Combining Transition Metal Catalysis with Radical Chemistry: Dramatic Acceleration of Palladium-Catalyzed CH Arylation with Diaryliodonium Salts
作者:Sharon R. Neufeldt、Melanie S. Sanford
DOI:10.1002/adsc.201200738
日期:2012.12.14
This paper describes a photoredox palladium/iridium-catalyzed C-H arylation with diaryliodonium reagents. Details of the reaction optimization, substrate scope, and mechanism are presented along with a comparison to a related method in which aryldiazonium salts are used in place of diaryliodonium reagents. The unprecedentedly mild reaction conditions (25 masculineC in methanol), the requirement for
Palladium-catalyzed C–H activation of anilides at room temperature: ortho-arylation and acetoxylation
作者:Fan Yang、Feijie Song、Wei Li、Jingbo Lan、Jingsong You
DOI:10.1039/c3ra41981a
日期:——
Room-temperature ortho-arylation and acetoxylation of anilides have been achieved using cationic palladium (Pd[TFA]+) as catalyst and (NH4)2S2O8 as oxidant. Preliminary investigation of the mechanism suggests that palladium may have different oxidation states in the catalytic cycles of these two transformations.
The use of a dual palladium/organic photoredox catalytic system enables the directed arylation of arenes with aryldiazonium salts with a broad substrate scope at room temperature under mild reaction conditions. This study thus serves as not only an alternative route for the biaryl motifs but also a new example for the application of an organic photoredox catalyst.
The palladium-catalysed direct arylation of acetanilides by using C-H activation methodology has been demonstrated. Several acetanilides were coupled with aryl iodides in the presence of 10 mol% of Pd(OAc)2, 1·0 equiv of Cu(OTf)2, and 0·6 equiv of Ag2O to afford the corresponding products in moderate to excellent yields. The results showed that the amount of Ag2O was important for this protocol.
Twofold C−H Functionalization: Palladium-Catalyzed <i>Ortho</i> Arylation of Anilides
作者:Gordon Brasche、Jorge García-Fortanet,、Stephen L. Buchwald
DOI:10.1021/ol800619c
日期:2008.6.5
The ortho arylation of anilides to form biphenyls via a twofold C-H functionalization/C-C bond-forming process is described. The oxidative coupling takes place in the presence of 5-10 mol % of Pd(OAC)(2), 10-20 mol % of DMSO, and 4-11 equiv of the aryl substrate in TFA under an oxygen atmosphere. No metal-containing cocatalyst is required.