نتایج جستجو برای: acetals

تعداد نتایج: 957  

Journal: :Annalen der Chemie und Pharmacie 1859

Journal: :Organic & biomolecular chemistry 2014
B V Subba Reddy M Ramana Reddy B Sridhar Kiran Kumar Singarapu

An acetal-initiated Prins bicyclization approach has been developed for the stereoselective synthesis of hexahydrofuro[3,4-c]furan lignans. This also provides a direct way to generate a new series of octahydropyrano[3,4-c]pyran derivatives in a single-step process.

2017
Stefan van der Vorm Herman S Overkleeft Gijsbert A van der Marel Jeroen D C Codée

Glycosylations of 4,6-tethered glucosazide donors with a panel of model acceptors revealed the effect of acceptor nucleophilicity on the stereoselectivity of these donors. The differences in reactivity among the donors were evaluated in competitive glycosylation reactions, and their relative reactivities were found to be reflected in the stereoselectivity in glycosylations with a set of fluorin...

Journal: :Organic & biomolecular chemistry 2012
Milovan Stojanović Rade Marković Erich Kleinpeter Marija Baranac-Stojanović

Syntheses of thiazolidine-fused heterocycles via exo-mode cyclizations of vinylogous N-acyliminium ions incorporating heteroatom-based nucleophiles have been examined and discussed. The formation of (5,6)-membered systems was feasible with all nucleophiles tried (O, S and N), while the closing of the five-membered ring was restricted to O- and S-nucleophiles. The closure of a four-membered ring...

Journal: :Angewandte Chemie 2021

Abstract A new family of carbon‐bound boron enolates, generated by a kinetically controlled halogen exchange between chlorocatecholborane and silylketene acetals, is described. These C−boron enolates are demonstrated to activate 1,3‐enyne substrates in the presence Pd 0 /Senphos ligand complex, resulting first examples carboboration reaction an alkyne with enolate‐equivalent nucleophiles. Highl...

2016
Lingchun Li Chuanfa Ni Fei Wang Jinbo Hu

Aromatic cation activation is a useful strategy to promote deoxyfunctionalization; however, the deoxyfluorination of alcohols with cyclopropenium cation remains an unsolved problem due to the weak nucleophilicity of fluoride ion. Here we report the use of 3,3-difluoro-1,2-diarylcyclopropenes (CpFluors) as easily accessible and reactivity-tunable deoxyfluorination reagents. The electronic nature...

Journal: :Organic & biomolecular chemistry 2007
Jia-Li Jiang Jia Ju Ruimao Hua

1,2-Disubstituted-3,4-dihydronaphthalenes could be conveniently synthesized with high yields by the cycloaddition reactions of easily available vinylarenes with electron-deficient alkynes such as dimethyl, or diethyl acetylenedicarboxylate, methyl phenylpropiolate in the presence of DMF.DMA (N,N-dimethylformamide dimethyl acetal) as organocatalyst.

Journal: :Chemical communications 2016
Xidong Guan Kaiqi Fan Tongyang Gao Anping Ma Bao Zhang Jian Song

We construct a simple-structured super gelator with multi-stimuli responsive properties, among which anion responsiveness follows the Hofmeister series in a non-aqueous system. Versatile applications such as being rheological and self-healing agents, waste water treatment, spilled oil recovery and flexible optical device manufacture are integrated into a single organogelator, which was rarely r...

Journal: :Journal of lipid research 1965
V MAHADEVAN F PHILLIPS W O LUNDGERG

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