A palladium-catalyzeddirect access to ketones from aldehydes via C−H cleavage of arenes is described. The procedure utilizes air as a clean and free terminal oxidant.
Pd(<scp>ii</scp>)-catalysed o-aroylation of directing arenes using terminal aryl alkenes and alkynes
作者:Nilufa Khatun、Arghya Banerjee、Sourav K. Santra、Ahalya Behera、Bhisma K. Patel
DOI:10.1039/c4ra11014e
日期:——
A substrate-directed Pd-catalysed o-aroylation strategy has been demonstrated using new aroyl surrogates viz. terminal aryl alkenes and alkynes in the presence of TBHP. By a subtle change in catalyst from Cu to Pd, a differential selectivity is observed. While terminal aryl alkenes/alkynes in the presence of Cu/TBHP are reported to act as o-aryloxy (ArCOO–) sources, the use of Pd/TBHP installs an aroyl (ArCO–) group at the ortho position with respect to the directing arenes.
aldehydes leading to aryl ketones by the use of palladium(II) acetate, tert-butyl hydroperoxide, and chlorobenzene as the catalyst, oxidant, and solvent, respectively, is presented. Intra- and intermolecular kinetic isotope effects, radical trapping, and controlled experiments were carried out to support the proposed catalytic mechanism for the reaction. Syntheses of (2-hydroxyphenyl)(phenyl)methanones and
Four Tandem C–H Activations: A Sequential C–C and C–O Bond Making via a Pd-Catalyzed Cross Dehydrogenative Coupling (CDC) Approach
作者:Srimanta Guin、Saroj Kumar Rout、Arghya Banerjee、Shyamapada Nandi、Bhisma K. Patel
DOI:10.1021/ol302438z
日期:2012.10.19
the ortho C–H bond with respect to a directing group has been accomplished via a Pd(II)-catalyzed cross dehydrogenative coupling approach using alkylbenzene as the synthetic equivalent of an aroyl moiety. The reaction proceeds through sequential C–C and C–O bond making at the expense of four consecutive C–H bondcleavages (three sp3 benzylic C–H’s and one sp2 arene C–H) to selectively install an aroyl