality: d-glyceraldehyde acetonideAbsolute configuration: (2R,3R,9aS)