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Stereoselective Access (stereoselective + access)

Distribution by Scientific Domains

Chemistry	100%

Distribution within Chemistry

Organic Chemistry	62%
General & Introductory Chemistry	37%

Selected Abstracts

Anodic Oxidation and Organocatalysis: Direct Regio- and Stereoselective Access to meta -Substituted Anilines by ,-Arylation of Aldehydes,

ANGEWANDTE CHEMIE, Issue 1 2010

Synthese mit Potenzial: Durch anodische Oxidation und organokatalytische ,-Arylierung von Aldehyden mit elektronenreichen Aren sind meta -substituierte Aniline und Dihydrobenzofurane in guten Ausbeuten und mit hervorragenden Enantioselektivitäten zugänglich (siehe Schema; Pg=Schutzgruppe). Dieses neue Konzept verbindet Organokatalyse und Elektrochemie. [source]

ChemInform Abstract: Stereoselective Access to Substituted [(E)- or (Z)-1-(Trifluoromethyl)allyl]amines.

CHEMINFORM, Issue 30 2008
Guillaume Magueur
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Allylcyanation of Alkynes: Regio- and Stereoselective Access to Functionalized Di- or Trisubstituted Acrylonitriles.

CHEMINFORM, Issue 41 2006
Yoshiaki Nakao
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

ChemInform Abstract: Stereoselective Access to Hydroxy Oxetanes and Tetrahydrooxepines Through Isomerization of Oxiranyl Ethers.

CHEMINFORM, Issue 37 2001
Alessandro Mordini
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Asymmetric Synthesis of Isoquinoline Derivatives from Amino Acids

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 4 2005
Oxana Sieck
Abstract Reaction of isoquinolines 1 with N -arylsulfonylamino acid fluorides 2 provides a highly stereoselective access to new dihydroimidazo[2,1 -a]isoquinolin-3-ones 5 via intermediate N -acylisoquinolinium salts 3. Addition reactions to the en-amine double bond, such as hydrogenation or epoxidation with dimethyldioxirane, leads to tetrahydroimidazo[2,1 -a]isoquinoline-3-ones 6, 7 and oxiranes 8, respectively. Opening of the oxirane ring of the 8 with nucleophiles allows the synthesis of hydroxytetrahydroimidazo[2,1 -a]isoquinolin-3-ones 10 or 12 or of the polycyclic 1,4-dioxane 13 in high stereoselectivity. The regioselectivity of the oxiran ring opening depends on the kind of nucleophile and the conditions. Reaction of dihydroisoquinoline with O -TBDMS-mandelic acid chloride 15 leads to a tetrahydrooxazolo[2,3 -a]isoquinoline 17 with opposite facial selectivity as compared with dihydroimidazo[2,1 -a]isoquinolin-3-ones 5. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

Alkynyl Group as Activating Group: Base-Catalyzed Diastereoselective Domino Reactions of Electron-Deficient Enynes

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009
Wenbo Li
Abstract This paper describes a base-catalyzed domino reaction of electron-deficient enynes with malonate-derived ,,,-unsaturated esters and ketones, which provides a rapid, stereoselective access to multi-functionalized cyclopentanes and inden-5(6,H)-ones in high yields. In this reaction, the alkynyl group of the enyne acts as an activating group rather than a reacting group. [source]

Anionic Cross-Coupling Reaction of ,-Metallated Alkenyl Sulfoximines and Alkenyl Sulfoximines with Cuprates Featuring a 1,2-Metal-Ate Rearrangement of Sulfoximine-Substituted Higher Order Alkenyl Cuprates and an ,-Metallation of Alkenyl Sulfoximines by Cuprates

CHEMISTRY - A EUROPEAN JOURNAL, Issue 21 2008
Hans-Joachim Gais Prof.
Abstract (E)- and (Z)-configured ,-lithioalkenyl sulfoximines, which are available through lithiation of the corresponding alkenyl sulfoximines, undergo a anionic cross-coupling reaction (ACCR) with organocuprates with formation of the corresponding alkenyl cuprates and sulfinamide. The alkenyl cuprates can be trapped by electrophiles. The ACCR presumably proceeds via the formation of a higher-order sulfoximine-substituted alkenyl cuprate, which undergoes a 1,2-metal-ate rearrangement whereby the sulfoximine group acts as the nucleofuge. The parent (E)- and (Z)-configured alkenyl sulfoximines suffer upon treatment with an organocuprate a deprotonation at the ,-position with formation of the corresponding ,-cuprioalkenyl sulfoximines. These derivatives also enter into a similar ACCR with organocuprates. The ACCR of sulfoximines substituted homoallylic alcohols allows a stereoselective access to enantio- and diastereopure substituted homoallylic alcohols. [source]

A New, Efficient and Stereoselective Synthesis of Tricyclic and Tetracyclic Compounds by Samarium Diiodide Induced Cyclisations of Naphthyl-Substituted Arylketones,An Easy Access to Steroid-Like Skeletons

CHEMISTRY - A EUROPEAN JOURNAL, Issue 21 2007
Francesca Aulenta Dr.
Abstract In this report, we present the application of samarium diiodide induced cyclisations of naphthyl-substituted ketones towards an easy and stereoselective access to tri- and tetracyclic-functionalised compounds. Typical naphthalene derivatives were studied to investigate the scope and limitations of this novel cyclisation process. The model substrates studied demonstrate that the samarium ketyl cyclisations are essentially restricted to the formation of six-membered rings. The diastereoselectivity of these reactions is strongly influenced by the connection of the alkyl side chain to the naphthalene core. ,-Naphth-1-yl-substituted ketones furnished cyclisation products, such as 17 or 22,26, as single diastereomers, whereas ,-naphth-2-yl-substituted precursors gave mixtures of diastereomers,as demonstrated by the conversion of model compound 10 into tricyclic products 18,a/18,b, or that of cyclohexanone derivative 33 into tetracyclic diastereomers 34,a/34,b. Cyclic ketones as ketyl precursors furnished steroid-like tetracyclic skeletons; however, due to the cis/cis fusion of rings B/C and C/D these products have an "unnatural" bowl-like shape. Several of the cyclisation products have been identified by X-ray analyses, which not only proved the constitutions, but also the relative configurations and the preferred conformations. Steroid analogue 23 was subjected to subsequent transformations, which demonstrate that the styrene-like double bond of such compounds can be used for further structural diversification. First attempts to synthesise related azasteroids by incorporating nitrogen atoms into the ketone moiety are also reported. Thus, pyrrolidine derivatives 44 and 47 as well as piperidine derivatives 50 and 52 were subjected to samarium diiodide induced cyclisations. The expected tetracyclic products 48, 49,a/49,b, 51 and 53,a/53,b were obtained in moderate to good yields. The stereoselectivities observed follow the rules already established for the all-carbon precursors. The resulting products, bearing a nitrogen atom in ring D, are interesting azasteroid analogues with "unnatural" configuration. [source]