Asymmetric reduction of nitroalkenes with baker's yeast
摘要:
Various alpha,beta -disubstituted and trisubstituted nitroalkenes were chemoselectively reduced with baker's yeast to the corresponding nitroalkanes. Stereoselectivities of the reduction of alpha,beta -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. (C) 2001 Elsevier Science Ltd. All rights reserved.
Proton Magnetic Resonance Spectra of Some Amphetamines and Related Compounds and Observations on Rotamer Populations
作者:K. Bailey、A. W. By、K. C. Graham、D. Verner
DOI:10.1139/v71-524
日期:1971.10.1
β-nitro-α-phenyl-propanes having methyl or methoxy substituants on the phenyl ring (37 compounds in all) are presented. The α and β protons of the side-chain give a pattern usually analyzable as ABX. The data are discussed in terms of correlations of coupling constants and chemicalshifts with electronegativity of the substituent groups, steric and electronic effects, and apparent changes in rotamer
Primary kinetic hydrogen isotope effects in deprotonations of a nitroalkane by intramolecular phenolate groups
作者:Nicholas Backstrom、Neil A. Burton、C. Ian F. Watt
DOI:10.1002/poc.1631
日期:2010.8
2‐nitropropane, with kH/kD (25 °C) = 7.7 and 7.8, respectively. In both the cases, the isotopeeffects 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
已确定了由醚1-(2-甲氧基苯基)-2-硝基丙烷,7(X = H,L = H和D)和1-(2--2-甲氧基-醚)形成亚硝酸根阴离子的速率常数和动力学同位素效应5-硝基苯基)-2-硝基丙烷7(X = NO 2,L = H和D),相应酚中的1-(2-羟基苯基)-2-硝基丙烷3(X = H,L = H和D)和1-(2-羟基-5-硝基苯基)-2-硝基丙烷3(X = NO 2,L = H和D)在碱性水溶液中。对于醚7,氢氧化物的去质子化速率与k-(k H / k D)下的2-硝基丙烷的去质子化速率相当。(25°C)分别为7.7和7.8。在两种情况下,同位素效应通常取决于温度。对于相应的酚3,已经建立了条件,在该条件下,硝基烷的去质子化主要由动力学上首先形成的酚盐阴离子进行分子内去质子化,估计的有效摩尔浓度为EM〜250。对于3(X = H,L = H或D),k H / k D(25°C)= 7.8,E
Ligand-Enabled <i>meta</i>-Selective C–H Arylation of Nosyl-Protected Phenethylamines, Benzylamines, and 2-Aryl Anilines
作者:Qiuping Ding、Shengqing Ye、Guolin Cheng、Peng Wang、Marcus E. Farmer、Jin-Quan Yu
DOI:10.1021/jacs.6b11097
日期:2017.1.11
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
Asymmetric reduction of nitroalkenes with baker's yeast
作者:Yasushi Kawai、Yoshikazu Inaba、Norihiro Tokitoh
DOI:10.1016/s0957-4166(01)00029-5
日期:2001.2
Various alpha,beta -disubstituted and trisubstituted nitroalkenes were chemoselectively reduced with baker's yeast to the corresponding nitroalkanes. Stereoselectivities of the reduction of alpha,beta -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. (C) 2001 Elsevier Science Ltd. All rights reserved.