Synthesis of a Spiro D-Proline Analogue Bearing D-Fructose

A bicyclic spiro analogue of D-proline was synthesized from perbenzylated methyl D-fructoside. The synthetic steps required first a three carbon chain elongation at the anomeric position by C-glycosylation, secondly the introduction of the amino function at C-1, and finally the cyclization to the pyrrolidine ring and introduction of the carboxylic group.