Triafulvalenes, dications

Yoshida and his co-workers have continued to contribute greatly to the field of cyclopropenium ion chemistry. In addition to describing a large number of cyclopropenium ions, cyclopropen-ones, and -thiones in the patent literature they have produced the first triafulvalene dication (5). This was obtained, by treatment of (6 X = H) with butyl-lithium and then allowing the resulting carbenoid (6 X = Li) to react with (6 X = C1). The transformation illustrates... 

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