Molecules (Feb 2008)
A Facile Route to Diastereomeric Phosphorus Ylides. Chemoselective Synthesis of Dialkyl (E)-2-[1-(2-Oxocyclopentylidene)ethyl]-2-butenedioates
Abstract
2-Acetylcyclopentanone undergoes a smooth reaction with triphenylphosphineand dialkyl acetylenedicarboxylates to produce dialkyl 2-(1-acetyl-2-oxocyclopentyl)-3-(1,1,1-triphenyl-λ5-phosphanylidene)succinates. These compounds undergo intramolecularWittig reactions in boiling benzene to produce highly strained spirocyclobutenederivatives, which spontaneously undergo ring-opening reactions to produce dialkyl (E)-2-[1-(2-oxocyclopentyliden)ethyl]-2-butenedioates.
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