Ni-Catalyzed Regiodivergent and Stereoselective Hydroalkylation of Acyclic Branched Dienes with Unstabilized C(sp³) Nucleophiles

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(38), P. 16486 - 16492

Published: Sept. 1, 2020

Two complementary regiodivergent [(P,N)Ni]-catalyzed hydroalkylations of branched dienes are reported. When amides employed as unstabilized C(sp3) nucleophiles, a highly regioselective 1,4-addition process is favored. The addition products obtained in high yield and with excellent stereocontrol the internal olefin. With use chiral ligand imides carbon 3,4-addition protocol was developed, enabling construction two contiguous tertiary stereocenters single step moderate to levels diastereocontrol enantiocontrol. Both methods operate under mild reaction conditions, display broad scope, show functional group tolerance. synthetic potential 3,4-hydroalkylation established via series postcatalytic modifications.

Language: Английский

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A Palladium Complex as an Asymmetric π-Lewis Base Catalyst for Activating 1,3-Dienes

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(12), P. 4809 - 4816

Published: March 18, 2021

Here we report that palladium(0) complexes can coordinate in a η2 fashion to 1,3-dienes and significantly raise the energy of their highest occupied molecular orbital (HOMO) by donating electrons from d-orbitals empty antibonding orbitals double bonds (π*) via back-bonding. Thus, uncoordinated bond, as more reactive partner on basis principle vinylogy, directly attack imines, furnishing formal hydrodienylation reaction enantioselectively. A chemoselective cascade vinylogous addition/allylic alkylation difunctionalization process between imines with nucleophilic group is also compatible, trapping situ formed π-allylpalladium species after initial ene addition. This π-Lewis base catalytic mode, featuring simple η2coordination, activation, compatibility both conjugated neutral polyenes electron-deficient polyenes, elucidated control experiments density functional theory (DFT) calculations.

Language: Английский

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Orthogonal Regulation of Nucleophilic and Electrophilic Sites in Pd‐Catalyzed Regiodivergent Couplings between Indazoles and Isoprene

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(15), P. 8321 - 8328

Published: Jan. 19, 2021

Abstract Depending on the reactant property and reaction mechanism, one major regioisomer can be favored in a that involves multiple active sites. Herein, an orthogonal regulation of nucleophilic electrophilic sites regiodivergent hydroamination isoprene with indazoles is demonstrated. Under Pd‐hydride catalysis, 1,2‐ or 4,3‐insertion pathway respect to could controlled by choice ligands. In terms indazoles, occurs at either N 1 ‐ 2 ‐position governed acid co‐catalysts. Preliminary experimental studies have been performed rationalize mechanism regioselectivity. This study not only contributes practical tool for selective functionalization isoprene, but also provides guide manipulate regioselectivity ‐functionalization indazoles.

Language: Английский

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Mechanistic Study of Ni and Cu Dual Catalyst for Asymmetric C–C Bond Formation; Asymmetric Coupling of 1,3-Dienes with C-nucleophiles to Construct Vicinal Stereocenters

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(11), P. 6643 - 6655

Published: May 21, 2021

We report details of the reaction mechanism for a coupling 1,3-dienes with C-nucleophiles that was catalyzed by Ni/Cu cooperative catalyst system using Ni(cod)2 and [Cu(CH3CN)4]PF6 in presence chiral JOSIPHOS-type bisphosphine ligand iPr2NEt, providing direct access to highly valuable vicinal quaternary tertiary stereocenters high enantio- diastereoselectivity. The bimetallic exhibited broad substrate scope, including both cyclic/acyclic stabilized nucleophiles aryl-/alkyl-substituted 1,3-dienes. elucidated depth isolating characterizing four key complexes nickel copper conducting deuterium labeling experiments, kinetic studies, density functional theory calculations. turnover-limiting step this is proton-transfer diene-coordinated Ni complex 6 from cationic Cu 8 yield π-allyl 7 enolate 9, respectively. stereoselectivity also clarified according single-point calculations intermediates 9.

Language: Английский

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Evolution in heterodonor P-N, P-S and P-O chiral ligands for preparing efficient catalysts for asymmetric catalysis. From design to applications

Coordination Chemistry Reviews, Journal Year: 2021, Volume and Issue: 446, P. 214120 - 214120

Published: July 19, 2021

The success of phosphine-oxazoline ligands (PHOX) inspired the progress in P-oxazoline ligand families by modifying either backbone, electronic and/or steric properties phosphine group or exchanging to a phosphinite phosphite group. In this respect, structures chiral have become more diverse and new very efficient emerged, which improved catalytic performance some asymmetric transformations, with an increased versatility, both range reactions substrates/reagents. addition, most are synthesized from easily accessible amino alcohols, maintaining short synthetic route developed for PHOX ligands. New been replacing oxazoline functionality several other N-donor groups, e.g. imidazole, thiazole, oxazole, pyridine, etc., O- S-groups. This review offers critical overview utility these successful bidentate heterodonor P-N, P-O P-S applied metal-mediated processes. We illustrate how, through proper design, can be excellent source ligands, superior many than best C2-symmetric N,N P,P-ligands reported so far.

Language: Английский

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