28170-54-9Relevant articles and documents
N,N -Dialkyl- N′ -Chlorosulfonyl Chloroformamidines in Heterocyclic Synthesis. Part XV.
Innes, Dylan,Perkins, Michael V.,Liepa, Andris J.,Francis, Craig L.
, p. 610 - 623 (2018/09/18)
N,N-Dimethyl-N′-chlorosulfonyl chloroformamidine 1a underwent reactions with various anilines. In addition to the benzo[e][1,2,4]thiadiazine dioxides 8, from 1,3-NCC bis-nucleophilic substitution and bis-anilino adducts 9, some unexpected products were fo
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.
Comparative catalytic C-H vs. C-Si activation of arenes with Pd complexes directed by urea or amide groups
Rauf, Waqar,Thompson, Amber L.,Brown, John M.
supporting information; experimental part, p. 3874 - 3876 (2010/01/06)
Analysis of regiocontrol in Pd-catalysed C-H activation leads to observations of aryltrimethylsilyl activation and to superior results with urea-based substrates.
