Synthesis and Transformation of Pyrrole C-Glycoconjugates

Enantiomerically pure open chain ol-pyrrylalditols 2, 3,5, and 7 and dinuclear dipyrrylmethanes 8-10 bearing chiral alditolyl bridges have been synthesized by direct coupling of glyceraldehyde I, arabinose 4, and glucose 6 with pyrrole metal reagents based on magnesium-titanium(IV) or magnesium-cerium(III) blends. The mononuclear and dinuclear compounds were then exploited as precursors for the preparation of either cyclic C-nucleoside analogs 11-14, or the sugar porphyrin 16.