抄録
Although microwave irradiation has been used in chemical reactions as an efficient heating tool since 1986, we have found that microwave also contribute other factors while studying carbohydrate-related syntheses. 1) With microwave irradiation under Lewis acid conditions, methyl glycosides could behave as glycosyl donors. 2) In a case of synthesis Lewis X, microwave irradiation even at low temperatures was very effective as reducing byproducts and side-reactions. Especially, galactosylation for 4-OH in a fucosyl glucosamine acceptor has proceeded in high yield without producing byproducts, e.g., cleavage of the fucosyl bond or nucleophilic rearrangement of methylthio group. 3) Based on a preliminary study of microwave effect for coupling Fmoc-threonine having acetylated-Core2 to alanine onto supported resin, we successfully synthesized oligopeptide which consisted of twenty of amino acid residues with five of trisaccharides, a partial structure of MUC1 glycoprotein, in shorter time and higher yields. In addition, we also revealed that benzyl protection of glutamic acid was not suitable for basic microwave condition. 4) Microwave could activate azido groups and resulted to accelerate reductions by PPh_3 and Staudinger Ligations.
