1674-30-2Relevant academic research and scientific papers
In Situ Formation and Reactions of Chloromethyl-lithium under Sonochemical Conditions
Einhorn, Cathy,Allavena, Corinne,Luche, Jean-Louis
, p. 333 - 334 (1988)
Under sonication, bromochloromethane, a carbonyl compound, and lithium in tetrahydrofuran yield the corresponding α-chlorohydrin, which can cyclise to the epoxide, in excellent yields.
Catalytic Meerwein-Pondorf-Verley reduction by simple aluminum complexes
Campbell, E. Joseph,Zhou, Hongying,Nguyen, SonBinh T.
, p. 2391 - 2393 (2001)
(matrix presented) Catalytic MPV reduction was successfully carried out using simple aluminum precatalysts. Alkylaluminum reagents were converted to a low-aggregation aluminum alkoxide that was highly active for the MPV reduction of several carbonyl substrates in high yield (50-99%) using iPrOH as the reducing agent. A high degree of cisftrans selectivity was achieved in the reduction of 2-methylcyclohexanone (cis/trans = 20/80) by iPrOH. When chiral hydride sources were utilized in the reduction of 2-chloroacetophenone, high enantioselectivity (68-80% ee) was observed.
Dihydroxylation of styrene by sodium chlorite with scandium triflate
Ohkubo, Kei,Hirose, Kensaku,Shibata, Takekatsu,Takamori, Kiyoto,Fukuzumi, Shunichi
, (2017)
Dihydroxylation of styrene by chlorite (ClO2 ?) with scandium triflate [Sc(OTf)3] occurs efficiently to produce 1-phenylethane-1,2-diol under the ambient conditions. Scandium triflate acting as a strong Lewis acid is found to accelerate the disproportionation of ClO2 ? to produce ClO? and ClO3 ?. A scandium-chlorine dioxide complex (Sc3+ClO2 ?) is generated by the reaction of ClO? with ClO2 ? in the presence of Sc3 +. The binding of Sc3 + to ClO2 ? was detected by the electron paramagnetic resonance measurements, enhancing the reactivity and selectivity of styrene hydroxylation.
Enantioselective ring-opening of epoxides by HF-reagents: Asymmetric synthesis of fluoro lactones
Haufe, Günter,Bruns, Stefan,Runge, Martina
, p. 55 - 61 (2001)
The asymmetric ring opening of meso- and racemic-epoxides with different HF-reagents mediated by enantiopure (salen)chromium chloride provides optically active fluorohydrins with maximum 90% e.e. This reaction as well as lipase-catalyzed deracemization of
CeO2-nanocubes as efficient and selective catalysts for the hydroboration of carbonyl groups
Bhawar, Ramesh,Bose, Shubhankar Kumar,Patil, Kiran S.
supporting information, p. 15028 - 15034 (2021/09/04)
The CeO2-nanoparticle catalysed hydroboration of carbonyl compounds with HBpin (pin = OCMe2CMe2O) is reported to afford the corresponding borate esters in excellent yield. A series of aromatic and aliphatic aldehydes and ketones having synthetically important functional groups were well-Tolerated under mild reaction conditions. Further, chemoselective hydroboration of aldehydes over other reducible functional groups such as ketone, nitrile, hydroxide, alkene, alkyne, amide, ester, nitro, and halides was achieved. Importantly the catalyst can be recycled up to ten runs with slight loss in activity. This journal is
A phosphonium ylide as a visible light organophotoredox catalyst
Toda, Yasunori,Tanaka, Katsumi,Matsuda, Riki,Sakamoto, Tomoyuki,Katsumi, Shiho,Shimizu, Masahiro,Ito, Fuyuki,Suga, Hiroyuki
supporting information, p. 3591 - 3594 (2021/04/14)
A phosphonium ylide-based visible light organophotoredox catalyst has been designed and successfully applied to halohydrin synthesis using trichloroacetonitrile and epoxides. An oxidative quenching cycle by the ylide catalyst was established, which was confirmed by experimental mechanistic studies.
Chiral aminoalcohols and squaric acid amides as ligands for asymmetric borane reduction of ketones: Insight to in situ formed catalytic system by DOSY and multinuclear NMR experiments
Dobrikov, Georgi M.,Nikolova, Yana,Petkova, Zhanina,Shestakova, Pavletta
supporting information, (2021/11/27)
A series of squaric acid amides (synthesized in 66–99% isolated yields) and a set of chiral aminoalcohols were comparatively studied as ligands in a model reaction of reduction of α-chloroacetophenone with BH3?SMe2. In all cases, the aminoalcohols demonstrated better efficiency (up to 94% ee), while only poor asymmetric induction was achieved with the corresponding squaramides. A mechanistic insight on the in situ formation and stability at room temperature of intermediates generated from ligands and borane as possible precursors of the oxazaborolidine-based catalytic system has been obtained by1H DOSY and multinuclear 1D and 2D (1H,10/11B,13C,15N) NMR spectroscopy of equimolar mixtures of borane and selected ligands. These results contribute to better understanding the complexity of the processes occurring in the reaction mixture prior to the possible oxazaborolidine formation, which play a crucial role on the degree of enantioselectivity achieved in the borane reduction of α-chloroacetophenone.
Dynamic Kinetic Resolution of Alcohols by Enantioselective Silylation Enabled by Two Orthogonal Transition-Metal Catalysts
Oestreich, Martin,Seliger, Jan
supporting information, p. 247 - 251 (2020/10/29)
A nonenzymatic dynamic kinetic resolution of acyclic and cyclic benzylic alcohols is reported. The approach merges rapid transition-metal-catalyzed alcohol racemization and enantioselective Cu-H-catalyzed dehydrogenative Si-O coupling of alcohols and hydrosilanes. The catalytic processes are orthogonal, and the racemization catalyst does not promote any background reactions such as the racemization of the silyl ether and its unselective formation. Often-used ruthenium half-sandwich complexes are not suitable but a bifunctional ruthenium pincer complex perfectly fulfills this purpose. By this, enantioselective silylation of racemic alcohol mixtures is achieved in high yields and with good levels of enantioselection.
Organomagnesium Based Flash Chemistry: Continuous Flow Generation and Utilization of Halomethylmagnesium Intermediates
Von Keutz, Timo,Cantillo, David,Kappe, C. Oliver
supporting information, p. 7537 - 7541 (2020/10/12)
The generation of highly unstable chloromethylmagnesium chloride in a continuous flow reactor and its reaction with aldehydes and ketones is reported. With this strategy, chlorohydrins and epoxides were synthesized within a total residence time of only 2.6 s. The outcome of the reaction can be tuned by simply using either a basic or an acidic quench. Very good to excellent isolated yields, up to 97%, have been obtained for most cases (30 examples).
One-pot synthesis of 4-aryl-2-aminothiazoles from styrenes and thioureas promoted by tribromoisocyanuric acid
de Andrade, Vitor S.C.,de Mattos, Marcio C.S.
supporting information, (2020/07/03)
A simple and efficient one-pot protocol has been developed for the conversion of styrenes into 4-aryl-2-aminothiazoles using readily available starting materials. Tribromoisocyanuric acid was successfully used for the co-bromination and oxidation of styrenes to give phenacyl bromides, which in the presence of thioureas produced the corresponding 4-aryl-2-aminothiazoles in 48–70% yield. The protocol involves three reactions in one process: a tandem (formation of phenacyl bromides from styrenes) followed by a telescoped (conversion to thiazole) reaction.
