Theoretical study on selectivity trends in (<i>N</i>‐heterocyclic carbene)‐Pd catalyzed mizoroki–heck reactions: Exploring density functionals methods and molecular models

Silva, Vitor H. Menezes da; Batista, Ana Paula de Lima; Navarro, Oscar; Braga, Ataualpa Albert Carmo

doi:10.1002/jcc.24867

Cited by 13 publications

(3 citation statements)

References 71 publications

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“…In this mechanism, all species involved in the catalytic cycle are neutral. Intense investigation of the oxidative addition step by Amatore and Jutand led to the proposal of an anionic catalytic cycle with short-lived pentacoordinate intermediates (Scheme G, H). − Anionic species have been later identified in other cross-couplings − and encouraged the use of anionic palladium precatalysts in cross-coupling reactions. − Both mechanistic pathways have been the subject of detailed theoretical calculations. − …”

Section: Introductionmentioning

confidence: 99%

Understanding Anionic “Ligandless” Palladium Species in the Mizoroki–Heck Reaction

Schroeter

Straßner

2018

Inorg. Chem.

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The anionic complex [NBu][Pd(DMSO)Cl], as a "ligandless" system, was shown to be an active catalyst in the Mizoroki-Heck coupling of aryl chlorides in the absence of strongly σ-donating ligands. To investigate the experimentally observed influence of halides and the amount of water on the catalytic activity, we employed a combination of experiments and theoretical calculations. The presence of water was shown to be critical for the formation of the active palladium(0) species by oxidation of in situ generated tributylamine. Oxidative addition to an anionic palladium(0) species was found to be the rate-determining step of the catalytic cycle. For the ensuing steps, both neutral and anionic pathways were considered. It was shown that, in the absence of strongly σ-donating neutral ligands, chloride ions stabilize the catalytic intermediates. Therefore, an anionic pathway is preferred, which explains the need for tetrabutylammonium chloride as an additive. The study of the influence of bromide ions on the catalytic activity revealed that the strongly exergonic displacement of the neutral substrates by bromide ions lowers the catalytic activity.

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Section: Introductionmentioning

confidence: 99%

Understanding Anionic “Ligandless” Palladium Species in the Mizoroki–Heck Reaction

Schroeter

Straßner

2018

Inorg. Chem.

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“…To understand the factors that govern the stereochemical outcome of these reactions, we performed DFT calculations for a variety of transition states (TSs) usually invoked in the mechanistic rationale . Key to this transformation is the migratory insertion TS, which is generally treated as an irreversible step with prior rapid equilibration of intermediates (Curtin–Hammett scenario) . In addition, enantioselective arylation of similarly nonactivated five‐membered cyclic olefins with the L1 ligand is known to proceed through complexes in which the aryl group is trans to the oxazoline moiety of the ligand.…”

Section: Resultsmentioning

confidence: 99%

Enantioselective, Noncovalent, Substrate‐Directable Heck–Matsuda and Oxidative Heck Arylations of Unactivated Five‐Membered Carbocyclic Olefins

Oliveira

Angnes

Khan

et al. 2018

Chemistry A European J

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Highly diastereo- and enantioselective, noncovalent, substrate-directable Heck desymmetrizations of cyclopentenyl olefins containing hydroxymethyl and carboxylate functional groups are presented. These conformationally unbiased cyclic olefins underwent effective arylations in yields of up to 97 %, diastereoselectivity up to >20:1, and enantiomeric excesses of up to 99 %. Noncovalent directing effects were shown to be prevalent in both Heck-Matsuda and oxidative Heck reactions, allowing the preferential formation of cis-substituted aryl cyclopentenes containing two stereocenters, including quaternary stereocenters. These results further validate the internal out-of-coordination-sphere ion-dipole interaction concept directing the reaction diastereoselectivity to the cis-Heck product. This approach is complementary to existing methods using bis-phosphine monoxide ligands to give the opposite trans-diastereoisomer. The applicability of the method is showcased by the straightforward synthesis of a potent phosphodiesterase 4 inhibitor in a diastereo- and enantioselective manner. The reaction is operationally simple and has broad scope with regard to the nature of the arenediazonium salt and boronic acid employed. The mechanism and origin of stereoselectivity were investigated with control experiments and DFT calculations that fully supported the stabilizing internal out-of-coordination-sphere ion-dipole interaction between the resident functional group and cationic palladium.

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“…Highly regioselective carboxylate-assisted C–H activation processes can be accomplished, 14–17 particularly for ligands that contain chemical groups able to coordinate to Pd. These so-called directing groups 18 are able to bring the metal into the vicinity of a particular C–H bond.…”

Section: Introductionmentioning

confidence: 99%

Ion mobility mass spectrometry uncovers regioselectivity in the carboxylate-assisted C–H activation of palladium N-heterocyclic carbene complexes

Ibáñez-Ibáñez,

Mollar-Cuni,

Apaloo-Messan

et al. 2024

Dalton Trans.

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Theoretical study on selectivity trends in (N‐heterocyclic carbene)‐Pd catalyzed mizoroki–heck reactions: Exploring density functionals methods and molecular models

Cited by 13 publications

References 71 publications

Understanding Anionic “Ligandless” Palladium Species in the Mizoroki–Heck Reaction

Understanding Anionic “Ligandless” Palladium Species in the Mizoroki–Heck Reaction

Enantioselective, Noncovalent, Substrate‐Directable Heck–Matsuda and Oxidative Heck Arylations of Unactivated Five‐Membered Carbocyclic Olefins

Ion mobility mass spectrometry uncovers regioselectivity in the carboxylate-assisted C–H activation of palladium N-heterocyclic carbene complexes

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