53750-06-4Relevant academic research and scientific papers
Recoverable polystyrene-supported palladium catalyst for construction of all-carbon quaternary stereocenters via asymmetric 1,4-addition of arylboronic acids to cyclic enones
Bartá?ek, Jan,Váňa, Ji?í,Drabina, Pavel,Svoboda, Jan,Kocúrik, Martin,Sedlák, Milo?
, (2020/05/16)
The development of recoverable catalysts based on the combination of synthetically demanding ligands with transition metals attracts a lot of attention, especially from the environmental point of view. In this paper, we describe the preparation of a recoverable polystyrene supported chiral palladium catalyst based on PyOx ligand suitable for asymmetric 1,4-addition of arylboronic acids to cyclic 3-substituted five- and six-membered enones. In the reaction, all?carbon quaternary stereocenters are formed with a high level of enantioselectivity (up to 91% ee) and conversion (up to 99%). The catalyst was used in 6 cycles with no loss of enantioselectivity and only a small decrease in conversion. A solution of the problems associated with the transition from homogeneous to heterogeneous catalytic systems is discussed.
Pyridine-Hydrazone Ligands in Asymmetric Palladium-Catalyzed 1,4- and 1,6-Additions of Arylboronic Acids to Cyclic (Di)enones
de Gracia Retamosa, María,álvarez-Casao, Yolanda,Matador, Esteban,Gómez, ángela,Monge, David,Fernández, Rosario,Lassaletta, José M.
, p. 176 - 184 (2018/12/11)
Catalysts generated by combinations of Pd(TFA)2 and enantiomerically pure pyridine-hydrazone ligands have been applied to the 1,4-addition of arylboronic acids to β-substituted cyclic enones, building all-carbon quaternary stereocenters in high
Synthesis of diverse β-quaternary ketones via palladium-catalyzed asymmetric conjugate addition of arylboronic acids to cyclic enones
Holder, Jeffrey C.,Goodman, Emmett D.,Kikushima, Kotaro,Gatti, Michele,Marziale, Alexander N.,Stoltz, Brian M.
, p. 5781 - 5792 (2015/08/03)
Abstract The development and optimization of a palladium-catalyzed asymmetric conjugate addition of arylboronic acids to cyclic enone conjugate acceptors is described. These reactions employ air-stable and readily-available reagents in an operationally si
Palladium-catalyzed asymmetric quaternary stereocenter formation
Gottumukkala, Aditya L.,Matcha, Kiran,Lutz, Martin,De Vries, Johannes G.,Minnaard, Adriaan J.
supporting information; experimental part, p. 6907 - 6914 (2012/07/01)
An efficient palladium catalyst is presented for the formation of benzylic quaternary stereocenters by conjugate addition of arylboronic acids to a variety of β,β-disubstituted carbocyclic, heterocyclic, and acyclic enones. The catalyst is readily prepared from PdCl2, PhBOX, and AgSbF 6, and provides products in up to 99 % enantiomeric excess, with good yields. Based on this strategy, (-)-α-cuparenone has been prepared in only two steps. Copyright
Palladium-catalyzed asymmetric conjugate addition of arylboronic acids to five-, six-, and seven-membered β-substituted cyclic enones: enantioselective construction of all-carbon quaternary stereocenters
Kikushima, Kotaro,Holder, Jeffrey C.,Gatti, Michele,Stoltz, Brian M.
supporting information; experimental part, p. 6902 - 6905 (2011/06/19)
The first enantioselective Pd-catalyzed construction of all-carbon quaternary stereocenters via 1,4-addition of arylboronic acids to β-substituted cyclic enones is reported. Reaction of a wide range of arylboronic acids and cyclic enones using a catalyst
Rhodium-catalyzed asymmetric 1,4-addition of aryl alanes to trisubstituted enones: Binap as an effective ligand in the formation of quaternary stereocenters
Hawner, Christine,Mueller, Daniel,Gremaud, Ludovic,Felouat, Abdellah,Woodward, Simon,Alexakis, Alexandre
supporting information; experimental part, p. 7769 - 7772 (2010/12/25)
All for one and 1,4-all: Readily available aryl alanes are used in the rhodium-catalyzed asymmetric conjugate addition reaction with a variety of cyclic and acyclic enones. The enhanced reactivity of the system allows the use of the common binap ligand for the generation of quaternary benzylic stereocenters in excellent enantioselectivity (see scheme).
Copper-catalyzed asymmetric conjugate addition of aryl aluminum reagents to trisubstituted enones: Construction of aryl-substituted quaternary centers
Hawner, Christine,Li, Kangying,Cirriez, Virginie,Alexakis, Alexandre
supporting information; experimental part, p. 8211 - 8214 (2009/04/13)
(Chemical Equation Presented) Al be back: Novel aryl and alkenyl aluminum reagents are generated through a halogen/Li exchange-Li/Al transmetalation sequence. These aryl alanes are used in the copper-catalyzed asymmetric conjugate addition reaction to a variety of cyclic enones giving chiral aryl-substituted quaternary centers (see scheme). Both, electron-donating and electron-withdrawing groups give full conversion and very good ee values.
Enantioselective synthesis of all-carbon quaternary stereogenic centers by catalytic asymmetric conjugate additions of alkyl and aryl aluminum reagents to five-, six-, and seven-membered-ring β-substituted cyclic enones
May, Tricia L.,Brown, M. Kevin,Hoveyda, Amir H.
body text, p. 7358 - 7362 (2009/04/10)
(Chemical Equation Presented) Solution to pesky problems: Effective methods for catalytic asymmetric conjugate additions of alkyl and aryl aluminum reagents with unactivated β-substituted cyclopentenones are now available (see scheme). Transformations, pr
