An efficient and direct ruthenium-catalyzed regioselective hydroxymethylation of (hetero)arenes via C-H activation with paraformaldehyde as a hydroxymethylating reagent is described. The corresponding products can be obtained in good to excellent yield. A number of aryl aldehydes can also be used in place of paraformaldehyde giving the desired alcohol products with similarly good results.
Rh-Catalyzed CC Cleavage of Benzyl/Allylic Alcohols to Produce Benzyl/Allylic Amines or other Alcohols by Nucleophilic Addition of Intermediate Rhodacycles to Aldehydes and Imines
作者:Xi-Sha Zhang、Yang Li、Hu Li、Kang Chen、Zhi-Quan Lei、Zhang-Jie Shi
DOI:10.1002/chem.201201867
日期:2012.12.7
imines was slower than the CC cleavage and the equilibrium between the rhodacycle and phenylpyridine; iv) the whole transformation was a combination of two sequences of CC cleavage/nucleophilic addition and CC cleavage/protonation/CH activation/nucleophilic addition, with the latter being perhaps the main pathway. We also demonstrated the first example of cleavage of an C(alkenyl)C(benzyl) bond
Grignard-Type Arylation of Aldehydes via a Rhodium-Catalyzed CH Activation under Mild Conditions
作者:Luo Yang、Camille A. Correia、Chao-Jun Li
DOI:10.1002/adsc.201100232
日期:2011.5
An efficient Grignard‐type arylation of aldehydes via aryl CHactivation was achieved under mild conditions catalyzed by rhodium. The reaction provides an easy access to a wide variety of benzyl alcohols and can tolerate various functional groups as well as air and water.
Contribution of heterobifunctional ligands to transition metal-catalysed C--C coupling reactions
作者:Agnes LABANDE、Eric DEYDIER、Eric MANOURY、Jean-Claude DARAN、Catherine AUDIN、Rinaldo POLI
DOI:10.3906/kim-1507-73
日期:——
In this account the authors' latest results in C-C coupling catalysis are reviewed. First, an efficient catalytic system for the Kumada-Tamao-Corriu coupling reaction based on NHC-phosphine (NHC = N-heterocyclic carbene) nickel complexes is presented. Then the use of palladium complexes of chiral ferrocenyl NHC-phosphines in the asymmetric Suzuki-Miyaura coupling reaction is reported. High catalytic activities and moderate enantioselectivities (ee up to 46%) were obtained. Chiral ferrocenyl phosphine-ethers were also tested in the asymmetric Suzuki-Miyaura reaction yielding good activities and moderate enantioselectivities (ee up to 37%). Finally, the original synthesis of a ferrocenyl rhodium(III) complex and its successful use as catalyst for a C-C coupling reaction via C-H activation of 2-phenylpyridine is presented.
The chemical oxidation of rhodium(i) complexes [Rh(L)(COD)][BF4], where L is a ferrocenyl phosphine/N-heterocyclic carbene ligand, with 2 equiv. of a triaryl-aminium salt [(4-BrC6H4)3N][BF4] in acetonitrile gave planar chiral, air-stable [Rh(L–H)(MeCN)3][BF4]2 complexes where the ferrocene (C5H4CH2ImR or C5H4CH2BImCH2Mes) ring has been C–H activated at the position 2 in good to excellent yields. An