20859-11-4Relevant academic research and scientific papers
Cyclopentenone formation via hydrogen activation in the reactions of chromium carbene complexes with alkynes
Challener, Cynthia A.,Wulff, William D.,Anderson, Benjamin A.,Chamberlin, Steve,Faron, Katherine L.,Kim, Oak K.,Murray, Christopher K.,Xu, Yao-Chang,Yang, Dominic C.,Darling, Stephen D.
, p. 1359 - 1376 (2007/10/02)
The reactions of alkyl chromium carbene complexes with alkynes have been found to give cyclopentenones. Mechanisms are proposed to account for the formation of these products that involve metal hydride intermediates. As has been previously reported for tungsten, molybdenum alkyl complexes have been found to give 1,3-dienes rather than cyclopentenones. The difference between chromium and molybdenum and tungsten may be that a metal hydride intermediate can re-add to an olefin in the case of chromium rather than undergo reductive elimination. A mechanism for the formation of cyclopentenones involving a free vinylketene was ruled out on the basis of an experiment in which the free vinylketene was generated via thermolysis of a cyclobutenone and found not to give a cyclopentenone product but rather an intramolecular [2 + 2] cycloadduct.
FORMATION DE CETONES ETHYLENIQUES PAR ACTION D'ACIDE ACETYLSULFOACETIQUE SUR DES ALCENES
Loiseau, Andre-Michel,Luft, Robert,Zunino, Serge
, p. 144 - 152 (2007/10/02)
Monoalkyl- and 1,2-dialkylethylenes have a similar behaviour under the action of acetylsulfoacetic acid : the reaction does not necessarily stop after the formation of α- or β-enones, the yield of which is highly influenced by reaction time; thus, 1-acetoxy-1,3-dienes are identified in the case of α-enones.A different behaviour is shown by 1,1-dialkyl and trialkylethylenes, which can constitute an interesting source of highly branched enones.With this second group of alkenes, isomerisation of the alkene is sometimes observed prior to acetylation.Lastly, some alkenes undergo acetoxylation at the same time as acetylation.
