A CONVENIENT SYNTHESIS OF 3,3-DICHLOROAZETIDINES, A NEW CLASS OF AZETIDINES

A short synthesis of appropriately substituted 3,3-dichloroazetidines, a virtually unknown class of azetidines, is described. The reaction o f 3,3-dichloro-1-azaallylic carbanions, generated from N-(1-aryl-2,2-d ichloroethylidene)amines, with aromatic aldehydes produced alpha,alpha -dichloro-beta-hydroxy imines that, upon treatment with mesyl chloride , were converted into the corresponding beta-(mesyloxy) imines. Reacti on of these alpha,alpha-dichloro-beta-(mesyloxy) ketimines with potass ium cyanide or sodium borohydride in methanol furnished a variety of 2 -cyano- and 2-methoxy-3,3-dichloroazetidines in a stereoselective mann er. Reduction of beta-(mesyloxy) imines with sodium cyanoborohydride f ollowed cyclization with potassium carbonate in DMSO yielded 3,3-dichl oroazetidines as well.