Palladium on carbon–bromobenzene mediated esterification and transesterification

Esterification, transesterification and hydrogenation reactions of polyunsaturated compounds catalyzed by a recyclable polymer supported palladium catalyst

“…[Pd(AAEMA)2 ]in situ generated palladium nanoparticles. The reaction pathway could be similar to the one proposed by Aavula and co-workers[23] starting with an oxidative addition of bromobenzene additive to the coordinately unsaturated palladium(0) at the nanoparticle edge, affording Pd(II)-phenyl bromide intermediate, which in contact with hydrogen gas leads to generation of HBr and Pd(II) phenyl hydride species that, in turn, restores the initial Pd(0) by elimination of benzene (Scheme 2). Proton transfer from the generated HBr to the carbonyl oxygen of the carboxylic acid increases the electrophilicity of the carbonyl carbon, promoting the well-known Fischer esterification with alcohol[43] (Scheme 2).Scheme 2: Possible reaction mechanism for the esterification with alcohol promoted by Pd-pol.This mechanism was confirmed by the high catalytic activity showed by the hot filtered motherliquor let under stirring at 40 °C under air in the absence of metal catalyst.…”

Development of the Applications of Palladium on Charcoal in Organic Synthesis

“…For example, Aavula's group reported a Pd/C‐catalyzed bromobenzene‐mediated esterification and transesterification of carboxylic acids with various alcohols for their conversion into the corresponding esters [Eq. (34)] ).…”

“… Proposed mechanism for the Pd/C‐PhBr‐catalyzed carboxylic acid esterification. Redrawn with permission . Copyright 2013, Elsevier Ltd.…”

Synthesis of Nitriles from Aldehydes with Elongation of the Molecule with Two Carbon Atoms

“…With these results in hand, we proceeded to investigation of the substrate scope of the developed methodology under the optimized reaction conditions (Scheme ). A wide range of aldehydes could be successfully employed, including those containing various functional groups prone to reduction by dihydrogen . ortho ‐, meta ‐ and para ‐substituted aldehydes formed nitriles in good yields ( 1a , 1f , 1i ).…”