Synthesis Of Cyclobutanes Research Articles

ChemInform Abstract: Synthesis of Cyclobutenes by Highly Selective Transition‐Metal‐Catalyzed Ring Expansion of Cyclopropanes.

AbstractChemInform 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.

Synthesis of Cyclobutenes by Highly Selective Transition‐Metal‐Catalyzed Ring Expansion of Cyclopropanes

Kleine Ringe: Eine hoch chemoselektive, regioselektive und stereospezifische Synthese polysubstituierter Cyclobutene durch katalysatorgesteuerte Ringerweiterung von Cyclopropanen über Metallcarbenzwischenstufen wird beschrieben. Übergangsmetallkatalysatoren haben einen deutlichen Einfluss auf die Reaktivität und Selektivität der Metallcarbenzwischenstufe dieser Ringerweiterungsreaktion.

Synthesis of Cyclobutenes by Highly Selective Transition‐Metal‐Catalyzed Ring Expansion of Cyclopropanes

Synthesis of Cyclobutenes by Highly Selective Transition‐Metal‐Catalyzed Ring Expansion of Cyclopropanes

Synthesis of Cyclobutanes via a Stereoselective Ring Contraction

Synthesis of Cyclobutanes via a Stereoselective Ring Contraction

Synthesis of Cyclobutanes

AbstractChemInform 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.

Photochemical studies on ladderane formation from conjugated esters in solution or solid phase

This letter describes a combined photochemical and X-ray crystallographic study of routes for the synthesis of cyclobutane or ladderane structures by a [2+2]-cycloaddition pathway and leads to a clearer definition of the 3-D structural requirements for such processes in the solid state.

Photocycloaddition of (Z)‐1,2‐Dichloroethylene to Enantiopure 2(5H)‐Furanones: An Efficient Strategy for the Diastereoselective Synthesis of Cyclobutane and Cyclobutene Derivatives.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of cyclobutane fused γ-butyro lactones through intramolecular [2+2] photocycloaddition. Application in a formal synthesis of grandisol

An approach to the synthesis of cyclobutane fused γ-butyrolactones is described. The key step involves a Cu(I) catalysed intramolecular (2+2) photocycloaddition of 1,6-dienes in which the two alkene units are tethered through acetal oxygen. The resulting bicyclic lactols were then oxidised to provide the title compounds. The synthetic potential of these lactones is illustrated by a formal synthesis of grandisol.

Nickel(0)-Catalyzed [2 + 2] Annulation of Electron-Deficient Allenes. Highly Regioselective Synthesis of Cyclobutanes

The nickel-catalyzed [2 + 2] annulations of electron-deficient allenes proceed efficiently in a highly regioselective manner under very mild conditions to give the head-to-head cyclodimerization products, bismethylenecyclobutanes, as single isomers in good to fair yields. We also carried out the stoichiometric reaction of these allenes in the presence of Ni(0) complexes and elucidated the mechanism of this highly selective reaction.

ChemInform Abstract: A Highly Enantioselective and Diastereoselective Synthesis of Cyclobutanes via Boronic Esters.

AbstractChemInform 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.

Intramolecular [2+2] photocycloaddition for the direct stereoselective synthesis of cyclobutane fused γ-lactols

A direct stereoselective route for the synthesis of γ-lactols fused to cyclobutanes via intramolecular [2+2] photocycloaddition of 1,6-dienes is described.

A highly enantioselective and diastereoselective synthesis of cyclobutanes via boronic esters.

[formula: see text] Deprotonation of enantiopure (R,R)-1,2-dicyclohexyl-1,2-ethanediol 1-chloro-4-cyanobutylboronates 5 with LDA followed by treatment with anhydrous magnesium bromide yields (R)-(trans-2-cyanocyclobutyl)boronic esters 7 in high diastereomeric and enantiomeric purity. No cyclobutane formation has been observed in the absence of at least a catalytic amount of magnesium halide.

A new approach to functionalized cyclobutanes: Stereoselective synthesis of the enantiomers of grandisol and fraganol

Enantiomerically enriched (+)-grandisol and (+)-fraganol were synthesized using as the key step a new stereoselective synthesis of cyclobutanes fused to γ-lactones by a stereochemically-controlled intramolecular alkylation of α-benzenesulfonyl-γ-lactones. This method provides a way to synthesize the enantiomers in a straightforward manner.

ChemInform Abstract: Synthesis of Cyclobutane and Cyclopentane Compounds Using Homogeneous Metal Complex Catalysts

AbstractChemInform 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.

Cathodic synthesis of cyclobutanes

Cathodic electrolysis of compounds with an activated methylene group in the presence of 1,3-dibromopropane affords 1,1-disubstituted cyclobutanes.

Synthesis of cyclobutane and cyclopentane compounds using homogeneous metal complex catalysts

Synthesis of cyclobutane and cyclopentane compounds using homogeneous metal complex catalysts

Synthese von Cyclobutan durch Dehalogenierung von 1,4‐Dihalogenbutanen mit Alkalimetalldämpfen. Zur Relation von radikalischen und metallorganischen Reaktionskanälen

Synthesis of Cyclobutane by Dehalogenation of 1,4‐Dihalogenbutane in Alkali‐Metall‐Bathway. The Relation of Radical and Metallorganic Reaction‐channels.Gasphase dehalogenation of 1,4‐dichloro‐, 1‐chlor‐4‐bromo, 1,4‐dibrombutanes and 1,4‐dibrompentane by Na/K vapors produces cyclobutane resp. methylcyclobutane with selectivities of resp. 55.5, 46.7, 32.0 and 17 moles/100 moles. Side products of the reaction are ethylene and hydrogen, yields of which increase with increasing temperature and rising degree of substitution of chlorine by bromine. A mechanism is discussed in which the initiation step is the generation of halobutyl radicals of the type H2Ċ(CH2)2CH2X (X = Cl, Br) which are reacting further in two ways – by formation of tetramethylenediradical, splitting off the second halogen atom, or by the formation of the metallorganic compound 1‐kalium‐4‐halogenbutane, which further cyclisize to cyclobutane splitting off KX.Using some methods of theoretical chemistry such as quantumchemical calculations based on ab initio (STO‐3G) and semiempirical (AM1) structures, on the relative energies of conformeres of halogenbutylradicals and on models of the metallorganic intermediates, but also by conformation calculations of the content of rotation isomers of the intermediate formed, the correlation between the two reaction channels in dependence of the type of halogen was estimated. The calculations showed, that only about 20% of cyclobutane are generated by the radical pathway. The high predominance of the metallorganic channel in the case of 1,4‐dichlorbutaneis caused by the high lifetime of chlorobutyl radicals in comparison with his bromoanalogues.

ChemInform Abstract: Synthesis of Cyclobutenes by the Novel Photochemical Ring Contraction of 4‐Substituted 2‐Amino‐3,5‐dicyano‐6‐phenyl‐4H‐pyrans.

A partir de l'amino-7 phenyl-9 oxa-8 spiro [4.5] decadiene-6,9 (I), obtention de l'amide de l'acide dicyano-1,3 phenyl-2 spiro [3.4] octene-2 carboxylique-1, du benzenepropiolonitrile et de l'amide de l'acide cyclopentylidene-2 nitrolo-3 propionique. A partir d'autres derives de (I) on obtient principalement du benzenepropiolonitrile

Synthesis of cyclobutenes by the novel photochemical ring contraction of 4-substituted 2-amino-3,5-dicyano-6-phenyl-4H-pyrans [Erratum to document cited in CA111(3):23119v

Synthesis of cyclobutenes by the novel photochemical ring contraction of 4-substituted 2-amino-3,5-dicyano-6-phenyl-4H-pyrans [Erratum to document cited in CA111(3):23119v

Synthesis of cyclobutenes by the novel photochemical ring contraction of 4-substituted 2-amino-3,5-dicyano-6-phenyl-4H-pyrans

A partir de l'amino-7 phenyl-9 oxa-8 spiro [4.5] decadiene-6,9 (I), obtention de l'amide de l'acide dicyano-1,3 phenyl-2 spiro [3.4] octene-2 carboxylique-1, du benzenepropiolonitrile et de l'amide de l'acide cyclopentylidene-2 nitrolo-3 propionique. A partir d'autres derives de (I) on obtient principalement du benzenepropiolonitrile