Palladium-catalyzed cross-coupling reactions of 2-indolyldimethylsilanols with substituted aryl halides

[reaction: see text] A mild and general cross-coupling reaction of 2-indolylsilanols has been developed. The experimental variables that lead to successful coupling are (1) the use of sodium tert-butoxide as the activator, (2) the use of copper(I) iodide in stoichiometric quantities, and (3) the use of Pd2(dba)3.CHCl3 as the catalyst. Under these conditions N-(Boc)-2-indolyldimethylsilanol reacts with a variety of aromatic iodides to afford the coupling products in good yield (70-84%).     

Palladium-catalyzed cross-coupling reactions between dihydropyranylindium reagents and aryl halides. synthesis of C-aryl glycals

[reaction: see text] Palladium(0)-catalyzed cross-coupling reactions between tris(dihydropyranyl)indium 1 and aryl halides 2 have been investigated. Aryl iodides and electron-deficient aryl bromides couple efficiently with the in situ-generated indium reagents in the presence of 1-5 mol % Cl(2)Pd(PPh(3))(2) to produce substituted dihydropyrans 3 with minimal (<10%) dimer (4) formation. Organoindium reagents derived from D-glucal also undergo cross couplings with aryl iodides to produce C-aryl glycals.     

Palladium-catalyzed cross-coupling of aryl electrophiles with dimethylalkynylaluminum reagents

[reaction: see text] Alkynyldimethylaluminum reagents are easily available from terminal alkynes and trimethylaluminum via a triethylamine-catalyzed metalation. These compounds can react with various aromatic and heterocyclic halides in the presence of palladium in a fast and efficient way. This catalyzed cross-coupling reaction provides a simple entry to numerous internal alkynes, using a readily available, inexpensive, and nontoxic metalating agent.     

Palladium-catalyzed cross-coupling of benzyl thioacetates and aryl halides

A method for preparing benzyl aryl thioethers utilizing an in situ deprotection of benzyl thioacetates as an alternative to free thiols as starting materials has been developed and optimized. Good to excellent yields of diverse benzyl aryl thioethers are obtained with air-stable, odor-free, and easy to prepare thioesters. A one-pot protocol for forming benzyl aryl thioethers from a benzyl halide, potassium thioacetate, and an aryl bromide has also been demonstrated.     

Palladium-catalyzed cross-coupling reaction of tricyclopropylbismuth with aryl halides and triflates

The palladium-catalyzed cross-coupling reaction of tricyclopropylbismuth with aryl and heterocyclic halides and triflates is reported. The reaction tolerates numerous functional groups and does not require anhydrous conditions. The method was successfully extended to the cross-coupling of triethylbismuth.     

Palladium-catalyzed cross-coupling of cyclopropanols with aryl halides under mild conditions

Intra- and intermolecular palladium-catalyzed cross-coupling of cyclopropanols with aryl halides can be achieved in good yields under mild conditions.     

One-pot Negishi cross-coupling reactions of in situ generated zinc reagents with aryl chlorides, bromides, and triflates

In situ generated aryl, heteroaryl, alkyl, or benzylic polyfunctional zinc reagents obtained by the addition of zinc and LiCl to the corresponding organic iodides undergo smooth Pd(0)-catalyzed cross-coupling reactions with aryl bromides, chlorides, and triflates in the presence of PEPPSI as a catalyst. This procedure avoids the manipulation of water and air-sensitive organozinc reagents and produces cross-coupling products in high yields.     

Palladium-catalyzed cross-coupling reactions of B-alkyl-9-BBN or trialkylboranes with aryl and 1-alkenyl halides

The reactions of trialkylboranes or B-alkyl-9-BBN with aryl and 1-alkenyl halides take place readily in the presence of PdCl₂(dppf) and sodium hydroxide or methoxide to afford alkylated arenes and alkenes in excellent yields.     

Palladium-catalyzed Hiyama cross-coupling reactions of aryl mesylates

The combination of palladium acetate with XPhos shows high efficiency in the Hiyama cross-coupling reactions of aryl mesylates with arylsilanes. The reactions proceed smoothly to generate the corresponding biaryl compounds in good yields.     

Palladium-catalyzed homocoupling and cross-coupling reactions of aryl halides in poly(ethylene glycol)

The direct coupling of aryl halides to prepare symmetrical and unsymmetrical biaryls were performed successfully in poly(ethylene glycol) (PEG) using Pd(OAc)2 as the catalyst in the absence of other additives or reductants. The selectivity toward biaryl depended on the amount of PEG used. Excessive PEGs induce the increase of hydrodehalogenation product, and the best selectivity to biaryl is obtained when the concentration of the hydroxyl group in PEG achieves 100 mol % relative to aryl halides. The catalyst system could be recycled and reused up to five times with no loss of catalytic activity.     

Palladium-catalyzed cross-coupling reactions of carboxylic anhydrides with organozinc reagents

[reaction: see text] Negishi-type cross-coupling reaction was effected by employing organozincs and anhydrides or mixed anhydrides that formed in situ from sodium salts of the corresponding acids and ethyl chloroformate under the catalysis of palladium(0). A general method for preparing symmetrical/unsymmetrical ketones was developed.     

Cobalt-catalyzed cross-coupling reactions of alkyl halides with aryl Grignard reagents and their application to sequential radical cyclization/cross-coupling reactions

Reactions of alkyl halides with arylmagnesium bromides in the presence of cobalt(II)(diphosphine) complexes are discussed. Treatment of 1-bromooctane with phenylmagnesium bromide with the aid of a catalytic amount of CoCl₂(dppp) [DPPP=1,3-bis(diphenylphosphino)propane] yielded octylbenzene in good yield. The reaction mechanism would include single electron transfer from an electron-rich cobalt complex to alkyl halide to generate the corresponding alkyl radical. The mechanism was justified by CoCl₂(dppe)-catalyzed [DPPE=1,2-bis(diphenylphosphino)ethane] sequential radical cyclization/cross-coupling reactions of 6-halo-1-hexene derivatives that yielded benzyl-substituted cyclopentane skeletons.     

Palladium-catalyzed cyclization and cross-coupling of acetylenic aryl triflates with organotin reagents

Acetylenic aryl triflates reacted readily with vinyltributyltin, allyltributyltin, 1-(trimethylsilyl)-2-(tributylstannyl)acetylene, and trimethylsilyltributyltin in the presence of a palladium catalyst to produce (Z)-indanylidene and (Z)-tetralinylidene substituted compounds, the stereospecificity of the reactions for the synthesis of these compounds being ≥98%.     

Palladium-catalyzed denitrogenative cross-coupling of aryl halides with arylhydrazines under mild reaction conditions

Transition Metal Chemistry - A greener approach for the synthesis of various functionalized biaryl frameworks in good to excellent yield through palladium-catalyzed denitrogenative cross-coupling...     

Manganese-catalyzed cross-coupling reactions of aliphatic amines with aryl halides

An efficient and convenient protocol has been developed for the N-arylation of aliphatic amines with differently substituted aryl halides using a MnCl₂·4H₂O/l-proline catalyst and NaOt-Bu as the base in DMSO.     

Palladium-catalyzed Suzuki cross-coupling of aryl halides with aryl boronic acids in the presence of glucosamine-based phosphines

Carbohydrate-substituted phosphines are easily obtained in quite good yields by coupling of protected or non-protected d-glucosamine with the corresponding diphenylphosphino acid. These neutral ligands, in association with palladium acetate, are very active catalysts in the Suzuki cross-coupling reaction. The polyhydroxy phosphines are more active than the peracetylated phosphines. The process tolerates electron-rich as well as electron-poor substituents. Excellent turnovers, up to 97?000 are observed.     

Palladium-catalyzed cross-coupling reactions of allylic halides and acetates with indium organometallics

The palladium(0)-catalyzed cross-coupling reaction of allylic halides and acetates with indium organometallics is reported. In this synthetic transformation, triorganoindium compounds and tetraorganoindates (aryl, alkenyl, and methyl) react with cinnamyl and geranyl halides and acetates to afford the S(N)2 product regioselectively and in good yield. The reaction proceeds with net inversion of the stereochemical configuration.     

Palladium-catalyzed selective carboelimination and cross-coupling reactions of benzocyclobutenols with aryl bromides

The palladium-catalyzed selective β-carboelimination and cross-coupling chemistry of benzocyclobutenols is described. In contrast to the base-mediated ring-opening reactions of benzocyclobutenols, this variant proceeds with exclusive cleavage of the proximal bond.     

Iron-catalyzed cross-coupling of primary and secondary alkyl halides with aryl grignard reagents

An iron-catalyzed cross-coupling reaction of a primary or secondary alkyl halide with an aryl Grignard reagent proceeds under mild conditions to give the corresponding coupling product in quantitative yield.     

Manganese-catalyzed cross-coupling reaction between aryl Grignard reagents and alkenyl halides

Aryl Grignard reagents react stereospecifically with alkenyl halides in the presence of manganese chloride (10%) to afford good yields of cross-coupling products.