The Origin of Anti‐Markovnikov Regioselectivity in Alkene Hydroamination Reactions Catalyzed by [Rh(DPEphos)]⁺

Abstract

The development of regioselective anti-Markovnikov alkene's hydroamination is a long-standing goal in catalysis. The [Rh(COD)(DPEphos)](+) complex is the most general and regioselective group 9 catalyst for such a process. The reaction mechanism for intermolecular hydroamination of alkenes catalyzed by [Rh(DPEphos)](+) complex is analyzed by means of DFT calculations. Hydroamination (alkene vs. amine activation routes) as well as oxidative amination pathways are analyzed. According to the computational results the operating mechanism can be generally described by alkene coordination, amine nucleophilic addition, proton transfer through the metal center and reductive elimination steps. The mechanism for the formation of the oxidative amination side product goes via a β-elimination after the nucleophilic addition and metal center protonation steps. The origin of the regioselectivity for the addition process (Markovnikov vs. anti-Markovnikov additions) is shown to be not charge but orbitally driven. Remarkably, η(2) to η(1) slippage degree on the alkene coordination mode is directly related to the regioselective outcome.

Energy Decomposition Analyses Reveal the Origins of Catalyst and Nucleophile Effects on Regioselectivity in Nucleopalladation of Alkenes

“…8 In contrast, computational studies on the regioselective nucleopalladation of alkenes are limited due to the complexity of regioselectivity control. 9 The potential competition between cis - and trans -nucleopalladation pathways 1c,10 further complicated the computational analysis (Figure 1a). Here, we present a systematic computational approach to quantitatively analyze the contributions of different types of effects to the regioselectivity in cis - and trans -nucleopalladations with different palladium catalysts and a variety of N - and O -nucleophiles with different formal charges, steric hinderances, and nucleophilicities (Figure 1c).…”

Kinetics and Mechanism of the Platinum(II)‐Catalyzed Hydroarylation of Vinyl Arenes with 1,2‐Dimethylindole

“…The studies have established the increasing extent of η 2 →η 1 slippage toward the η 1 ‐termally coordinated structure with the increasing electron donor ability of the para substituent . Indeed, DFT calculations of the stoichiometric outer‐sphere addition of methoxide to the cationic platinum π‐vinyl arene complexes {(tmeda)PtCl[η 2 ‐CH 2 =C(H) p ‐C 6 H 4 X]} + ClO 4 − ascribed the kinetic regioselectivity of nucleophilic addition to the extent of η 2 →η 1 alkene slippage and resultant localization of the Pt‐alkene LUMO on the terminal or internal carbon atom of the coordinated C=C bond …”

“…2020, 60, 437 -445 nucleophilic addition to the extent of η 2 !η 1 alkene slippage and resultant localization of the Pt-alkene LUMO on the terminal or internal carbon atom of the coordinated C=C bond. [41,42]…”

External electric field: a new catalytic strategy for the anti-Markovnikov hydrohydrazination of parent hydrazine

“…67 The geometries of the reactants (Rs), transition states (TSs), intermediates (IMs), and products (Ps) were fully optimized at the level of M06/6-31G(d) 68 because this functional has been proved previously in the hydroamination reactions. [69][70][71][72][73] All of the stationary points were also calculated by frequency calculations at the same level of theory to conrm that all transition states had only one imaginary frequency, while the others had no imaginary frequency. Furthermore, the transition states were analyzed by intrinsic reaction coordinate (IRC) [74][75][76] calculations with the aim of testing the TSs correctly connecting the former and the later stationary points.…”