Benzylic C–H activation and C–O bond formation via aryl to benzylic 1,4-palladium migrations
摘要:
A procedure for benzylic C-H activation has been developed using a palladium 1,4-aryl to benzylic migration as a key step. Carboxylates and phenoxides readily trap the resulting benzylic palladium intermediates obtained from palladium 'through space' migration. Aryl bromides and iodides have been successfully employed in this reaction, furnishing moderate to good yields. The mechanism of this reaction has been studied by deuterium-labeling experiments, which suggest that the migration of palladium from an aryl to a benzylic position occurs reversibly. The reaction conditions developed for the migration process also oxidize the neighboring benzylic alcohols to the corresponding aldehydes and ketones. (C) 2008 Elsevier Ltd. All rights reserved.
Palladium(0) nanoparticle-catalyzed sp2 C–H activation: a convenient route to alkyl–aryl ketones by direct acylation of aryl bromides and iodides with aldehydes
作者:Laksmikanta Adak、Sukalyan Bhadra、Brindaban C. Ranu
DOI:10.1016/j.tetlet.2010.05.067
日期:2010.7
Palladium(0) nanoparticles efficiently catalyze aliphatic aldehyde C–H functionalization by aryl halides to produce alkyl–arylketones in good yields. A wide range of substituted aryl and hetero-aryl bromides/iodides and open-chain aldehydes of varied chain length participated in this reaction.
efficient AuIII‐catalyzed method to generate the highly reactive cyclic o‐quinodimethane (o‐QDM) species from easily available enynals or enynones is presented (see scheme). This method produced a variety of structurally unique fan‐like products with the advantages of mild reaction conditions, excellent diastereoselectivities, and high functional‐group tolerance.