Solvent-Free Buchwald-Hartwig Amination of Heteroaryl Chlorides by N-Heterocyclic Carbene-Palladium Complex (SIPr)Ph2Pd(cin)Cl at Room Temperature

Using the robust N-heterocyclic carbene-palladium complex (SIPr)Ph2Pd(cin)Cl, a highly efficient and easy-to-operate method has been developed at room temperature for the solvent-free Buchwald-Hartwig amination of heteroaryl chlorides with various amines. The amount of catalyst can be as low as 0.05 wt %. The system was demonstrated on 47 substrates and successfully applied to the synthesis of commercial pharmaceuticals and candidate drugs with high yields. Furthermore, the protocol can be used to prepare aniline derivatives on a multigram scale without yield loss.

Transition metal complexes with functionalized indenyl phosphine ligands: structures and catalytic properties

Transition-metal indenyl complexes usually exhibit different reactivities compared with their cyclopentadienyl analogues. Up to now, at least 10 metal-indenyl bonding modes have been reported. Because of the "indenyl effect", transition-metal indenyl complexes usually show enhanced reactivity in substitution and related reactions. This review provides an overview on the use and impact of indenyl phosphines in organometallic chemistry and transition-metal-catalysed reactions in the recent two decades. Some cationic and zwitterionic metal complexes supported by P,N-substituted indene or indenide ligands are described. They have been reported to induce the cleavage of E-H (E = H, Si and B) bonds and can be used as catalysts for addition of E-H bonds to unsaturated substrates. 2-Aryl indenyl phosphine ligands L3-L11 have been proven to be a class of versatile ligands for palladium-catalysed C-C and C-N cross-coupling reactions. Moreover, optically active tethered indenyl phosphine ligands can have better stereoselective control over the chirality arising at the metal center in the oxidative addition of their rhodium complexes with alkyl halides.

Sodium Butylated Hydroxytoluene: A Functional Group Tolerant, Eco-Friendly Base for Solvent-Free, Pd-Catalysed Amination

NaBHT (sodium 2,6-di-tert-butyl-4-methylphenolate), a strong, but hindered and lipophilic base, has been effectively paired with similarly lipophilic, high-reactivity Pd-NHC (N-heterocyclic carbene) catalysts to produce an ideal combination for performing solvent-free (melt) cross-coupling amination. The mild nucleophilicity of NaBHT, coupled with the anti-oxidant properties of its conjugate acid byproduct, BHT means the process seems to have no functional group incompatibilities. Highly effective coupling of base-sensitive and redox-active functional groups was observed in all cases with only 0.1-0.2 mol percent catalyst. Comparisons using the standard base for this reaction, KOtBu, led to poor couplings or complete degradation in most applications - only NaBHT works.

(DiMeIHeptCl)Pd: A Low-Load Catalyst for Solvent-Free (Melt) Amination

(DiMeIHept^Cl)Pd, a hyper-branched N-aryl Pd NHC catalyst, has been shown to be efficient at performing amine arylation reactions in solvent-free ("melt") conditions. The highly lipophilic environment of the alkyl chains flanking the Pd center serves as lubricant to allow the complex to navigate through the paste-like environment of these mixtures. The protocol can be used on a multi-gram scale to make a variety of aniline derivatives, including substrates containing alcohol moieties.

Pd-Catalyzed C(sp2)-H Imidoylative Annulation: A General Approach To Construct Dibenzoox(di)azepines

A general method to construct the scaffolds of dibenzooxazepine and dibenzodiazepine, through Pd-catalyzed isocyanide insertion and intramolecular C(sp²)-H activation, has been developed. This is the first example of seven-membered heterocycle formation by C-H imidoylative annulation.

Rigid hindered N-heterocyclic carbene palladium precatalysts: synthesis, characterization and catalytic amination

Rigid hindered N-heterocyclic carbene palladium complexes have been developed and exhibited high activities for a variety of (hetero)aryl chlorides with (hetero)anilines and amines under aerobic conditions.

N-Arylated bisferrocene pyrazole for the dual-mode detection of hydrogen peroxide: an AIE-active fluorescent “turn ON/OFF” and electrochemical non-enzymatic sensor

N-Arylated bisferrocene pyrazoles for the dual-mode detection of H₂O₂ by AIE-active fluorescence and non-enzymatic electrochemical methods.

Mixed er-NHC/phosphine Pd(ii) complexes and their catalytic activity in the Buchwald–Hartwig reaction under solvent-free conditions

A single catalyst for solvent-free Buchwald–Hartwig amination with both primary and secondary amines.