RESUMO
[Ir(COD)Cl]2/tris(2,4-di-t-butylphenyl)phosphite-catalyzed addition reactions of arylboronic acids with aldehydes were described. The Ir(I) catalyst, generated from [Ir(COD)Cl]2 and tris(2,4-di-t-butylphenyl)phosphite, was an efficient catalyst system for the addition reactions of a variety of arylboronic acids with aromatic and aliphatic aldehydes. The easy availability of the catalyst and good yields make these reactions potentially useful in organic synthesis.
RESUMO
Controlled Pd(0)-catalyzed Suzuki cross-coupling polymerizations of AB-type monomers with tris(1-adamantyl)phosphine (Ad3P) as the ligand was described. Ad3P-coordinated acetanilide-based palladacycle complex (1) was demonstrated to be an efficient initiator for controlled Suzuki cross-coupling polymerization, affording polymers with narrow Ds and well-controlled end groups. Our study provided an efficient ligand and an efficient initiator for controlled Suzuki cross-coupling polymerizations.
RESUMO
t-Bu3P-coordinated 2-phenylaniline-based palladacycle complex (1) as the unique source of Pd(0)/t-Bu3P to form efficient initiators with ArBr for controlled Suzuki cross-coupling polymerizations of AB-type monomers was described. The in situ generated initiators were demonstrated to be robust initiator systems for controlled Suzuki cross-coupling polymerization, affording polymers with unprecedentedly narrow PDIs and well-controlled functional end groups. 31P NMR study suggested that the fast and efficient generation of ArPd(t-Bu3P)Br complexes from precatalyst 1 and ArBr might be the reason for better control of polymerization with precatalyst 1/ArBr as initiators. Our study provided a family of unprecedented, highly efficient initiators for controlled Suzuki cross-coupling polymerizations and a direct route to access conjugated polymers with a variety of heterobisfunctional chain end groups.
RESUMO
The use of electron-poor, fluoro-containing arylboronic acids as general coupling partners for nickel(0) /tricyclohexylphosphine-catalyzed cross-coupling of aryl arenesulfonates is described. Electron-poor fluoro-containing arylboronic acids were found to react, faster than electron-rich/neutral arylboronic acids, with (4-methoxyphenyl)(4-methylbenzenesulfonato-κO)bis(tricyclohexylphosphine)nickel. Bis(1,5-cyclooctadiene)nickel(0)/tricyclohexylphosphine, (4-methoxyphenyl)(4-methylbenzenesulfonato-κO)bis(tricyclohexylpho sphine)nickel and bis(tricyclohexylphosphine)nickel (II) bromide were all found to be efficient catalysts/catalyst precursors.
RESUMO
A general strategy toward the synthesis of well-defined conjugated polymers with controlled heterobisfunctional chain ends via combination of controlled Pd(0)/t-Bu3P Suzuki cross-coupling polymerization with the post-polymerization modification of the triflate (OTf) group was disclosed.
RESUMO
tBu3P-Coordinated 2-phenylaniline-based palladacycle complex was demonstrated to be an efficient precatalyst for Pd-catalyzed coupling reactions of aryl halides with polyfluoroarenes via C-H activation strategy. The readily accessibility and easy handling nature of tBu3P- coordinated 2-aminobiphenyl-based palladacycle complex and the high yields of the reaction makes tBu3P-coordinated 2-aminobiphenyl-based palladacycle complex an attractive precatalyst for the cross-coupling reaction of aryl halides with polyfluoroarenes.
RESUMO
t -Bu3P-Coordinated 2-phenylaniline-based palladacycle complex, [2'-(amino-kN)[1,1'-biphenyl]-2-yl-kC]chloro(tri-t-butylphosphine)palladium, as a general, highly efficient precatalyst for the Suzuki cross-coupling polymerization of aryl dibromides with aryldiboronic acids is described. Such t-Bu3P-coordinated 2-aminobiphenyl-based palladacycle complex-catalyzed Suzuki cross-coupling polymerization afforded polymers within an hour, with the yields and the molecular weights comparable to or higher than that of polymers obtained by using other palladium catalysts with much longer polymerization time. Our study provided a highly efficient catalyst system for the Suzuki cross-coupling polymerization of aryl dihalides with aryldiboronic acids. Our study also paved the road for us to investigate other monodentate ligand-coordinated palladacycle complexes including N-heterocyclic carbine-coordinated ones for cross-coupling polymerizations.
RESUMO
The title compound, C(18)H(14)O(2), is almost planar with a dihedral angle of 1.24â (2)° between the phenyl-ethynyl and styryl groups. The acet-oxy group is tilted by 82.46â (2) and 82.26â (3)° with respect to the benzene ring planes.
RESUMO
Controlled Pd(0)/t-Bu(3)P-catalyzed Suzuki cross-coupling polymerizations of AB-type monomers via the chain-growth mechanism with an ArPd(t-Bu(3)P)I complex as the initiator are described. ArPd(t-Bu(3)P)I complexes, either prepurified or generated in situ from Pd(2)(dba)(3)/t-Bu(3)P/ArI (dba = dibenzylideneacetone) without separation/purification, were found to be efficient initiators in general for the controlled Suzuki cross-coupling polymerization, with narrow polydispersity indexes (PDIs) of 1.13-1.35 being observed. The Pd(2)(dba)(3)/t-Bu(3)P/p-BrC(6)H(4)I combination was identified as a highly robust initiator system, with PDIs of ≤1.20 in general and as low as 1.13 being obtained. Higher number-average molecular weights (M(n)) were achieved without a significant increase in the PDI (from 1.14 for a polymer with a M(n) = 9500 to 1.20 for a polymer with M(n) = 31,400) by using a smaller amount of the Pd(2)(dba)(3)/t-Bu(3)P/p-BrC(6)H(4)I initiator in the polymerization.
RESUMO
Rh(I)/diene-catalyzed addition reactions of arylboroxines/arylboronic acids with unactivated ketones to form tertiary alcohols in good to excellent yields are described. By using C(2)-symmetric (3aR,6aR)-3,6-diaryl-1,3a,4,6a-tetrahydropentalenes as ligands, the asymmetric version of such an addition reaction, with up to 68% ee, was also realized.
Assuntos
Álcoois/síntese química , Ácidos Borônicos/química , Cetonas/química , Ródio/química , Álcoois/química , Catálise , Técnicas de Química Combinatória , Estrutura MolecularRESUMO
Tandem aldol condensation of aldehydes with methyl ketones followed by anionic four-electron donor-based (Type I) platinacycle-catalyzed addition reactions of arylboronic acids to form ß-arylated ketones is described. Good to excellent yields of ß-arylated ketones were obtained for the tandem reactions of aromatic/aliphatic aldehydes, methyl ketones and arylboronic acids, and moderate yields were observed for the tandem reaction with α, ß-unsaturated aldehydes as the aldehyde source.
RESUMO
CuCl/bipyridine-catalyzed addition reactions of arylboroxines with aldehydes and α,ß-unsaturated ketones at elevated temperatures were described. By using the microwave energy, CuCl/bipyridine-catalyzed addition reactions of arylboroxines with aldimines were also realized.
RESUMO
Two polymorphs of (2-carboxyethyl)(phenyl)phosphinic acid, C(9)H(11)O(4)P, crystallize in the chiral P2(1)2(1)2(1) space group with similar unit-cell parameters. They feature an essentially similar hydrogen-bonding motif but differ slightly in their detailed geometric parameters. For both polymorphs, the unequivocal location of the hydroxy H atoms together with the expected differences in the P-O bond lengths establish unequivocally that both forms contain the S isomer; the protonated phosphinic acid and carboxy O atoms serve as hydrogen-bond donors, while the second phosphinic acid O atom acts as a double hydrogen-bond acceptor and the remaining carboxy O atom is not involved in hydrogen bonding. Thus, an undulating two-dimensional supramolecular layer aggregate is formed based on an R(4)(3)(20) ring unit. Such polymorphism derives from the rotation of the C-C single bonds between the two hydrogen-bond-involved carboxy and phosphinic acid moieties.
RESUMO
RuCl3·3H2O was found to be an effective catalyst for reactions of indoles, 2-methylthiophene, and 2-methylfuran with aldehydes to afford the corresponding bis(indolyl)methanes, bis(thienyl)methanes, and bis(fur-2-yl)methanes in moderate to excellent yields. Experimental results indicated that mono(indolyl)methanol is not the reaction intermediate under these reaction conditions.
Assuntos
Metano/análogos & derivados , Metano/síntese química , Rutênio/química , Catálise , Metano/química , Estrutura MolecularRESUMO
The title compound, [Mg(C(3)H(10)NO(6)P(2))(2)](n), synthesized by a hydro-thermal method, adopts a one-dimensional polymeric chain structure and is isotypic with the previously reported Cd complex based on the ligand N,N-dimethyl-amino-methane-1,1-diphospho-nic acid (H(4)L). The asymmetric unit contains one half Mg(2+) ion and one H(3)L(-) anion. The unique Mg(2+) ion lies on an inversion center and is octa-hedrally coordinated by O atoms from six phospho-nate groups of four different H(3)L(-) anions. Each H(3)L(-) anion, with one protonated N atom and two phospho-nate OH groups, serves as a tridentate ligand. Two of its six phospho-nate O atoms chelate to a Mg(2+) cation in a bidentate fashion, while a third O atom bridges to a neighbouring Mg(2+) ion. The inter-connection of Mg(2+) ions by the H(3)L(-)anions leads to the formation of a polymer chain along the a axis in which the adjacent Mg(2+) ions are doubly bridged by two equivalent H(3)L(-) anions. These discrete chains are further assembled into a three-dimensional supra-molecular network via O-Hâ¯O and N-Hâ¯O hydrogen bonds involving the non-coordin-ated phospho-nate O atoms and the protonated N atoms.
RESUMO
A new, anionic four-electron donor-based (type I) palladacycle-catalyzed sequential reaction of 2-bromobenzaldehydes with arylboronic acids based on the addition reaction, cyclization via C-H activation-oxidation sequence is described. Our study provided an efficient access to a variety of substituted fluorenones/indenofluorenediones from readily available arylboronic acids and 2-bromobenzaldehydes.
Assuntos
Benzaldeídos/química , Ácidos Borônicos/química , Compostos de Bromo/química , Fluorenos/síntese química , Paládio/química , Catálise , Ciclização , Estrutura Molecular , OxirreduçãoRESUMO
The synthesis and application of a series of optically active 1,1'-spirobiindane-7,7'-diol (SPINOL)-based phosphoric acids are described. These SPINOL-based phosphoric acids were prepared from (R)-SPINOL in three steps and exhibited excellent enantioselectivities for the reactions of indoles with aldimines and ß,γ-unsaturated-α-ketoesters. Our study provides a family of promising chiral phosphoric acids to the asymmetric organocatalysis toolbox.
RESUMO
Sequential aldol condensation of aldehydes with methyl ketones followed by transition metal-catalyzed addition reactions of arylboronic acids to form ß-substituted ketones is described. By using the 1,1'-spirobiindane-7,7'-diol (SPINOL)-based phosphite, an asymmetric version of this type of sequential reaction, with up to 92% ee, was also realized. Our study provided an efficient method to access ß-substituted ketones and might lead to the development of other sequential/tandem reactions with transition metal-catalyzed addition reactions as the key step.
Assuntos
Aldeídos/química , Ácidos Borônicos/química , Cetonas/química , Ródio/química , Catálise , Metilação , Estrutura MolecularRESUMO
Tandem orthoplatinated triaryl phosphite-catalyzed addition reactions of arylboronic acids with aldehydes followed by oxidation to yield aryl ketones is described. 3-Pentanone was identified as a suitable oxidant for the tandem aryl ketone formation reaction. By using microwave energy, aryl ketones were obtained in high yields with the catalyst loading as low as 0.01%.
Assuntos
Aldeídos/química , Ácidos Borônicos/química , Cetonas/síntese química , Compostos Organoplatínicos/química , Catálise , Cetonas/química , Estrutura Molecular , Oxirredução , EstereoisomerismoRESUMO
Transition metal-catalyzed addition of arylboronic acids to 2-formylbenzoates afforded 3-substituted phthalides. By using SPINOL-based phosphites as ligands, a Rh(I)-catalyzed asymmetric version of such an addition reaction was achieved.