33026-37-8Relevant academic research and scientific papers
A Pd(II)-Functionalized Covalent Organic Framework for Catalytic Conjugate Additions of Arylboronic Acids to β,β-Disubstituted Enones
Heintz, Patrick M.,Schumacher, Brian P.,Chen, Minda,Huang, Wenyu,Stanley, Levi M.
, p. 4286 - 4290 (2019/08/16)
A palladium(II)-functionalized covalent organic framework (Pd@TpBpy COF) constructed from 1,3,5-triformylphloroglucinol (Tp) and [2,2′-bipyridine]-5,5′-diamine (Bpy) is reported as a recyclable catalyst for conjugate additions in aqueous media. Additions
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 Cyclohexanones through a Catalytic Cationic Cyclization of Alkynols or Enynes
Alonso, Pedro,Fontaneda, Raquel,Pardo, Pilar,Fa?anás, Francisco J.,Rodríguez, Félix
supporting information, p. 1659 - 1662 (2018/03/23)
A novel procedure for the synthesis of cyclohexanones from alkynol or enyne derivatives through a cationic cyclization has been developed. The key points to obtain the six-membered ring derivatives are the use of starting materials containing a terminal alkyne, the use of tetrafluoroboric acid as a promoter of the cationic cyclization, and the appropriate selection of 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP) as solvent. This strategy can be extended to the biomimetic cationic cyclization of several terpene-derived polyenynes.
Cobalt-Catalyzed Regioselective Olefin Isomerization under Kinetic Control
Liu, Xufang,Zhang, Wei,Wang, Yujie,Zhang, Ze-Xin,Jiao, Lei,Liu, Qiang
supporting information, p. 6873 - 6882 (2018/05/30)
Olefin isomerization is a significant transformation in organic synthesis, which provides a convenient synthetic route for internal olefins and remote functionalization processes. The selectivity of an olefin isomerization process is often thermodynamically controlled. Thus, to achieve selectivity under kinetic control is very challenging. Herein, we report a novel cobalt-catalyzed regioselective olefin isomerization reaction. By taking the advantage of fine-tunable NNP-pincer ligand structures, this catalytic system features high kinetic control of regioselectivity. This mild catalytic system enables the isomerization of 1,1-disubstituted olefins bearing a wide range of functional groups in excellent yields and regioselectivity. The synthetic utility of this transformation was highlighted by the highly selective preparation of a key intermediate for the total synthesis of minfiensine. Moreover, a new strategy was developed to realize the selective monoisomerization of 1-alkenes to 2-alkenes dictated by installing substituents on the γ-position of the double bonds. Mechanistic studies supported that the in situ generated Co-H species underwent migratory insertion of double bond/β-H elimination sequence to afford the isomerization product. The less hindered olefin products were always preferred in this cobalt-catalyzed olefin isomerization due to an effective ligand control of the regioselectivity for the β-H elimination step.
Palladium complexes with chiral imidazole ligands as potential catalysts for asymmetric C[sbnd]C coupling reactions
Zawartka, Wojciech,Gniewek, Andrzej,Trzeciak, Anna M.
, p. 595 - 599 (2016/11/30)
Two palladium complexes of the type [Pd(im)2Cl2] containing chiral imidazole ligands (im?=?1-bornyloxymethylene imidazole, 1-fenchyloxymethylyne imidazole) were synthesized and structurally characterized. The square planar structure of one of the complexes was confirmed by the X-ray analysis. The new palladium complexes were tested as catalysts in various C[sbnd]C bond forming reactions, namely Suzuki–Miyaura, carbonylative Suzuki–Miyaura, asymmetric Heck-type coupling reactions and asymmetric conjugate addition of phenylboronic acid to heterocyclic acceptors. In all the reactions the cross-coupling products were obtained with high yield and selectivity under mild conditions. In case of coupling of 2,3-dihydrofuran with phenylboronic acid ee value ca. 10 was observed.
MOF-253-Pd(OAc)2: A recyclable MOF for transition-metal catalysis in water
Van Zeeland, Ryan,Li, Xinle,Huang, Wenyu,Stanley, Levi M.
, p. 56330 - 56334 (2016/07/06)
We report palladium(ii)-functionalized MOF-253 (MOF-253-Pd(OAc)2) as a recyclable catalyst to form all-carbon quaternary centers via conjugate additions of arylboronic acids to β,β-disubstituted enones in aqueous media. We demonstrate MOF-253-Pd(OAc)2 can be reused 8 times to form ketone products in yields above 75% while maintaining its crystallinity. Additions of a range of stereoelectronically diverse arylboronic acids to a variety of β,β-disubstituted enones catalyzed by MOF-253-Pd(OAc)2 occur in modest-to-high yields (34-95%).
Palladium-Catalyzed Conjugate Addition of Arylboronic Acids to β,β-Disubstituted Enones in Aqueous Media: Formation of Bis-benzylic and ortho-Substituted Benzylic Quaternary Centers
Van Zeeland, Ryan,Stanley, Levi M.
, p. 5203 - 5206 (2015/09/15)
Palladium-catalyzed conjugate addition of arylboronic acids to β,β-disubstituted enones in aqueous media is reported. Additions of a wide range of arylboronic acids to β,β-disubstituted enones occur to form ketone products bearing benzylic all-carbon quaternary centers. These reactions are promoted by a simple catalyst prepared from palladium trifluoracetate and 2,2′-bipyridine. The use of aqueous sodium trifluoracetate as the reaction medium significantly enhances reactivity and enables the formation of challenging bis-benzylic and ortho-substituted benzylic all-carbon quaternary centers.
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
1,4-Addition of aryl boronic acids to α,β-unsaturated ketones catalyzed by a CCC-NHC pincer rhodium complex
Reilly, Sean W.,Box, Hannah K.,Kuchenbeiser, Glenn R.,Rubio, Ramel J.,Letko, Christopher S.,Cousineau, Kandarpa D.,Hollis, T. Keith
supporting information, p. 6738 - 6742 (2014/12/11)
An air- and water-stable CCC-NHC pincer Rh complex catalyzed the 1,4-addition of aryl boronic acids to α,β-unsaturated ketones and aldehydes. This bench top method proceeds in eco-friendly solvents including methanol and water. The scope of boronic acids was expanded to include heterocyclic examples.
Efficient formation of benzylic quaternary centers via palladium catalysis
Gottumukkala, Aditya L.,Suljagic, Jasmin,Matcha, Kiran,De Vries, Johannes G.,Minnaard, Adriaan J.
, p. 1636 - 1639 (2013/10/21)
Four's a crowd: An efficient protocol for the formation of benzylic quaternary centers via arylation of enones using a catalyst made from Pd(O 2CCF3)2 and 2,2′-bipyridine is developed. For cyclic substrates, catalyst loadi
