Browse
Submit Data
Databases
API
Help

Dataset Information

29 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Nickel-catalyzed cycloadditive couplings of enynes and isocyanates.

ABSTRACT: A mild and general route for preparing dienamides is described. Nickel imidazolylidene complexes were used to mediate cycloadditive coupling between enynes and isocyanates. Dienamides were prepared in excellent yields and with good E:Z selectivity. These dienamides can be further manipulated through oxidative cyclization methods. When a terminal enyne is employed, cyclization affords a lactam rather than a dienamide.

SUBMITTER: D'Souza BR

PROVIDER: S-EPMC2792207 | biostudies-literature | 2009 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Nickel-catalyzed cycloadditive couplings of enynes and isocyanates.

D'Souza Brendan R BR Louie Janis J

Organic letters 20090901 18

A mild and general route for preparing dienamides is described. Nickel imidazolylidene complexes were used to mediate cycloadditive coupling between enynes and isocyanates. Dienamides were prepared in excellent yields and with good E:Z selectivity. These dienamides can be further manipulated through oxidative cyclization methods. When a terminal enyne is employed, cyclization affords a lactam rather than a dienamide. ...[more]

PMID: 19739689

Similar Datasets

Nickel/Photoredox-Catalyzed Amidation via Alkylsilicates and Isocyanates.

Project description:A nickel/photoredox, dual-catalyzed amidation reaction between alkylsilicate reagents and alkyl/aryl isocyanates is reported. In contrast to the previously reported reductive coupling process, this protocol is characterized by mild reaction conditions and the absence of a stoichiometric reductant. A mechanistic hypothesis involving a nickel-isocyanate adduct is proposed based on literature precedent and further validation by experimental results.

| S-EPMC5784433 | biostudies-literature

Nickel-catalyzed synthesis of acrylamides from alpha-olefins and isocyanates.

Project description:[reaction: see text] The nickel(0)-catalyzed coupling of alpha-olefins and isocyanates proceeds in the presence of the N-heterocyclic carbene ligand IPr to provide alpha,beta-unsaturated amides. Carbon-carbon bond formation occurs preferentially at the 2-position of the olefin. The N-tert-butyl amide products can be converted to the corresponding primary amides under acidic conditions.

| S-EPMC3148187 | biostudies-literature

Construction of 1,5-enynes by stereospecific Pd-catalyzed allyl-propargyl cross-couplings.

Project description:The palladium-catalyzed cross-coupling of chiral propargyl acetates and allyl boronates delivers chiral 1,5-enynes with excellent levels of chirality transfer and can be applied across a broad range of substrates.

| S-EPMC3374959 | biostudies-literature

Nickel-catalyzed Suzuki-Miyaura couplings in green solvents.

Project description:The nickel-catalyzed Suzuki-Miyaura coupling of aryl halides and phenol-derived substrates with aryl boronic acids using green solvents, such as 2-Me-THF and tert-amyl alcohol, is reported. This methodology employs the commercially available and air-stable precatalyst, NiCl2(PCy3)2, and gives biaryl products in synthetically useful to excellent yields. Using this protocol, bis(heterocyclic) frameworks can be assembled efficiently.

| S-EPMC3768281 | biostudies-literature

Nickel-catalyzed Suzuki-Miyaura cross-couplings of aldehydes.

Project description:Transition-metal-catalyzed cross-couplings have been extensively used in the pharmaceutical and agrochemical industries for the construction of diverse C-C bonds. Conventional cross-coupling reactions require reactive electrophilic coupling partners, such as organohalides or sulfonates, which are not environmentally friendly and not naturally abundant. Another disadvantage associated with these transformations is the need for an exogenous base to facilitate the key transmetalation step, and this reagent inevitably induces side reactions and limits the substrate scope. Here, we report an unconventional Suzuki-type approach to the synthesis of biaryls, through nickel-catalyzed deformylative cross coupling of aldehydes with organoboron reagents under base-free conditions. The transformation tolerates structurally diverse (hetero)aryl substituents on both coupling partners and shows high reactivity and excellent functional group tolerance. Furthermore, the protocol was carried out on gram scale and successfully applied to the functionalization of complex biologically active molecules. Mechanistic investigations support a catalytic cycle involving the oxidative addition of the nickel into the aldehyde C(acyl)-H bond with subsequent hydride transfer, transmetalation, decarbonylation and reductive elimination processes.

| S-EPMC6488620 | biostudies-literature

Nickel-catalyzed regiodivergent sulfonylarylation of 1,3-enynes to access allenes and dienes.

Project description:The radical-mediated difunctionalization of 1,3-enynes facilitates rapid access to structurally diverse allenes and dienes. Whereas, owing to the existence of multiple active sites in conjugated 1,3-enynes, regulating selectivity in difunctionalized addition via a single transition-metal-catalyzed radical tandem process remains elusive. Herein, we disclose an intriguing protocol of substrate-controlled nickel-catalyzed regiodivergent sulfonylarylation of 1,3-enynes with the assistance of sulfonyl chlorides and arylboronic acids. This valuable synthetic utility respectively delivers a series of highly functionalized and synthetically challenging allenyl sulfones and dienyl sulfones from fine-tuned 1,3-enynes by one step, which provides a facile approach for complex sulfone-containing drug molecules synthesis.

| S-EPMC11339949 | biostudies-literature

Enantiospecific, nickel-catalyzed cross-couplings of allylic pivalates and arylboroxines.

Project description:We have developed an enantiospecific, nickel-catalyzed cross-coupling of unsymmetric 1,3-disubstituted allylic pivalates with arylboroxines. The success of this reaction relies on the use of BnPPh2 as a supporting ligand for the nickel(0) catalyst and NaOMe as a base. This method shows excellent functional group tolerance and broad scope in both the allylic pivalate and arylboroxine, enabling the preparation of 1,3-diaryl allylic products in high yields with excellent levels of regioselectivity and stereochemical fidelity.

| S-EPMC4084837 | biostudies-literature

Nickel-catalyzed cross-coupling of photoredox-generated radicals: uncovering a general manifold for stereoconvergence in nickel-catalyzed cross-couplings.

Project description:The cross-coupling of sp(3)-hybridized organoboron reagents via photoredox/nickel dual catalysis represents a new paradigm of reactivity for engaging alkylmetallic reagents in transition-metal-catalyzed processes. Reported here is an investigation into the mechanistic details of this important transformation using density functional theory. Calculations bring to light a new reaction pathway involving an alkylnickel(I) complex generated by addition of an alkyl radical to Ni(0) that is likely to operate simultaneously with the previously proposed mechanism. Analysis of the enantioselective variant of the transformation reveals an unexpected manifold for stereoinduction involving dynamic kinetic resolution (DKR) of a Ni(III) intermediate wherein the stereodetermining step is reductive elimination. Furthermore, calculations suggest that the DKR-based stereoinduction manifold may be responsible for stereoselectivity observed in numerous other stereoconvergent Ni-catalyzed cross-couplings and reductive couplings.

| S-EPMC4576934 | biostudies-literature

Nickel-Catalyzed Cycloisomerization of Enynes: Catalyst Generation via C-H Activation of Carbene Ligands.

Project description:The combination of Ni(0) and an N-heterocyclic carbene act as a precatalyst for the cycloisomerization of enynes to afford 1,3-dienes. During the course of the reaction, a nickel hydride is formed from oxidative addition of the ortho C-H on the carbene ligand. Deuteriumn labeling studies are presented.

| S-EPMC3203641 | biostudies-literature

Nickel-catalyzed amination of aryl carbamates and sequential site-selective cross-couplings.

Project description:We report the amination of aryl carbamates using nickel-catalysis. The methodology is broad in scope with respect to both coupling partners and delivers aminated products in synthetically useful yields. Computational studies provide the full catalytic cycle of this transformation, and suggest that reductive elimination is the rate-determining step. Given that carbamates are easy to prepare, robust, inert to Pd-catalysis, and useful for arene functionalization, these substrates are particularly attractive partners for use in synthesis. The sequential use of carbamate functionalization/site-selective cross-coupling processes highlights the utility of this methodology.

| S-EPMC6520651 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data