86728-74-7Relevant academic research and scientific papers
Stereoselective template-directed C-glycosidation. Synthesis of 5-membered oxygen heterocycles via cation-mediated intramolecular cyclization reactions
Craig,Craig, Donald,Pennington,Pennington, Mark W.,Warner,Warner, Peter
, p. 8539 - 8542 (1993)
Construction of 5-membered oxygen heterocycles by intramolecular template- directed C-glycosidation is described. Alkylation of thioglycoside 5 with enone 6 followed by enol etherification gave cyclization substrates 8. Compound 8a underwent silver(I) trifluoromethanesulfonate-mediated ring- closure to give a 1.7:1 mixture of 9α and 9β; isomer 8s gave an 8.5:1 ratio. Some derivatization reactions of the bicyclic products are described.
Photo-Induced Dihydroxylation of Alkenes with Diacetyl, Oxygen, and Water
Masuda, Yusuke,Ikeshita, Daichi,Murakami, Masahiro
, (2021/02/09)
Herein reported is a photo-induced production of vicinal diols from alkenes under mild reaction conditions. The present dihydroxylation method using diacetyl (= butane-2,3-dione), oxygen, and water dispenses with toxic reagents and intractable waste generation.
Arylboronic acid-mediated glycosylation of 1,2-dihydroxyglucoses
Izumi, Sanae,Kobayashi, Yusuke,Takemoto, Yoshiji
, p. 350 - 362 (2019/07/31)
- We explored direct dehydrative coupling of tetrahydro-2H-pyran-2,3-diol or a 1,2-dihydroxy sugar with various alcohols using a range of arylboronic acids. Among the catalysts, 2-borono-4-trifluoromethylbenzoic acid efficiently promoted acetalization of tetrahydro-2H-pyran-2,3-diol. Ferroceniumboronic acid showed the best catalytic activity for glycosylation of the 1,2-dihydroxy sugar. The major products were 1,2-cJi-a-D-glucopyranosides.
A chemoenzymatic synthesis of deoxy sugar esters involving stereoselective acetylation of hemiacetals catalyzed by CALB
Villo, Ly,Kreen, Malle,Kudryashova, Marina,Metsala, Andrus,Tamp, Sven,Lille, Uelo,Pehk, Tonis,Parve, Omar
experimental part, p. 44 - 51 (2011/07/30)
An extension of the scope of the chemoenzymatic strategy for the synthesis of stereochemically pure pyranose deoxy sugar esters of different carboxylic acids has been achieved. The objective of the work was to extend the strategy to the synthesis of furanose deoxy sugar derivatives and additionally, to N-Boc-protected amino acid esters. With all used carboxylic acids (deoxycholic acid, α-methoxyphenylacetic acid, N-Boc-l-phenylalanine and N-Boc-l-tyrosine) the lipase-catalyzed stereoselective acetylation of furanose or pyranose hemiacetal moiety as a key step afforded one desired stereochemically pure acetylated hemiacetal deoxy sugar ester in high de.
Template-directed intramolecular C-glycosidation. Formation of tetrahydrofurans and application to the synthesis of a higher-order sugar
Craig, Donald,Pennington, Mark W.,Warner, Peter
, p. 13495 - 13512 (2007/10/03)
Cation-mediated cyclisation reactions of silyl enol ether-containing thioglycosides give bicyclic ketotetrahydrofurans. Cyclisation of an analogous 3-phenyl-2-propenyl ether-containing substrate gives an intermediate in the total synthesis of the higher-order sugar 2,3-dideoxy-D- manno-2-octulopyranosonic acid.
The Mechanism of the β-Acyloxyalkyl Radical Rearragement. Part 2: β-Acyloxytetrahydropyranyl Radicals
Beckwith, Athelstan L. J.,Duggan, Peter J.
, p. 1673 - 1680 (2007/10/02)
The rate of rearrangement of the 3-butanoyloxytetrahydropyran-2-yl radical (4) to give the product 5 of 1,2-migration of the acyloxy group has been determined by competition against the reaction of 4 with tributylstannane.The rate constant is larger than that for rearrangement of the acylic radical 18 but less than that for the substituted cholestanyl radical 19.Experiments with 17O- and 18O-labelled substrates indicate that the rearrangement of 4 proceeds with ca. 33percent transposition of the ether and carbonyl oxygen atoms, while there is also a small amount of scrambling in the product 12 formed by direct reduction of 4.The isotope labelling studies and the Arrhenius parameters (log 1> = 12.7, Eact = 58 kJ mol-1) are consistent with the view that the reaction proceeds, at least in part, via dissociation into a tight anion radical-cation pair 22.A pathway via the three-membered transition sturcture 21 might also be involved.
Methods for Pyranoannulation: An Approach to a New Class of Polyethers
Kozikowski, Alan P.,Ghosh, Arun K.
, p. 3017 - 3019 (2007/10/02)
Several methods have been developed for fusing a pyran ring to an existing pyran ring structure such that the ring oxygens assume a vicinal (ethylene glycol) relationship.The tricyclic structure 13, a previously unknown substance, was prepared through a combination of these methods.
Oxidation of Cyclic Ethers by Iodine Tris(trifluoroacetate). - Synthesis and NMR Analysis of Trifluoroacetylated Deoxypentopyranoses and of 3-Deoxy-threo-pentose
Buddrus, Joachim,Herzog, Helmut,Bauer, Hans
, p. 1950 - 1958 (2007/10/02)
Oxidation of tetrahydro-2H-pyran (2) by iodine tris(trifluoroacetate) (1) yields the dideoxypentopyranose derivatives 3a-b and the ring-contracted compound 4.Similarly, 3-(trifluoroacetoxy)tetrahydro-2H-pyran (5) is oxidized to yield the deoxypentopyranose derivatives 6a-d and the ring-contracted compound 7.Hydrolysis of 6b yields 3-deoxy-threo-pentose 8 which is thus available in 3 or 4 steps, respectively, instead of 9 steps before.The solution of 8 in water contains the 4 ring-tautomers 8a-d. - Analysis of the 1H NMR spectra of 6a-d reveals that (a) the anomeric effect of the trifluoroacetoxy group is larger than that of the acetoxy group and (b) that the 1H signals are shifted downfield by trifluoroacetoxy groups (OX) located in γ or even in δ position, provided that H and OX have a well-defined orientation.
