Process for producing optically active 2- (2',2'-dihalovinyl)-cyclopropane-1- carboxylic acids substituted in the 3-position, and derivatives thereof, as well as novel 4-(2',2', 2'-trihaloethyl)-cyclobutane-1-sulfonic acid salts

Abstract From the Canadian patent

A novel process for the preparation of optically active 2-(2',2'-dihalogenovinyl)-cyclopropane-1-carboxylic acids substituted in the 3-position, and derivatives thereof, and also novel 4-(2',2',2'-trihalogenoethyl)cyclobutane-1-sulfonic acid salts are described. In the said process, racemates of specific cyclobutanones are reacted either with the sulfurous acid salt of an optically actlve base or in the presence of water and sulfur dloxide with an optically actlve base to give a 4- (2',2',2'-trihalogenoethyl)-cyclobutane-1-sulfonic acid salt. The resulting pure diastereomers are either reacted direct in the presence of a base to give optically active …