778-18-7Relevant academic research and scientific papers
Insights into the formation of symmetrical trimers of dialkylated ketenes starting from acid chloride precursors
Saaidi, Pierre-Loic,Doridot, Gabriel,Jeanneau, Erwann,Hasserodt, Jens
, p. 1011 - 1018 (2008/03/17)
Application of known dialkyl ketene di- and trimerization to more complex precursors could readily open the route to highly functionalized symmetrical cyclobuta-1,3-diones and cyclohexa-1,3,5-triones. We report herein the results on three substrates containing either a C=C double bond or a protected glycol moiety as illustrative functionalized groups. The nature of the substituents is found to be crucial: while cyclopentenyl and more constrained dioxolanocyclopentenyl precursors efficiently dimerize, a diallylic derivative fails. At the millimolar scale, methoxide-catalyzed trimerization shows limited reproducibility, even for the reported substrate tetramethylcyclobuta-1,3-dione. However, systematic studies, including the use of microwaves, demonstrate that formation of symmetrical trimers is favored under solvent-free conditions and conventional heating, which allowed us to isolate and characterize trispiro[4.1.4.1.4.1]octadeca-2,9,15-triene-6,12,18-trione.
