157492-92-7Relevant academic research and scientific papers
α-Mercurio-Substituted Phosphorus Ylides: A Simple Route to Vinylmercury Compounds
Steiner, Matthias,Pritzkow, Hans,Gruetzmacher, Hansjoerg
, p. 1177 - 1184 (2007/10/02)
The synthesis of novel α-mercurio-substituted phosphorus ylides, Ph3P=CR2 3a-d (R = Me, Et, iPr, Ph) is easily accomplished by mixing equivalent amounts of a phosphorus ylide 1a-d with Hg2 in an inert solvent.These organometallic compound are completely characterized including an X-ray analysis of 3a.Their reaction with benzaldehyde yields vinylmercury amides (E)/(Z)-PhHC=CR 4a-d.In reactions involving 3a-c the stereochemistry in the absence of a lithium salt is contrary to the stereochemistry of the established Wittig olefination reaction with non-stabilized phosphorus ylides like 1a-d.From the reported results, the preliminary conclusion is drawn that the stereochemistry is mainly controlled by steric interactions.Only in one case a remarkable salt effect is observed.When 3c reacts with benzaldehyde in the presence of LiBr and THF as solvent up to 95percent of (E)-4c is formed.The semistabilized ylide 3d gives under all conditions studied a 50:50 mixture of (E)/(Z)-4d.The vinylmercury amides 4a, c are cleaved by hydrous NaOH to yield divinylmercury compounds (E,E)-(PhHC=CR)2Hg and (Z,Z)-(PhHC=CR)2Hg (R = Me: 7a; R = iPr: 7c).The compound 4d is cleanly cleaved by NaBH4 in hydrous 3 M NaOH to yield a 50:50 mixture of cis- and trans-stilbene (8). - Key Words: Phosphorus ylides / Olefination reactions / Mercury compounds / Vinyl compounds
