Selective hetero- and carbo-cycle syntheses via masked cyclopalladated secondary amine and ketone functions

C–H Activation at a Bidentate Ligand Coordinated to Palladium(II) – an Electrophilic Attack Supported by an External Base

“…The palladium‐centered C–H activation was investigated by a kinetic study that allowed the elucidation of the kinetic parameters of this reaction. Similar C–H activation processes have been reported as primary steps in a series of palladium‐catalyzed and pyridine‐directed reactions, namely, for carbazole6 and indole7 syntheses as well as arene–alkyne8 and arene–allene9 couplings.…”

“…General Procedure for the Synthesis of the Guanidinium Salts 1a–1e: 7 Concentrated nitric acid was added to a solution of the appropriate arylamine in ethanol followed by a 50 % aqueous solution of cyanamide (1.5 equiv.). The reaction mixture was heated under reflux for 16 h and then cooled to 0 °C, diethyl ether was then added.…”

Palladium-mediated intramolecular C–N bond formation involving allyl substituted pyridines. Application to a novel strategy for the synthesis of the skeleton of berberinium derivatives

“…The cyclopalladated compounds: bis [(2-pyridyl(h)naphtyl (kN, kC 1 )] di(m-chloro) dipalladium 4a, 16 bis [2-(2-pyridyl)phenyl (kN, kC 1 )] di(m-chloro) dipalladium 5a[17], bis [2-(2-pyridyl)methylphenyl (kN, kC 1 )] di(m-chloro) dipalladium 6a[18] and bis [2-pyridyl-2-aminophenyl (kN, kC 1 )] di(m-chloro) dipalladium 7a[19] were prepared according to published methods. mmol) in 20 ml of dichloromethane was stirred for 1 h at r.t. A black heterogenous solution was observed.…”

Palladium complexes of N-aryl-2-pyridylamines

“…The oxidative cyclisation product 5 could, however, not be obtained by further heating in dichlorobenzene or acetic acid or by microwave promoted reaction conditions. Such cyclopalladation complexes are normally quite unreactive, but CO, alkene and alkyne [28] insertion has been carried out. Acetato-bridged complexes may also give the pyridine-ligand derivative by pyridine treatment [27].…”

“…Acetatobridged 5-ring palladacyclic dimers are reported to exhibit a ''boat'' form to permit greater electron delocalization. [29] Such dimeric 5-ring acetato-bridged [30-32] and 6-ring chloro-bridged [32] palladacycles are known to be formed as single trans isomers, often by an indirect C-H activation route, using a precursor (PdAr-CH 2 NMe 2 Cl) 2 palladacycle as the Pd source [27,28] It has, however, been shown that 5-ring palladacyclic dimeric complexes also may adopt both cis and/or trans geometry depending on intermolecular interactions [33]. The H 2 O 2 /benzoquinone protocol represents a simple and new preparation method for the dimeric acetato-bridged 6-membered ring palladacycle 13.…”