40641-81-4Relevant academic research and scientific papers
Tethered Silanoxyiodination of Alkenes
Dhokale, Ranjeet A.,Seidl, Frederick J.,Shinde, Anand H.,Mague, Joel T.,Sathyamoorthi, Shyam
, p. 9233 - 9243 (2021)
We present the first examples of tethered silanoxyiodination reactions of allylic alcohols. The products are useful silanediol organoiodide synthons and are formed with high regioselectivity and diastereocontrol. The reaction is scalable greater than 10-fold without loss of yield or selectivity. Furthermore, the products are starting materials for further transformations, including deiodination, C-N bond installation, epoxide synthesis, and desilylation. DFT calculations provide a basis for understanding the exquisite 6-endo selectivity of this silanoxyiodination reaction and show that the observed products are both kinetically and thermodynamically preferred.
Discovery of a new series of monoamine reuptake inhibitors, the 1-amino-3-(1H-indol-1-yl)-3-phenylpropan-2-ols
Kim, Callain Y.,Mahaney, Paige E.,McConnell, Oliver,Zhang, Yingru,Manas, Eric,Ho, Douglas M.,Deecher, Darlene C.,Trybulski, Eugene J.
, p. 5029 - 5032 (2009)
A novel series of monoamine reuptake inhibitors, the 1-amino-3-(1H-indol-1-yl)-3-phenylpropan-2-ols, have been discovered by combining virtual and focused screening efforts with design techniques. Synthesis of the two diastereomeric isomers of the molecule followed by chiral resolution of each enantiomer revealed the (2R,3S)-isomer to be a potent norepinephrine reuptake inhibitor (IC50 = 28 nM) with excellent selectivity over the dopamine transporter and 13-fold selectivity over the serotonin transporter.
Three- and two-site heteropolyoxotungstate anions as catalysts for the epoxidation of allylic alcohols by H2O2 under biphasic conditions: Reactivity and kinetic studies of the [Ni3(OH2)3(B-PW9O34){WO5(H2O)}]7?, [Co3(OH2)6(A-PW9O34)2]12?, and [M4(OH2)2(B-PW9O34)2]10? anions, where M?=?Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)
Abram, Paulus Hengky,Burns, Robert C.,Li, Lichun
, (2019/10/19)
The trimetallic phosphopolyoxotungstate anions [Ni3(OH2)3(B-PW9O34){WO5(H2O)}]7? and [Co3(OH2)6(A-PW9O34)2]12? have been studied as epoxidation catalysts for oxygen transfer from 30% H2O2 to a range of allylic alcohols under biphasic conditions (1,2-dichloroethane/H2O) at 15 °C. The reaction mechanism involves coordination of an allylic alcohol at an M(II) site in each case, prior to transfer of a peroxy oxygen from an adjacent W(O2) site. The latter is formed from a terminal W = O unit by reaction with H2O2. Evidence of W(O2) formation was obtained through IR studies. The W(O2) group forms the epoxide by transfer of an oxygen atom to the C[dbnd]C bond of the coordinated allylic alcohol. Kinetic studies using 3-methyl-2-buten-1-ol as the allylic alcohol substrate have been modelled with all three metal sites catalytically active. The reaction involves an autocatalysis mechanism involving an induction period, which can be rationalised by proposing not only coordination of the allylic alcohol to M(II), but also the product hydroxy epoxide, both through their –OH groups. The autocatalysis is generated by formation of the W(O2) group adjacent to a coordinated hydroxy epoxide, which competes with coordination of allylic alcohol. The mechanism requires some twenty-one steps involving just the generic steps listed above, with all three metal sites catalytically active. Temperature-dependent kinetic studies and subsequent Eyring analyses have shown that the Co(II)-containing catalyst is the most active of the two. Analogous studies of the epoxidation of 3-methyl-2-buten-1-ol by the two-site [M4(OH2)2(B-PW9O34)2]10? ions as catalysts, where M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II), at 15 °C gave an order of reactivity of Cu(II) > Ni(II) > Zn(II), Co(II), Mn(II), which mostly mimics the natural order of stability constants (the Irving-Williams series), suggesting that the formation of the allylic alcohol complexes play a dominant role in this series of related complex anions, with greater replacement of water by allylic alcohol leading to greater reactivity.
Enantiocomplementary Epoxidation Reactions Catalyzed by an Engineered Cofactor-Independent Non-natural Peroxygenase
Crotti, Michele,Kataja, Kim M.,Poelarends, Gerrit J.,Saravanan, Thangavelu,Xu, Guangcai
, p. 10374 - 10378 (2020/04/23)
Peroxygenases are heme-dependent enzymes that use peroxide-borne oxygen to catalyze a wide range of oxyfunctionalization reactions. Herein, we report the engineering of an unusual cofactor-independent peroxygenase based on a promiscuous tautomerase that accepts different hydroperoxides (t-BuOOH and H2O2) to accomplish enantiocomplementary epoxidations of various α,β-unsaturated aldehydes (citral and substituted cinnamaldehydes), providing access to both enantiomers of the corresponding α,β-epoxy-aldehydes. High conversions (up to 98 %), high enantioselectivity (up to 98 % ee), and good product yields (50–80 %) were achieved. The reactions likely proceed via a reactive enzyme-bound iminium ion intermediate, allowing tweaking of the enzyme's activity and selectivity by protein engineering. Our results underscore the potential of catalytic promiscuity for the engineering of new cofactor-independent oxidative enzymes.
Efficient and selective oxidation of alcohols to carbonyl compounds at room temperature by a ruthenium complex catalyst and hydrogen peroxide
Wang, Jie-Xiang,Zhou, Xian-Tai,Han, Qi,Guo, Xiao-Xuan,Liu, Xiao-Hui,Xue, Can,Ji, Hong-Bing
, p. 19415 - 19421 (2019/12/24)
In this study, convenient and selective oxidation of alcohols using aqueous hydrogen peroxide to yield carbonyl compounds was studied. Using the ruthenium-(4-methylphenyl-2,6-bispydinyl) pyridinedicarboxylate complex [Ru(mpbp)(pydic)] as a catalyst, primary and secondary alcohols were oxidized to aldehydes and ketones at room temperature with a satisfactory yield and excellent selectivity. The influence of various reaction parameters, such as solvent, catalyst and oxidant amount on both the activity and selectivity was also evaluated. Kinetic studies showed that the oxidation of alcohol was first order in terms of the substrate and hydrogen peroxide, and was second order in terms of the catalyst. A plausible mechanism involving ruthenium-oxo species with electrophilic character was proposed based on the in situ UV-vis spectroscopy studies and Hammett plots.
SO2F2-Mediated Epoxidation of Olefins with Hydrogen Peroxide
Ai, Chengmei,Zhu, Fuyuan,Wang, Yanmei,Yan, Zhaohua,Lin, Sen
, p. 11928 - 11934 (2019/10/02)
An inexpensive, mild, and highly efficient epoxidation protocol has been developed involving bubbling SO2F2 gas into a solution of olefin, 30% aqueous hydrogen peroxide, and 4 N aqueous potassium carbonate in 1,4-dioxane at room temperature for 1 h with the formation of the corresponding epoxides in good to excellent yields. The novel SO2F2/H2O2/K2CO3 epoxidizing system is suitable to a variety of olefinic substrates including electron-rich and electron-deficient ones.
Enantioselective Access to Chiral Cyclic Sulfamidates Through Iridium-Catalyzed Asymmetric Hydrogenation
Liu, Yuanhua,Huang, Yi,Yi, Zhiyuan,Liu, Gongyi,Dong, Xiu-Qin,Zhang, Xumu
supporting information, p. 1582 - 1586 (2019/02/19)
The Iridium-catalyzed asymmetric hydrogenation of cyclic sulfamidate imines was successfully developed with N-methylated ZhaoPhos L2 as the ligand. A variety of chiral cyclic sulfamidates were obtained with excellent results (up to 99% yield, 99% ee). Furthermore, this asymmetric hydrogenation can be employed as the key reaction step to prepare the important intermediates in organic synthesis. (Figure presented.).
Borylation and rearrangement of alkynyloxiranes: A stereospecific route to substituted α-enynes
Fuentespina, Ruben Pomar,De La Cruz, José Angel Garcia,Durin, Gabriel,Mamane, Victor,Weibel, Jean-Marc,Pale, Patrick
supporting information, p. 1416 - 1424 (2019/07/10)
1,3-Enynes are important building blocks in organic synthesis and also constitute the key motif in various bioactive natural products and functional materials. However, synthetic approaches to stereodefined substituted 1,3-enynes remain a challenge, as they are limited to Wittig and cross-coupling reactions. Herein, stereodefined 1,3-enynes, including tetrasubstituted ones, were straightforwardly synthesized from cis or trans-alkynylated oxiranes in good to excellent yields by a one-pot cascade process. The procedure relies on oxirane deprotonation, borylation and a stereospecific rearrangement of the so-formed alkynyloxiranyl borates. This stereospecific process overall transfers the cis or trans-stereochemistry of the starting alkynyloxiranes to the resulting 1,3-enynes.
Towards Mechanistic Understanding of Liquid-Phase Cinnamyl Alcohol Oxidation with tert-Butyl Hydroperoxide over Noble-Metal-Free LaCo1–xFexO3 Perovskites
Waffel, Daniel,Alkan, Baris,Fu, Qi,Chen, Yen-Ting,Schmidt, Stefan,Schulz, Christof,Wiggers, Hartmut,Muhler, Martin,Peng, Baoxiang
, p. 1155 - 1163 (2019/09/06)
Noble-metal-free perovskite oxides are promising and well-known catalysts for high-temperature gas-phase oxidation reactions, but their application in selective oxidation reactions in the liquid phase has rarely been studied. We report the liquid-phase oxidation of cinnamyl alcohol over spray-flame synthesized LaCo1–xFexO3 perovskite nanoparticles with tert-butyl hydroperoxide (TBHP) as the oxidizing agent under mild reaction conditions. The catalysts were characterized by XRD, BET, EDS and elemental analysis. LaCo0.8Fe0.2O3 showed the best catalytic properties indicating a synergistic effect between cobalt and iron. The catalysts were found to be stable against metal leaching as proven by hot filtration, and the observed slight deactivation is presumably due to segregation as determined by EDS. Kinetic studies revealed an apparent activation energy of 63.6 kJ mol?1. Combining kinetic findings with TBHP decomposition as well as control experiments revealed a complex reaction network.
A carboxylate-bridged Mn(II) compound with 6-methylanthranilate/bipy: oxidation of alcohols/alkenes and catalase-like activity
Kilic, Yalcin,Bolat, Serkan,Kani, Ibrahim
, p. 2293 - 2303 (2018/05/14)
A novel manganese compound, [Mn2(μ1,3-6-CH3-2-NH2C6H4COO)2(bipy)4](ClO4)2 (bipy?=?2,2′-bipyridine), was synthesized and used as a catalyst precursor in the oxidation of alkenes and primary alcohols to corresponding aldehydes, ketones, and acids. The six-coordinate compound has a binuclear structure in which two Mn(II) ions adopt a syn-anti μ1,3-bridging mode with two carboxylate groups and two chelated bipy ligands. The compound exhibits good activity in the oxidation of cyclohexene to 2-cyclohexene-1-one as the major product (93% conv. in 3?h, 79.3% selectivity) and of cinnamyl alcohol to cinnamaldehyde as the major product with 46% selectivity (100% conv. in 1.5?h) with tert-butyl hydroperoxide (TBHP) in acetonitrile at 70?°C. Furthermore, the catalase-like activity of the compound was studied in different solvents (acetonitrile, methanol, Tris-HCl buffer; TOF?=?29,910?h?1 in Tris-HCl buffer).
