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Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
Asymmetric Sulfur-Ylide-Mediated Formal [4+1]-Annulation Reaction: Scope and Mechanism
Sébastien Clergue1, Olivier Rousseau1, Thierry Delaunay1
1Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Place Louis Pasteur 1 box L4.01.02, 1348, Louvain-la-Neuve, France.
Abstract:
A formal [4+1]-annulation strategy between sulfur ylides and 1,3-dienes was developed to afford functionalized cyclopentanoids. The process consists of a stereoselective cyclopropanation reaction followed, in situ, by a stereospecific MgI2 -catalyzed vinylcyclopropane-cyclopentene rearrangement. The use of chiral sulfur ylides provided cyclopentanoids with excellent enantiocontrol. A combined experimental and computational mechanistic study showed that the stereospecificity of the rearrangement could be accounted for by a double SN 2 reaction mechanism involving iodide.
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