1220015-97-3Relevant academic research and scientific papers
Exceptionally mild palladium(II)-catalyzed dehydrogenative C-H/C-H arylation of indolines at the C-7 position under air
Jiao, Lin-Yu,Smirnov, Polina,Oestreich, Martin
, p. 6020 - 6023 (2014)
An improved method for the dehydrogenative C-H/C-H cross-coupling at the C-7 position of indolines containing a urea as a directing group is reported. The new protocol is a rare example of an aerobic palladium(II)-catalyzed cross dehydrogenative coupling (CDC) reaction that proceeds at low temperature. The use of either Cu(OAc)2 in an open flask or dioxygen (balloon) at 50 °C tolerates indolines not substituted at C-2 and C-3, thereby extending the scope of the previous method that suffers from indoline-to-indole oxidation.
Cationic Pd(II)-catalyzed C-H activation/cross-coupling reactions at room temperature: Synthetic and mechanistic studies
Nishikata, Takashi,Abela, Alexander R.,Huang, Shenlin,Lipshutz, Bruce H.
supporting information, p. 1040 - 1064 (2016/07/06)
Cationic palladium(II) complexes have been found to be highly reactive towards aromatic C-H activation of arylureas at room temperature. A commercially available catalyst [Pd(MeCN)4](BF4)2 or a nitrile-free cationic palladium(II) complex generated in situ from the reaction of Pd(OAc)2 and HBF4, effectively catalyzes C-H activation/cross-coupling reactions between aryl iodides, arylboronic acids and acrylates under milder conditions than those previously reported. The nature of the directing group was found to be critical for achieving room temperature conditions, with the urea moiety the most effective in promoting facile coupling reactions at an ortho C-H position. This methodology has been utilized in a streamlined and efficient synthesis of boscalid, an agent produced on the kiloton scale annually and used to control a range of plant pathogens in broadacre and horticultural crops. Mechanistic investigations led to a proposed catalytic cycle involving three steps: (1) C-H activation to generate a cationic palladacycle; (2) reaction of the cationic palladacycle with an aryl iodide, arylboronic acid or acrylate, and (3) regeneration of the active cationic palladium catalyst. The reaction between a cationic palladium(II) complex and arylurea allowed the formation and isolation of the corresponding palladacycle intermediate, characterized by X-ray analysis. Roles of various additives in the stepwise process have also been studied.
Direct synthesis of 8-aryl tetrahydroquinolines via pd-catalyzed ortho-arylation of aryl ureas in water
Jiang, Zhen,Zhang, Lingjuan,Dong, Chaonan,Su, Xiaoming,Li, Huanrong,Tang, Weijun,Xu, Lijin,Fan, Qinghua
, p. 1025 - 1028 (2013/03/13)
An efficient protocol for the direct synthesis of 8-arylated tetrahydroquinolines via Pd-catalyzed ortho-arylation of aryl ureas with aryl iodides was developed. The reaction proceeded smoothly in water under ligand-free and surfactant-free conditions, pr
Cationic palladium(II) catalysis: C-H activation/suzuki-miyaura couplings at room temperature
Nishikata, Takashi,Abela, Alexander R.,Huang, Shenlin,Lipshutz, Bruce H.
supporting information; experimental part, p. 4978 - 4979 (2010/06/14)
Cationic palladium(II) catalyst realized facile C?H activation of aryl urea with arylboronic acids at room temperature. This reaction is extremely mild to carry out aromatic CH activations through electrophilic substitution.
