The Total Synthesis of C-Glycosides with Completely Resolved Seven-Carbon Backbone Polyol Stereochemistry: Stereochemical Correlations and Access to L-Configured and Other Rare Carbohydrates

The de novo synthesis of a full set of hydroxymethyl C‐glycosides from only two precursors is described. The seven‐carbon target molecules contain five stereocentres and bridge the stereochemical gap between natural D‐configured and non‐natural L‐configured series of hexoses. Key steps include hydroxylation, differential protection, stereoselective reduction and desymmetrization of 8‐oxabicyclo[3.2.1]oct‐6‐enes. C‐Terminus differentiation and C‐terminus excision of the seven‐carbon polyol backbone lead to hexoses, including those of the L‐series. A stereochemical and genetic classification of C‐glycosides is presented. The de novo synthesis of a full set of hydroxymethyl C‐glycosides (see scheme) from only two precursors is described. The seven‐carbon target molecules contain five stereocentres and bridge the stereochemical gap between natural D‐configured and non‐natural L‐configured series of hexoses. A stereochemical and genetic classification of C‐glycosides is presented.