Browse
Submit Data
Databases
API
Help

Dataset Information

21 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Ni-Catalyzed Regioselective 1,2-Dialkylation of Alkenes Enabled by the Formation of Two C(sp³)-C(sp³) Bonds.

ABSTRACT: We disclose a Ni-catalyzed vicinal difunctionalization of alkenes with benzyl halides and alkylzinc reagents, which produces products with two new alkyl-alkyl bonds. This alkene dialkylation is effective in combining secondary benzyl halides and secondary alkylzinc reagents with internal alkenes, which furnishes products with three contiguous all-carbon secondary stereocenters. The products can be readily elaborated to access complex tetralene, benzosuberene, and bicyclodecene cores. The reaction also features as the most efficient alkene difunctionalization process to date with catalyst loadings down to 500 ppm and the catalytic turnover number (TON) and turnover frequency (TOF) registering up to 2 × 10³ and 165 h^-1 at rt, respectively.

SUBMITTER: Dhungana RK

PROVIDER: S-EPMC7953840 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Intermolecular dialkylation of alkenes with two distinct C(sp3)─H bonds enabled by synergistic photoredox catalysis and iron catalysis.

Project description:The functionalization of unactivated C(sp3)─H bonds represents one of the most powerful and most atom-economical tools for the formation of new carbon-based chemical bonds in synthesis. Although cross-dehydrogenative coupling reactions of two distinct C─H bonds for the formation of carbon-carbon bonds have been well investigated, controlled functionalizations of two or more different C(sp3)─H bonds across a functional group or a molecule (e.g., an alkene or alkyne) in a single reaction remain challenging. Here, we present a three-component dialkylation of alkenes with common alkanes and 1,3-dicarbonyl compounds via synergistic photoredox catalysis and iron catalysis for the synthesis of two functionalized 1,3-dicarbonyl compounds. Mechanistic studies suggest that the photoredox catalysis serves as a promotion system to allow the dialkylation to proceed under mild conditions by reducing the oxidation and reduction potentials of the iron intermediates and the reaction partners.

| S-EPMC6440757 | biostudies-literature

Ni-catalyzed 1,2-benzylboration of 1,2-disubstituted unactivated alkenes.

Project description:Nickel-catalyzed 1,2-carboboration of alkenes is emerging as a useful method for chemical synthesis. Prior studies have been limited to only the incorporation of aryl groups. In this manuscript, a method for the 1,2-benzylboration of unactivated alkenes is presented. The reaction combines readily available alkenes, diboron reagents and benzylchlorides to generate synthetically versatile products with control of stereochemistry. The utility of the products as well as the mechanistic details of the process are also presented.

| S-EPMC7066668 | biostudies-literature

Mechanism of Ni-Catalyzed Reductive 1,2-Dicarbofunctionalization of Alkenes.

Project description:Ni-catalyzed cross-electrophile coupling reactions have emerged as appealing methods to construct organic molecules without the use of stoichiometric organometallic reagents. The mechanisms are complex: plausible pathways, such as "radical chain" and "sequential reduction" mechanisms, are dependent on the sequence of the activation of electrophiles. A combination of kinetic, spectroscopic, and organometallic studies reveals that a Ni-catalyzed, reductive 1,2-dicarbofunctionalization of alkenes proceeds through a "sequential reduction" pathway. The reduction of Ni by Zn is the turnover-limiting step, consistent with Ni(II) intermediates as the catalyst resting-state. Zn is only sufficient to reduce (phen)Ni(II) to a Ni(I) species. As a result, commonly proposed Ni(0) intermediates are absent under these conditions. (Phen)Ni(I)-Br selectively activates aryl bromides via two-electron oxidation addition, whereas alkyl bromides are activated by (phen)Ni(I)-Ar through single-electron activation to afford radicals. These findings could provide insight into achieving selectivity between different electrophiles.

| S-EPMC7058187 | biostudies-literature

Synthesis of (diarylmethyl)amines using Ni-catalyzed arylation of C(sp3)-H bonds.

Project description:The first nickel catalyzed deprotonative cross coupling between C(sp3)-H bonds and aryl chlorides is reported, allowing the challenging arylation of benzylimines in the absence of directing group or stoichiometric metal activation. This methodology represents a convenient access to the (diarylmethyl)amine moiety, which is widespread in pharmaceutically relevant compounds.

| S-EPMC4786957 | biostudies-literature

Three-Component 1,2-Carboamidation of Bridged Bicyclic Alkenes via RhIII-Catalyzed Addition of C-H Bonds and Amidating Reagents.

Project description:A three-component method is described for the preparation of syn-1,2-disubstituted bridged bicyclic compounds. The reaction was demonstrated for readily available aromatic and heteroaromatic C-H bond substrates with tertiary and secondary amide, lactam, pyrazole, and triazole directing groups and a variety of bridged bicyclic alkenes, including norbornene, benzonorbornadiene, oxygen- and nitrogen-bridged analogs, and an unsaturated tropinone. A broad dioxazolone scope was also observed. The use of a chiral Cp-derived RhIII catalyst enables asymmetric synthesis of products.

| S-EPMC8026749 | biostudies-literature

Directed nickel-catalyzed 1,2-dialkylation of alkenyl carbonyl compounds.

Project description:A nickel-catalyzed conjunctive cross-coupling of non-conjugated alkenes, alkyl halides, and alkylzinc reagents is reported. Regioselectivity is controlled by chelation of a removable bidentate 8-aminoquinoline directing group. Under optimized conditions, a wide range of 1,2-dialkylated products can be accessed in moderate to excellent yields. To the best of our knowledge, this report represents the first example of three-component 1,2-dialkylation of non-conjugated alkenes to introduce differentiated alkyl fragments.

| S-EPMC6001383 | biostudies-literature

Cobalt-catalyzed, aminoquinoline-directed coupling of sp(2) C-H bonds with alkenes.

Project description:A method for cobalt-catalyzed, aminoquinoline-directed ortho-functionalization of sp(2) C-H bonds with alkenes has been developed. Reactions proceed at room temperature in trifluoroethanol solvent, use oxygen from air as an oxidant, and require Mn(OAc)3 as a cocatalyst. Benzoic, heteroaromatic, and acrylic acid aminoquinoline amides react with ethylene as well as mono- and disubstituted alkenes affording products in good yields. Excellent functional group tolerance is observed; halogen, nitro, ether, and unprotected alcohol functionalities are compatible with the reaction conditions.

| S-EPMC4155791 | biostudies-literature

Cobalt catalyzed carbonylation of unactivated C(sp3)-H bonds.

Project description:A general efficient regioselective cobalt catalyzed carbonylation of unactivated C(sp3)-H bonds of aliphatic amides was demonstrated using atmospheric (1-2 atm) carbon monoxide as a C1 source. This straightforward approach provides access to α-spiral succinimide regioselectively in a good yield. Cobalt catalyzed sp3 C-H bond carbonylation is reported for the first time including the functionalization of (β)-C-H bonds of α-1°, 2°, 3° carbons and even internal (β)-C-H bonds. Our initial mechanistic investigation reveals that the C-H activation step is irreversible and will possibly be the rate determining step.

| S-EPMC5369400 | biostudies-literature

Enantio- and regioselective CuH-catalyzed hydroamination of alkenes.

Project description:A highly enantio- and regioselective copper-catalyzed hydroamination reaction of alkenes has been developed using diethoxymethylsilane and esters of hydroxylamines. The process tolerates a wide variety of substituted styrenes, including trans-, cis-, and ?,?-disubstituted styrenes, to yield ?-branched amines. In addition, aliphatic alkenes coupled to generate exclusively the anti-Markovnikov hydroamination products.

| S-EPMC3874865 | biostudies-literature

Visible-light promoted regioselective amination and alkylation of remote C(sp3)-H bonds.

Project description:The C-N cross coupling reaction has always been a fundamental task in organic synthesis. However, the direct use of N-H group of aryl amines to generate N-centered radicals which would couple with alkyl radicals to construct C-N bonds is still rare. Here we report a visible light-promoted C-N radical cross coupling for regioselective amination of remote C(sp3)-H bonds. Under visible light irradiation, the N-H groups of aryl amines are converted to N-centered radicals, and are then trapped by alkyl radicals, which are generated from Hofmann-Löffler-Freytag (HLF) type 1,5-hydrogen atom transfer (1,5-HAT). With the same strategy, the regioselective C(sp3)-C(sp3) cross coupling is also realized by using alkyl Hantzsch esters (or nitrile) as radical alkylation reagents. Notably, the α-C(sp3)-H of tertiary amines can be directly alkylated to form the C(sp3)-C(sp3) bonds via C(sp3)-H - C(sp3)-H cross coupling through the same photoredox pathway.

| S-EPMC7081228 | biostudies-literature