Regioselective One-Pot Protection of d-Glucosamine
摘要:
A highly regioselective one-pot transformation of 2-azido2-deoxy-1,3,4,6-tetra-O-trimethylsilyl-D-glucopyranose via sequential additions of various reagents was systematically studied, yielding the fully protected derivatives and the 1-, 3-, 4-, as well as 6-alcohols, respectively.
study of various metal trifluoromethanesulfonates as efficient catalysts in the regioselectivereductiveringopening of benzylidene acetals is described, including the effects of solvents, reducing agents, and temperature. These catalysts are found to be effective in cleaving the 4,6‐O‐acetalrings of hexopyranosides at either O4 or O6, respectively. When used in conjunction with a 1 M solution of
combination with cyanuric chloride (TCT) has been used to obtain 6-hydroxy-4-benzyl ether derivatives from 4,6-benzylidene acetals of carbohydrates. The nature of hydride donor determines the regioselectivity of acetal opening. High regioselectivity, scope for using a broad range of substrates, functional group tolerance, mild reaction conditions, easy handling process, inexpensive reagents and wide application