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Key Mechanistic Features in Palladium-Catalyzed Methylcyclopropanation of Norbornenes With Vinyl Bromides: Insights From DFT Calculations.

ABSTRACT: DFT calculations were performed to elucidate mechanistic details of an unusual palladium-catalyzed methylcyclopropanation from [2 + 1] cycloadditions of (Z)-2-bromovinylbenzene and endo-N-(p-tolyl)-norbornenesuccinimide. The reaction proceeds via oxidative addition (OA), intermolecular alkene insertion, deprotonation/protonation, intramolecular alkene insertion, ?-H elimination and reductive elimination (RE). Protonation is the rate-limiting step and requires an overall barrier of 28.5 kcal/mol. The sources of two protons for protonation and exchange have also been clarified and the calculations agree with experimental observations.

SUBMITTER: Ying F

PROVIDER: S-EPMC6445852 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Key Mechanistic Features in Palladium-Catalyzed Methylcyclopropanation of Norbornenes With Vinyl Bromides: Insights From DFT Calculations.

Ying Fang F Zhang Yutong Y Xiang Chuyue C Song Zhijun Z Xie Hujun H Bao Weiliang W

Frontiers in chemistry 20190327

DFT calculations were performed to elucidate mechanistic details of an unusual palladium-catalyzed methylcyclopropanation from [2 + 1] cycloadditions of (<i>Z</i>)-2-bromovinylbenzene and endo-N-(p-tolyl)-norbornenesuccinimide. The reaction proceeds via oxidative addition (OA), intermolecular alkene insertion, deprotonation/protonation, intramolecular alkene insertion, β-H elimination and reductive elimination (RE). Protonation is the rate-limiting step and requires an overall barrier of 28.5 kc ...[more]

PMID: 30972329

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