Construction of Unusual and Congested Polycyclic Structures via Benzannulated Enediynyl Alcohols Derived from Truxenone

摘要

Condensation between truxenone(8)and the lithium acetylide derived from 0.9,2.5,and 5.0 equiv of 1-ethynyl-2-(phenylethynyl)benzene produced the corresponding benzannulated enediynyl alcohol 9,diol 14,and triol 16,respectively.On exposure of these alcohols to thionyl chloride,cascade cyclization reactions occurred to furnish polycyclic compounds 13,15,and 18 in a single operation.The unusual architectures of these polycyclic compounds were established by NMR spectroscopy and X-ray structure analyses.