34322-76-4Relevant academic research and scientific papers
Ligand-Enabled meta-Selective C-H Arylation of Nosyl-Protected Phenethylamines, Benzylamines, and 2-Aryl Anilines
Ding, Qiuping,Ye, Shengqing,Cheng, Guolin,Wang, Peng,Farmer, Marcus E.,Yu, Jin-Quan
supporting information, p. 417 - 425 (2017/05/16)
A Pd-catalyzed, meta-selective C-H arylation of nosyl-protected phenethylamines and benzylamines is disclosed using a combination of norbornene and pyridine-based ligands. Subjecting nosyl protected 2-aryl anilines to this protocol led to meta-C - H arylation at the remote aryl ring. A diverse range of aryl iodides are tolerated in this reaction, along with select heteroaryl iodides. Select aryl bromides bearing ortho-coordinating groups can also be utilized as effective coupling partners in this reaction. The use of pyridine ligands has allowed the palladium loading to be reduced to 2.5 mol %. Furthermore, a catalytic amount of 2-norbomene (20 mol %) to mediate this meta-C - H activation process is demonstrated for the first time. Utilization of a common protecting group as the directing group for meta-C-H activation of amines is an important feature of this reaction in terms of practical applications.
Primary kinetic hydrogen isotope effects in deprotonations of a nitroalkane by intramolecular phenolate groups
Backstroma, Nicholas,Burtona, Neil A.,Watta, C. Ian F.
experimental part, p. 711 - 722 (2011/05/06)
Rate constants and kinetic isotope effects have been determined for the formation of nitronate anions from the ethers 1-(2-methoxyphenyl)-2- nitropropane, 7(X=H, L=H and D) and 1-(2-methoxy-5-nitrophenyl)-2-nitropropane, 7(X=NO2, L=H and D), and from the corresponding phenols, 1-(2-hydroxyphenyl)-2-nitropropane, 3(X=H, L=H and D), and 1-(2-hydroxy-5- nitrophenyl)-2-nitropropane, 3(X=NO2, L=H and D), in aqueous basic medium. For the ethers 7, rates of deprotonation by hydroxide are comparable with those found for deprotonations of 2-nitropropane, with kH/k D (25 °C)=7.7 and 7.8, respectively. In both the cases, the isotope effects are conventionally temperature dependent. For the corresponding phenols 3, conditions have been established under which the deprotonations of the nitroalkane are dominated by intramolecular deprotonation by the kinetically first-formed phenolate anion, with an estimated effective molarity EM ～ 250. For 3 (X=H, L=H or D), kH/kD (25 °C)=7.8, with EaD - EaH =6.9 kJ mol-1 and AH/AD=0.5. For 3(X=NO2, L=H or D), rates of intramolecular deprotonation are reduced 30-fold, and an elevated kinetic isotope effect is found (kH/kD (25 °C)=10.7). Activation parameters (EaD - EaH =17.8 kJ mol-1 and AH/AD=0.008) are compatible with an enhanced tunnelling contribution to reactivity in the H-isotopomer. Copyright
Asymmetric reduction of nitroalkenes with baker's yeast
Kawai, Yasushi,Inaba, Yoshikazu,Tokitoh, Norihiro
, p. 309 - 318 (2007/10/03)
Various α,β-disubstituted and trisubstituted nitroalkenes were chemoselectively reduced with baker's yeast to the corresponding nitroalkanes. Stereoselectivities of the reduction of α,β-disubstituted nitroalkenes were modest to low, and e.e.s up to 52% were obtained. Trisubstituted nitroalkenes could be reduced to the corresponding nitroalkanes with excellent enantioselectivities, moderate diastereoselectivities and in good yield.
