16460-85-8Relevant academic research and scientific papers
Cobalt-Catalyzed Asymmetric 1,4-Hydroboration of Enones with HBpin
Ren, Xiang,Lu, Zhan
supporting information, 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.
Highly Enantioselective Iridium-Catalyzed Hydrogenation of Conjugated Trisubstituted Enones
Peters, Bram B. C.,Jongcharoenkamol, Jira,Krajangsri, Suppachai,Andersson, Pher G.
supporting information, 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.
Mechanistic-Insight-Driven Rate Enhancement of Asymmetric Copper-Catalyzed 1,4-Addition of Dialkylzinc Reagents to Enones
Lewis, William,Nouch, Ryan,Robinson, David,Willcox, Darren,Woodward, Simon
supporting information, (2020/03/13)
The combination of [Cu(MeCN)4]TFA·TFAH (TFA = O2CCF3) with Feringa's phosphoramidite ligand (LA) provides an exceptionally active (0.75 mol %) catalyst for asymmetric conjugate additions of ZnR2 (R = Et and Me at -40 to -80 °C) to enones. Kinetic and other studies of the addition of ZnEt2 to cyclohex-2-en-1-one indicate a transition state stoichiometry composition of (ZnEt2)3(enone)4Cu2(LA)3 that is generated by transmetalation from Et2Zn(enone)2. Catalyst genesis is significantly slower than turnover (which has limited previous attempts to attain useful kinetic data); in the initial stages, varying populations of catalytically inactive, off-cycle, species are present. These issues are overcome by a double-dose kinetic analysis protocol. A rest state of [LACu(Et)(μ-TFA)(μ-{(enone)(ZnEt)2(enolate)})CuLA2]+ (through the equivalence of enolate = enone + ZnEt2) is supported by DFT studies (ωB97X-D/SRSC). Rate-determining ZnEt2(enone)2 transmetalation drives the exceptionally high catalytic activity of this system.
Copper-catalyzed enantioselective 1,4-conjugate addition of dialkylzinc reagents to α,β- and α,β,γ,δ-unsaturated ketones
Rexiti, Rukeya,Lu, Jian,Sha, Feng,Wu, Xin-Yan
, p. 3596 - 3604 (2019/06/04)
An enantioselective Cu(II)-catalyzed conjugate addition of dialkylzinc reagents to α,β- or α,β,γ,δ-unsaturated ketones with chiral cyclohexane-based amidophosphine ligands was developed. With 2 mol% of Cu(OAc)2·H2O/L5, the conjugate
Enantiopure sulfoximines-catalyzed 1, 4-additions to 2-en-ketone
Zhao, Hongwei,Han, Hui,Yang, Hengquan,wang, Li
, p. 210 - 213 (2018/06/26)
An efficient chiral catalyst procedure for the preparation of β-chiral ketone via the 1, 4-additions reaction of 2-en-ketone has been developed using enantiopure sulfoximines modified with functional groups as ligands. The carefully design and synthesized
Copper-catalyzed enantioselective conjugate addition of diethylzinc to acyclic enones with chiral sulfoxide-phosphine ligands
Yang, Tingting,Zhang, Yongling,Cao, Peng,Wang, Min,Li, Li,Li, Dong,Liao, Jian
supporting information, p. 2707 - 2711 (2016/05/10)
The copper-catalyzed enantioselective conjugate addition of diethylzinc to acyclic enones was achieved with chiral sulfoxide-phosphine (SOP) ligands. This process showed good functional group tolerance and gave the 1, 4-adducts with excellent enantioselec
C2-symmetric functionalized azolium salt from serine ester for Cu-catalyzed asymmetric conjugate addition reaction
Kondo, Junko,Harano, Ayako,Dohi, Kenta,Sakaguchi, Satoshi
, p. 66 - 71 (2014/11/08)
C2-symmetric ester-amide functionalized azolium salt was synthesized from readily available α-amino ester such as L-serine methyl ester. The combination of a Cu salt and the chiral azolium salt promoted the asymmetric conjugate addition reactio
Functionalized BINOL-mono-PHOS for multinuclear Cu-catalysts in asymmetric conjugate addition of organozinc reagents
Endo, Kohei,Yakeishi, Sayuri,Hamada, Daisuke,Shibata, Takanori
supporting information, p. 547 - 549 (2013/06/05)
Functionalization of BINOL-mono-PHOS achieved the Cucatalyzed highly asymmetric conjugate addition of organozinc reagents to enones. The incorporation of a bulky hydroxy group at the 3'-position of BINOL-mono-PHOS dramatically improved the yield and enantioselectivity. The present novel BINOL-mono-PHOS ligands are effective in the Cu-catalyzed asymmetric conjugate addition of organozinc reagents in both acyclic enones and cyclohexenone.
BINAM- mono -PHOS as new entry for multinuclear copper catalysts in asymmetric conjugate addition of organozinc reagents
Endo, Kohei,Takayama, Ryotaro,Shibata, Takanori
, p. 1155 - 1159 (2013/06/27)
The readily functionalized ligands, BINAM-PHOS, participate in the copper-catalyzed asymmetric conjugate addition of organozinc reagents to enones. The incorporation of benzoyl derivatives on nitrogen atoms was crucial to promote the reaction. Notably, BI
Modulation of multifunctional N,O,P ligands for enantioselective copper-catalyzed conjugate addition of diethylzinc and trapping of the zinc enolate
Ye, Fei,Zheng, Zhan-Jiang,Deng, Wen-Hui,Zheng, Long-Sheng,Deng, Yuan,Xia, Chun-Gu,Xu, Li-Wen
supporting information, p. 2242 - 2253 (2013/09/23)
In this work, we have successfully synthesized a new family of chiral Schiff base-phosphine ligands derived from chiral binaphthol (BINOL) and chiral primary amine. The controllable synthesis of a novel hexadentate and tetradentate N,O,P ligand that contains both axial and sp3-central chirality from axial BINOL and sp3-central primary amine led to the establishment of an efficient multifunctional N,O,P ligand for copper-catalyzed conjugate addition of an organozinc reagent. In the asymmetric conjugate reaction of organozinc reagents to enones, the polymer-like bimetallic multinuclear Cu-Zn complex constructed in situ was found to be substrate-selective and a highly excellent catalyst for diethylzinc reagents in terms of enantioselectivity (up to >99 % ee). More importantly, the chirality matching between different chiral sources, C2-axial binaphthol and sp3-central chiral phosphine, was crucial to the enantioselective induction in this reaction. The experimental results indicated that our chiral ligand (R,S,S)-L1- and (R,S)-L4-based bimetallic complex catalyst system exhibited the highest catalytic performance to date in terms of enantioselectivity and conversion even in the presence of 0.005 mol % of catalyst (S/C=20 000, turnover number (TON)=17 600). We also studied the tandem silylation or acylation of enantiomerically enriched zinc enolates that formed in situ from copper-L4-complex-catalyzed conjugate addition, which resulted in the high-yield synthesis of chiral silyl enol ethers and enoacetates, respectively. Furthermore, the specialized structure of the present multifunctional N,O,P ligand L1 or L4, and the corresponding mechanistic study of the copper catalyst system were investigated by 31P NMR spectroscopy, circular dichroism (CD), and UV/Vis absorption. Match maker: The chiral bimetallic multinuclear Cu-Zn complex that contains a novel phosphine ligand and bears matching axial and sp3-central chirality from binaphthol and chiral amine was found to be a highly efficient catalyst in the enantioselective conjugate addition of an organic zinc reagent. Copyright
