Secondary Alkyl Bromides Research Articles

ChemInform Abstract: Nickel‐Catalyzed Reductive Cross‐Coupling of (Hetero)Aryl Iodides with Fluorinated Secondary Alkyl Bromides.

AbstractThe reaction fails for trifluoromethylated tertiary alkyl bromides and gives only poor yields for trifluoromethylated primary alkyl chlorides (not shown).

Palladium-Catalyzed Alkoxycarbonylation of Unactivated Secondary Alkyl Bromides at Low Pressure

Palladium-Catalyzed Alkoxycarbonylation of Unactivated Secondary Alkyl Bromides at Low Pressure

ChemInform Abstract: Copper‐Catalyzed Cross‐Coupling Reaction of Allyl Boron Ester with 1°/2°/3°‐Halogenated Alkanes.

AbstractThe scalable method succeeds efficiently starting from primary, secondary, and tertiary alkyl bromides and tolerates various functional groups.

Nickel-Catalyzed Reductive Cross-Coupling of (Hetero)Aryl Iodides with Fluorinated Secondary Alkyl Bromides.

A mild and efficient nickel-catalyzed reductive cross-coupling between fluorinated secondary alkyl bromides and (hetero)aryl iodides is described. The use of FeBr2 as an additive successfully overcomes the hydrodebromination and β-fluorine elimination of fluorinated substrates and allows the efficient synthesis of a wide range of trifluoromethyl and difluoroalkyl containing aliphatic compounds with a fluoroalkyl substituted tertiary carbon center. The notable features of this protocol are the synthetic and operational simplicity without preparation of moisture sensitive organometallic reagents and excellent functional group compatibility, even toward active proton containing substrates.

ChemInform Abstract: Borylation of Primary and Secondary Alkyl Bromides Catalyzed by Cu2O Nanoparticles.

AbstractCu2O nanoparticles supported on carbon black are developed as an efficient catalyst for the synthesis of alkylboronic esters (III) and (V) directly from the corresponding alkyl halides.

ChemInform Abstract: Cobalt‐Catalyzed Negishi Cross‐Coupling Reactions of (Hetero)Arylzinc Reagents with Primary and Secondary Alkyl Bromides and Iodides.

AbstractA one‐pot Negishi‐type cross‐coupling reaction of initially formed diarylzinc reagents with primary and secondary alkyl iodides is developed.

ChemInform Abstract: Expedient Copper‐Catalyzed Borylation Reactions Using Amino Acids as Ligands.

AbstractConditions for the borylation of primary and secondary alkyl bromides equipped with various functional groups using dipinacolyl hypodiborate (II) or bis(neopentylglycolato)diboron (IV) are elaborated.

Computational Insight into Nickel-Catalyzed Carbon-Carbon versus Carbon-Boron Coupling Reactions of Primary, Secondary, and Tertiary Alkyl Bromides.

The nickel-catalyzed alkyl-alkyl cross-coupling (C-C bond formation) and borylation (C-B bond formation) of unactivated alkyl halides reported in the literature show completely opposite reactivity orders in the reactions of primary, secondary, and tertiary alkyl bromides. The proposed Ni(I) /Ni(III) catalytic cycles for these two types of bond-formation reactions were studied computationally by means of DFT calculations at the B3LYP level. These calculations indicate that the rate-determining step for alkyl-alkyl cross-coupling is the reductive elimination step, whereas for borylation the rate is determined mainly by the atom-transfer step. In borylation reactions, the boryl ligand involved has an empty p orbital, which strongly facilitates the reductive elimination step. The inability of unactivated tertiary alkyl halides to undergo alkyl-alkyl cross-coupling is mainly due to the moderately high reductive elimination barrier.

ChemInform Abstract: Copper Nanoparticle‐Catalyzed Borylation of Alkyl Bromides with an Organodiboron Compound.

Borylation of primary and secondary alkyl bromides with bis(pinacolato)diboron was carried out in the presence of commercially available copper nanoparticles as catalysts. The reaction went to completion in the absence of phosphines at room temperature. The catalytic system showed high activity, broad substrate scope, and good functional group tolerance.

Cobalt-catalyzed negishi cross-coupling reactions of (hetero)arylzinc reagents with primary and secondary alkyl bromides and iodides.

We report a cobalt-catalyzed cross-coupling of di(hetero)arylzinc reagents with primary and secondary alkyl iodides or bromides using THF-soluble CoCl2 ⋅2 LiCl and TMEDA as a ligand, which leads to the corresponding alkylated products in up to 88 % yield. A range of functional groups (e.g. COOR, CN, CF3 , F) are tolerated in these substitution reactions. Remarkably, we do not observe rearrangement of secondary alkyl iodides to unbranched products. Additionally, the use of cyclic TBS-protected iodohydrins leads to trans-2-arylcyclohexanol derivatives in excellent diastereoselectivities (up to d.r.=99:1).

ChemInform Abstract: Nickel‐Catalyzed Reductive Alkylation of Halogenated Pyridines with Secondary Alkyl Bromides.

Abstract This article highlights Ni-catalyzed cross-electrophile coupling of halogenated pyridines with secondary alkyl bromides using zinc as the terminal reductant. With this protocol, we have successfully achieved different alkyl-substituted pyridines in moderate to excellent yields.

Carbon–Carbon Bond Formation Reactivity of a Four-Coordinate NHC-Supported Iron(II) Phenyl Compound

The preparation and characterization of a NHC-coordinated (NHC = N-heterocyclic carbene) ferrous phenyl complex [(IPr2Me2)2FePh2] (1; IPr2Me2 = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) as well as its C–C bond formation reactivity have been studied. The four-coordinate iron(II) phenyl complex was prepared from the reaction of ferrous chloride with PhMgBr and IPr2Me2. It reacts with nonactivated primary and secondary alkyl bromides and chlorides to furnish cross-coupling products and the iron(II) monophenyl species (IPr2Me2)2FePhX (X = Br (2), Cl). When it is treated with cyclooctatetraene (cot) or [Cp2Fe][BArF4] in the presence of PMe3, it undergoes coordination or one-electron oxidation induced reductive elimination of biphenyl to form the corresponding iron(0) or iron(I) species [(IPr2Me2)2Fe(η4-cot)] (3) or [(IPr2Me2)2Fe(PMe3)2][BArF4] (4). All of these iron-containing products have been fully characterized by various spectroscopic methods. Complex 1 and (IPr2Me2)2FeCl2 catalyze the reaction of n...

Borylation of primary and secondary alkyl bromides catalyzed by Cu2O nanoparticles

A Cu2O nanoparticle catalyzed borylation of alkylboronic esters is developed, with mild reaction conditions, high yield and in the absence of ligands which otherwise are essential in homogenous catalysis, using bis(pinacolato)diboron as the boron source.

ChemInform Abstract: Mild and Phosphine‐Free Iron‐Catalyzed Cross‐Coupling of Nonactivated Secondary Alkyl Halides with Alkynyl Grignard Reagents.

A simple protocol for iron-catalyzed cross-coupling of nonactivated secondary alkyl bromides and iodides with alkynyl Grignard reagents at room temperature has been developed. A wide range of secondary alkyl halides and terminal alkynes are tolerated to afford the substituted alkynes in good yields. A slight modification of the reaction protocol also allows for cross-coupling with a variety of primary alkyl halides.

DFT study of the single electron transfer mechanisms in Ni-Catalyzed reductive cross-coupling of aryl bromide and alkyl bromide

Ni-catalyzed reductive cross-coupling reactions of electrophilic regents provide an important method to form C–C bonds. The present study explored several single electron transfer mechanisms for Ni-catalyzed reductive cross-coupling of aryl bromide and secondary alkyl bromide using Density Functional Theory (DFT) calculations. The results showed that two of the proposed mechanisms were feasible. One was a six-step catalytic cycle including oxidative addition, reduction, radical production, radical addition, reductive elimination and catalyst regeneration. The other was a five-step mechanism involving radical production, reduction, oxidative addition, radical addition, and reductive elimination. The rate-limiting step for both mechanisms was the radical addition step with the energy barrier of 10.42 kcal/mol. All DFT calculations were implemented in the gas phase.

Nickel-Catalyzed Reductive Alkylation of Halogenated Pyridines with Secondary Alkyl Bromides

This article highlights Ni-catalyzed cross-electrophile coupling of halogenated pyridines with secondary alkyl bromides using zinc as the terminal reductant. With this protocol, we have successfully achieved different alkyl-substituted pyridines in moderate to excellent yields.

Cobalt-Catalyzed Chelation-Assisted Alkylation of Arenes with Primary and Secondary Alkyl Halides

Cobalt–N-heterocyclic carbene catalytic systems have been developed for chelation-assisted ortho-alkylation of aromatic compounds with alkyl halides. Aryl imines can be selectively monoalkylated at room temperature by various primary or secondary alkyl chlorides or bromides. The catalytic system can also be applied to 2-arylpyridine derivatives, which in the absence of steric hindrance are amenable to dialkylation by an excess of the alkyl halide. Mechanistic experiments, including reactions of stereochemical probes and radical clocks, indicate that the reaction involves single-electron transfer from the cobalt center to the alkyl halide to form the corresponding alkyl radical, which has a finite lifetime before it undergoes C–C bond formation.

Mild and phosphine-free iron-catalyzed cross-coupling of nonactivated secondary alkyl halides with alkynyl Grignard reagents.

A simple protocol for iron-catalyzed cross-coupling of nonactivated secondary alkyl bromides and iodides with alkynyl Grignard reagents at room temperature has been developed. A wide range of secondary alkyl halides and terminal alkynes are tolerated to afford the substituted alkynes in good yields. A slight modification of the reaction protocol also allows for cross-coupling with a variety of primary alkyl halides.

NHC–copper hydrides as chemoselective reducing agents: catalytic reduction of alkynes, alkyl triflates, and alkyl halides

The NHC–copper-catalyzed Z-selective semi-reduction of terminal and internal alkynes, as well as the NHC–copper-catalyzed reduction of primary alkyl triflates and primary and secondary alkyl iodides and bromides are described. The high chemoselectivity demonstrated in these examples illustrates the mild nature of copper hydride complexes as reducing agents, which have applications in synthetic chemistry beyond their traditional role in the reduction of activated alkenes and carbonyl compounds.

Expedient Iron‐Catalyzed Coupling of Alkyl, Benzyl and Allyl Halides with Arylboronic Esters

While attractive, the iron-catalyzed coupling of arylboron reagents with alkyl halides typically requires expensive or synthetically challenging diphosphine ligands. Herein, we show that primary and secondary alkyl bromides and chlorides, as well as benzyl and allyl halides, can be coupled with arylboronic esters, activated with alkyllithium reagents, by using very simple iron-based catalysts. The catalysts used were either adducts of inexpensive and widely available diphosphines or, in a large number of cases, simply [Fe(acac)3] with no added co-ligands. In the former case, preliminary mechanistic studies highlight the likely involvement of iron(I)-phosphine intermediates.