Stereoselective Electro‐2‐deoxyglycosylation from Glycals
作者:Miao Liu、Kai‐Meng Liu、De‐Cai Xiong、Hanyu Zhang、Tian Li、Bohan Li、Xianjin Qin、Jinhe Bai、Xin‐Shan Ye
DOI:10.1002/anie.202006115
日期:2020.8.24
report a novel and highly stereoselective electro‐2‐deoxyglycosylation from glycals. This method features excellent stereoselectivity, scope, and functional‐group tolerance. This process can also be applied to the modification of a wide range of natural products and drugs. Furthermore, a scalable synthesis of glycosylated podophyllotoxin and a one‐pot trisaccharide synthesis through iterative electroglycosylations
Substituent Dependence of the Diastereofacial Selectivity in Iodination and Bromination of Glycals and Related Cyclic Enol Ethers
作者:Antonella Boschi、Cinzia Chiappe、Antonietta De Rubertis、Marie Françoise Ruasse
DOI:10.1021/jo000799x
日期:2000.12.1
azide trapping of any cationic intermediate, it is concluded that these brominations which do not go through an ionic intermediate are concerted additions of bromine and methanol with very loose rate- and product-determining transition states. Finally, the substituent conformation at C-4 influences drastically the stereoselectivity in all these brominations. Evidence for alpha-anomeric control of the
An efficient and benign method for the regio- and stereoselective synthesis of halohydrins and β-halo ethers from dihydropyrans, dihydrofurans and anhydro sugars in the presence of a halide salt and hydrogen peroxide is presented with tungstate-exchanged takovite as oxidation catalyst.
Stereoelectronic control in two-step additions to initiated by electrophilic halogens
作者:Giuseppe Bellucci、Cinzia Chiappe、Felicia D'Andrea、Giacomo Lo Moro
DOI:10.1016/s0040-4020(97)00064-1
日期:1997.3
The product distribution obtained in electrophilic reactions of Br-2, N-bromosuccinimmide (NBS), tetrabutylammonium tribromide, tetrabutylammonium bromochloride, NBS-Et(3)N . 3HF, ICI-NaN3 and MCPBA-KF with tri-O-benzyl-D-glucal in aprotic and protic solvents have been determined by NMR. The results have been rationalized on the basis of the stereoelectronic alpha-anomeric effect able to stabilize the transition state related to the electrophilic or nucleophilic step. (C) 1997 Elsevier Science Ltd.
Classon, Bjoern; Garegg, Per J.; Samuelsson, Bertil, Canadian Journal of Chemistry, 1981, vol. 59, p. 339 - 343
作者:Classon, Bjoern、Garegg, Per J.、Samuelsson, Bertil