beta-Oxy-alpha-diazo-carbonyl compounds. Part 5: An improved synthesis of beta-hydroxy-alpha-diazo esters derived from monosaccharides and synthetic applications in the chemistry of 3-deoxy-2-ulosonic acids

Reactions of ethyl 2-diazoacetate with aldehydo sugars and monosaccharide d erivatives in their hemiacetal form are reported. The use of diethyl zinc l ed to an improvement of yields and shorter reaction times compared with neu tral conditions as previously described. The resulting products represent p otentially useful substrates for the synthesis of 3-deoxy-2-keto-ulosonic a cid derivatives. Thus, diazo derivatives from D-mannose were transformed in to Ko and 3-epimer Ko derivatives in a straightforward process by reaction with mCPBA. (C) 2001 Published by Elsevier Science Ltd.