Alkylation of Thallous Cyclopentadienide with Tropylium Ion Synthesis of 11,12-Dihydrosesquifulvalene

Abstract
The alkylation of thallous cyclopentadienide (1) has been shown to give 5-substituted cyclopentadienes without the complications due to prototropic shifts which accompany alkylation of alkali metal cyclopentadienides.1 In seeking a route to the interesting (CH)12 hydrocarbon2 11,12-di-hydrosesquifulvalene (3), it appeared likely that alkylation of 1 with tropylium fluoroborate (2) would afford a ready means of access to this system.