. . "Described are processes for preparing novel 4- and 5-phenyl-pentenals, lower alkyl and lower alkylene acetals thereof having the structure: ##STR1## wherein one of X and Y is phenyl and the other of X and Y is hydrogen and A is a moiety selected from the group consisting of: ##STR2## WHEREIN Rb and Rb ' separately are the same or different lower alkyl or Rb and Rb ' taken together form a lower alk" . . .