Aldehydes and ketones, on treatment with a low-valent cerium reagent, undergo reductive dimerization to produce the corresponding pinacols in high yield.
醛和酮经低价铈试剂处理后,进行还原二聚化,从而以高收率生产相应的频哪醇。
Enantioselective Cathodic Reduction of Some Prochiral Ketones in the Presence of (1<i>R</i>,2<i>S</i>)-(-)-<i>N</i>,<i>N</i>-Dimethylephedrinium Tetrafluoroborate at a Mercury Pool Cathode
作者:Ashok K. Yadav、Arpita Singh
DOI:10.1246/bcsj.75.587
日期:2002.3
The enantioselective cathodic reduction of some prochiral ketones viz. acetophenone (I), propiophenone (II), butyrophenone (III), valerophenone (IV), isobutyrophenone (V), and pivalophenone (VI) has been accomplished at a mercurypoolcathode in N,N-dimethylformamide (DMF)–water (90 : 10) using tetrabutylammonium fluoroborate (TBA·BF4) as a supporting electrolyte in the presence of (1R,2S)-(-)-N,N
Herein, we successfully achieve this goal by employing a recyclable solid acid/ionicliquidcatalyst system. The dehydration of alkyl- and cycloalkyl-derived diols in an Amberlyst-15/[Emim]Cl system afforded the corresponding 1,3-dienes in good yields, while a Nafion/[Emim]Cl system was demonstrated to be a better catalyst system for the dehydration of aryl-substituted substrates. Our protocol features
Highly regioselective and chemoselective titanocene mediated Barbier-type allylation reactions
作者:Sara P. Morcillo、Ángela Martínez-Peragón、Verena Jakoby、Antonio J. Mota、Christian Kube、José Justicia、Juan M. Cuerva、Andreas Gansäuer
DOI:10.1039/c3cc49230c
日期:——
carboxylate 1 is an excellent chemoselective reagent for unprecedented alpha-regioselective Barbier-type reactions. It constitutes the first titanocene(III) able to tolerate epoxides and readily reduced carbonyl compounds, such as aromatic and alpha,beta-unsaturated aldehydes.
Samarium(II) triflate was readily prepared by the reaction of samarium(III) triflate with sec-butyllithium at room temperature in THF. Its reducing ability was examined by pinacol coupling of carbonyl compounds. Sm(OTf)2 mediated Grignard-type reaction in THF-HMPA effectively; alkylation and allylation of ketones or aldehydes by simple alkyl, allyl, and benzyl halides proceeded via organosamarium intermediates
三氟甲磺酸钐 (II) 很容易通过三氟甲磺酸钐 (III) 与仲丁基锂在室温下在 THF 中反应制备。通过羰基化合物的频哪醇偶联来检测其还原能力。Sm(OTf)2在THF-HMPA中有效介导格氏型反应;通过有机钐中间体通过简单的烷基、烯丙基和苄基卤化物对酮或醛进行烷基化和烯丙基化。