Visible light-mediated metal-free double bond deuteration of substituted phenylalkenes
作者:Roman Iakovenko、Jan Hlaváč
DOI:10.1039/d0gc03081c
日期:——
Photoactivated metal free deuteration of a double bond was developed in an environmentally friendly manner.
双键的光活化金属无氘化反应以环境友好的方式进行了开发。
Stereodivergent Alkyne Reduction by using Water as the Hydrogen Source
作者:Santhosh Rao、Kandikere Ramaiah Prabhu
DOI:10.1002/chem.201803147
日期:2018.9.18
homogeneous Pd‐catalyzed stereodivergent reduction of alkynes to Z and E alkenes by using H2O as the H2 source is presented. Mediated by a diboron reagent, the transfer hydrogenation has been accomplished to yield the desired geometrical isomer by rational ligand selection. The switchable stereoselectivity achieved using simple phosphine ligands is generally excellent. D2O has also been used as a D2 source
transfer semihydrogenation of internal alkynes employing a previously described bifunctional ruthenium‐based PC(sp3)P complex, 20 mol% of sodium formate and nearly stoichiometric formic acid. Semihydrogenation of the terminal alkynes results in the formation of the corresponding styrenes. The mechanism of the reaction includes stepwise transfer of both the hydride and the proton of the formic acid to the
该手稿描述了使用先前描述的双功能钌基PC(sp 3)P络合物,20 mol%的甲酸钠和接近化学计量的甲酸进行内部炔烃E选择性转移半氢化的有效方案。末端炔烃的半氢化导致形成相应的苯乙烯。该反应的机理包括将氢化物和甲酸的质子逐步转移到底物上。这一事实允许通过简单地施加甲酸/甲酸钠/ D 2来开发用于合成单氘代烯烃的简便方案。以O混合物为氢源。通常已经实现了高产率,选择性和官能团相容性。
Studies of pyrazines. Part 8. Pyrolysis of 2-alkoxypyrazines; substituent effects and stereospecificity
±-threo-2-deuterio-1,2-diphenylethyl) have been pyrolysed to elucidate the substituenteffects on the rate and stereospecificity of the reaction. Activation parameters (log A and Ea) for the first eight compounds listed were determined. The reaction was accelerated by α-substitution; this was a combination of both polar and steric effects. The stereospecificity of the reaction was high.
anti-hydromagnesiation of aryl alkynes was established using 1 : 1 molar combination of sodium hydride (NaH) and magnesium iodide (MgI2) without the aid of any transition metal catalysts. The resulting alkenylmagnesium intermediates could be trapped with a series of electrophiles, thus providing facile accesses to stereochemically well-defined functionalized alkenes. Mechanistic studies by experimental