135186-09-3Relevant articles and documents
Photocatalytic Stoichiometric Oxidant-Free Synthesis of Linear Unsaturated Ketones from 1,2-Disubstituted Cyclopropanols
Laktsevich-Iskryk, Marharyta V.,Krech, Anastasiya V.,Zhabinskii, Vladimir N.,Khripach, Vladimir A.,Hurski, Alaksiej L.
, p. 1077 - 1086 (2021)
A one-step catalytic oxidant-free synthesis of unsaturated ketones from 1,2-disubstituted cyclopropanols is reported. Previously for this transformation, only two- and three-step protocols have been developed. The reaction proceeds under irradiation with visible light in the presence of catalytic amounts of both an acridinium photocatalyst and a cobaloxime complex. 2-Aryl-substituted cyclopropanols react giving α,β-unsaturated ketones, while dehydrogenative ring opening of 2-alkyl-substituted substrates affords mixtures of α,β- and β,γ-enones. The reaction starts with one-electron oxidation of a cyclopropanol to cyclopropyloxy radical, presumably, by the photoexcited acridinium catalyst. We also found that Co(dmgBF 2) 2(MeCN) 2complex under an air atmosphere and irradiation with blue LEDs or upon heating can serve as a hydroxycyclopropane oxidant.
Synthesis of cyclopropanols via cyclopropanation of zinc enolates
Ito, Saeko,Shinokubo, Hiroshi,Oshima, Koichiro
, p. 5253 - 5256 (1998)
The reaction of α-iodoketones with diethylzinc afforded zinc enolates which were convened into the corresponding cyclopropanols in good yields upon treatment with CH2I2 and Et2Zn. The use of α-iodoketone having a carbon- carbon double bond as a substrate proved that cyclopropanation of the enolate moiety proceeded chemoselectively. Cyclopropanation of the zinc enolates derived from α,β-unsaturated ketones via 1,4-addition of organozinc species was also achieved.
The Cyclopropane Ring as a Reporter of Radical Leaving-Group Reactivity for Ni-Catalyzed C(sp3)-O Arylation
Mills, L. Reginald,Monteith, John J.,Dos Passos Gomes, Gabriel,Aspuru-Guzik, Alán,Rousseaux, Sophie A. L.
, p. 13246 - 13254 (2020/09/01)
The ability to understand and predict reactivity is essential for the development of new reactions. In the context of Ni-catalyzed C(sp3)-O functionalization, we have developed a unique strategy employing activated cyclopropanols to aid the design and optimization of a redox-active leaving group for C(sp3)-O arylation. In this chemistry, the cyclopropane ring acts as a reporter of leaving-group reactivity, since the ring-opened product is obtained under polar (2e) conditions, and the ring-closed product is obtained under radical (1e) conditions. Mechanistic studies demonstrate that the optimal leaving group is redox-active and are consistent with a Ni(I)/Ni(III) catalytic cycle. The optimized reaction conditions are also used to synthesize a number of arylcyclopropanes, which are valuable pharmaceutical motifs.
Stereospecific construction of chiral tertiary and quaternary carbon by nucleophilic cyclopropanation with bis(iodozincio)methane
Nomura, Kenichi,Matsubara, Seijiro
supporting information; experimental part, p. 147 - 152 (2010/04/23)
The reaction of a ketone having a leaving group at the aposition, such as a,bepoxy ketone or asulfonyloxy ketone, with bis(iodozincio) methane affords a zinc alkoxide of cyclopropanol. The reaction proceeds by nucleophilic addition of the dizinc to the carbonyl group and a sequential intramolecular nucleophilic substitution of the introduced iodozinciomethyl group to the adjacent electrophilic carbon that has a leaving group. When an optically active a,β-epoxy ketone or asulfonyloxy ketone is treated with the dizinc, a zinc alkoxide of cyclopropanol having a chiral tertiary or quaternary carbon in the cyclopropane ring is obtained, and the obtained zinc alkoxide of cyclopropanol acts as a chiral ho-moenolate. When it is treated with an electrophile in the presence of copper cyanide, it gives an optically active a-tertiary or -quaternary ketone that retains high optical purity.