Lewis-Acid-Catalyzed Synthesis of Amadori and Heyns Dipeptides.

Amadori and Heyns reactions are milestone reactions of
carbohydrate chemistry. There have been little efforts in
transforming these rearrangement reactions to useful catalytic
tools. We demonstrate herein, synthesis of Amadori and Heyns
dipeptides via Lewis acid-catalysis. The accomplished catalytic
Amadori and Heyns synthesis is devoid of protection and
deprotection steps either for dipeptides or for reducing sugar.
By the developed catalytic method we achieved, tagatose
Amadori dipeptides via reaction of D-galactose with dipeptides
including L-alanyl glycine, L-alanyl-L-alanine, L-alanyl-L-glutamine, glycyl-L-phenylalanine, L-leucyl glycine, L-pheynylalanylL-valine in excellent yield. In addition, Heyns dipeptides were
also achieved by employing D-fructose and dipeptides consisting of L-alanyl glycine, L-alanyl-L-alanine, L-alanyl-L-glutamine,
glycyl-L-phenylalanine, L-leucyl glycine. The realized Lewis acid
mediated catalytic method is practical, quantitative, and avoids
chromatographic separation techniques.