6552-45-0Relevant 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.
Bimetallic Catalysis: Asymmetric Transfer Hydrogenation of Sterically Hindered Ketones Catalyzed by Ruthenium and Potassium
Slagbrand, Tove,Kivij?rvi, Tove,Adolfsson, Hans
, p. 3445 - 3449 (2015/11/10)
An efficient protocol for the asymmetric reduction of sterically hindered ketones under transfer-hydrogenation conditions was developed. The corresponding chiral alcohols were obtained in good to excellent yields with enantiomeric excess values up to 99 %. The role of the cation associated with the base present in the reduction reaction was investigated. In contrast to previous studies on this catalyst system, potassium ions rather than lithium ions significantly enhanced the reaction outcome.
A method for synthesis of homoallylic bromide
Qi, Wenke,Wang, Peipei,Fan, Liyuan,Zhang, Songlin
, p. 5918 - 5924 (2013/07/26)
Cyclopropyl Grignard reagents react with carbonyl compounds in the presence of diethyl phosphite to give homoallylic bromides. The reaction is effectively carried out under mild conditions in a one-pot fashion with moderate to good yields.
Oxygen acidity of ring methoxylated 1,1-diarylalkanol radical cations bearing α-cyclopropyl groups. The competition between O-neophyl shift and C-cyclopropyl β-scission in the intermediate 1,1-diarylalkoxyl radicals
Bietti, Massimo,Fiorentini, Simone,Pato, Iria Perez,Salamone, Michela
, p. 3167 - 3175 (2007/10/03)
A product and time-resolved kinetic study on the reactivity of the radical cations generated from cyclopropyl(4-methoxyphenyl)phenylmethanol (1) and cyclopropyl[bis(4-methoxyphenyl)]methanol (2) has been carried out in aqueous solution. In acidic solution, 1.+ and 2.+ display very low reactivities toward fragmentation, consistent with the presence of groups at Cα (aryl and cyclopropyl) that after Cα-C β bond cleavage would produce relatively unstable carbon-centered radicals. In basic solution, 1.+ and 2.+ display oxygen acidity, undergoing -OH-induced deprotonation from the α-OH group, leading to the corresponding 1,1-diarylalkoxyl radicals 1r. and 2r., respectively, as directly observed by time-resolved spectroscopy. The product distributions observed in the reactions of 1.+ and 2.+ under these conditions (cyclopropyl phenyl ketone, cyclopropyl(4-methoxyphenyl) ketone, and 4-methoxybenzophenone from 1.+; cyclopropyl(4-methoxyphenyl) ketone and 4,4′- dimethoxybenzophenone from 2.+) have been rationalized in terms of a water-induced competition between O-neophyl shift and C-cyclopropyl β-scission in the intermediate 1,1-diarylalkoxyl radicals 1r. and 2r..
A catalytic and enantioselective cyclopropylation of aldehydes using dicyclopropylzinc
Shibata, Takanori,Tabira, Hayami,Soai, Kenso
, p. 177 - 178 (2007/10/03)
Enantioselective cyclopropylation of various aldehydes proceeds using dicyclopropylzinc in the presence of a catalytic amount of chiral amino alcohol or thiophosphoramidate with Ti(OPr1)4 to provide enantiomerically enriched cyclopropyl alkanols (up to 96.6% ee).
Regiospecific Nucleophilic Substitution in Cyclopropylcarbinols. Stereospecific Opening of the Cyclopropane Ring
Matveeva,Kvasha,Kurts
, p. 17 - 20 (2007/10/03)
Reactions of cyclopropylcarbinols with hydrobromic acid and the triphenylphosphine-tetrabromomethane complex at 0°C result in stereospecific opening of the cyclopropane ring with formation of trans-homoallyl bromides.
Mechanistic Evidence regarding the Magnesium Halide Transformation of Cyclopropylmethanols into Homoallylic Halides
McCormick, J. P.,Fitterman, Alan S.,Barton, Donald L.
, p. 4708 - 4712 (2007/10/02)
Cyclopropylmethanols are converted into homoallylic halides in high yield by treatment with magnesium bromide or iodide in refluxing, anhydrous diethyl ether.For uncovering of the details of the reaction mechanism, (cyclopropylphenylmethoxy)magnesium bromide (3a) was prepared by treatment of cyclopropylphenylmethanol (1) with hydridomagnesium bromide.Alkoyoxymagnesium bromide 3a was stable in refluxing diethyl ether and was not changed when treated with tetrabutylammonium bromide but was transformed into 4-bromo-1-phenyl-1-butene by treatment with hydrogen bromide or magnesium bromide.These results, together with first-order kinetics for the reaction of magnesium halide with 1, suggest a mechanism involving rapid formation of an intermediate ion pair (4), a magnesium oxonium bromide, which undergoes rate-determining ring opening to give homoallylic halide.A Hammett study of the reaction of substituted cyclopropylphenylmethanols with magnesium iodide provides a p value of -1.82, revealing substantial positive charge development on the carbinol carbon in the latter step.This investigation provides one of only a very few reported examples of Hammett studies used to probe positive charge development for a reaction carried out in anhydrous diethyl ether.
