54435-79-9Relevant academic research and scientific papers
Highly Enantioselective Iridium-Catalyzed Hydrogenation of Conjugated Trisubstituted Enones
Peters, Bram B. C.,Jongcharoenkamol, Jira,Krajangsri, Suppachai,Andersson, Pher G.
, p. 242 - 246 (2021/01/13)
Asymmetric hydrogenation of conjugated enones is one of the most efficient and straightforward methods to prepare optically active ketones. In this study, chiral bidentate Ir-N,P complexes were utilized to access these scaffolds for ketones bearing the stereogenic center at both the α- and β-positions. Excellent enantiomeric excesses, of up to 99%, were obtained, accompanied with good to high isolated yields. Challenging dialkyl substituted substrates, which are difficult to hydrogenate with satisfactory chiral induction, were hydrogenated in a highly enantioselective fashion.
Cobalt-Catalyzed Asymmetric 1,4-Hydroboration of Enones with HBpin
Ren, Xiang,Lu, Zhan
, p. 8370 - 8374 (2021/11/01)
Herein, a series of new 8-OIQ cobalt complexes were synthesized and used for cobalt-catalyzed chemo- and enantioselective 1,4-hydroboration of enones with HBpin to access chiral β,β-disubstituted ketones with good to excellent chemo- and enantioselectivties. This protocol is operationally simple and shows a broad substrate scope.
Chemoselective reduction of ?,￠-unsaturated carbonyl and carboxylic compounds by hydrogen iodide
Matsumoto, Shoji,Marumoto, Hayato,Akazome, Motohiro,Otani, Yasuhiko,Kaiho, Tatsuo
, p. 590 - 599 (2021/03/29)
The selective reduction of ?,￠-unsaturated carbonyl compounds was achieved to produce saturated carbonyl compounds with aqueous HI solution. The introduction of an aryl group at an ? or ￠ position efficiently facilitated the reduction with good yield. The reaction was applicable to compounds bearing carboxylic acids and halogen atoms. Through the investigation of the reaction mechanism, it was found that Michael-type addition of iodide occurred to produce ￠-iodo compounds followed by the reduction of C-I bond via anionic and radical paths.
HIGHLY ENANTIOSELECTIVE ACCESS TO CYCLIC BETA-AMINO ACIDS
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Paragraph 0117; 0118, (2021/06/11)
Disclosed herein is a method of forming a compound of formula I: wherein the substituents are defined in the specification. In particular, the compounds of formula I can be converted to amino acids bearing quaternary stereocenters with exceptional optical purities.
Alcohol Dehydrogenases and N-Heterocyclic Carbene Gold(I) Catalysts: Design of a Chemoenzymatic Cascade towards Optically Active β,β-Disubstituted Allylic Alcohols
González-Granda, Sergio,Lavandera, Iván,Gotor-Fernández, Vicente
, p. 13945 - 13951 (2021/04/22)
The combination of gold(I) and enzyme catalysis is used in a two-step approach, including Meyer–Schuster rearrangement of a series of readily available propargylic alcohols followed by stereoselective bioreduction of the corresponding allylic ketone intermediates, to provide optically pure β,β-disubstituted allylic alcohols. This cascade involves a gold N-heterocyclic carbene and an enzyme, demonstrating the compatibility of both catalyst types in aqueous medium under mild reaction conditions. The combination of [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene][bis(trifluoromethanesulfonyl)-imide]gold(I) (IPrAuNTf2) and a selective alcohol dehydrogenase (ADH-A from Rhodococcus ruber, KRED-P1-A12 or KRED-P3-G09) led to the synthesis of a series of optically active (E)-4-arylpent-3-en-2-ols in good yields (65–86 %). The approach was also extended to various 2-hetarylpent-3-yn-2-ol, hexynol, and butynol derivatives. The use of alcohol dehydrogenases of opposite selectivity led to the production of both allyl alcohol enantiomers (93->99 % ee) for a broad panel of substrates.
Asymmetric Alkoxy- and Hydroxy-Carbonylations of Functionalized Alkenes Assisted by β-Carbonyl Groups
Dong, Kaiwu,Ji, Xiaolei,Ren, Xinyi,Shen, Chaoren,Tang, Lin,Tian, Xinxin,Wang, Zhen
, p. 17693 - 17700 (2021/07/10)
As a fundamental type of carbonylation reaction, the alkoxy- and hydroxy-carbonylation of unsaturated hydrocarbons constitutes one of the most important industrial applications of homogeneous catalysis. However, owing to the difficulties in controlling multi-selectivities for asymmetric hydrocarbonylation of alkenes, this reaction is typically limited to vinylarenes and analogues. In this work, a highly efficient asymmetric alkoxy- and hydroxy-carbonylation of β-carbonyl functionalized alkenes was developed, providing practical and easy access to various densely functionalized chiral molecules with high optical purity from broadly available alkenes, CO, and nucleophiles (>90 examples, 84–99 % ee). This protocol features mild reaction conditions and a broad substrate scope, and the products can be readily transformed into a diverse array of chiral heterocycles. Control experiments revealed the key role of the β-carbonyl group in determining the enantioselectivity and promoting the activity, which facilitates chiral induction by coordination to the transition metal as rationalized by DFT calculations. The strategy of utilizing an innate functional group as the directing group on the alkene substrate might find further applications in catalytic asymmetric hydrocarbonylation reactions.
Catalytic Asymmetric Transfer Hydrogenation of trans-Chalcone Derivatives Using BINOL-derived Boro-phosphates
Na, Fei,Lopez, Susana S.,Beauseigneur, Alice,Hernandez, Lucas W.,Sun, Zhuoxin,Antilla, Jon C.
, p. 5953 - 5957 (2020/08/12)
Chiral phosphoric-acid-catalyzed asymmetric reductions of trans-chalcones have been investigated in this work. A BINOL-derived boro-phosphate-catalyzed asymmetric transfer hydrogenation of the carbon-carbon double bond of trans-chalcone derivatives employing borane as a hydride source was realized. This methodology provides a convenient procedure to access chiral dihydrochalone derivatives in high yields and with high enantioselectivities under mild conditions.
Acylation of Alkenes with the Aid of AlCl3 and 2,6-Dibromopyridine
Tanaka, Shinya,Kunisawa, Tsukasa,Yoshii, Yuji,Hattori, Tetsutaro
supporting information, p. 8509 - 8513 (2019/11/03)
Friedel-Crafts-type acylation of alkenes with acyl chlorides has been successfully conducted with a wide substrate scope by the combined use of AlCl3 and 2,6-dibromopyridine. Trisubstituted alkenes afford allylketones or vinylketones depending on the presence or absence of hydrogen atom(s) at the β-position to the acylation site, while monosubstituted alkenes exclusively afford vinylketones.
Bi(OTf)3 catalyzed synthesis of acyclic β-sulfanyl ketones via a tandem Meyer-Schuster rearrangement/conjugate addition reaction
Wang, Yuan,Yin, Yan,Zhang, Qinglin,Pan, Wanyong,Guo, Huifeng,Pei, Keke
, p. 2030 - 2034 (2019/07/03)
A new strategy to prepare acyclic β-carbonyl thioethers from propargyl alcohols and sulfur nucleophiles is reported. The investigation of the reaction substrates scope indicated that primary 3-aryl propargyl alcohols and thiols underwent the transformation smoothly. The reaction probably proceeded a Bi(OTf)3-catalyzed tandem Meyer-Schuster rearrangement of 3-aryl propargyl alcohol, followed by a thiol Michael conjugate addition of thiols to in situ generated α, β-unsaturated ketones. The method was 100% atom economic, high-yielding, and easy to handle, making it a valuable method for the construction of β-carbonyl sulfides.
Chiral 1,3,2-Diazaphospholenes as Catalytic Molecular Hydrides for Enantioselective Conjugate Reductions
Miaskiewicz, Solène,Reed, John H.,Donets, Pavel A.,Oliveira, Caio C.,Cramer, Nicolai
supporting information, p. 4039 - 4042 (2018/03/13)
Secondary 1,3,2-diazaphospholenes have a polarized P?H bond and are emerging as molecular hydrides. Herein, a class of chiral, conformationally restricted methoxy-1,3,2-diazaphospholene catalysts is reported. We demonstrate their catalytic potential in asymmetric 1,4-reductions of α,β-unsaturated carbonyl derivatives, including enones, acyl pyrroles, and amides, which proceeded in enantioselectivities of up to 95.5:4.5 e.r.
