Distortion/Interaction Analysis Reveals the Origins of Selectivities in Iridium-Catalyzed C–H Borylation of Substituted Arenes and 5-Membered Heterocycles

Abstract

The iridium-catalyzed borylation of mono-and disubstituted arenes and heteroarenes has been studied with density functional theory. The distortion/interaction model was employed to understand the origins of selectivities in these reactions. Computations revealed that the transition states for C−H oxidative addition are very late, resembling the aryl iridium hydride intermediate with a fully formed Ir−C bond. Consequently, the regioselectivity is mainly controlled by differences in the interaction energies between the iridium catalyst and arene carbon.

Iridium-catalysed regioselective borylation of carboranes via direct B–H activation

“…f). (5) B(3,6)–H bonds were more reactive than B(4,5,7,11)–H ones in the above borylation, suggesting that the activation of cage B–H bond may proceed via oxidative addition pathway136373839555657, instead of electrophilic substitution mechanism303132333435 as the electron density in o -carborane follows the trend: B(3,6)<B(4,5,7,11)<B(8,10)<B(9,12)127.…”

“…On the basis of the aforementioned experimental results and literature work303645464748495051525354555657, a proposed mechanism for the borylation reaction is shown in Fig. 5.…”

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

“…561 In a related study in 2014, Merlic, Houk, and co-workers investigated the borylation of substituted arenes and heterocycles. 562 Their computations at the SMD (n-octane) M06/6-311G(d,p)(SDD)//B3LYP/6-31G(d)(LANL2DZ) level of theory suggested that C−H oxidative addition transition states are very late and in close resemblance to the aryl Ir hydride intermediate. Thus, regioselectivity is mainly interaction energy controlled.…”

Theoretical and Computational Study of a Complex System Consisting of Transition Metal Element(s): How to Understand and Predict Its Geometry, Bonding Nature, Molecular Property, and Reaction Behavior

“…Also, the C(sp Another important development is to achieve regioselective CH σ-bond activation in these direct borylation reactions, which is also an important target in the chemistry of CH activation because regioselective CH σ-bond activation is not easy. The factors for controlling regioselectivity have been discussed in theoretical work of borylation of substituted arenes, heterocycles, 119 and chlorosilane. 117 In the direct borylation of alkylamines and alkylethers, the regioselectivity has been experimentally and theoretically well investigated.…”