title: Mild aromatic palladium-catalyzed protodecarboxylation: kinetic assessment of the decarboxylative palladation and the protodepalladation steps.
abstract: Mechanism studies of a mild palladium-catalyzed decarboxylation of aromatic carboxylic acids are described. In particular, reaction orders and activation parameters for the two stages of the transformation were determined. These studies guided development of a catalytic system capable of turnover. Further evidence reinforces that the second stage, protonation of the arylpalladium intermediate, is the rate-determining step of the reaction. The first step, decarboxylative palladation, is proposed to occur through an intramolecular electrophilic palladation pathway, which is supported by computational and mechanism studies. In contrast to the reverse reaction (C-H insertion), the data support an electrophilic aromatic substitution mechanism involving a stepwise intramolecular protonation sequence for the protodepalladation portion of the reaction.
authors.affiliation: Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Dickstein
authors.forename: John M
authors.initials: JM
authors.lastname: Curto
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Gutierrez
authors.forename: Carol A
authors.initials: CA
authors.lastname: Mulrooney
authors.forename: Marisa C
authors.initials: MC
authors.lastname: Kozlowski
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry*; D002384:Catalysis; D003653:Decarboxylation; D004987:Ethers / Q000138:chemical synthesis* / Q000737:chemistry; D007700:Kinetics; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D002264:Carboxylic Acids; D004987:Ethers; D009942:Organometallic Compounds; D010165:Palladium