Intra- and intermolecular photocyclization of vinylbenzo-1,4-quinones

Iwamoto, Hisao; Takuwa, Akio; Hamada, Kensaku; Fujiwara, Ryuji

doi:10.1039/a809530b

Cited by 24 publications

(16 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Inspired by a related reaction, [16] we also studied the photochemistry of 1a (Scheme 4). Irradiation in C 6 D 6 at wavelengths gretaer than 410 nm yielded the dimer 10a.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

1,4-Benzoquinones with Styryl Substituents

2002

View full text Add to dashboard Cite

2-Styryl-1,4-benzoquinone (1) and compounds 2 and 3 containing 1 as a substructure all proved to be highly reactive towards thermal or photochemical [4π + 2π] cyclodimerization reactions. Chemo-, regio-and stereoselective processes lead to dimers (compounds 1−10), which can undergo secondary reactions consisting of the addition of nucleophiles combined with a twofold keto-enol tautomerism (10 Ǟ 12). An alternative process is dehydrogenation/oxidation followed by an intramolecular [4π + 2π] cycloaddition (10 Ǟ 11).

show abstract

“…Inspired by a related reaction, [16] we also studied the photochemistry of 1a (Scheme 4). Irradiation in C 6 D 6 at wavelengths gretaer than 410 nm yielded the dimer 10a.…”

Section: Resultsmentioning

confidence: 99%

“…C q ), 124.3, 124.4 (olefin CH) ppm. MS (EI, 70 eV): m/z (%) ϭ 328 (100) [M ϩ· ], 286(17), 244(16). C20 H 24 O 4 (328.4): calcd.…”

mentioning

confidence: 99%

1,4-Benzoquinones with Styryl Substituents

2002

View full text Add to dashboard Cite

show abstract

“…7,8 The process is believed to be initiated by an electron transfer (ET) followed by a crucial C-H oxidation, similar to photoreduction by amines. 9-12 Intramolecular variants are known, 13,14 but for these reactions a direct hydrogen abstraction (Norrish Type II-like) process cannot be ruled out. For the present purposes, we sought to employ an ET mechanism, as this seemed better suited for longer wavelengths.…”

Section: Introduction and Synthesismentioning

confidence: 99%

Mechanistic Studies of the Photoinduced Quinone Trimethyl Lock Decaging Process

et al. 2017

View full text Add to dashboard Cite

Mechanistic studies of a general reaction that decages a wide range of substrates on exposure to visible light are described. The reaction involves a photochemically initiated reduction of a quinone mediated by an appended thioether. After reduction, a trimethyl lock system incorporated into the quinone leads to thermal decaging. The reaction could be viewed as an electron-transfer initiated reduction of the quinone or as a hydrogen abstraction -Norrish Type II -reaction. Product analysis, kinetic isotope effects, stereochemical labeling, radical clock, and transient absorption studies support the electron transfer mechanism. The differing reactivities of the singlet and triplet states are determined, and the ways in which this process deviates from typical quinone photochemistry are discussed. The mechanism suggests strategies for extending the reaction to longer wavelengths that would be of interest for applications in chemical biology and in a therapeutic setting.

show abstract

“…[14] For example, benzoquinone 13 with an O-benzyl group furnished benzylidene acetal 14 (Scheme 8a). Isopropenylc ongener 15 reacted as well, giving benzofuran 17 [15] via isomerization of the primary product 16 (Scheme 8b). Quinone 18 with ab utenyl side chain gave dihydronaphthalene 21,p resumably via biradicals 19 and 20 (Scheme 8c).…”

Section: Benzoquinones and Naphthoquinonesmentioning

confidence: 99%