C-H Bond Activation by [{(Diimine)Pd(μ-OH)}2]2+ Dimers: Mechanism-Guided Catalytic Improvement
Abstract
These conclusions—that the hydroxy-bridged dimer 1b is the most reactive species in the Pd system, considerably more reactive than either 2a or 2b towards C-H bond activation, and that there is an important solvent-assisted component in the rate law—suggest a way to substantially improve the catalytic conversion of cyclohexene into benzene [Eq. (3)]. Our previous studies involved 2b (or mixtures of 1b and 2b) in the noncoordinating solvent dichloroethane. In a typical experiment, after 24 h under 1 atm of O2 with 5 mol% of 2b as the catalyst, 8% of the cyclohexene had been converted into benzene; furthermore, there was an initiation period before any reaction occurred, and competing disproportionation of cyclohexene to benzene and cyclohexane was a major side reaction.[3] In contrast, under the same conditions but using only 1 mol% of pure 1b as the catalyst and TFE as solvent, conversion was 25% after 24 h, with no induction period or competing isomerization.[7]
Additional Information
© 2008 Wiley-VCH. Received: September 10, 2008. Published online: November 12, 2008. This work was supported by BP through the MC2 program, and Caltech through a Switzer fellowship to P.F.O. We thank Larry Henling and Michael Day for assistance with crystallography.Attached Files
Supplemental Material - BERacie08supp.pdf
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Additional details
- Eprint ID
- 13070
- DOI
- 10.1002/anie.200804455
- Resolver ID
- CaltechAUTHORS:BERacie08
- BP MC2 program
- Robert and Patricia Switzer Foundation
- Created
-
2009-01-16Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field