- A theoretically-guided optimization of a new family of modular P,S-ligands for iridium-catalyzed hydrogenation of minimally functionalized olefins
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A library of modular iridium complexes derived from thioether-phosphite/phosphinite ligands has been evaluated in the asymmetric iridium-catalyzed hydrogenation of minimally functionalized olefins. The modular ligand design has been shown to be crucial in finding highly selective catalysts for each substrate. A DFT study of the transition state responsible for the enantiocontrol in the Ir-catalyzed hydrogenation is also described and used for further optimization of the crucial stereodefining moieties. Excellent enantioselectivities (enantiomeric excess (ee) values up to 99%) have been obtained for a range of substrates, including E- and Z-trisubstituted and disubstituted olefins, α,β-unsaturated enones, tri- and disubstituted alkenylboronic esters, and olefins with trifluoromethyl substituents.
- Margalef, Jèssica,Caldentey, Xisco,Karlsson, Erik A.,Coll, Mercè,Mazuela, Javier,Pàmies, Oscar,Diéguez, Montserrat,Pericàs, Miquel A.
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p. 12201 - 12214
(2015/03/31)
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- Aqueous asymmetric transfer hydrogenation using modular hydrophobic aminoalcohols
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A series of new modular Ru/aminoalcohol systems were used as enantioselective catalysts in the asymmetric transfer hydrogenation reaction in both water and 2-propanol. The catalytic behavior exhibited in these two media follows different tendencies regard
- Alza, Esther,Bastero, Amaia,Jansat, Susanna,Pericas, Miquel A.
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p. 374 - 378
(2008/09/19)
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- Computer assisted, mechanism directed design of a new ligand for the highly enantioselective catalytic addition of diethylzinc to aldehydes
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A new ligand, (1R,2R)-1-(cis-2,6-dimethylpiperidino)-1-phenyl-3-trityloxypropan-2-ol 1c, designed on the basis of molecular modelling (AMI) studies to increase the energy gap between the re and si attacks in the aminoalcohol promoted addition of diethylzi
- Vidal-Ferran, Anton,Moyano, Albert,Pericas, Miquel A.,Riera, Antoni
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p. 8773 - 8776
(2007/10/03)
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- An efficient catalytic asymmetric epoxidation method
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This article describes a highly effective catalytic asymmetric epoxidation method for olefins using,potassium peroxomonosulfate (Oxone, Dupont) as oxidant and a fructose-derived ketone(l) as catalyst. High enantioselectivies have been obtained-for trans-disubstituted and trisubstituted olefins which can bear functional groups such as tributylsilyl ether, acetal, chloride, and ester. The enantiomeric excesses cis-olefins and terminal olefins are not high yet. The current epoxidation shows that the catalyst efficiency is enhanced dramatically-upon raising the pH. Mechanitic studies show that the epoxidation mainly proceeds via a spiro transition state, which provides a model for predicting the stereochemical outcome of the reaction. The planar transition state, likely to be the main competing pathway. The extent of the involvement of the planar mode is subject to the steric of the alkyl groups on the olefins.
- Wang, Zhi-Xian,Tu, Yong,Frohn, Michael,Zhang, Jian-Rong,Shi, Yian
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p. 11224 - 11235
(2007/10/03)
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