The successful closure of the cyclobutane ring by treatment of a, a'-dibromoadipic esters with sodium cyanidel could not be extended to 1, I-di-brom0-1~ 4-diaroylbutanes. The latter underwent closure to cyanodihydro-lJ4-pyrans, ie, to six-membered rings. 2 The present work grew out of an attempt to extend the method to the closure of a 1,: S-dibromo-1, 3- diaroylpropane (I). It was thought that this compound might yield a
