Boron Trifluoride Mediated Reaction of 1,9-Dihalopentacyclo(5.4.0.0(2,6).0(3,10).0(5,9)undecane-8,11-diones with Ethyl Diazoacetate: A Novel Synthetic Entry into the Cyclopent(a)indene Ring System

摘要

Reaction of 1,9-dibromo- or 1,9-dichloropentacyclo(5.4.0.02,6.03,10.05,9) undecane-8,11-diones (4 or 5, respectively) with ethyl diazoacetate in the presence of boron trifluoride etherate results in the formation of ethyl-2-bromo-(or ethyl 2-chloro-)-4-hydroxy-3(3aH)-oxo-8,8a-dihydrocyclopent(a)inden-5- carboxylate (6 (42%) and 7 (40%), respectively). A mechanism that accounts for the course of each of the rearrangements 4 yields 6 and 5 yields 7 is suggested. Keywords: Pentacycloundecanediones, Lewis acid, Catalyzed rearrangement, Ethyl diazoacetate, Cage molecules, Diones, Cyclic compounds, Reprints. (MJM)