Reaction of chloral with 2-acetylcyclopentanone (3a) in the presence of potassium carbonate in tetrahydrofuran spontaneously yielded 2-(2'-chlorovinyl) cyclobutenecarboxylic acid (6a). The pathway, which involves the transient existence of oc-(2, 2, 2- trichloroethylidene) cyclopentanone (4a) followed by the Favorskii-type rearrangement, has been postulated for the formation of 6a. The reaction of chloral with 1-morpholino-1- ...