A rhodium(III)-catalyzed C–H allylation of (hetero)arenes by using 2-methylidenetrimethylene carbonate as an efficient allylic source has been developed for the first time. Five different directing groups including oxime, N-nitroso, purine, pyridine, and pyrimidine were compatible, delivering various branched allylarenes bearing an allylic hydroxyl group in moderate to excellent yields.
Palladium-catalyzed arene C(sp2)–H acetoxylation has emerged as a powerful tool to construct a carbon–oxygen (C–O) bond. However, the requirement of stoichiometric chemical oxidants for this transformation possesses a significant disadvantage. To solve this fundamental problem, we now report an anodic oxidation strategy to achieve arene C(sp2)–H acetoxylation.
Direct Oxygenation of C–H Bonds through Photoredox and Palladium Catalysis
作者:Sk. Sheriff Shah、Maniklal Shee、Amit Kumar Singh、Amrita Paul、N. D. Pradeep Singh
DOI:10.1021/acs.joc.9b03197
日期:2020.3.6
This report presents the oxygenation of C-H bonds via the merger of photocatalysis and Pd catalysis. Herein, we describe the utilization of a photocatalyst to oxidize an organopalladium(II) intermediate to high-valent PdIII or PdIV intermediates, which promotes the formation of C-O bonds. The demonstrated method works efficiently with various directing groups, such as oxime ether and benzothiazole
C(sp2)–H bond oxidation of oximes or azobenzenes with diverse carboxylic acids has been developed. In contrast to the previous catalytic systems, this protocol features mild conditions (close to room temperature for most cases) and a broad substrate scope (up to 64 examples), thus constituting a versatile method to directly prepare diverse O-aryl esters. Moreover, the superiority of the nitrate additive
Palladium-catalyzed decarboxylative acylation of O-methyl ketoximes with α-keto acids
作者:Minyoung Kim、Jihye Park、Satyasheel Sharma、Aejin Kim、Eonjeong Park、Jong Hwan Kwak、Young Hoon Jung、In Su Kim
DOI:10.1039/c2cc38433g
日期:——
A mild, practical and efficient palladium-catalyzed decarboxylative ortho-acylation of O-methyl ketoximes with α-keto acids via CâH bond activation is described. In these reactions, a broad range of O-methyl ketoximes and α-keto acids undergoes the decarboxylative cross-coupling reactions with high selectivities and good tolerance.