Mechanisms of replacement reactions in carbohydrate chemistry

Replacement reactions, mechanisms of, in carbohydrate chemistry, IX, 1-57 Rhamnose,... 

R. U. Lcmieux, Some implications in carbohydrate chemistry of theories relating to the mechanisms of replacement reactions, Adv. Carbohydr. Chem. Biochem 9 1 (1954). H. Tsu-tsumi and Y. Ishido, Syntheses of 1-O-acylaldose derivatives via the corresponding 0-glycosyI-pseudourcas, Carbohydr. Res. Ill 75 (1982). S. Horvat, L. Varga, and J. Horvat, A new utility of O-glycosylpseudoureas for synthesis of glucopeptides and (1— 6)-disaccharides, Synthesis 209 (1986). 

Lederer, E., Glycnlipids of Acid-fast Bacteria, 16, 207-238 Lemieux, R. U., Some Implications in Carbohydrate Chemistry of Theories Relating to the Mechanisms of Replacement Reactions, 9, 1-57 Lemieux, R, U., and Wolfrom, M. L., The Chemistry of Streptomycin, 3, 337-384... 

Some Implications in Carbohydrate Chemistry of Theories Relating to the Mechanisms of Replacement Reactions, R. U. Lemieux, Adv. Carbohydr. Chem., 9 (1954) 1-57. 

SOME IMPLICATIONS IN CARBOHYDRATE CHEMISTRY OF THEORIES RELATING TO THE MECHANISMS OF REPLACEMENT REACTIONS... 

A treatment of the many types of replacement reaction which have received study by carbohydrate chemists would of necessity be superficial and thus defeat the present purpose. Instead, an attempt will be made to gather all information which sheds light on the mechanisms of a few types of reaction. The reactions of 0-acyl derivatives of sugars, glycosides, and glycosyl halides were chosen because of the central role these substances play in carbohydrate chemistry. 

Lemieux has recently discussed the implications in carbohydrate chemistry of theories relating to the mechanisms of replacement reactions, and so treatment of reaction mechanisms in this article has been limited to very recent work. 

The course of the reaction of the poly-O-acylglycosyl halides with nucleophilic reagents has recently received attention. Thus, Lemieux has related the theories of the mechanism of replacement reactions to some reactions in carbohydrate chemistry, and has summarized our knowledge concerning the mechanism of reaction of the poly-O-acylglycosyl halides. Hence, only those aspects of the subject which have become clarified by recent work need be discussed here. 

The life and work of one of the greatest carbohydrate scientists of our time, Raymond U. Lemieux, is recalled here in a sensitive account by Bundle (Edmonton). During a remarkably productive career extending over more than half a century, Lemieux pioneered the application of NMR spectroscopy in chemistry, developed rational approaches for glycosidic coupling, made major contributions to our understanding of three-dimensional carbohydrate structures and protein binding, and made important contributions in the biomedical area. His own articles in these Advances include the chemistry of streptomycin in Volume 3, the mechanisms of replacement reactions in Volume 9, and in Volume 50 a consideration of Emil Fischer s lock and key concept of enzyme specificity. 

---