23154-08-7

The reaction of dichloroketene with cyclopropyl-substituted methylenecyclopropanes leads to good yields of substituted cyclobutanones containing a spiro fragment at position 2.The reaction of the 5,5-dichlorospirohexan-4-ones synthesized in this way with potassium hydroxide leads to 6-hydroxy-5-oxaspiroheptan-4-ones, while the reaction with sodium methoxide makes it possible to synthesize substituted esters of cyclopropanecarboxylic acids.

In the reaction of 1-cyclopropyl-1-(1-bromocyclopropyl)methylenecyclopropane and 1-methyl-1-(1-bromocyclopropyl)methylenecyclopropane with butyllithium or magnesium in tetrahydrofuran the organometallic derivatives of cyclopropyl-substituted methylenecyclopropanes with the metal atom in the cyclopropane fragment are formed.The reaction of the obtained organometallic compounds with electrophilic agents can be used to introduce deuterium, the trimethylsilyl group, and other substituents into the cyclopropane fragment.The metallation of the above-mentioned bromides with methyllithium is not suitable for the synthesis of organometallic compo unds, since the alkylation products are formed quantitatively.When treated with magnesium in tetrahydrofuran with subsequent decomposition with water, 1,1-di(1-bromocyclopropyl)-methylenecyclopropane gives a mixture of 4-cyclopropylidenedispiroheptane and 1,1-dicyclopropylmethylenecyclopropane, the composition of which depends on the reaction conditions.