87470-73-3Relevant articles and documents
Reagent controlled stereoselective synthesis of teichoic acid α-(1,2)-glucans
Berni, Francesca,Enotarpi, Jacopo,Overkleeft, Hermen S.,Van Der Marel, Gijs,Wang, Liming,Codée, Jeroen D. C.
, p. 2038 - 2050 (2020/03/27)
The stereoselective construction of 1,2-cis-glycosidic linkages is key in the assembly of biologically relevant glycans, but remains a synthetic challenge. Reagent-controlled glycosylation methodologies, in which external nucleophiles are employed to modu
Secondary amine salt catalyzed controlled activation of 2-deoxy sugar lactols towards alpha-selective dehydrative glycosylation
Ghosh, Titli,Mukherji, Ananya,Srivastava, Hemant Kumar,Kancharla, Pavan K.
, p. 2870 - 2875 (2018/05/03)
A new organocatalytic glycosylation method exploiting the lactol functionality has been disclosed. The catalytic generation of glycosyl oxacarbenium ions from lactols under forcible conditions via weakly Br?nsted-acidic, readily available secondary amine salts affects the diastereoselective glycosylation of 2-deoxypyranoses and furanoses. This operationally simple iminium catalyzed activation of 2-deoxy hemi-acetals is a potential alternative to the existing cumbersome methods that need specialized handling. The mechanisms for this unique transformation and kinetic/thermodynamic effects have been discussed based on both experimental evidence and theoretical studies.
Oxidative activation of C-S bonds with an electropositive nitrogen promoter enables orthogonal glycosylation of alkyl over phenyl thioglycosides
Kitowski, Annabel,Jiménez-Moreno, Ester,Salvadó, Míriam,Mestre, Jordi,Castillón, Sergio,Jiménez-Osés, Gonzalo,Boutureira, Omar,Bernardes, Gon?alo J.L.
, p. 5490 - 5493 (2017/11/07)
A method for the selective activation of thioglycosides that uses the N+-thiophilic reagent Omesitylenesulfonylhydroxylamine (MSH) as a promoter is presented. The reaction proceeds via anomeric mesitylensulfonate intermediates, which could be isolated and fully characterized by placing a fluorine atom at the C2 position. In the presence of a soft Lewis acid, glycosylation reaction proceeds at ambient temperature with good yields. It is further demonstrated that it is possible to orthogonally activate S-ethyl in the presence of S-phenyl donors, enabling the design of sequential glycosylation strategies.
Hydrogenolytic cleavage of naphthylmethyl ethers in the presence of sulfides
Adero, Philip O.,Jarois, Dean R.,Crich, David
, p. 11 - 16 (2017/07/04)
With the aid of a series of model thioether or thioglycoside containing polyols protected with combinations of benzyl ethers and 2-naphthylmethyl ethers it is demonstrated that the latter are readily cleaved selectively under hydrogenolytic conditions in the presence of the frequently catalyst-poisoning sulfides. These results suggest the possibility of employing 2-naphthylmethyl ethers in place of benzyl ethers in synthetic schemes when hydrogenolytic deprotection is anticipated in the presence of thioether type functionality.
In(III) triflate-catalyzed detritylation and glycosylation by solvent-free ball milling
Kumar, Vajinder,Yadav, Narender,Kartha, K.P. Ravindranathan
, p. 18 - 26 (2014/10/16)
A highly efficient In(III) triflate-assisted method for the detritylation of O-trityl derivatives of carbohydrates, phenols, and alcohols using solvent-free mechanochemical method is described. In the case of carbohydrates, further reaction in the presence of an acceptor sugar leads to highly efficient glycosylation in the same pot resulting in the formation of the desired glycoside-product in very high yields. The method was applied successfully to the synthesis of a combinatorial library of galactose-based (1,6)-linked cyclohexa-, hepta-, and octasaccharides on gram scale.
HClO4-silica-catalysed regioselective opening of benzylidene acetals and its application towards regioselective HO-4 glycosylation of benzylidene acetals in one-pot
Dara, Saidulu,Saikam, Varma,Yadav, Mahipal,Singh, Parvinder Pal,Vishwakarma, Ram A.
supporting information, p. 93 - 96 (2014/05/20)
Here we report a high-yielding method for the regioselective reductive ring opening of 4,6-O-benzylidene acetals of hexapyranosides using inexpensive and robust HClO4-SiO2 as the acidic catalyst and triethylsilane as the hydride dono
Selective deprotection method of N -phenylcarbamoyl group
Akai, Shoji,Tanaka, Rika,Hoshi, Hidekazu,Sato, Ken-Ichi
, p. 8802 - 8808 (2013/09/24)
We report an improved method for the selective deprotection of the N-phenylcarbamoyl group, which yields the corresponding alcohol without affecting other protecting groups. Deprotection was performed using di-tert-butyl dicarbonate and tetra-n-butylammon
α-Selective organocatalytic synthesis of 2-deoxygalactosides
Balmond, Edward I.,Coe, Diane M.,Galan, M. Carmen,McGarrigle, Eoghan M.
, p. 9152 - 9155 (2012/10/29)
Alpha rules: A thiourea acts as an efficient organocatalyst for the glycosylation of protected galactals to form oligosaccharides containing a 2-deoxymonosaccharide moiety (see scheme). The reaction is highly stereoselective for α-linkages and proceeds by way of a syn-addition mechanism. Copyright
Stereodirecting effect of the pyranosyl C-5 substituent in glycosylation reactions
Dinkelaar, Jasper,De Jong, Ana Rae,Van Meer, Robert,Somers, Mark,Lodder, Gerrit,Overkleeft, Herman S.,Codee, Jeroen D. C.,Van Der Marel, Gijsbert A.
supporting information; experimental part, p. 4982 - 4991 (2009/10/09)
(Chemical Equation Presented) The stereodirecting effect of the glycosyl C-5 substituent has been investigated in a series of D-pyranosyl thioglycoside donors and related to their preferred positions in the intermediate 3H4 and
Sonochemistry: A powerful way of enhancing the efficiency of carbohydrate synthesis
Deng, Shenglou,Gangadharmath, Umesh,Chang, Cheng-Wei Tom
, p. 5179 - 5185 (2007/10/03)
Using sonication as a means of facilitating organic reactions in carbohydrate chemistry was explored under the conditions used for traditional organic synthesis. An array of representative reactions, including hydroxy group manipulation (acylation, protection/deprotection, acyl group migration), thioglycoside synthesis, azidoglycoside synthesis, 1,3-dipolar cycloaddition and reductive cleavage of benzylidene, commonly used in the synthesis of carbohydrate derivatives was examined. A series of glycosylation reactions that employ thioglycosides, glycosyl trichloroacetimidate, glycosyl bromide and glycosyl acetate as the glycosyl donors was also examined. Our results demonstrate that sonication can significantly shorten the reaction time, enhance the reactivity of reactant and lead to superior yield and excellent stereoselectivity. More importantly, a general protocol of glycosylation may finally be developed. Sonication is compatible to the conditions used for traditional organic synthesis. We believe that sonication can also be applied to other areas of synthetic processes.