Nascent-HBr-Catalyzed Removal of Orthogonal Protecting Groups in Aqueous Surfactants
作者:Shilpi Gupta、Smritilekha Bera、Dhananjoy Mondal
DOI:10.1021/acs.joc.9b02561
日期:2020.2.21
the hydrophobic core of the confined micellar medium in aqueous surfactant is described for the first time. The sustained-release nascent-HBr enabled the chemoselective cleavages of acid-sensitive orthogonal functionalities present in carbohydrates, amino alcohols, and hydroxylated acyclic compounds in good to excellent yields.
Synthesis and removal of trichloroethylidene derivatives of carbohydrates
作者:Nusrat Jahan、Maxine J. Kirshenbaum、T. Bruce Grindley
DOI:10.1016/j.carres.2022.108545
日期:2022.5
Two hexoses and two pentoses have been reacted with two equivalents of trichloroacetaldehyde using boron trifluoride etherate as promoter in dioxane at reflux. The major products are exo-1,2-O-trichloroethylidenealdofuranoses in every case in varying yields, identical to the products previously obtained in lower yields using sulfuric acid or hydrochloric acid as promoter in trichloroacetaldehyde as
Synthesis and Glycosidic Reaction of 1,2-Anhydromanno-, Lyxo-, Gluco-, and Xylofuranose Perbenzyl Ethers
作者:Yuguo Du、Fanzuo Kong
DOI:10.1080/07328309608005693
日期:1996.9
Stereospecific synthesis of 1,2-anhydromanno-, lyxo-, gluco-, and xylofuranose perbenzyl ethers was successfully achieved via intramolecular S(N)2 reaction of the corresponding C-1 alkoxide with C-2 bearing tosyloxy group. The key intermediates, furanose 2-sulfonates, were prepared from the corresponding 1,2-diols and tosyl chloride under phase transfer conditions in good yields. Condensation of the anhydro sugars with 1,2:3,4-di-O-isopropylidene-alpha-D-galactopyranose or N-benzyloxycarbonyl L-serine methyl ester in the absence of catalyst gave 1,2-trans-linked glycofuranosides in high yield.