Solvent Dependent Photochemical Reactions of 3-(2-Alkylphenyl)-2,2-dimethyl-3-oxopropanoates and Their Related Compounds

Saito, Masaichi; Kamei, Yumiko; Kuribara, Kanae; Yoshioka, Michikazu; Hasegawa, Tadashi

doi:10.1021/jo981433b

Cited by 10 publications

(8 citation statements)

References 25 publications

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“…3 Irradiation of a hexane solution of 1-(o-methylphenyl)-2,2dimethyl-1,3-diketone resulted in benzocyclobutenol. 4 Irradiation of 2,2-dimethyl-1,3-diphenylpropan-1,3-dione in the presence of TEA led to the formation of anti-2,2-dimethyl-1,3-diphenylcyclopropan-1,3-diol 5 as the main product. This reaction proceeds via one-electron transfer from the excited state of the diketone to the ground state of amine, followed by rearrangement of the resulting anion radical.…”

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confidence: 99%

Photocyclization of 2-Chloro-Substituted 1,3-Diarylpropan-1,3-diones to Flavones

Košmrlj

Ŝket

2007

Org. Lett.

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The photochemical behavior of 2-halo-substituted 1,3-diarylpropan-1,3-dione strongly depends on the nature of the halogen atom bonded and the presence of electron-donor groups on the phenyl ring. In the case of 2-chloro-1,3-diphenylpropan-1,3-dione and 1-(3,5-dimethoxyphenyl)-3-phenylpropan-1,3-dione, cyclization to flavones was the sole reaction pathway, whereas in the case of 2-chloro-1,3-di(4-methoxyphenyl)propan-1,3-dione, only products derived from alpha-cleavage were observed. 2-Fluoro derivatives of 1,3-diarylpropan-1,3-diones were photostable; on the other hand, 2-chloro-2-fluoro derivates resulted in 3-fluoroflavones.

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confidence: 99%

Photocyclization of 2-Chloro-Substituted 1,3-Diarylpropan-1,3-diones to Flavones

Košmrlj

Ŝket

2007

Org. Lett.

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“…It was somewhat surprising that no photo-Claisen rearrangement to the 4-position was observed. However, there is evidence that similar systems give primarily rearrangement to the 2-position. , Further, alkyl groups ortho to the anthraquinone carbonyl are well-known to be photo-oxidized. − Apparently, migration of the benzyl radical to the 4-position is a minor event, and the product obtained from such migration is further transformed over the course of the reaction. Attempts to detect a 4-benzyl product in all reactions failed.…”

Section: Resultsmentioning

confidence: 99%

Photochemistry of 1,n-Dibenzyloxy-9,10-anthraquinones

Sarma

Jones

2010

J. Org. Chem.

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The photochemistry of a series of 9,10-anthraquinones with multiple benzyloxy substituents was investigated. In polar solvent, the expected Blankespoor oxidative cleavage reaction is the major reaction pathway, but in most cases, several minor products were observed. In nonpolar solvents, the abundance of these minor products increases dramatically. Four types of product were observed with the favored reaction pathway shifting with minor changes in substitution on the anthraquinone. Several types of product require cleavage of the C-O bond on the benzyloxy group and, apparently, follow a photo-Claisen-type mechanism. Others involve the expected 1,5-diradical but do not exhibit the single-electron transfer usually observed in the Blankespoor-type reaction. The results indicate the importance of considering the medium and photoredox behavior in anthraquinone photochemistry.

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“…8 Irradiation of 1-(omethylphenyl)-2,2-dimethyl-1,3-diketone in hexane generates benzocyclobutenol. 9 Wirz and co-workers investigated the primary photochemical reactions of acetate and fluoride substituted dimethoxybenzoin derivatives using sub-picosecond laser flash photolysis. Dimethoxybenzoin generates a preoxetane biradical intermediate through the cyclization process, followed by a heterolytic dissociation of the leaving groups with generation of the cation species (Scheme 1).…”

Section: ■ Introductionmentioning

confidence: 99%

“…For instance, irradiation of 2,2-dimethyl-1,3-diphenylpropan-1,3-dione in the presence of triethylamine led to the formation of anti-2,2-dimethyl-1,3-diphenylcyclopropan-1,3-diol as the main product . Irradiation of 1-( o -methylphenyl)-2,2-dimethyl-1,3-diketone in hexane generates benzocyclobutenol . Wirz and co-workers investigated the primary photochemical reactions of acetate and fluoride substituted dimethoxybenzoin derivatives using sub-picosecond laser flash photolysis.…”

Section: Introductionmentioning

confidence: 99%

Investigations on the Photochemical Reaction Mechanisms of Selected Dibenzoylmethane Compounds

et al. 2021

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In this work, combined time-resolved spectroscopies of femtosecond transient absorption, nanosecond transient absorption, and DFT calculations were performed to unravel the photocyclization reaction mechanisms of selected dibenzoylmethane (DBM) derivatives, including 2-chloro-1,3-diphenylpropan-1,3-dione (1a), 2-chloro-1-(3,5-dimethoxyphenyl)-3-phenylpropan-1,3-dione (1b), 2-chloro-2-fluoro-1,3-diphenylpropan-1,3-dione (1c), and 2-chloro-2-fluoro-1,3-di(4-methoxyphenyl)propan-1,3-dione (1d). Photocyclization reaction mechanisms for 1a and 1b are similar, where a C–Cl heterolysis occurs yielding an α-ketocation intermediate, followed by cyclization to generate the cation species. On the other hand, 1c and 1d undergo dechlorination primarily producing a radical species, which further experiences cyclization yielding cyclized radical species. The dominant factor leading to the different reaction mechanisms is the involvement of a fluorine atom bonded at α-C. Due to the meta-effect, the p-methoxy substitution on the benzene ring inhibits the photocyclization reaction and reduces the yield of photocyclization.

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Solvent Dependent Photochemical Reactions of 3-(2-Alkylphenyl)-2,2-dimethyl-3-oxopropanoates and Their Related Compounds

Cited by 10 publications

References 25 publications

Photocyclization of 2-Chloro-Substituted 1,3-Diarylpropan-1,3-diones to Flavones

Photocyclization of 2-Chloro-Substituted 1,3-Diarylpropan-1,3-diones to Flavones

Photochemistry of 1,n-Dibenzyloxy-9,10-anthraquinones

Investigations on the Photochemical Reaction Mechanisms of Selected Dibenzoylmethane Compounds

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