181761-28-4

Upstream product

• 4996-21-8 1-(4-chloro-phenyl)-2,2-dihydroxy-ethanone 
• 33398-28-6 ethyl 4-(triphenylphosphoranylidene)-(2E)-2-butenoate 
• 33398-36-6 [(2E)-4-ethoxy-4-oxo-2-buten-1-yl]triphenylphosphonium bromide 

Relevant academic research and scientific papers

Cyclopent-2-en-1-ones from [3 + 2]-annulation of 3-ethoxycarbonyl-2-propenylidene(triphenyl)phosphorane and glyoxals: Synthesis of cis-jasmone

3-Ethoxycarbonyl-2-propenylidene(triphenyl)phosphorane (2) reacted with glyoxal monohydrates (5) to give 2-substituted 5-ethoxycarbonylcyclopent-2-en-1-ones (6) by [3 + 2]-annulation reaction in the presence of a base. Compounds 6 were easily converted to 2-substituted cyclopent-2-en-1-ones by deethoxycarbonylation. An application of the annulation to synthesis of cis-jasmone is also described.