532-65-0Relevant academic research and scientific papers
Access to Chiral HWE Reagents by Rhodium-Catalyzed Asymmetric Arylation of γ,δ-Unsaturated β-Ketophosphonates
Yin, Long,Zhang, Dewei,Xing, Junhao,Wang, Yuhan,Wu, Changhui,Lu, Tao,Chen, Yadong,Hayashi, Tamio,Dou, Xiaowei
, p. 5869 - 5875 (2018)
Asymmetric arylation of ?,?-unsaturated β-ketophosphonates with arylboronic acids is reported. By using the (R)-diene? ligated rhodium(I) chloride complex as a catalyst under none basic conditions, the corresponding β-ketophosphonates bearing a ?-chiral center were obtained in high yields (up to 99%) with good to excellent enantioselectivities (up to >99% ee). The enantioenriched products can be readily converted to diverse chiral β′-aryl enones by the Horner-Wadsworth-Emmons reaction.
Lewis Base-Catalyzed Enantioselective Conjugate Reduction of β,β-Disubstituted α,β-Unsaturated Ketones with Trichlorosilane: E/ Z-Isomerization, Regioselectivity, and Synthetic Applications
Sugiura, Masaharu,Ashikari, Yasuhiko,Takahashi, Yuka,Yamaguchi, Koki,Kotani, Shunsuke,Nakajima, Makoto
, p. 11458 - 11473 (2019/10/11)
The chiral bisphosphine dioxide-catalyzed asymmetric conjugate reduction of acyclic β,β-disubstituted α,β-unsaturated ketones with trichlorosilane affords saturated ketones having a stereogenic carbon center at the carbonyl β-position with high enantioselectivities. Because the E/Z-isomerizations of enone substrates occur concomitantly, reduction products with the same absolute configurations are obtained from either (E)- or (Z)-enones. Conjugate reduction is accelerated in the presence of an electron-rich aryl group at the β-position of the enone owing to its carbocation-stabilizing ability. Computational studies were also conducted in order to elucidate the origin of the observed enantioselectivity. The regio- and enantioselective reductions of dienones were realized and applied to the syntheses of ar-turmerone, turmeronol A, mutisianthol, and jungianol, which are optically active sesquiterpenes.
Cobalt-Catalyzed Enantioselective Synthesis of Chiral gem-Bis(boryl)alkanes
Teo, Wei Jie,Ge, Shaozhong
supporting information, p. 12935 - 12939 (2018/09/20)
We report an asymmetric synthesis of enantioenriched gem-bis(boryl)alkanes in an enantioselective diborylation of 1,1-disubstituted alkenes catalyzed by Co(acac)2/(R)-DM-segphos. A range of activated and unactivated alkenes underwent this asymmetric diborylation in the presence of cyclooctene as a hydrogen acceptor, affording the corresponding gem-bis(boryl)alkanes with high enantioselectivity. The synthetic utility of these chiral organoboronate compounds was demonstrated through several stereospecific derivatizations and the synthesis of sesquiterpene and sesquiterpenoid natural products.
Highly efficient Rh-catalyzed asymmetric hydrogenation of α,β-unsaturated nitriles
Yan, Qiaozhi,Kong, Duanyang,Li, Meina,Hou, Guohua,Zi, Guofu
, p. 10177 - 10181 (2015/09/01)
A highly efficient enantioselective hydrogenation of α,β-unsaturated nitriles catalyzed by Rh-(R,R)-f-spiroPhos complex has been developed. With Rh-(R,R)-f-spiroPhos catalyst and under mild conditions, a wide range of α,β-unsaturated nitriles including the (E)- and (Z)-isomers of 3-alkyl-3-aryl, 3,3-diaryl, and 3,3-dialkyl α,β-unsaturated nitriles were hydrogenated to the corresponding chiral nitriles with excellent enantioselectivities (up to 99.9% ee) and high turnover numbers (TON up to 10,000).
Copper-Catalyzed Asymmetric Conjugate Addition of Dimethylzinc to Acyl-N-methylimidazole Michael Acceptors: A Powerful Synthetic Platform
Drissi-Amraoui, Sammy,Morin, Marie S. T.,Crévisy, Christophe,Baslé, Olivier,Marciadefigueiredo, Renata,Mauduit, Marc,Campagne, Jean-Marc
, p. 11830 - 11834 (2015/10/05)
An efficient copper-catalyzed enantioselective conjugate addition of dimethylzinc to α,β- and α,β,γ,δ-unsaturated 2-acyl-N-methylimidazoles has been achieved using a chiral bidentate hydroxyalkyl-NHC ligand. The reactions proceeded with both excellent regio- and enantioselectivity (14 examples, 87-95 % ee) to afford the desired 1,4-adducts, which were easily transformed to the corresponding aldehydes, esters, and ketones. Subsequently, this powerful methodology was therefore successfully applied in the synthesis of natural products. Furthermore, an iterative process was also disclosed leading to highly desirable 1,3-desoxypropionate skeletons (up to 94 % d.e.). The enantioselective conjugate addition of dimethylzinc to (poly)unsaturated 2-acyl-N-methylimidazoles proceeds under Cu catalysis with excellent regio- and enantioselectivities (up to 95 % ee). The resulting 1,4-adducts can be easily transformed to the corresponding aldehydes, esters, ketones, and amines. This methodology was successfully applied in the synthesis of 1,3-desoxypropionate subunits and natural products.
Cobalt-bisoxazoline-catalyzed asymmetric kumada cross-coupling of racemic α-bromo esters with aryl grignard reagents
Mao, Jianyou,Liu, Feipeng,Wang, Min,Wu, Lin,Zheng, Bing,Liu, Shangzhong,Zhong, Jiangchun,Bian, Qinghua,Walsh, Patrick J.
, p. 17662 - 17668 (2015/02/02)
The first cobalt-catalyzed asymmetric Kumada cross-coupling with high enantioselectivity has been developed. The reaction affords a unique strategy for the enantioselective arylation of α-bromo esters catalyzed by a cobalt-bisoxazoline complex. A variety of chiral α-arylalkanoic esters were prepared in excellent enantioselectivity and yield (up to 97% ee and 96% yield). The arylated products were transformed into α-arylcarboxylic acids and primary alcohols without erosion of ee. The new enantioenriched α-arylpropionic esters synthesized herein are potentially useful in the development of nonsteroidal anti-inflammatory drugs. This method was conducted on gram-scale and applied to the synthesis of highly enantioenriched (S)-fenoprofen and (S)-ar-turmerone.
Formulation of Curcumin With Enhanced Bioavailability of Curcumin and Method of Preparation and Treatment Thereof
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Page/Page column, (2014/04/18)
Disclosure provides a formulation of curcuminoid with essential oil of turmeric to enhance the bioavailability of curcumin and to augment the biological activity of curcumin, wherein curcumin is the main constituent of curcuminoid and wherein Ar-turmerone is the main constituent of the essential oil of turmeric. An application of curcuminoid with essential oil of turmeric to enhance the bioavailability of curcumin for oral supplementation against a variety of diseases and method of doing the same is provided.
Preparation and use of enantioenriched 2-aryl-propylsulfonylbenzene derivatives as valuable building blocks for the enantioselective synthesis of bisabolane sesquiterpenes
Serra, Stefano
, p. 1561 - 1572 (2015/02/05)
We have demonstrated that different enantioenriched 2-arylpropylsufonylbenzene derivatives are very useful building blocks for the synthesis of aromatic bisabolane sesquiterpenes. Their preparation and the exploitation of their chemical reactivity have been comprehensively investigated. Accordingly, the naturally occurring bisabolane sesquiterpenes (-)-curcuphenol, (-)-xanthorrhizol, (+)-glandulone A, (+)-curcudiol, (+)-turmerone and (+)-curcudiol-10-one were synthesized in high enantiomeric purity. It is worth noting that the compounds (+)-curcudiol-10-one and (+)-glandulone A were prepared in enantioenriched form for the first time. Through the proposed synthetic approaches, we were able to confirm both chemical structures and the absolute configurations previously assigned to the two aforementioned sesquiterpenes.
Effect of multinuclear copper/aluminum complexes in highly asymmetric conjugate addition of trimethylaluminum to acyclic enones
Endo, Kohei,Hamada, Daisuke,Yakeishi, Sayuri,Shibata, Takanori
, p. 606 - 610 (2013/02/23)
Al and friends: Asymmetric conjugate addition of Me3Al to β,β-disubstituted α,β-unsaturated ketones in the presence copper and L1 leads to a highly efficient construction of an all-carbon-substituted chiral quaternary center. This result is the first example of an asymmetric conjugate addition of Me3Al to acyclic enones to give a chiral quaternary carbon center with excellent yield and enantioselectivity under mild reaction conditions. Copyright
Catalytic enantioselective β-alkylation of α,β-unsaturated aldehydes by combination of transition-metal- and aminocatalysis: Total synthesis of bisabolane sesquiterpenes
Afewerki, Samson,Breistein, Palle,Pirttil?, Kristian,Deiana, Luca,Dziedzic, Pawel,Ibrahem, Ismail,C?rdova, Armando
, p. 8784 - 8788 (2011/09/15)
Branching out! The first co-catalytic enantioselective (up to 98:2 e.r.) β-alkylation of α,β-unsaturated aldehydes by combination of simple chiral amine and copper catalysts provides β-branched aldehydes in a one-pot protocol (see scheme). The methodology was applied to the short total syntheses of bisabolane sesquiterpenes (S)-(+)-curcumene, (E)-(S)-(+)-3- dehydrocurcumene and (S)-(+)-tumerone.
