• Carbon-carbon bonds with CO2: Insights from computational studies 

      Obst, Marc; Pavlovic, Ljiljana; Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-02-17)
      In this mini-review, we provide an overview of recent computational studies on homogeneous transition metal-catalyzed carbon-carbon bond formation with CO2. We cover substitution and addition reactions involving different metals (mainly Ni, Rh, Cu) and substrates (alkanes, alkenes, alkynes, arenes) with focus on the mechanistic details. The CO2 insertion step is generally found to be rate-limiting. ...
    • Cobalt-Catalyzed Asymmetric Hydrogenation of Enamides: Insights into Mechanisms and Solvent Effects 

      Pavlovic, Ljiljana; Mendelsohn, Lauren N.; Zhong, Hongyu; Chirik, Paul J.; Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-25)
      The mechanistic details of the (<sup>Ph</sup>BPE)Co-catalyzed asymmetric hydrogenation of enamides are investigated using computational and experimental approaches. Four mechanistic possibilities are compared: a direct Co(0)/Co(II) redox path, a metathesis pathway, a nonredox Co(II) mechanism featuring an azametallacycle, and a possible enamide−imine tautomerization pathway. The results indicate ...
    • Computational and experimental insights into asymmetric Rh‐catalyzed hydrocarboxylation with CO2 

      Pavlovic, Ljiljana; Pettersen, Martin; Gevorgyan, Ashot; Vaitla, Janakiram; Bayer, Annette; Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-18)
      The asymmetric Rh‐catalyzed hydrocarboxylation of α,β‐unsaturated carbonyl compounds was originally developed by Mikami and co‐workers but gives only moderate enantiomeric excesses. In order to understand the factors controlling the enantioselectivity and to propose novel ligands for this reaction, we have used computational and experimental methods to study the Rh‐catalyzed hydrocarboxylation with ...
    • Computational and experimental insights into asymmetric Rh‐catalyzed hydrocarboxylation with CO2 

      Pavlovic, Ljiljana; Pettersen, Martin; Gevorgyan, Ashot; Vaitla, Janakiram; Bayer, Annette; Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-18)
      The asymmetric Rh‐catalyzed hydrocarboxylation of α,β‐unsaturated carbonyl compounds was originally developed by Mikami and co‐workers but gives only moderate enantiomeric excesses. In order to understand the factors controlling the enantioselectivity and to propose novel ligands for this reaction, we have used computational and experimental methods to study the Rh‐catalyzed hydrocarboxylation with ...
    • Ligand and solvent effects on CO2 insertion into group 10 metal alkyl bonds 

      Deziel, Anthony P.; Espinosa, Matthew; Pavlovic, Ljiljana; Charboneau, David J.; Hazari, Nilay; Hopmann, Kathrin Helen; Mercado, Brandon Q. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-02-09)
      The insertion of carbon dioxide into metal element σ-bonds is an important elementary step in many catalytic reactions for carbon dioxide valorization. Here, the insertion of carbon dioxide into a family of group 10 alkyl complexes of the type (<sup>R</sup>PBP)M(CH<sub>3</sub>) (<sup>R</sup>PBP = B(NCH<sub>2</sub>PR<sub>2</sub>)<sub>2</sub>C<sub>6</sub>H<sub>4</sub><sup>−</sup>; R = Cy or <sup>t</sup>Bu; ...
    • Mechanistic Insights into Carbamate Formation from CO2 and Amines: The Role of Guanidine–CO2 Adducts, 

      Mannisto, Jere K.; Pavlovic, Ljiljana; Tiainen, Tony; Nieger, Martin; Sahari, Aleksi; Hopmann, Kathrin Helen; Repo, Timo (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-02)
      Capture of CO<sub>2</sub> by amines is an attractive synthetic strategy for the formation of carbamates. Such reactions can be mediated by superbases, such as 1,1,3,3-tetramethylguanidine (TMG), with previous implications that zwitterionic superbase–CO<sub>2</sub> adducts are able to actively transfer the carboxylate group to various substrates. Here we report a detailed investigation of zwitterionic ...
    • Mechanistic Investigations of the Asymmetric Hydrogenation of Enamides with Neutral Bis(phosphine) Cobalt Precatalysts 

      Mendelsohn, Lauren N.; Pavlovic, Ljiljana; Zhong, Hongyu; Friedfeld, Max R.; Shevlin, Michael; Hopmann, Kathrin Helen; Chirik, Paul J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-11)
      The mechanism of the asymmetric hydrogenation of prochiral enamides by well-defined, neutral bis(phosphine) cobalt(0) and cobalt(II) precatalysts has been explored using(R,R)-<sup>iPr</sup>DuPhos ((R,R)-<sup>iPr</sup>DuPhos = (+)-1,2-bis[(2R,5R)-2,5-diisopropylphospholano]benzene) as a representative chiral bis(phosphine) ligand. A series of (R,R)-(<sup>iPr</sup>DuPhos)Co(enamide) (enamide = ...
    • N-Heteroaryl Carbamates from Carbon Dioxide via Chemoselective Superbase−Catalysis: Substrate Scope and Mechanistic Investigation 

      Mannisto, Jere K.; Pavlovic, Ljiljana; Heikkinen, Johannes; Tiainen, Tony; Sahari, Aleksi; Maier, Norbert; Rissanen, Kari; Nieger, Martin; Hopmann, Kathrin Helen; Repo, Timo (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-16)
      We report a mild superbase-catalyzed and nitrogen-selective carboxylation of N-heteroaryls, with subsequent alkylation enabling the synthesis of drug-like O-alkyl carbamates in good yields (av. 86%). Our findings suggest a partial revision of the current mechanistic understanding as superbases upon mixing with indoles and azoles generally form uncharged hydrogen-bonded complexes and not ionic salts ...
    • Rhodium-Catalyzed Hydrocarboxylation: Mechanistic Analysis Reveals Unusual Transition State for Carbon–Carbon Bond Formation 

      Pavlovic, Ljiljana; Vaitla, Janakiram; Bayer, Annette; Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-12)
      The mechanism of rhodium-COD-catalyzed hydrocarboxylation of styrene derivatives and α,β-unsaturated carbonyl compounds with CO<sub>2</sub> has been investigated using density functional theory (PBE-D2/IEFPCM). The calculations support a catalytic cycle as originally proposed by Mikami and co-workers including β-hydride elimination, insertion of the unsaturated substrate into a rhodium–hydride bond, ...
    • To Bind or Not to Bind: Mechanistic Insights into C–CO2 Bond Formation with Late Transition Metals 

      García-López, Diego; Pavlovic, Ljiljana; Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-03)
      In transition metal-mediated carboxylation reactions, CO<sub>2</sub> inserts into a metal–nucleophile bond. At the carboxylation transition state (TS), CO<sub>2</sub> may interact with the metal (<i>inner</i>-sphere path) or may insert without being activated by the metal (<i>outer</i>-sphere path). Currently, there is no consensus as to which path prevails. In order to establish general predictions ...
    • Understanding the Influence of Lewis Acids on CO2 Hydrogenation: The Critical Effect Is on Formate Rotation 

      Pavlovic, Ljiljana; Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-11)
      Lewis acids (LAs) have been shown to accelerate hydrogenation of C0<sub>2</sub>, but the underlying mechanistic details remain to be elucidated. We have employed computational methods to investigate how LAs affect CO<sub>2</sub> hydrogenation with a range of known metal-hydrides (L<sub>n</sub>Ir–H, L<sub>n</sub>Ru–H, L<sub>n</sub>Mn–H, L<sub>n</sub>Co–H). Our results show that LAs can alter the ...