13368-65-5Relevant articles and documents
Highly enantioselective copper(I)-phosphoramidite-catalysed additions of organoaluminium reagents to enones
Alexakis, Alexandre,Albrow, Victoria,Biswas, Kallolmay,D'Augustin, Magali,Prieto, Oscar,Woodward, Simon
, p. 2843 - 2845 (2005)
Simple phosphoramidite ligands afford good to excellent levels of enantioselectivity in 1,4-additions of AIR3 species to enones; sequential carboalumination-ACA cascades are possible. The Royal Society of Chemistry 2005.
Asymmetric hydrogenation of substituted 2-pyrones
Fehr, Matthias J.,Consiglio, Giambattista,Scalone, Michelangelo,Schmid, Rudolf
, p. 5768 - 5776 (1999)
Various substituted 2-pyrones have been hydrogenated with high enantioselectivity (up to 97% ee) to the corresponding 5,6-dihydropyrones using cationic ruthenium catalysts containing the (6,6'-dimethoxybiphenyl- 2,2'diyl)bis[3,5-di(tert-butyl)phenylphosphine] ligand. When substituents at position 3 are absent, 5,6-dihydropyrones are further hydrogenated to the fully saturated δ-lactones. In the case of 4,6-dimethyl-2H-pyran-2-one, the diastereoselectivity of the second hydrogenation step was determined by the chirality of the applied catalyst, while for the 4,5,6-trimethyl-2H-pyran2- one a double asymmetric induction effect was observed. Other cyclic substrates with endo- or exocyclic double bonds were hydrogenated, although with substantially lower enantioselectivity with respect to the 2-pyrones.
Scalemic β-amino sulfide ligands: Use in enantioselective conjugate additions and X-ray analysis of a dimeric copper(I) complex
Cran, Graeme A.,Gibson, Colin L.,Handa, Sheetal,Kennedy, Alan R.
, p. 2511 - 2514 (1996)
The enantioselective conjugate addition using a number of scalemic β-amino sulfide ligands to achieve enantiomeric excesses of up to 64% are described together with the X-ray absolute structure analysis of a dimeric copper(I) complex.
Total Synthesis of (+)-Sarcophytin
Nannini, Leonardo J.,Nemat, Suren J.,Carreira, Erick M.
, p. 823 - 826 (2018)
A total synthesis of the cembranoid (+)-sarcophytin is presented, featuring a Diels–Alder cycloaddition of an enone as the dienophile with an ester-derived dienoate. The study highlights a peculiar geometric preference for the Z dienoate to furnish the cy
CATALYTIC ASYMMETRIC SYNTHESES II. HYDROGENATION OF α,β-UNSATURATED KETONES USING CHIRAL RUTHENIUM COMPLEXES
Massonneau, Viviane,Maux, Paul Le,Simonneaux, Gerard
, p. 269 - 274 (1987)
α,β-Unsaturated ketones have been hydrogenated in the presence of HRuCl(TBPC)2 (TBPC) = (-)-trans-1,2-bis(diphenylphosphinomethyl)cyclobutane) to give ketones with a maximum optical purity of 62percent.Factors affecting the stereoselectivity of the catalytic reaction are discussed.
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
, (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.
Asymmetric Baeyer-Villiger oxidation: Classical and parallel kinetic resolution of 3-substituted cyclohexanones and desymmetrization of: Meso -disubstituted cycloketones
Wu, Wangbin,Cao, Weidi,Hu, Linfeng,Su, Zhishan,Liu, Xiaohua,Feng, Xiaoming
, p. 7003 - 7008 (2019/07/31)
Regioselectivity is a crucial issue in Baeyer-Villiger (BV) oxidation. To date, few reports have addressed asymmetric BV oxidation of 3-substituted cycloketones due to the high difficulty of controlling regio- and stereoselectivity. Herein, we report the asymmetric BV oxidation of 3-substituted and meso-disubstituted cycloketones with chiral N,N′-dioxide/Sc(iii) catalysts performed in three ways: classical kinetic resolution, parallel kinetic resolution and desymmetrization. The methodology was applied in the total and formal synthesis of bioactive compounds and natural products. Control experiments and calculations demonstrated that flexible and adjustable catalysts played a significant role in the chiral recognition of substrates.
