An approach for quinolines via palladium-catalyzed Heck coupling followed by cyclization

2-Iodoaniline reacts with α,β-unsaturated carbonyl compounds in DMF at 100 °C in the presence of a catalytic amount of a palladium catalyst along with a base to afford the corresponding quinolones or quinolines in moderate to good yields.     

A novel strategy for the synthesis of 6H-chromeno [4, 3-b] quinoline by intramolecular Heck cyclization

A novel procedure for the synthesis of various derivatives of 6H-chromeno [4, 3-b] quinolines from intramolecular Heck reaction of 2-chloro-3-(phenoxymethyl) quinolines is described in this study. Intramolecular cyclization of N-alkylated indoles was efficiently investigated as well. The reaction is catalyzed by bis (triphenylphosphine) palladium (II) dichloride in acetonitrile at 80 °C.     

Novel formation of 1,3-oxazepine heterocycles via palladium-catalyzed intramolecular coupling reaction

The oxazepine ring systems containing pyridazinone moiety were constructed via palladium-catalyzed intramolecular coupling reaction. The best conditions for this reaction were Pd(OAc)₂ as a palladium source, 1,1′-bis(diphenylphosphino)-ferrocene (DPPF) as the ligand, and K₂CO₃ as base at 80 °C in toluene. The products have potential applications as biological and medicinal relevant compounds.     

Pd-catalyzed intramolecular Heck reaction for the synthesis of 2-methylbenzofurans

A new strategy for the synthesis of 2-Methylbenzofurans via the intramolecular Heck reaction has been developed. This efficient palladium-catalyzed system showed good catalytic activity. Various substituted 2-methylbenzofurans could be afforded in good to excellent yields.     

Phenylethenyl-substituted silicones via Heck coupling reaction

Systematic studies of several palladium complexes (Pd(OAc)₂, [PdCl₂(cod)], [Pd₂(dba)₃], [Pd(PPh3)4], [PdCl(SnCl₃)(P{p-Tol}₃)₂], [Pd₂Cl₂(SnCl₃)₂(P{p-Tol}₃)₂]) as potential catalytic systems for arylation of vinylsiloxanes via Heck coupling reactions are described. Catalytic activity and selectivity were studied for a model reaction of trimethylvinylsilane with PhBr and m-ClC₆H₆Br and then the most effective systems were applied for functionalisation of tetramethyltetravinylcyclotetrasiloxane and poly(dimethylsiloxane-co-methylvinylsiloxane), leading to the silicone fluids having high refractive index (1.5–1.6).     

Palladium-catalyzed intramolecular 5-endo-trig oxidative Heck cyclization: a facile pathway for the synthesis of some sesquiterpene precursors

An efficient and convenient method for the construction of substituted cyclopentenones via palladium-catalyzed intramolecular 5-endo-trig oxidative cyclization has been introduced as a powerful new strategy for the synthesis of sesquiterpenes.     

Palladium complexes of phosphinamine ligands in the intramolecular asymmetric Heck reaction

The synthesis of two novel cyclisation substrates for the asymmetric intramolecular Heck reaction is reported. Their cyclisation, in addition to a known substrate for cis-decalin formation, were tested with palladium complexes of BINAP and heterobidentate oxazoline-containing ligands. In general BINAP provides a more active catalyst system for the range of substrates tested although excellent enantioselectivities of up to 85% were obtained with the P,N ligands studied. A trend was noted whereby the t-leucine-derived oxazoline ligands were more reactive and enantioselective than the valine-derived analogues. Similarly, the diphenylphosphinoferrocenyloxazoline ligands were more reactive and selective than the corresponding diphenylphosphinophenyloxazoline ligands.     

Intramolecular Heck cyclization to the galanthamine-type alkaloids: total synthesis of (±)-lycoramine

A novel approach towards the construction of the galanthamine skeleton was demonstrated by the total synthesis of (±)-lycoramine. The key steps include a Pd-catalyzed intramolecular cyclization to form the seven-membered azepane ring and a spontaneous intramolecular Michael addition to afford the five-membered furan ring. This synthetic route has also been demonstrated to be useful for the preparation of novel derivatives with simplified galanthamine skeletons.     

Arylmaleic anhydrides via Heck arylation of fumaric acid

Palladium-catalyzed arylation of fumaric acid with aryl iodides is found to be a very simple, economic and scalable approach to arylmaleic anhydrides. The reaction is facilitated by the presence of donor moieties on the aryl fragment and does not occur with strong acceptor groups.     

An efficient palladium-catalyzed Heck coupling of aryl chlorides with alkenes

Catalyst system PdCl₂(PCy₃)₂/Cs₂CO₃ in dioxane was found to be the efficient catalyst system for Heck cross-coupling reactions of deactivated, neutral, and activated aryl chlorides with a variety of alkenes under mild conditions to afford selectively E-arylated alkenes in good to excellent yields.     

Synthesis of fused heterocycles with a benzazepinone moiety via intramolecular Heck coupling

The preparation of fused heterocycles with a benzazepinone moiety was realised via an intramolecular Heck coupling reaction either at position 2 or at position 3 of the heterocyclic system. This method allowed the synthesis of the pyrrolo[2,3-c]azepinone core and Paullone derivatives.     

A facile synthesis of indolo[3,2,1-jk]carbazoles via palladium-catalyzed intramolecular cyclization

A new efficient synthesis of indolo[3,2,1-jk]carbazoles by the palladium-catalyzed cyclization of N-(2-bromoaryl)carbazoles is described. The reaction involves intramolecular C-C bond formation, coupled with the cleavage of a C-X bond and a C-H bond on carbazole ring. Substitutions on N-aryl core with either electron-donating or electron-withdrawing groups are introduced, and different reaction factors for cyclization are evaluated.     

Novel synthesis of medium-sized oxa-heterocycles by palladium-catalyzed intramolecular Heck reaction

An efficient and high yielding method for the synthesis of eight-membered heterocyclic skeletons has been developed via palladium-catalyzed intramolecular Heck reaction.     

Facile construction of pyrrolophenanthridone skeleton via a one-pot intramolecular Heck reaction and oxidation

Construction of pyrrolophenanthridone skeleton via a one-pot Pd-catalyzed intramolecular Heck reaction followed by oxidation has been achieved in moderate to good yields. The reaction mechanism has been proposed.     

New Heck coupling strategies for the synthesis of paullone and dimethyl paullone

The short total synthesis of paullone (1) and dimethyl paullone (2) via a novel palladium-catalyzed intramolecular coupling using the o-bromo- and o-iodo anilides of indoles (3 and 3a) and N-methyl indole 4 is described.     

Catalytic activity of Pd(II) and Pd(II)/DAB-R systems for the Heck arylation of olefins

Palladium-catalyzed reactions of aryl bromides with various olefins involving Pd(II)/diazabutadiene (DAB-R) systems have been investigated. The scope of a coupling process using Pd(II) sources and an α-diimine as ligand in the presence of Cs₂CO₃ as base was tested using various substrates. The Pd(OAc)₂/DAB-Cy (1, DAB-Cy=1,4-dicyclohexyl-diazabutadiene) system presents the highest activity with respect to electron-neutral and electron-deficient aryl bromides in coupling with electron rich olefins. The synthesis and X-ray characterization of a Pd(II)-diazabutadiene ligand is reported. Extensive optimization experiments showed that another Pd(II) source, Pd(acac)₂ (acac=acetylacetonate), proved to activate aryl bromides at high temperatures, low catalyst loadings when the appropriate concentration of ⁿBu₄NBr additive was employed. The effect of the DAB-Cy ligand is important at very low catalyst loadings and high temperatures. Pd(acac)₂ and Pd(acac)₂/DAB-Cy precatalysts were very effective for the arylation of various olefins with aryl bromides with respect to reaction rate, catalyst loadings, and functional group tolerance.     

Intramolecular arylation of benzimidazoles via Pd(II)/Cu(I) catalyzed cross-dehydrogenative coupling

Electron poor benzimidazole substrates were arylated via an intramolecular cross-dehydrogenative coupling (CDC) reaction. These CDC reactions were catalyzed by a Pd(II)/Cu(I) catalyst system, capable of producing moderate yields on a large library of substrates. The substrate scope consisted of tethered arene-benzimidazoles that upon coupling, produced a fused polycyclic motif.     

Palladium mediated bis- and tris-biaryl Heck coupling for the synthesis of heterocycles

A simple and straightforward palladium mediated ligand free bis- and tris-biaryl coupling on an unactivated phenylbenzyl ether system to produce hitherto unreported heterocyclic compound is described.     

含有酯基二茂铁亚胺环钯化合物催化Suzuki和Heck反应

合成并表征了系列含有酯基二茂铁亚胺环钯化合物.结果表明,该系列环钯催化剂在纯水或有机溶剂中均能高效催化Heck和Suzuki偶联反应.     

Synthesis of medium-sized carbocyclic ketones via the intramolecular B-alkyl Liebeskind-Srogl coupling reaction

Synthesis of medium-sized carbocyclic ketones via the intramolecular B-alkyl Liebeskind-Srogl coupling reaction is described. The sequence of hydroboration of ω-alkenyl thiol ester with 9-BBN and the Liebeskind-Srogl reaction results in the formation of medium-sized carbocyclic ketones with good yield.