Shell Internationale Research Maatschappij, B.v.

Shell Oil Comapny

Helena Austermuhle-Bertola

Petrus A Kramer

Marinus J Van Den Brink

A novel process is disclosed for the preparation of cyano-substituted cyclopropane derivatives of the following general formula: ##STR1## wherein R.sub.1, R.sub.2 and Hal have the meanings given in the description. The process comprises the steps of cyclizing and dehydrohalogenating, in the presence of a base, a 4,6,6,6-tetrahalo-2-cyano-3,3-dialkylhexanoic acid or an alkyl ester thereof, followed by thermal decarboxylation of the resulting cyclized and dehydrohalogenated product. Under selected conditions cyclization, dehydrohalogenation and decarboxylation occur simultaneously in one reaction zone. The resulting cyano-substituted cyclopropane derivatives are useful as intermediates in the production of insecticidally active compounds.

Preparation of cyano-substituted cyclopropane derivatives

A novel process is disclosed for the preparation of cyclopropanecarbonitriles of the general formula: ##STR1## wherein R.sub.1, R.sub.2 and Hal have the meanings given in the description; which comprises heating the corresponding ammonium or aminium cyclopropanecarboxylate in the presence of a polar aprotic solvent. The process produces cyclopropanecarbonitriles, in high yields, which are useful as intermediates in the production of insecticidally active compounds.

Preparation of cyclopropanecarbonitriles

A process for the preparation of an ester of cyanoacetic acid having the following general formula: ##STR1## (wherein R represents an aliphatic or cycloaliphatic hydrocarbyl group), which comprises contacting an alkali metal carboxylate of general formula: ##STR2## (wherein M represents an alkali metal atom) with a hydrocarbyl halide of general formula:

Preparation of esters

Cyclobutanones and cyclobutenones are prepared by contacting a 2-haloacyl halide with an ethylenically unsaturated compound or an alkyne in an inert aprotic solvent at a temperature above 5.degree. C in the presence of zinc and/or tin.

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Amsterdam, Netherlands

Helena Austermuhle-Bertola