1775-27-5Relevant articles and documents
Synthesis and spectral properties of fluorescent photochromic diarylethenes with 6,6a-dihydropentalene-2(1H)-one ethene "bridge"
Lonshakov, Dmitry V.,Shirinian, Valerii Z.,Zavarzin, Igor V.,Lvov, Andrey G.,Krayushkin, Mikhail M.
, p. 105 - 112 (2014)
An alternative synthetic strategy for the preparation of 6,6a-dihydropentalene-2(1H)-one derivatives comprising the stage of the regioselective α-bromination of cyclopentenone system has been proposed. The method along with the bromination process includes the alkylation of ethyl 4-aryl-3-oxobutanoate with bromocyclopentenones and intramolecular carbocyclization reaction of alkylated product. The cyclization reaction has been studied in detail and it was found that the yields of the main and side products depend strongly on alkali concentration, and the method can be also used to design 8,8a-dihydrocyclopenta[a]inden-2(1H)-one unit. The spectral properties of the compounds obtained have been studied, and it was found that pentalenone derivatives as well as starting cyclopentenones, exhibit photochromic properties; in addition, the former, unlike the latter, are also fluorescent.
Acridine Orange Hemi(Zinc Chloride) Salt as a Lewis Acid-Photoredox Hybrid Catalyst for the Generation of α-Carbonyl Radicals
Das, Sanju,Mandal, Tanumoy,De Sarkar, Suman
supporting information, p. 755 - 765 (2021/12/10)
A readily accessible organic-inorganic hybrid catalyst is reported for the reductive fragmentation of α-halocarbonyl compounds. The robust hybrid catalyst is a self-stabilizing combination of ZnCl2 Lewis acid and acridine orange as the photoactive organic dye. Mechanistic specifics of this hybrid catalyst have been studied in detail using both photophysical and electrochemical experiments. A systematic study enabled the discovery of the appropriate Lewis acid for the effective LUMO stabilization of α-halocarbonyl compounds and thereby lowering of reduction potential within the range of a standard organic dye. This strategy resolves the issues like dehalogenative hydrogenation or homo-coupling of alkyl radicals by guiding the photoredox cycle through an oxidative quenching pathway. The cooperativity between the photoactive organic dye and the Lewis acid counterparts empowers functionalization with a wide range of coupling partners through efficient and controlled generation of alkyl radicals and serves as an appropriate alternative to the expensive late transition metal-based photocatalysts. To demonstrate the application potential of this cooperative catalytic system, four different synthetic transformations of α-carbonyl bromides were explored with broad substrate scopes.
A metal-free aerobic oxidative bromination of anilines and aryl ketones with 2-methylpyridinium nitrate as a reusable ionic liquid
Li, Ming-Fang,Wang, Jian,Ke, Yong-Xin,Pan, Song-Cheng,Yin, Hong,Du, Wenting,Li, Jing-Hua
, p. 267 - 270 (2020/01/08)
An aerobic oxidative bromination of anilines and aryl ketones catalyzed by recyclable 2-methylpyridinium nitrate ionic liquid is achieved in water using hydrobromic acid as the bromine source and molecular oxygen as the oxidant. The catalytic system shows good efficiency and atom economy.
A Method for the Catalytic Enantioselective Synthesis of Chiral α-Azido and α-Amino Ketones from Racemic α-Bromo Ketones, and Its Generalization to the Formation of Bonds to C, O, and S
Da Silva Gomes, Roberto,Corey
supporting information, p. 20058 - 20061 (2019/12/27)
A new and practical method has been developed for the transformation of racemic α-bromo ketones to chiral α-azido and α-amino ketones with high enantioselectivity using phase transfer, ion-pair mediated reactions with a recoverable chiral quaternary salt (10 mol %) as catalyst in fluorobenzene-water. The process has been generalized to a variety of other attachments including of C, O, S, and NHR.
