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Mechanistic investigations of bipyrimidine-promoted palladium-catalyzed allylic acetoxylation of olefins

Lin, Bo-Lin and Labinger, Jay A. and Bercaw, John E. (2009) Mechanistic investigations of bipyrimidine-promoted palladium-catalyzed allylic acetoxylation of olefins. Canadian Journal of Chemistry, 87 (1). pp. 264-271. ISSN 0008-4042. https://resolver.caltech.edu/CaltechAUTHORS:LINcjc08

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Abstract

Several pyridine-like ligands were found to improve Pd(OAc)2-catalyzed allylic oxidation of allylbenzene to cinnamyl acetate by p-benzoquinone in acetic acid. The best ligand examined, bipyrimidine, was used to identify the catalyst precursor for this system, (bipyrimidine)Pd(OAc)2, which was fully characterized. Mechanistic studies suggest the reaction takes place through disproportionation of (bipyrimidine)Pd(OAc)2 to form a bipyrimidine-bridged dimer, which reacts with olefin to form a Pd^II-olefin adduct, followed by allylic C–H activation to produce (η^3-allyl)Pd^II species. The (η^3-allyl)Pd^II intermediate undergoes a reversible acetate attack to generate a Pd^0-(allyl acetate) adduct, which subsequently reacts with p-benzoquinone to release allyl acetate and regenerate (bipyrimidine)Pd(OAc)2. No KIE is observed for the competition experiment between allylbenzene-d0 and allylbenzene-d5 (CD2=CDCD2C6H5), suggesting that allylic C–H activation is not rate-determining. Catalytic allylic acetoxylations of other terminal olefins as well as cyclohexene were also effected by (bipyrimidine)Pd(OAc)2.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1139/V08-133DOIArticle
ORCID:
AuthorORCID
Labinger, Jay A.0000-0002-1942-9232
Additional Information:© 2008 NRC Canada. Received 17 April 2008. Accepted 2 July 2008. Published on the NCR Research Press Web site at canjchem.ncr.ca on 15 October 2008. We thank Dr. Michael W. Day and Lawrence M. Henling for performing the X-ray crystallographic analysis. b.-L. Lin also thanks George S. Chen for suggestions in preparing the manuscript. This work has been generously supported by BP through the MC2 program.
Funders:
Funding AgencyGrant Number
BP MC2 programUNSPECIFIED
Subject Keywords:olefin; palladium catalysis; allylic C-H oxidation; p-benzoquinone; bipyrimidine.
Issue or Number:1
Record Number:CaltechAUTHORS:LINcjc08
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:LINcjc08
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13763
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:06 Apr 2009 21:37
Last Modified:03 Oct 2019 00:44

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