Conformations of Bridged Diphenyls. V. A Nuclear Magnetic Resonance Comparative Study of the Conformations of Identically Substituted Diphenyl Ethers, Sulfides, Methanes, Ketones, Sulfoxides, and Sulfones

Benjamins, Harm; Chandler, W. David

doi:10.1139/v74-093

Cited by 12 publications

(5 citation statements)

References 5 publications

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“…The photolysate was worked up to afford a mixture of methyl 3-acetylbenzoate (72%) and methyl 4-acetylbenzoate (28%). The latter was reported to show 'H NMR signals at 8.15 and 7.97 ppm (24). Photolysis of ACHBF?…”

Section: General Procedures Of Photoadditionmentioning

confidence: 96%

The photoaddition of 1,3-diketonatoboron difluorides with benzene derivatives

Chow¹,

Ouyang²

1991

Can. J. Chem.

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The boron difluoride complexes of 2-acetylcyclohexanone, 2-acetylcyclopentanone, and acetylacetone (abbreviated as ACHBF2, ACPBF2, and AABF2) were irradiated in the presence of benzene to give the 1:1 adducts as the primary photoadducts; for certain BF2 complexes, toluene, chlorobenzene, benzonitrile, and methyl benzoate were also used as substrates. The 1,5-diketone photoadducts were assumed to form by a [2+2] photocycloaddition followed by cyclobutane opening and hydrolysis to give 1,2 adducts. They undergo a variety of secondary thermal reactions, probably acid catalyzed, to give enol ethers, enol acetates, acetophenones, and ketonylacetophenones. The efficiency of these secondary reactions determines the final products. Photoaddition with a monosubstituted benzene preferentially occurs at the 3,4 bond without regioselectivity. Under oxygen, ACHBF2 photolytically reacts with benzene to give a secondary oxidation product of a 10-membered cyclic alkylphe-none, which is proven by X-ray crystallographic analysis to have the benzene ring and carbonyl group in orthogonal orientation. It is shown that the singlet excited state ACHBF2 initiates the photoaddition, probably through the formation of the benzene exciplex, which could be detected by its emission. While the Stern–Volmer rates are small, the quantum yield of photoaddition products is as high as 0.12–0.19 under limiting conditions. Key words: [2+2] photocycloaddition, non-planar alkanophenone, macrocyclic alkanophenone, boron difluoride complexes, photoaddition to benzenes.

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Section: General Procedures Of Photoadditionmentioning

confidence: 96%

The photoaddition of 1,3-diketonatoboron difluorides with benzene derivatives

Chow¹,

Ouyang²

1991

Can. J. Chem.

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“…This compound is known. 33 1,3,5-Trimethyl-2-(4-(trifluoromethyl)benzyl)benzene (3k). White solid, yield 99% (165.3 mg); 94% (157.0 mg); Eluent: Petroleum ether/EtOAc = 40/1.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Conversion of Aryl Aldehydes to Benzyl Iodides and Diarylmethanes by H₃PO₃/I₂

Xiao

Xiang

et al. 2021

J. Org. Chem.

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For the first time, H 3 PO 3 was used as both the reducing reagent and the promotor in the reductive benzylation reactions with aryl aldehydes. By using a H 3 PO 3 /I 2 combination, various aromatic aldehydes underwent iodination reactions and Friedel−Crafts type reactions with arenes via benzyl iodide intermediates, readily producing benzyl iodides and diarylmethanes in good yields. Intramolecular cyclization reactions also took place, giving the corresponding cyclic compounds. This new strategy features easy-handling, low-cost, and metal-free conditions.

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“…For ortho-substituted diphenyl ethers and many other bridged diphenyls there is ample evidence to suggest that the twist, H-inside conformations are the most stable (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26). Figure 3, which was prepared in the manner of Gust and Mislow (6), displays all eight possible twist conformers for a triply ortho-substituted diphenyl ether.…”

Section: Introductionmentioning

confidence: 99%

Conformations of Bridged Diphenyls. VI. Substituent Effects and Internal Rotation in Triply Ortho-substituted Diphenyl Ethers

Benjamins¹,

Dar²,

Chandler³

1974

Can. J. Chem.

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Experimental evidence is presented to support the hypothesis that, in triply ortho-substituted diphenyl ethers, conformer interconversion involves both rings. The free energy barrier, measured by p.m.r., is sensitive to substituent effects arising in the ring having only one ortho substituent. The exceptionally high barrier found when an ortho iodine is present is consistent with the existence of a substituent-inside intermediate occurring during conformer conversion.

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Conformations of Bridged Diphenyls. V. A Nuclear Magnetic Resonance Comparative Study of the Conformations of Identically Substituted Diphenyl Ethers, Sulfides, Methanes, Ketones, Sulfoxides, and Sulfones

Cited by 12 publications

References 5 publications

The photoaddition of 1,3-diketonatoboron difluorides with benzene derivatives

The photoaddition of 1,3-diketonatoboron difluorides with benzene derivatives

Conversion of Aryl Aldehydes to Benzyl Iodides and Diarylmethanes by H₃PO₃/I₂

Conformations of Bridged Diphenyls. VI. Substituent Effects and Internal Rotation in Triply Ortho-substituted Diphenyl Ethers

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Conformations of Bridged Diphenyls. V. A Nuclear Magnetic Resonance Comparative Study of the Conformations of Identically Substituted Diphenyl Ethers, Sulfides, Methanes, Ketones, Sulfoxides, and Sulfones

Cited by 12 publications

References 5 publications

The photoaddition of 1,3-diketonatoboron difluorides with benzene derivatives

The photoaddition of 1,3-diketonatoboron difluorides with benzene derivatives

Conversion of Aryl Aldehydes to Benzyl Iodides and Diarylmethanes by H3PO3/I2

Conformations of Bridged Diphenyls. VI. Substituent Effects and Internal Rotation in Triply Ortho-substituted Diphenyl Ethers

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Conversion of Aryl Aldehydes to Benzyl Iodides and Diarylmethanes by H₃PO₃/I₂