Generation of Methylene by Photolysis of Hydrocarbons

Richardson, D. B.; Durrett, L. R.; Martin, James; Putnam, William E.; Slaymaker, S. C.; Dvoretzky, Isaac

doi:10.1021/ja01090a047

Cited by 51 publications

(16 citation statements)

References 2 publications

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“…55 In addition, due to the cyclopropyl group adjacent to the aromatic ring, 3b is prone to dissociate, giving methylene, as reported in similar cases. 49 The prolonged irradiation at 266 nm then gives rise to the excitation of 3b in the final reaction step 50,51 and to dissociation into nph and excited methylene, rapidly captured by the solvent to give methylcyclohexane, as already shown for the direct mechanism.…”

Section: The Journal Of Physical Chemistry Amentioning

confidence: 73%

Photochemical Reactivity of 1,6-Methano[10]annulene

et al. 2017

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1,6-Methano [10]annulene solutions in cyclohexane have been subjected to continuous and pulsed UV irradiation. Photolysis occurs in both cases, giving naphthalene as a minor and major product, respectively. The wavelength dependence of the reaction in solution indicates that the photochemical process occurs, exciting 1,6-methano[10]annulene in the second and third singlet electronic excited states. The reaction kinetics has been determined under pulsed irradiation. From the time dependence of concentrations, along with support of density functional theory calculations and early published data, two mechanisms are proposed for naphthalene production. Reaction steps such as direct migration of the bridging methylene of 1,6-methano[10]annulene to cyclohexane and 1,6-methano[10]annulene isomerization to benzotropilidene have been identified. The calculated energy diagrams relative to the ground and lowest excited states allow one to relate these steps to processes such as electrocyclic closure and sigmatropic shift. The norcaradienic form of 1,6-methano [10]annulene results in the critical species for methylene migration and the sigmatropic [1,5] shift. The present results and those arising from photolysis in the gas phase are good examples of the photochemical reactivity of 1,6-methano[10]annulene.

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Section: The Journal Of Physical Chemistry Amentioning

confidence: 73%

Photochemical Reactivity of 1,6-Methano[10]annulene

et al. 2017

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“…Volger reported that tricycle 26 , which is in equilibrium with its norcaradiene tautomer 26′ , reacts in the presence of [Rh(CO) 2 Cl] 2 to give hexamethylbenzene quantitatively (Scheme A) . Later, Gassman described the possibility of using highly electrophilic PhWCl 3 –EtAlCl 2 to carry out a cyclopropane–alkene metathesis via retro-cyclopropanation of simple ethylcyclopropane (Scheme B). , Furthermore, several groups disclosed the photolytic decarbenation reaction of phenanthrene derivatives 27 (Scheme C). − …”

Section: Construction Of 3-membered Rings Catalyzed By Goldmentioning

confidence: 99%

“… 304 , 305 Furthermore, several groups disclosed the photolytic decarbenation reaction of phenanthrene derivatives 27 ( Scheme 17 C). 306 − 309 …”

Section: Construction Of 3-membered Rings Catalyzed By Goldmentioning

confidence: 99%

Gold-Catalyzed Synthesis of Small Rings

et al. 2020

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Three- and four-membered rings, widespread motifs in nature and medicinal chemistry, have fascinated chemists ever since their discovery. However, due to energetic considerations, small rings are often difficult to assemble. In this regard, homogeneous gold catalysis has emerged as a powerful tool to construct these highly strained carbocycles. This review aims to provide a comprehensive summary of all the major advances and discoveries made in the gold-catalyzed synthesis of cyclopropanes, cyclopropenes, cyclobutanes, cyclobutenes, and their corresponding heterocyclic or heterosubstituted analogs.

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“…10 Typical reactions of the diazo group include loss of N 2 to form transient carbenes 13 or carbenoid species in either the singlet or triplet state, [14][15][16] which may react intramolecularly or intermolecularly in a variety of modes. [17][18][19][20][21][22][23][24][25][26][27] Singlet carbenes, generally formed thermally or photochemically, tend to react indiscriminately, [28][29][30][31][32] whereas triplet (diradical) carbenes 33,34 show greater selectivity. 35,36 Carbenoids, formed catalytically by the action of copper salts on diazo compounds, [37][38][39][40] are of lower energy, typically reacting with unsaturated functions to form cyclopropanes, 41,42 and may display carbocation-like character.…”

Section: Introductionmentioning

confidence: 99%