Abstract: Condensation of a mixture of sodium 1, 2-dicarbomethoxy-and 1, 3- dicarbomethoxycyclopentadienides with di-n-propylcyclopropenone in hot acetic anhydride yields the pentatriafulvalene diesters VI11 and X in trace amounts. In contrast, reaction of the dicarbomethoxycyclopentadienides with di-n-propylethoxycyclopropenium fluoroborate (XI, R= n-CaH7) gives the diesters VI and VI1 in 41 and 10 yields, respectively; the diphenyl ...