Mechanism, Reactivity, and Selectivity of Nickel-Catalyzed [4 + 4 + 2] Cycloadditions of Dienes and Alkynes

Hong, Xin; Holte, Dane; Götz, Daniel C. G.; Baran, Phil S.; Houk, K. N.

doi:10.1021/jo502219d

Cited by 16 publications

(9 citation statements)

References 73 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Fürstner et al isolated a ferracyclopentane complex from the reaction of [(dippp)Fe(η 2 -C 2 H 4 ) 2 ] with a cyclopropene compound . The limited ability of those iron(0) species in mediating the reductive coupling reactions of nonactivated alkenes and alkynes might have its thermodynamics cause as a calculation study by Houk et al showed that the conversions of the nickel(0) species (PMe 3 )Ni(RCCR) 2 (R = Me and COOMe) to their reductive coupling products are energetically uphill …”

Section: Resultsmentioning

confidence: 66%

See 1 more Smart Citation

Three-Coordinate Iron(0) Complexes with N-Heterocyclic Carbene and Vinyltrimethylsilane Ligation: Synthesis, Characterization, and Ligand Substitution Reactions

et al. 2019

View full text Add to dashboard Cite

Low-coordinate iron(0) species are implicated as intermediates in a range of iron-catalyzed organic transformations. Isolable iron(0) complexes with coordination numbers of less than four, however, are rarely known. In continuing with our interests in three-coordinate iron(0) complexes with N-heterocyclic carbene (NHC) and alkene ligation, we report herein the synthesis and ligand substitution reactivity of three-coordinate iron(0) complexes featuring monodentate alkene ligands, [(NHC)Fe(η 2 -vtms) 2 ] (vtms = vinyltrimethylsilane, NHC = 1,3bis(2′,6′-diisopropylphenyl)-imidazol-2-ylidene (IPr), 1; 1,3-bis(2′,6′-diisopropylphenyl)-4,5-tetramethylene-imidazol-2-ylidene (cyIPr), 2; 1,3-bis(2′,6′-diisopropylphenyl)-4,5,6,7-tetrahydro-1,3-diazepin-2-ylidene (7-IPr), 3). Complexes 1−3 were synthesized from the one-pot reactions of ferrous dihalides with the N-(2,6diisopropylphenyl)-substituted NHC ligands, vtms, and KC 8 . Reactivity study of 1 revealed its facile ligand substitution reactions with terminal aryl alkynes, ketones, isocyanides, and CO, by which iron(0) complexes [(IPr)Fe(η 2 -HCCAr)] (Ar = Ph, 5; p-CH 3 C 6 H 4 , 6; 3,5-(CF 3 ) 2 C 6 H 3 , 7), [(IPr)Fe(η 2 -OCPh 2 ) 2 ] (8), [(IPr)Fe(CNR) 4 ] (R = 2,6-Me 2 C 6 H 3 , 9; Bu t , 10), and (IPr)Fe(CO) 4 (11) were prepared in good yields. These iron(0) complexes have been characterized by 1 H NMR, solution magnetic susceptibility measurement, singlecrystal X-ray diffraction study, 57 Fe Mossbauer spectroscopy, and elemental analysis. Characterization data and computational studies suggest S = 1 ground-spin states for three-coordinate iron(0) complexes 1−3 and 5−8 and S = 0 ground states for 9− 11. Theoretical studies on the three-coordinate complexes 1, 6, and 8 indicated pronounced metal-to-ligand backdonation from occupied Fe 3d orbitals to the π* orbitals of the CC, CC, and CO moieties of the π ligands. In addition, 1 proved an effective precatalyst for the cyclotrimerization reaction of alkynes.

show abstract

Section: Resultsmentioning

confidence: 66%

“…However, neither 1,3-dienes nor cyclobutadienes that could be formed from the proposed ferracyclopentadidene intermediates B was detected. The failure to detect ferracyclopentadidene intermediates B might be related to the high activity of this species …”

Section: Resultsmentioning

confidence: 99%

Three-Coordinate Iron(0) Complexes with N-Heterocyclic Carbene and Vinyltrimethylsilane Ligation: Synthesis, Characterization, and Ligand Substitution Reactions

et al. 2019

View full text Add to dashboard Cite

show abstract

“…342 They showed that the E/Z selectivity is determined in the Ni-mediated oxidative cyclization of butadienes which is both kinetically and thermodynamically favorable only between s-cis and s-trans dienes. However, electron-deficient alkynes coordinate to Ni more strongly than the dienes and thus make the trimerization of alkynes the favored pathway.…”

Section: Cyclization Reactionsmentioning

confidence: 99%

Computational Studies of Synthetically Relevant Homogeneous Organometallic Catalysis Involving Ni, Pd, Ir, and Rh: An Overview of Commonly Employed DFT Methods and Mechanistic Insights

et al. 2015

View full text Add to dashboard Cite

“…We have been involved in numerous collaborations aimed at understanding transition metal-catalyzed reactions, sometimes involving asymmetric catalysis. Our first investigation, before the days of DFT, involved a collaboration with Paul Wender on the stereoselectivity of his Ni-catalyzed 4 + 4 cycloadditions, a reaction related to a Ni-catalyzed 4 + 4 + 2 reaction that we studied in 2014 with Phil Baran . Our study of Ni-catalyzed reactions expanded in this century into studies of the mechanisms of reductive couplings, , including stereoselectivity with chiral ligands and a Rh(I) catalyst …”

Section: Organometallic Catalysismentioning

confidence: 99%

Theory and Modeling of Asymmetric Catalytic Reactions

et al. 2016

Self Cite

View full text Add to dashboard Cite

Modern density functional theory and powerful contemporary computers have made it possible to explore complex reactions of value in organic synthesis. We describe recent explorations of mechanisms and origins of stereoselectivities with density functional theory calculations. The specific functionals and basis sets that are routinely used in computational studies of stereoselectivities of organic and organometallic reactions in our group are described, followed by our recent studies that uncovered the origins of stereocontrol in reactions catalyzed by (1) vicinal diamines, including cinchona alkaloid-derived primary amines, (2) vicinal amidophosphines, and (3) organo-transition-metal complexes. Two common cyclic models account for the stereoselectivity of aldol reactions of metal enolates (Zimmerman-Traxler) or those catalyzed by the organocatalyst proline (Houk-List). Three other models were derived from computational studies described in this Account. Cinchona alkaloid-derived primary amines and other vicinal diamines are venerable asymmetric organocatalysts. For α-fluorinations and a variety of aldol reactions, vicinal diamines form enamines at one terminal amine and activate electrophilically with NH(+) or NF(+) at the other. We found that the stereocontrolling transition states are cyclic and that their conformational preferences are responsible for the observed stereoselectivity. In fluorinations, the chair seven-membered cyclic transition states is highly favored, just as the Zimmerman-Traxler chair six-membered aldol transition state controls stereoselectivity. In aldol reactions with vicinal diamine catalysts, the crown transition states are favored, both in the prototype and in an experimental example, shown in the graphic. We found that low-energy conformations of cyclic transition states occur and control stereoselectivities in these reactions. Another class of bifunctional organocatalysts, the vicinal amidophosphines, catalyzes the (3 + 2) annulation reaction of allenes with activated olefins. Stereocontrol here is due to an intermolecular hydrogen bond that activates the electrophilic partner in this reaction. We have also studied complex organometallic catalysts. Krische's ruthenium-catalyzed asymmetric hydrohydroxyalkylation of butadiene involves two chiral ligands at Ru, a chiral diphosphine and a chiral phosphate. The size of this combination strains the limits of modern computations with over 160 atoms, multiple significant steps, and a variety of ligand coordinations and conformations possible. We found that carbon-carbon bond formation occurs via a chair Zimmerman-Traxler-type transition structure and that a formyl CH···O hydrogen bond from aldehyde CH to phosphate oxygen, as well as steric interactions of the two chiral ligands, control the stereoselectivity.

show abstract

Mechanism, Reactivity, and Selectivity of Nickel-Catalyzed [4 + 4 + 2] Cycloadditions of Dienes and Alkynes

Cited by 16 publications

References 73 publications

Three-Coordinate Iron(0) Complexes with N-Heterocyclic Carbene and Vinyltrimethylsilane Ligation: Synthesis, Characterization, and Ligand Substitution Reactions

Three-Coordinate Iron(0) Complexes with N-Heterocyclic Carbene and Vinyltrimethylsilane Ligation: Synthesis, Characterization, and Ligand Substitution Reactions

Computational Studies of Synthetically Relevant Homogeneous Organometallic Catalysis Involving Ni, Pd, Ir, and Rh: An Overview of Commonly Employed DFT Methods and Mechanistic Insights

Theory and Modeling of Asymmetric Catalytic Reactions

Contact Info

Product

Resources

About