1347032-52-3Relevant academic research and scientific papers
Palladium-catalyzed benzylic C-H benzylation via bis-benzylpalladium(II) complexes in water: An effective pathway for the direct construction of N-(1,2-diphenylethyl)anilines
Hikawa, Hidemasa,Izumi, Kyoko,Ino, Yukari,Kikkawa, Shoko,Yokoyama, Yuusaku,Azumaya, Isao
, p. 1037 - 1048 (2015/03/30)
A strategy for the N-benzylation/benzylic C-H benzylation cascade of anilines by the π-benzylpalladium system using a water-soluble palladium(0)/sodium diphenylphosphinobenzene-3-sulfonate (TPPMS) catalyst and benzyl alcohol in water has been developed. This tandem process is devised as a novel and efficient synthetic route for N-(1,2-diphenylethyl)anilines. Benzylic C-H activation of a mono-N-benzylated intermediate with a π-benzylpalladium(II) complex affords a bis-π-benzylated palladium(II) intermediate. The nucleophilic η1-σ-benzyl anion ligand attacks the electrophilic η3-π-benzyl ligand to give a dibenzylated product. The intermolecular competition between mono-N-benzylaniline and its monodeuterated form (monodeuterated at the benzylic group) with benzyl alcohol gave a KIE=4.6, suggesting that C-H bond cleavage was involved in the rate-determining step. Hammett studies on the rate constants of benzylation by various substituted anthranilic acids and mono-N-benzylanilines show a good correlation between the log(kX/kH) and the σ values of the respective substituents. From the slope, negative ρ values are obtained, suggesting that there is a build-up of positive charge in the transition state. The reaction of anilines with electron-donating and electron-withdrawing groups affords the corresponding N-(1,2-diphenylethyl)anilines in moderate to good yields (54-86%). Interestingly, the reaction of anthranilic acids proceeded smoothly to give only the corresponding dibenzylated products in good to excellent yields (70-87%). The carboxyl group of the anthranilic acids acts as a directing group in the benzylic C-H activation process.
Palladium-catalyzed benzylation of unprotected anthranilic acids with benzyl alcohols in water
Hikawa, Hidemasa,Yokoyama, Yuusaku
supporting information; experimental part, p. 6512 - 6515 (2012/02/02)
Palladium-catalyzed benzylation of unprotected anthranilic acids with benzyl alcohols in the presence of Pd(OAc)2 (5 mol %) and sodium diphenylphosphinobenzene-3-sulfonate (TPPMS, 10 mol %) in water at 120-C for 16 h gave only dibenzylated anthranilic acids in good yields. Water may play important roles for the smooth generation of the (?3-benzyl)palladium species by activation of the hydroxyl group of the benzyl alcohol. 2011 American Chemical Society.
