Certain halides possessing a relatively reactive a-hydrogen such as 9-halogenofluorenes or its derivatives are converted to dimeric olefines by the action of methanolic potassium hydroxide in acetone at room temperature. Thus, 9-bromo-(or chloro)-fluorene25 gave dibiphenyleneethylene (I). The corresponding substituted I are obtained in good yields from 2-nitro-9-bromofluorene33, l-chloro-9-bromofluorene, 2, 9-dibromofluorene53, 3, 9- ...
