Synfacts 2007(4): 0367-0367  
DOI: 10.1055/s-2007-968372
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart · New York

Fully Substituted Furans by One-Pot Propargylation-Cycloisomerization

Contributor(s): Victor Snieckus, Todd Macklin
V. Cadierno*, J. Gimeno*, N. Nebra
Universidad de Oviedo, Spain
Further Information

Publication History

Publication Date:
23 March 2007 (online)

Significance

A ruthenium-catalyzed, TFA-mediated reaction of propargylic alcohols with 1,3-dicarbonyl compounds leads to the formation of tetra­substituted furans in modest to excellent yields. The reaction proceeds via initial condensation to form a γ-keto alkyne followed by Ru-catalyzed cycloisomerization. The reaction with tert-butyl acetoacetate as the β-diketo component gave a trisubstituted furan, a result of TFA-induced hydrolysis and decarboxylation. A propargylated intermediate was isolated, characterized, and shown to undergo cyclization to a furan product. Significant R1 substitution patterns were not widely explored; however, one internal propargylic alcohol (phenylbut-2-yn-1-ol) was successfully converted into a furan thus indicating potential for 5-Me variation.