Theoretical model for N-heterocyclic carbene-catalyzed decarboxylation reactions

Zhang, Min; Wang, Xinghua; Yang, Tingting; Qiao, Yan; Wei, Donghui

doi:10.1039/d1qo00413a

Cited by 22 publications

(8 citation statements)

References 43 publications

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“…Because of the reliability of DFT on the mechanistic studies of organocatalytic reactions, [31][32][33][34] transition metal-catalyzed reactions [35][36][37][38][39] and enzyme-catalyzed reactions, [40] all the calculations were performed with the Gaussian 09 program by using DFT. The geometries of all stationary points were optimized by using the B3LYP [41] density functional and the 6-31G(d, p) [29,42] basis set (denoted as Level 1).…”

Section: Computational Detailsmentioning

confidence: 99%

Unraveling origin of chemoselectivity and regioselectivity of iridium‐catalyzed B(4)–H functionalization of o‐carborane by alkyne

Chen

Liu

et al. 2022

J of Physical Organic Chem

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Functionalization at target site is an extremely challenging subject for surface modification of o‐carborane. It is a common tactic to introduce a directing group onto the C(2)–H vertex to induce exclusive B(4,5)–H functionalizations. In this study, was investigated. The computational results indicate that the formal [4 + 2] annulation going via the reductive elimination mechanism has kinetic priority than alkenylation via the decarboxylation mechanism. This is in excellent agreement with the experimental results of carborano‐isocoumarin as the major product. Given the alkyne insertion product, the protonation of alkene is likely to occur before decarboxylation followed by protonation of carborane. The reductive elimination of HOPiv is the regioselectivity determining step, and the non‐covalent interaction analysis discloses that it is the steric repulsion of the methyl on C(1) atom of carborane towards the iridacycle and the Cp* group that causes the higher barrier for the B(3)–H activation, which finally leads to the specific B(4)–H functionalization.

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Section: Computational Detailsmentioning

confidence: 99%

Unraveling origin of chemoselectivity and regioselectivity of iridium‐catalyzed B(4)–H functionalization of o‐carborane by alkyne

Chen

Liu

et al. 2022

J of Physical Organic Chem

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“…Early computational studies found that the decarboxylation step has a relatively higher barrier. Recent density functional theory (DFT) studies suggested a relatively low barrier for the decarboxylation step due to the presence of NHC·H + .…”

Section: Introductionmentioning

confidence: 99%

Mechanisms and Stereoselectivities in the NHC-Catalyzed [4 + 2] Annulation of 2-Bromoenal and 6-Methyluracil-5-carbaldehyde

Li,

Zhang,

Zhang

2023

J. Org. Chem.

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To disclose the reaction mechanism and selectivity in the NHC-catalyzed reaction of 2-bromoenal and 6-methyluracil-5-carbaldehyde, a systematic computational study has been performed. According to DFT computations, the catalytic cycle is divided into eight elementary steps: nucleophilic attack of the NHC on 2-bromoenal, 1,2-proton transfer, C–Br bond dissociation, 1,3-proton transfer, addition to 6-methyluracil-5-carbaldehyde, [2 + 2] cycloaddition, NHC dissociation, and decarboxylation. The Bronsted acid DABCO·H+ plays a crucial role in proton transfer and decarboxylation steps. The addition to 6-methyluracil-5-carbaldehyde determines both chemoselectivity and stereoselectivity, leading to R-configured carbocycle-fused uracil, in agreement with experimental results. NCI analysis indicates that the CH···N, CH···π, and LP···π interactions should be the key factor for determining the stereoselectivity. ELF analysis shows the main role of the NHC in promoting C–Br bond dissociation. The mechanistic insights obtained in the present work may guide the rational design of potential NHC catalysts.

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“…Due to the reliability of density functional theory (DFT) in mechanistic studies of organocatalytic reactions, 34–42 transition metal-catalyzed reactions 43–49 and enzyme catalyzed reactions, 50–52 all the calculations were performed using the Gaussian09 53 program using density functional theory. B3LYP 54 -D3 in conjunction with the standard 6-31G(d, p) basis set was employed for all geometry optimizations.…”

Section: Introductionmentioning

confidence: 99%

The chiral pyridoxal-catalyzed biomimetic Mannich reaction: the mechanism and origin of stereoselectivity

Han

Zhang

et al. 2022

Org. Chem. Front.

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Theoretical model for N-heterocyclic carbene-catalyzed decarboxylation reactions

Abstract: Identifying the special role of N-heterocyclic carbene (NHC) remains to be one of the most important challenges in organocatalysis field. Herein, we proposed a theoretical model for NHC-catalyzed decarboxylation reactions,...

Cited by 22 publications

References 43 publications

Unraveling origin of chemoselectivity and regioselectivity of iridium‐catalyzed B(4)–H functionalization of o‐carborane by alkyne

Unraveling origin of chemoselectivity and regioselectivity of iridium‐catalyzed B(4)–H functionalization of o‐carborane by alkyne

Mechanisms and Stereoselectivities in the NHC-Catalyzed [4 + 2] Annulation of 2-Bromoenal and 6-Methyluracil-5-carbaldehyde

The chiral pyridoxal-catalyzed biomimetic Mannich reaction: the mechanism and origin of stereoselectivity

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