Über Methylendesoxy‐benzoine, IV. Mitteil.: Über die Umlagerung von Acetylen‐γ‐glykolen mit Acetylchlorid

Fiesselmann, Hans; Sasse, Klaus

doi:10.1002/cber.19560890730

Cited by 21 publications

(3 citation statements)

References 23 publications

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“…The synthesis of the acyclic precursor appears to be relatively unproblematic. The only starting material that is not commercially available is the fragment containing the substituted CC backbone, but this can be prepared in a few steps starting from acetylene, cyclohexanone, and KOH, for example, see ref . Glorius and co-workers have recently discovered an efficient strategy for preparation of highly substituted imidazolium salts, which has been successfully applied in the synthesis of several 4,5-dialkyl-substituted unsaturated imidazolium salts .…”

Section: Resultsmentioning

confidence: 99%

An Evolutionary Algorithm for de Novo Optimization of Functional Transition Metal Compounds

et al. 2012

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Development of functional inorganic and transition metal compounds is usually based on ad hoc qualified guesses, with computational methods playing a lesser role than in drug discovery. A de novo evolutionary algorithm (EA) is presented that automatically generates transition metal complexes using a search space constrained around chemically meaningful structures assembled from three kinds of fragments: a part shared by all structures and typically containing the metal center itself, one or several parts consisting of ligand skeletons, and unconstrained parts that may grow and vary freely. In EA optimizations, using a cost-efficient fitness function based on a linear quantitative structure-activity relationship model for catalytic activity, we demonstrate the capabilities of the method by retracing the transition from the first-generation, phosphine-based Grubbs olefin metathesis catalysts to second-generation catalysts containing N-heterocyclic carbene ligands instead of phosphines. Moreover, DFT calculations on selected high-fitness, last-generation structures from these evolutionary experiments suggest that, in terms of catalytic activity, the structures arrived at by virtual evolution alone compare favorably with existing, highly active catalysts. The structures from the evolution experiments are, however, complex and probably difficult to synthesize, but a set of manually simplified variations thereof might form the leads for a new generation of Grubbs catalysts.

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Section: Resultsmentioning

confidence: 99%

An Evolutionary Algorithm for de Novo Optimization of Functional Transition Metal Compounds

et al. 2012

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“…Ethynylbenzene (EB) 10 was prepared from 1 ,2-dibromoethylbenzene and redistilled over calcium hydride before use, bp 44-45°C/25 mmHg (bp 44oC/25 mmHg). 10 Thiophenol (TP, Wako Pure Chern.…”

Section: Methodsmentioning

confidence: 99%

“…10 Thiophenol (TP, Wako Pure Chern. Industries) was distilled before use, bp 71-72oC/ 15mmHg (7loC/15mmHg).U CC1 4 (Wako Pure Chern.…”

Section: Methodsmentioning

confidence: 99%

Cis Addition Reaction of Thiophenol to Ethynylbenzene and Isomerization of Adduct as a Model of Poly(1,4-benzenedithiol-co-1,4-diethynylbenzene)

Kobayashi

Takayanagi

Ohashi

et al. 1991

Polym J

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ABSTRACT:The mechanisms of cis polyaddition of I ,4-benzenedithiol to 1 ,4-diethynylbenzene were studied by means of a model reaction. As the model reaction, the addition reaction of thiophenol (TP) to ethynylbenzene (EB) was carried out in a NMR glass tube at 34oC under atmosphere of nitrogen and the reaction course was monitored by 1 H NMR method. Under an atmosphere of nitrogen an anti-Markownikoff type product, /J-phenylthiostyrene, with 80% of the cis structure was obtained at various molar ratios of TP to EB. On the other hand, under an atmosphere of air, the addition reaction proceeded almost quantitatively for 4h to form the anti-Markownikofftype adduct, which was initially rich in the cis structure, but cis content decreased gradually to below 50% even after the hundred conversion. In the case of the polyaddition of I ,4-benzenedithiol to 1 ,4-diethynylbenzene, high cis polymers were obtained initially both in solution and also in solid state polymerization. Consequently, the cis polymerization mechanism is the same as the cis adduct formation. MIND013 calculations with intermediates and products indicated that the trans adduct is more stable that the cis adduct, while the intermediate radical for the cis adduct (cis*) is 3.4 kca1 mol-1 lower than that for the trans adduct (trans*). Accordingly, the cis adduct and cis vinylene of the polymer are preferentially formed by kinetic control. The effects of oxygen, thiophenol, AIBN and reaction temperature on the isomerization of the cis to trans adduct were also studied by 1 H NMR method. It was found that the isomerization of the cis to trans adduct hardly occurred in the absence of oxygen, AIBN or phenylthio radical at 34oC. The free radical addition reactions of thiols to acetylenes have been carried out under several conditions. In the case of aromatic acetylene, it was found that the addition reaction took place easily to yield l ,2-disubstituted ethenes in an anti-Markownikoff manner , 1 -3 But, the cis-trans ratio ofproduc_ts was affected by reaction conditions such as temperature, 4 • 5 atmosphere, time and a molar ratio of thiols to acetylenes. 6 Oswald 6 studied the addition reaction of thiophenol to ethynylbenzene at various molar ratios at ooc with UV-irradiation for 2 h. It was found that a high excess of ethynylbenzene over thiophenol (1.1 : 0.05) resulted in the formation of a high cis content mixture (more than 95%). However, a high excess of thiophenol over ethynylbenzene (0.05 : 1.0) resulted in the formation of a low cis content mixture (ca. 16%). These results do not clearly indicate whether the ratio of the cis and trans adducts is controlled by the molar ratio of ethynylbenzene and thiophenol or the cis adduct produced is isomerized to the trans adduct.Previously, the authors reported the poly-1029

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Phenylacetylene

Campbell

2003

Organic Syntheses

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Über Methylendesoxy‐benzoine, IV. Mitteil.: Über die Umlagerung von Acetylen‐γ‐glykolen mit Acetylchlorid

Cited by 21 publications

References 23 publications

An Evolutionary Algorithm for de Novo Optimization of Functional Transition Metal Compounds

An Evolutionary Algorithm for de Novo Optimization of Functional Transition Metal Compounds

Cis Addition Reaction of Thiophenol to Ethynylbenzene and Isomerization of Adduct as a Model of Poly(1,4-benzenedithiol-co-1,4-diethynylbenzene)

Phenylacetylene

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