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Various benzo-and dibenzoannelated cycloheptatrienylidenes (cycloheptatetraenes) have been generated in methanol and ethanol by alkoxide-induced dehydrochlorination of chlorocycloheptatrienes and, where applicable, by photolysis of tosylhydrazone sodium salts. 1,2-and 3,4-benzoannelated systems (19, 20 and 28, 29) give identical mixtures of allyl ethers (23, 25) arising from the benzotropylium ion 24. Formation of 24 and of vinyl ether 36 compete in the 2,3-benzoannelated case (34, 37). The 2,3:4,5-dibenzoannelated intermediate 40 yields the vinyl ether 41 exclusively. Obviously, ethers arise by two distinct routes; either the hydrogen or the OR group of alcohols may be attached to the dicoordinate carbon of the intermediate(s). The protonation route, leading to tropylium ions, is attributed to cycloheptatrienylidenes. When the carbene is destabilized and the tetraene stabilized, by appropriate benzoannelation, vinyl ethers are formed by addition of ROH to cycloheptatetraenes (in analogy

Benzocycloheptatriene derivatives such as the chlorides (I), (VIII), and (IX) or the tosylhydrazone (VII) are submitted to solvolysis with sodium ethoxide (II) in ethanol, yielding the isomeric ethoxybenzocycloheptatrienes (III) ‐ (VI) and (X).

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