Synthesis of the Pseudopterane and Furanocembrane Ring Systems by Intraannular Cyclization of β- and γ-Alkynyl Allylic Alcohols

Article abstract of DOI:10.1021/jo00086a018

The prototype pseudopterane and furanocembrane systems 15 and 26 were prepared through a "furan last" approach.The former was obtained in 64percent yield upon treatment of the 12-membered β-alkynyl allylic alcohol 14 with KO-t-Bu and 18-c-6 in THF-t-BuOH.The latter was formed in 88percent yield from the 14-membered γ-alkynyl allylic alcohol 25 under comparable conditions.The carbocyclic precursors to these allylic alcohols, 11 and 24, were secured through intramolecular Horney-Emmons condensation of keto phosphonates 10 and 23, respectively, under Masamune-Roush conditions.