Condensation between unprotected aldoses and dibenzoylmethane catalyzed by NaHCO3 in the cosolvents EtOH and H2O (4:1) under microwave irradiation gave aryl ketone β-C-glycosides 6b–i in higher yields (from 50% with C-riboside 6g up to 99% with C-glucoside 6b) and better anomeric selectivities (β-configuration >95%) in a shorter reaction time (90 min), compared with previous conventional methodologies. This method provides an attractive alternative to the existing means for the preparation of high value ketone β-C-glycosides.Condensation between unprotected aldoses and dibenzoylmethane catalyzed by NaHCO3 in the co-solvents EtOH–H2O (4:1) under microwave irradiation gave aryl ketone β-C-glycosides 6b-i with higher yields (from 50% with C-riboside 6g up to 99% with C-glucoside 6b) and better anomeric selectivities (β-configuration >95%) in a shorter reaction time (90 min), compared with previous conventional methodologies.

An efficient three-step synthesis of d-mannoheptulose was successfully accomplished from 2,3,4,5,6-penta-O-benzyl-d-mannose. First, an olefinated sugar was prepared from 2,3,4,5,6-penta-O-benzyl-d-mannose via a Wittig reaction. Second, the key step, a 2-hydroxyoxirane product was unexpectedly obtained by oxidation of the olefinated sugar with potassium permanganate in aqueous acetone. Finally d-mannoheptulose was synthesized through debenzylation and hydrolysis in an overall yield of 39%.