885273-16-5Relevant articles and documents
N, C-Disubstituted Biarylpalladacycles as Precatalysts for ppm Pd-Catalyzed Cross Couplings in Water under Mild Conditions
Thakore, Ruchita R.,Takale, Balaram S.,Gallou, Fabrice,Reilly, John,Lipshutz, Bruce H.
, p. 11647 - 11657 (2019/11/29)
Various monosubstitution and disubstitution patterns on the parent biarylamine skeleton characteristic of palladacycles, as well as the counterion effect, have been studied while looking for ways to increase the effectiveness of the catalyst formed under micellar catalysis conditions in water, with the goal of reducing the amount of Pd needed for coupling reactions. Several substituted palladacycles containing readily accessible ligands were chosen for evaluation. The results indicate that (1) preactivation of Pd(II) salts as precursors for Suzuki-Miyaura (SM) couplings via treatment with a reducing agent is not required; (2) reactions could be performed with approximately half the loading of Pd, relative to that previously required based on a combination of a Pd(II) salt and ligand; and (3) the most effective palladacycle precatalyst has been identified as that containing an isopropyl group on both an aryl ring and on nitrogen, together with the ligand EvanPhos and triflate as the counterion (P13). This precatalyst is also effective in other C-C bond-forming reactions, such as Heck and Sonogashira couplings. No organic solvents were needed for these processes, while the aqueous reaction medium could be recycled several times. A one-pot, four-step sequence involving Suzuki-Miyaura, reduction, alkylation, and acylation reactions highlights the potential for this precatalyst to maximize synthetic gain while minimizing costs and waste generation.
NOVEL PRECATALYST SCAFFOLDS FOR CROSS-COUPLING REACTIONS, AND METHODS OF MAKING AND USING SAME
-
Page/Page column 55; 56; 57, (2016/05/02)
The present invention provides novel transition-metal precatalysts that are useful in preparing active coupling catalysts. In certain embodiments, the precatalysts of the invention are air-stable and moisture-stable. The present invention further provides methods of making and using the precatalysts of the invention.
Design of a versatile and improved precatalyst scaffold for palladium-catalyzed cross-coupling: (η3-1-tBu-indenyl)2(μ-Cl)2Pd2
Melvin, Patrick R.,Nova, Ainara,Balcells, David,Dai, Wei,Hazari, Nilay,Hruszkewycz, Damian P.,Shah, Hemali P.,Tudge, Matthew T.
, p. 3680 - 3688 (2015/06/16)
We describe the development of (η3-1-tBu-indenyl)2(μ-Cl)2Pd2, a versatile precatalyst scaffold for Pd-catalyzed cross-coupling. Our new system is more active than commercially available (η3-cinnamyl)2(μ-Cl)2Pd2 and is compatible with a range of NHC and phosphine ligands. Precatalysts of the type (η3-1-tBu-indenyl)Pd(Cl)(L) can either be isolated through the reaction of (η3-1-tBu-indenyl)2(μ-Cl)2Pd2 with the appropriate ligand or generated in situ, which offers advantages for ligand screening. We show that the (η3-1-tBu-indenyl)2(μ-Cl)2Pd2 scaffold generates highly active systems for a number of challenging cross-coupling reactions. The reason for the improved catalytic activity of systems generated from the (η3-1-tBu-indenyl)2(μ-Cl)2Pd2 scaffold compared to (η3-cinnamyl)2(μ-Cl)2Pd2 is that inactive PdI dimers are not formed during catalysis.
Transforming Suzuki-Miyaura cross-couplings of MIDA boronates into a green technology: No organic solvents
Isley, Nicholas A.,Gallou, Fabrice,Lipshutz, Bruce H.
supporting information, p. 17707 - 17710 (2014/01/06)
New technology has been developed that enables Suzuki-Miyaura couplings involving widely utilized MIDA boronates to be run in water as the only medium, mainly at room temperature. The protocol is such that no organic solvent is involved at any stage; from the reaction through to product isolation. Hence, using the E factor scale as a measure of greenness, the values for these cross-couplings approach zero.
A new palladium precatalyst allows for the fast Suzuki-Miyaura coupling reactions of unstable polyfluorophenyl and 2-heteroaryl boronic acids
Kinzel, Tom,Zhang, Yong,Buchwald, Stephen L.
supporting information; experimental part, p. 14073 - 14075 (2011/01/04)
Boronic acids which quickly deboronate under basic conditions, such as polyfluorophenylboronic acid and five-membered 2-heteroaromatic boronic acids, are especially challenging coupling partners for Suzuki-Miyaura reactions. Nevertheless, being able to use these substrates is highly desirable for a number of applications. Having found that monodentate biarylphosphine ligands can promote these coupling processes, we developed a precatalyst that forms the catalytically active species under conditions where boronic acid decomposition is slow. With this precatalyst, Suzuki-Miyaura reactions of a wide range of (hetero)aryl chlorides, bromides, and triflates with polyfluorophenyl, 2-furan, 2-thiophene, and 2-pyrroleboronic acids and their analogues proceed at room temperature or 40 °C in short reaction times to give the desired products in excellent yields.
SLOW RELEASE OF ORGANOBORONIC ACIDS IN CROSS-COUPLING REACTIONS
-
Page/Page column 53, 55-56, (2010/04/27)
A method of performing a chemical reaction includes reacting a compound selected from the group consisting of an organohalide and an organo-pseudohalide, and a protected organoboronic acid represented by formula (I) in a reaction mixture: R1-B-T; where R1 represents an organic group, T represents a conformationalIy rigid protecting group, and B represents boron having sp3 hybridization. When unprotected, the corresponding organoboronic acid is unstable by the boronic acid neat stability test. The reaction mixture further includes a base having a pKB of at least 1 and a pal ladium catalyst. The method further includes forming a cross-coupled product in the reaction mixture.
Ligand-free and heterogeneous palladium on carbon-catalyzed hetero-suzuki-miyaura cross-coupling
Kitamura, Yoshiaki,Sako, Satoko,Tsutsui, Azusa,Monguchi, Yasunari,Maegawa, Tomohiro,Kitade, Yukio,Sajiki, Hironao
experimental part, p. 718 - 730 (2010/06/16)
A ligand-free and heterogeneous palladium on carbon (Pd/C)-catalyzed hetero-SuzukiMiyaura coupling reaction has been developed. The protocol enables the construction of both heterocyclic-alicyclic and heterocyclic-heterocyclic biaryl derivatives in good to excellent yields. Furthermore, Pd/C could be reused. The time-course study clarified that palladium was leached into the reaction media as the reaction proceeded and then completely deposited on the carbon support.
Ligand-free Pd/C-catalyzed Suzuki-Miyaura coupling reaction for the synthesis of heterobiaryl derivatives
Kitamura, Yoshiaki,Sako, Satoko,Udzu, Takahiro,Tsutsui, Azusa,Maegawa, Tomohiro,Monguchi, Yasunari,Sajiki, Hironao
, p. 5069 - 5071 (2008/09/17)
We have developed a mild and efficient protocol for the ligand-free and heterogeneous Pd/C-catalyzed hetero Suzuki-Miyaura coupling reaction that allows for the synthesis of both heteroaryl-aryl and heteroaryl-heteroaryl derivatives in good to excellent yields. The Royal Society of Chemistry.
