1.3- Cyclopentadiene benzvalene from

CarbenoU synthesis of hydrocarbons. Katz et al. - reported a simple synthesis of the previously rare valence isomer of benzene, benzvalene (3), from cyclopentadiene (1). The diene is first converted into the cyclopentadienyl anion (2) by treatment with methyllithium in dimethyl ether then a solution of methylene chloride and methyl-lithium in diethyl ether is added at —45°. Benzvalene (3) was obtained in 24, yield together with a trace (6.4%) of benzene. 

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