Browsing by Author "Mong, Kwok-Kong T."

Now showing 1 - 4 of 4

A mild and general method for preparation of alpha-glycosyl chlorides
(2009-08-05)
Chang, Chih-Wei
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Chang, Shih-Sheng
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Chao, Chin-Sheng
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Mong, Kwok-Kong T.
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應用化學系
A mild and efficient chlorination method for production of glycosyl chlorides is first described which employs inexpensive trichlorotriazine (TCT) and DMF as a chlorination reagent and is compatible with typical acid-labile hydroxyl protecting functions. The scope and limitations, reaction mechanism and its application in the sequential glycosylations are discussed. (C) 2009 Elsevier Ltd. All rights reserved.
General Homologation Strategy for Synthesis of L-glycero- and D-glycero-Heptopyranoses
(2015-11-20)
Mulani, Shaheen K.
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Cheng, Kuang-Chun
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Mong, Kwok-Kong T.
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應用化學系
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Department of Applied Chemistry
A general and stereospecific homologation strategy for the synthesis of heptopyranosides is reported. The strategy employs the Wittig olefination and proline-catalyzed a-aminoxylation to achieve one carbon elongation and stereoselective hydroxylation at the C6 position, respectively. The l-glycero- and d-glycero-heptopyranosides can be obtained with nearly perfect stereoselectivity. Further study reveals the difference in the chemical shift of the C6 proton of l/d-glycero-heptopyranosyl diastereomers, which is found to be useful for assignment of the configuration of heptopyranosides.
Joined use of oxazolidinone and desymmetric amino protection: a new strategy for protection of glucosamine
(2010-04-07)
Lin, Shih-Che
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Chao, Chin-Sheng
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Chang, Chiu-Ching
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Mong, Kwok-Kong T.
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應用化學系
Joined use of N-benzyl oxazolidinone and N-benzyl-N-benzyloxycarbonyl (N-BnCbz) desymmetric amino-protecting function is reported. The new synthetic approach enables the facile preparation of type I and type 2 LacNAc disaccharides in satisfactory yields. One-pot deprotection of N-BnCbz and O-benzyl ether is achieved by hydrogenolysis under mild conditions. (C) 2010 Elsevier Ltd. All rights reserved.
Versatile acetylation of carbohydrate substrates with bench-top sulfonic acids and application to one-pot syntheses of peracetylated thioglycosides
(2008-04-07)
Chao, Chin-Sheng
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Chen, Min-Chun
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Lin, Shih-Che
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Mong, Kwok-Kong T.
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應用化學系
Inexpensive and readily available sulfonic acids, p-toluenesulfonic acid, and sulfuric acid are versatile and efficient catalysts for the peracetylation of a broad spectrum of carbohydrate substrates in good yield and in a practical time frame. Three appealing features in sulfonic acid-catalyzed acetylation of free sugars were explored including (1) suppression of furanosyl acetate formation for D-galactose and L-fucose; (2) high yielding chemoselective acetylation of sialic acid under appropriate conditions; and (3) peracetylation of amino sugars with different amino protecting functions. Simple one-pot two step acetylation-thioglycosidation methods for the expeditious synthesis of p-tolyl per-O-acetyl thioglycosides were also delineated. (C) 2008 Elsevier Ltd. All rights reserved.