5558-04-3Relevant academic research and scientific papers
CuBr2-catalyzed ring opening/formylation reaction of cyclopropyl carbinols with DMF to synthesize formate esters
Zhuang, Daijiao,Gatera, Tharcisse,Yan, Rulong
supporting information, (2020/10/19)
An unprecedented protocol for the synthesis of formate esters has been developed by employing N,N-dimethylformamide (DMF) as both the source of CHO and solvent. This reaction undergoes ring opening of the cyclopropyl carbinols and in situ formation of homoallylic alcohols, which reacts with DMF to give the desired products. The substrate cyclopropyl carbinols with different groups participate smoothly in this process and the desired products are obtained in moderate to good yields.
Direct Synthesis of Enones by Visible-Light-Promoted Oxygenation of Trisubstituted Olefins Using Molecular Oxygen
Harada, Shinji,Matsuda, Daiki,Morikawa, Takahiro,Nishida, Atsushi
, p. 1372 - 1377 (2020/10/02)
A one-step synthesis of enones from olefins is described. The reaction was performed under visible-light irradiation in the presence of molecular oxygen and a photocatalyst. The reaction proceeded with various types of trisubstituted olefins to give enones in good yields with high regioselectivity. In particular, oxygen- and nitrogen-containing functional groups, heteroaromatic rings, and cyclopropanes were tolerated. Mechanistic studies and previous reports indicated that the active oxygen species generated in the reaction system is singlet oxygen.
Oxygenation of styrenes catalyzed by N-doped carbon incarcerated cobalt nanoparticles
Yasukawa, Tomohiro,Kobayashi, Shū
supporting information, p. 1980 - 1985 (2019/12/24)
NCI-Co catalyzed olefin oxygenation reactions were investigated. Among the metals examined, including noble metals, the reaction proceeded specifically on Co catalysts, and nitrogen dopant was crucial for the catalytic activity. The presence of NaBH4 as a hydride source, the corresponding alcohols were obtained in high yields. The substrates bearing a reductant-sensitive functional group were made tolerant by changing the reductant and using an additive, and furthermore, the corresponding ketones were accessed by changing reaction conditions. A preliminary examination of other SOMOphiles suggested that the heterogeneous catalyst systems have the potential to be applied to more general hydrofunctionalization of olefins to form various kinds of bonds. Several mechanistic studies suggested that the reaction proceeded in a heterogeneous manner and formed a radical intermediate on cobalt nanoparticle species.
Iridium-catalyzed asymmetric hydrogenation of 3,3-disubstituted allylic alcohols in ethereal solvents
Bernasconi, Maurizio,Ramella, Vincenzo,Tosatti, Paolo,Pfaltz, Andreas
supporting information, p. 2440 - 2444 (2014/03/21)
Ir-phosphinomethyl-oxazoline complexes have been identified as efficient, highly enantioselective catalysts for the asymmetric hydrogenation of 3,3-disubstituted allylic alcohols and related homoallylic alcohols. In contrast to other N,P ligand complexes, which require weakly coordinating solvents, such as dichloromethane, these catalysts perform well in more ecofriendly THF or 2-MeTHF. Their synthetic potential was demonstrated with the formal total synthesis of four bisabolane sesquiterpenes. Particularly high enantioselectivity values in the asymmetric hydrogenation of 3,3-disubstituted allylic alcohols and related homoallylic alcohols have been achieved with Ir-phosphinomethyloxazoline catalysts. In contrast to other N,P-ligand complexes, which require weakly coordinating solvents, such as CH 2Cl2, these catalysts perform well in more ecofriendly THF or 2-MeTHF (see scheme; CODa =a 1,5-cyclooctadiene). Copyright
Selenium-catalyzed regioselective cyclization of unsaturated carboxylic acids using hypervalent iodine oxidants
Singh, Fateh V.,Wirth, Thomas
supporting information; experimental part, p. 6504 - 6507 (2012/02/02)
A new and convenient selenium-catalyzed regioselective cyclization of γ, δ-unsaturated carboxylic acids to the corresponding 3, 6-dihydro-2Hpyran- 2-ones is described. The cyclization products have been obtained in good to excellent yields using diphenyl diselenide as a catalyst and [bis(trifluoroacetoxy)iodo]benzene as a stoichiometric oxidant 2011 American Chemical Society.
Synthesis of 1,2,4-trioxepanes and 1,2,4-trioxocanes via photooxygenation of homoallylic alcohols
Singh, Chandan,Pandey, Shilpi,Saxena, Gunjan,Srivastava, Nisha,Sharma, Malvika
, p. 9057 - 9061 (2007/10/03)
(Chemical Equation Presented) Homoallylic alcohols 4a-d, easily accessible in two steps from cyclopropyl methyl ketone, underwent a highly regioselective reaction with singlet oxygen to yield γ-hydroxyhydroperoxides 5a-d in 57-72% yield. Acid-catalyzed reaction of 5a-d with acetone, cyclopentanone, and cyclohexanone furnished 1,2,4-trioxepanes 8a-d, 9a-d, and 10a-d in good yields. Homoallylic alcohol 12 also underwent a highly regioselective photooxygenation to yield δ-hydroxyhydroperoxide 13 in 67% yield, which on reaction with acetone, cyclopentanone, and cyclohexanone, furnished 1,2,4-trioxocanes 16-18 in 41-55% yield.
Structural effects on the β-scission reaction of tertiary arylcarbinyloxyl radicals. The role of α-cyclopropyl and α-cyclobutyl groups
Bietti, Massimo,Gente, Giacomo,Salamone, Michela
, p. 6820 - 6826 (2007/10/03)
A product and time-resolved kinetic study on the reactivity of tertiary arylcarbinyloxyl radicals bearing α-cyclopropyl and α-cyclobutyl groups has been carried out. Both the 1-cyclopropyl-1-phenylethoxyl (1 .) and α,α-dicyclopropylphenylmethoxyl (2.) radicals undergo β-scission to give cyclopropyl phenyl ketone as the major or exclusive product with rate constants higher than that measured for the cumyloxyl radical. It is proposed that in the transition state for β-scission of 1. and 2., formation of the C=O double bond is assisted by overlap with the C-C bonding orbitals of the cyclopropane ring. With tertiary arylcarbinyloxyl radicals bearing α-cyclobutyl groups such as the 1-cyclobutyl-1-phenylethoxyl (4.) and 1-cyclobutyl-1-phenylpropoxyl (5.) radicals, the fragmentation regioselectivity is essentially governed by the stability of the radical formed by β-scission. Accordingly, 4. undergoes exclusive C-cyclobutyl bond cleavage to give acetophenone, whereas with 5., competition between C-cyclobutyl and C-ethyl bond cleavage, leading to propiophenone and cyclobutylphenyl ketone in a 2:1 ratio, is observed.
Reactivity and selectivity in the oxidation of styrene derivatives. V. studies on the oxidation of α-substituted styrenes
Suprun
, p. 52 - 58 (2007/10/03)
The liquid phase oxidation of α-phenyl-1a, α-trimethylsilyloxy 1b, α-cyclopropyl-1c, α-trifluoromethyl-1d styrene, and styrene 1e with oxygen in chlorobenzene and cumene solution in the temperature range 55-125°C was investigated. The product yields were determined gaschromatographically. The epoxide selectivity increases up to 90°C with increasing temperature. The epoxides of 1a and 1c rearrange at higher temperatures, therefore their yield decreases. The relative chain propagation constants (kpC=C) were determined by competitive oxidations of cumene. WILEY-VCH Verlag GmbH, 1999.
Regioselective ring-opening of cyclopropyl ketones with organometallic reagents
Ichiyanagi, Tsuyoshi,Kuniyama, Satoru,Shimizu, Makoto,Fujisawa, Tamotsu
, p. 1149 - 1150 (2007/10/03)
Regioselective ring-opening reaction of cyclopropyl ketones was conducted successfully, in which the reaction of cyclopropyl phenyl ketone with trimethylaluminum catalyzed by nickel acetyl-acetonate gave the ring-opening product in up to 76% yield.
[(3-dimethylamino)propyl]dimethylaluminum: A convenient reagent for methylation and ethynylation of carbonyl compounds
Baidossi, Wael,Rosenfeld, Ayelet,Wassermann, Brigit C.,Schutte, Stefan,Schumann, Herbert,Blum, Jochanan
, p. 1127 - 1130 (2007/10/03)
At 60-80°C the title compound methylates a variety of mono- and diketones. Aromatic aldehydes undergo simple methylation by the reagent only after initial treatment with an equivalent amount of AlCl3. Upon reaction of Me2Al(CH2)3NMe2 with terminal acetylenes the aluminum complex is converted into a carbonyl-alkynylation reagent.
