100009-29-8Relevant academic research and scientific papers
Asymmetric aminolysis of aromatic epoxides: A facile catalytic enantioselective synthesis of anti-β-amino alcohols
Bartoli, Giuseppe,Bosco, Marcella,Carlone, Armando,Locatelli, Manuela,Massaccesi, Massimo,Melchiorre, Paolo,Sambri, Letizia
, p. 2173 - 2176 (2004)
The first asymmetric aminolysis of trans-aromatic epoxides with anilines is described. The process affords enantioenriched anti-β-amino alcohols in up to 99% ee. The complete regio- and diastereoselectivity observed uses commercially available [Cr(Salen)CI] as a Lewis acid catalyst and in combination with a very simple experimental procedure renders the present reaction a facile and practical tool for the synthesis of chiral nonracemic anti-β-amino alcohols.
Copper-Catalyzed Transfer Hydrodeuteration of Aryl Alkenes with Quantitative Isotopomer Purity Analysis by Molecular Rotational Resonance Spectroscopy
Alansari, Isabella Y.,Clark, Joseph R.,Holdren, Martin S.,Neill, Justin L.,Pate, Brooks H.,Reyes, Albert,Sloane, Samantha E.,Sonstrom, Reilly E.,Vang, Zoua Pa
supporting information, p. 7707 - 7718 (2021/06/21)
A copper-catalyzed alkene transfer hydrodeuteration reaction that selectively incorporates one hydrogen and one deuterium atom across an aryl alkene is described. The transfer hydrodeuteration protocol is selective across a variety of internal and terminal alkenes and is also demonstrated on an alkene-containing complex natural product analog. Beyond using 1H, 2H, and 13C NMR analysis to measure reaction selectivity, six transfer hydrodeuteration products were analyzed by molecular rotational resonance (MRR) spectroscopy. The application of MRR spectroscopy to the analysis of isotopic impurities in deuteration chemistry is further explored through a measurement methodology that is compatible with high-throughput sample analysis. In the first step, the MRR spectroscopy signatures of all isotopic variants accessible in the reaction chemistry are analyzed using a broadband chirped-pulse Fourier transform microwave spectrometer. With the signatures in hand, measurement scripts are created to quantitatively analyze the sample composition using a commercial cavity enhanced MRR spectrometer. The sample consumption is below 10 mg with analysis times on the order of 10 min using this instrument - both representing order-of-magnitude reduction compared to broadband MRR spectroscopy. To date, these measurements represent the most precise spectroscopic determination of selectivity in a transfer hydrodeuteration reaction and confirm that product regioselectivity ratios of >140:1 are achievable under this mild protocol.
Copper-catalyzed formal transfer hydrogenation/deuteration of aryl alkynes
Sloane, Samantha E.,Reyes, Albert,Vang, Zoua Pa,Li, Lingzi,Behlow, Kiera T.,Clark, Joseph R.
, p. 9139 - 9144 (2020/11/30)
A copper-catalyzed reduction of alkynes to alkanes and deuterated alkanes is described under transfer hydrogenation and transfer deuteration conditions. Commercially available alcohols and silanes are used interchangeably with their deuterated analogues as the hydrogen or deuterium sources. Transfer deuteration of terminal and internal aryl alkynes occurs with high levels of deuterium incorporation. Alkyne-containing complex natural product analogues undergo transfer hydrogenation and transfer deuteration selectively, in high yield. Mechanistic experiments support the reaction occurring through a cis-alkene intermediate and demonstrate the possibility for a regioselective alkyne transfer hydrodeuteration reaction.
Iterative synthesis of alkenes by insertion of lithiated epoxides into boronic esters
Bojaryn, Kevin,Fritsch, Stefan,Hirschhaüser, Christoph
supporting information, p. 2218 - 2222 (2019/04/10)
The insertion of lithiated epoxides into boronic esters followed by thermal syn-elimination provides a stereospecific entry to alkenes. This process avoids transition metals and is amenable to iteration to provide higher substitution patterns.
Diastereoselective borocyclopropanation of allylic ethers using a boromethylzinc carbenoid
Benoit, Guillaume,Charette, André B.
supporting information, p. 1364 - 1367 (2017/02/10)
A borocyclopropanation of (E)- and (Z)-allylic ethers and styrene derivatives via the Simmons-Smith reaction using a novel boromethylzinc carbenoid is described. The carbenoid precursor is prepared via a 3-step sequence from inexpensive and commercially available starting materials. This methodology allows for the preparation of 1,2,3-substituted borocyclopropanes in high yields and diastereoselectivities. Several postfunction-alization reactions were also performed to illustrate the versatility of these building blocks.
The synthesis of (R,S)-reboxetine employing a tandem cyclic sulfate rearrangement - Opening process
Yu, Jin,Ko, Soo Y.
experimental part, p. 650 - 654 (2012/09/22)
(R,S)-Reboxetine was synthesized in nine steps and with 43% overall yield starting from trans-cinnamyl alcohol. Following silylation and AD steps, the two hydroxyl groups at C-1 and C-2 were simultaneously activated to the cyclic sulfate. A series of tandem reactions initiated by desilylation transposed the activation to C-3, then to C-1, where nucleophilic displacements took place in succession. During this process, the configuration at C-2 was inverted while that at C-1 was retained through a double inversion.
Direct, iridium-catalyzed enantioselective and regioselective allylic etherification with aliphatic alcohols
Ueno, Satoshi,Hartwig, John F.
, p. 1928 - 1931 (2008/12/22)
(Chemical Equation Presented) From alcohol to ether: Iridium-catalyzed allylations yield α chiral ether derivatives directly from aliphatic alcohols with a simple alkali metal base (see equation). These reactions form ethers from primary, secondary, and tertiary alkoxides with high enantioselectivity. By-products from isomerization were suppressed by the use of an alkyne additive.
Biomimetic iron-catalyzed asymmetric epoxidation of aromatic alkenes by using hydrogen peroxide
Gelalcha, Feyissa Gadissa,Anilkumar, Gopinathan,Tse, Man Kin,Brueckner, Angelika,Beller, Matthias
experimental part, p. 7687 - 7698 (2009/08/07)
A novel and general biomimetic non-heme Fe-catalyzed asymmetric epoxidation of aromatic alkenes by using hydrogen peroxide is reported herein. The catalyst consists of ferric chloride hexahydrate (FeCl3·OH 2O), pyridine-2,6-dicarboxylic acid (H2-(pydic)), and readily accessible chiral N-arenesulfonyl-N′-benzyl-substituted ethylenediamine ligands. The asymmetric epoxidation of styrenes with this system gave high conversions but poor enantiomeric excesses (ee), whereas larger alkenes gave high conversions and ee values. For the epoxidation of trans-stilbene (1a), the ligands (S,S)-N-(4-toluenesulfonyl)-1,2- diphenylethylenediamine ((S,S)-4a) and its N′-benzylated derivative ((S,S)-5a) gave opposite enantiomers of trans-stilbene oxide, that is, (S,S)-2a and (R,R)-2a, respectively. The enantioselectivity of alkene epoxidation is controlled by steric and electronic factors, although steric effects are more dominant. Preliminary mechanistic studies suggest the in situ formation of several chiral Fe-complexes, such as [FeCl(L*)2-(pydic)] ·HCl (L* = (S,S)-4a or (S,S)-5a in the catalyst mixture), which were identified by ESIMS. A UV/Vis study of the catalyst mixture, which consisted of FeCl3·6H2O, H2(pydic), and (S,S)-4a, suggested the formation of a new species with an absorbance peak at λ = 465 nm upon treatment with hydrogen peroxide. With the aid of two independent spin traps, we could confirm by EPR spectroscopy that the reaction proceeds via radical intermediates. Kinetic studies with deuterated styrenes showed inverse secondary kinetic isotope effects, with values of k H/kD = 0.93 for the β carbon and kH/k D=0.97 for the a carbon, which suggested an unsymmetrical transition state with stepwise O transfer. Competitive epoxidation of para-substituted styrenes revealed a linear dual-parameter Hammett plot with a slope of 1.00. Under standard conditions, epoxidation of la in the presence of ten equivalents of H218O resulted in an absence of the isotopic label in (S,S)-2a. A positive non-linear effect was observed during the epoxidation of la in the presence of (S,S)-5a and (R,R)-5a.
Iridium-catalyzed enantioselective synthesis of allylic alcohols: Silanolates as hydroxide equivalents
Lyothier, Isabelle,Defieber, Christian,Carreira, Erick M.
, p. 6204 - 6207 (2007/10/03)
(Chemical Equation Presented) Masked hydroxide: A highly regio- and enantioselective Ir-catalyzed allylic etherification of acyclic, achiral allylic carbonates can be achieved by using potassium silanolates as nucleophiles. The use of these hydroxide equi
Efficient and stereoselective synthesis of allylic ethers and alcohols
Pospisil, Jiri,Marko, Istvan E.
, p. 5983 - 5986 (2007/10/03)
(Chemical Equation Presented) A short and efficient synthesis of allylic TBS ethers and allylic alcohols has been developed, based upon a unique Kocienski-Julia olefination reaction. Allylic alcohols and allylic ethers are obtained in good to excellent yields and with high (E)-selectivity. The conditions are mild and the procedure is broadly applicable.
