Related Experiment Video
Updated: Jan 11, 2026

Efficient Synthesis of Polyfunctionalized Benzenes in Water via Persulfate-promoted Benzannulation of α,β-Unsaturated Compounds and Alkynes
Published on: December 16, 2019
A Change in C-H Activation Mechanism: Experimental and Computational Investigations of Rh-Catalyzed Disubstituted
Christopher W Reid1, Chi Zhang2, Lauren E Baptiste1
1Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States.
Abstract:
We report the ethenylation of 1,3- and 1,2-disubstituted benzenes using [(η2-C2H4)2Rh-(μ-OAc)]2 as a catalyst precursor and Cu-(OPiv)2 as the oxidant. The regioselectivity of alkenylation for 1,3-disubstituted benzenes produces 3,5-disubstituted styrene products, while the alkenylation of 1,2-disubstituted benzenes produces 3,4-disubstituted styrene products. The rate of alkenylation is influenced by steric and electronic factors based on the substituents of the benzene unit. In all cases, 1,2-disubstituted benzenes react faster than 1,3-disubstituted benzenes, with a rate difference that is from 2 times up to >70 times more rapid for 1,2-disubstituted substrates. This is likely due to the difference in the number of accessible C-H bonds based on the steric protection of C-H bonds adjacent to functionality. Furthermore, the rate of alkenylation is influenced by the arene substituent electronics. The rates of alkenylation for 1,2-disubstituted benzenes follow the trend OMe > Me > CF3 > Cl, while for 1,3-disubstituted benzenes the trend is CF3 > Cl > Me > OMe. Using quantum mechanics DFT calculations, we found that the C-H activation step can occur by two different mechanisms. The electronic properties of substituents on the arene ring change the preferred C-H bond-breaking mechanism for 1,2-disubstituted and 1,3-disubstituted benzenes.
More Related Videos
10:10Application of Elemental Lanthanides in the Selective C-F Activation of Trifluoromethylated Benzofulvenes Providing Access to Various Difluoroalkenes
Published on: July 28, 2018
19:58Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions
Published on: July 30, 2017
Related Concept Videos
Reduction of Benzene to Cyclohexane: Catalytic Hydrogenation
Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism
Electrophilic Aromatic Substitution: Chlorination and Bromination of Benzene
Nucleophilic Aromatic Substitution: Elimination–Addition
Directing and Steric Effects in Disubstituted Benzene Derivatives
Electrophilic Aromatic Substitution: Friedel–Crafts Alkylation of Benzene