Browsing by Author "Cheng, Kuang-Chun"

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A concise synthesis of single components of partially sulfated oligomannans
(2015-01-01)
Mong, Kwok-Kong Tony
;
Shiau, Kai-Sheng
;
Lin, Yu Hsien
;
Cheng, Kuang-Chun
;
Lin, Chun-Hung
A concise synthesis of single components of C2 sulfated oligomannans including trimers, tetramers, and pentamers is reported. The synthesis features the application of the DMF-modulation method for the participatory thiomannoside donors in 1,2-trans alpha-glycosidic bond formation. The obtained oligomannans were fully characterized using H-1, C-13, COSY, and HSQC NMR spectroscopy.
General Homologation Strategy for Synthesis of L-glycero- and D-glycero-Heptopyranoses
(2015-11-20)
Mulani, Shaheen K.
;
Cheng, Kuang-Chun
;
Mong, Kwok-Kong T.
;
應用化學系
;
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.