Barbitursäurederivate, 33. Mitt. Racemat und Enantiomere der 1-N-Methyl-5-phenyl-5-propyl-2-thiobarbitursäure (Thio-MPPB), Synthese und Konfiguration
作者:Joachim Knabe、Lothar Schamber
DOI:10.1002/ardp.19823151011
日期:——
des entsprechenden Cyanessigesters mitN‐Methylthioharnstoff. 1 wird jedoch mit Hilfe von Dicyclohexylcarbodiimid aus Phenyl‐propyl‐cyanessigsäure und N‐Methylthioharnstoff erhalten, obwohl die Reaktion nur regioselektiv verläuft. Die Konfiguration der 1‐Enantiomere ist R(‐) und S(+). Sie ergibt sich aus dem Syntheseverlauf und wird durch chemische Korrelation mit MPPB bestätigt.
Cobalt-Catalyzed Reductive Carboxylation of α,β-Unsaturated Compounds with Carbon Dioxide
作者:Chika Hayashi、Takuo Hayashi、Tohru Yamada
DOI:10.1246/bcsj.20150043
日期:2015.6.15
The gaseous carbon dioxide incorporation reaction with α,β-unsaturated compounds was examined in the presence of a catalytic amount of bis(acetylacetonato)cobalt(II) and using diethylzinc as a redu...
在催化量的双(乙酰丙酮)钴 (II) 存在下,并使用二乙基锌作为还原剂,研究了气态二氧化碳与 α,β-不饱和化合物的掺入反应。
Cobalt-catalyzed Reductive Carboxylation on α,β-Unsaturated Nitriles with Carbon Dioxide
The reductive carboxylation of α,β-unsaturated carbonyl compounds with carbon dioxide was studied. After the screening of various transition-metal complex catalysts and reducing agents, it was found that the combination of bis(acetylacetonato)cobalt(II) and diethylzinc could effectively afford the corresponding α-carboxylate in high yield from α,β-unsaturated nitriles. The product was obtained after esterification by trimethylsilyldiazomethane. The highly selective carboxylation was observed at the α-position in the present study.