Syntheses of Some Bicyclo [3.3.0]octane Derivatives

Abstract

As part of a projected synthesis of pentalene (bicyclo [3.3.0]octatetraene), bicyclo [3.2.0]-2-hepten-6-one prepared by condensation of ketene and cyclopentadiene was converted by the Tiffeneau-Demjanov ring expansion procedure to a mixture of bicyclo [3.3.0]-2-octen-6-one and bicyclo [3.3.0]-2-octen-7-one. The ketonic mixture was reduced with lithium aluminum hydride and the resulting alcohols were converted to a mixture of tetrahydropentalenes by the Chugaev method. Unsuccessful attempts were made to transform the tetrahydropentalene mixture into pentalene by catalytic dehydrogenation procedures. Some of the steps in the Linstead synthesis of cis- and trans-bicyclo[3.3.O]octanes have been improved.

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