Showing papers on "Glycal published in 1990"
TL;DR: In this paper, an efficient catalytic procedure for the preparation of 2-deoxyglucosides from glucals without allylic or Ferrier rearrangement using triphenylphosphine hydrobromide and a wide variety of hydroxylic nucleophiles is described.
Abstract: An efficient catalytic procedure for the preparation of 2-deoxyglucosides from glucals without allylic or Ferrier rearrangement using triphenylphosphine hydrobromide and a wide variety of hydroxylic nucleophiles is described
189 citations
146 citations
TL;DR: The palladium-catalyzed coupling reaction of 4,6- O -benzylidene-3- O-tert -butyldimethylsilyl-1-tri- n -butylstannyl-D-glucal as mentioned in this paper with 3,5-dibenzyloxy-2-bromo-, alcohol gave a 78% yield of the C -arylated glycal.
67 citations
TL;DR: It is concluded that steric factors in the glycal and the nucleophile affect only the step of trans-diaxial opening of the intermediate iodonium ion in the iodoalkoxylation of the 6-membered cyclic enol ethers 3,4-di-O-acetyl-L-rhamnal, and related glycal derivatives.
52 citations
TL;DR: In this article, the synthesis of anthracycline C-glycoside constitutes a key development in a synthetic program directed toward synthesis of Cglycosides of the benzo [d] naphtho [1,2-b] pyran-6-one series related to the ravidomycin, gilvocarcin, chrysomycin class of antibiotics.
40 citations
TL;DR: In this paper, large-scale preparations of aldehyde 2 and sulfone 3 representing the C22-C27 and C28-C34 portions of the immunosuppressant FK-506 are described.
Abstract: Efficient large-scale preparations of aldehyde 2 and sulfone 3 representing the C22-C27 and C28-C34 portions of the immunosuppressant FK-506 are described. 2 is available from tri-O-acetyl-D-galactal
36 citations
TL;DR: In this paper, peracetylated glycals with olefins in the presence of Lewis acids gave 2,3-unsaturated C-glycosides in good to excellent yields.
Abstract: Treatment of peracetylated glycals with olefins in the presence of Lewis acids gave 2,3-unsaturated C-glycosides in good to excellent yields. The reaction was completely regioselective and showed a high degree of stereoselectivity leading mostly to the α-isomer. Generally the addition gave the C-glycoside with an unsaturated aglycone. However, with methylenecyclobutane and 1,1 disubstituted linear olefins halogeno derivatives were recovered. The reaction was also performed with acetylated 2-hydroxy glycals. In these conditions keto unsaturated α-C-glycosides were isolated.
34 citations
TL;DR: In this paper, a general procedure for the synthesis of 2-deoxy-β-D-glycosides involving the preparation of 3deoxyulosonic acid glycosides from glycals and their reductive decarboxylation is described.
Abstract: A general procedure for the synthesis of 2-deoxy-β-D-glycosides involving the preparation of 3-deoxyulosonic acid glycosides from glycals and their reductive decarboxylation is described.
29 citations
TL;DR: The addition of a sulphonyl radical to the external double bond of an allyl glycal generates a pro-chiral carbon radical which adds to the glycal double bond with a high diastereoselectivity as discussed by the authors.
28 citations
TL;DR: In this article, a synthesis of (+)-meroquinene is described in which two vicinal vinyl and carboxymethyl groups are efficiently introduced utilizing a carbon framework derived from D-glucose.
28 citations
TL;DR: In this article, an efficient route for selective synthesis of 2-deoxy-β-D-furanosyl C-glycosides has been developed and demonstrated by preparation of the isomers 5-[2′]-deoxyβ-d-ribo- (=arabino)furanosym]-1,3-dimethyl-2,4(1H,3H)-pyrimidinedione and 5]-2-deoxidine]-1.4-anhydro-2.5-hexylsilyl enol ether.
TL;DR: Synthese de dihydroxy-3,4 pyrroline-1 methanol-5 a partir de di-O-benzyl-1 O-isopropylidene-4,5 arabinopyranoside as mentioned in this paper.
TL;DR: In this paper, a reaction of 1−5 in refluxing benzene in the presence of one equivalent of triethylamine or especially pyridine predominantly leads to the formation of 1-cyanoglycals.
TL;DR: Synthese d'anhydro-3,6 O-t-butyldimethylsilyl-4 glucal a partir d'O-tosyl-6 glucal et de butyl chloro dimethyl silane
TL;DR: In this paper, the oxirane ring opening of 2,3-anhydro-pentopyranosides with organo-aluminate reagents is described, and the use of trialkylalkynluminates, deoxy-alkynyl sugars are obtained in good yields.
Abstract: The oxirane ring opening of2,3-anhydro-pentopyranosides and 2,3-anhydro-hexopyranosides with organoaluminate reagents is described. By the use of trialkylalkynlaluminates, deoxy-alkynyl sugars are obtained in good yields. Trialkylalkenylaluminates are less efficient and react only with the pentosides. Vinylmagnesium bromide is used as an alternative reagent for the introduction of a vinyl group
TL;DR: In this paper, a new solution is presented, where the key step is a stereospecific inframolecular iodocyclixation of a complex en01 ether.
TL;DR: The authors showed that nucleophiles selectively attacked the anomeric carbon atom from the same side of the leaving acetoxyl group at C-3 and showed that the reaction of the title compounds with sodium methoxide and sodium borodeuteride was mainly via the SN2′ mechanism.
TL;DR: Some amino, acetylated, and isopropylidene derivatives of leucrose have been prepared and characterised.
Journal Article•
TL;DR: In this paper, a 3,4,6-Tri-O-acetyl-2-azido-2,deoxyaldohexopyranosyl cyanides with the α-D-gluco, β-Dgluc, α -D-galacto, β −D-manno and α −D −manno configurations have been prepared and characterized.
TL;DR: Conjugate addition-rearrangement of N-p-metoxybenzylhydroxylamine to α,β-unsaturated sugar lactones followed by hydrogenolysis of the O-N bond in isoxazolidin-5-ones, and subsequent cyclization of the resulting β-amino acid, provides an effective route to 4-substituted azetidinones.
TL;DR: In this paper, it was shown that resume chloroacetates are susceptible to regioselective deprotectton by hydraztne acetate, and provide an interesting tool for the synthesis of monomers suitably tailored for the preparation of complex oligosaccharides.
TL;DR: The phenolates of coordinating metals are carbon nucleophiles as well as Lewis acids, and this dual reactivity has been exploited in the arylation reactions of electrophilically activated substrates, including hydroxylated carbonyl compounds and glycal derivatives.
Patent•
02 Aug 1990TL;DR: In this article, the stereoselectively preparing a substituted 1,2-anhydrosugar wherein a substituted glycal is converted into a 1 2 anhydrous sugar that is utilized to glycosylate a hydroxyl group containing glycal, is disclosed.
Abstract: Methods of stereoselectively preparing a substituted 1,2-anhydrosugar wherein a substituted glycal is converted into a 1,2-anhydrosugar that is utilized to glycosylate a hydroxyl group containing glycal, are disclosed. Methods of preparing a saccharide multimer wherein a nucleophile is reacted with a substituted 1,2-anhydrosugar having a plurality of non-participating substituents, are disclosed. In addition, methods of preparing stereospecific halo-substituted saccharide multimers by haloglycosylation of a glycosyl donor substituted glycal and a glycosyl acceptor glycal derivative in the absence of water and in the presence of a halonium ion, are disclosed. Methods of preparing stereospecific particle-linked halo-substituted saccharide multimers, by haloglycosylation of a particle-linked nucleophilic hydroxyl group with a substituted glycal and a halonium ion, are also disclosed.
TL;DR: In this paper, peracetylated glycals with olefins in the presence of Lewis acids gave 2,3-unsaturated C-glycosides in good to excellent yields.
Abstract: Treatment of peracetylated glycals with olefins in the presence of Lewis acids gave 2,3-unsaturated C-glycosides in good to excellent yields. The reaction was completely regioselective and showed a high degree of stereoselectivity leading mostly to the α-isomer. Generally the addition gave the C-glycoside with an unsaturated aglycone. However, with methylenecyclobutane and 1,1 disubstituted linear olefins halogeno derivatives were recovered. The reaction was also performed with acetylated 2-hydroxy glycals. In these conditions keto unsaturated α-C-glycosides were isolated.