Abstract: 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 R.sub.b and R.sub.b ' separately are the same or different lower alkyl or R.sub.b and R.sub.b ' taken together form a lower alkylene group either (i) comprising the step of intimately admixing the lithium salt of a Schiff base of acetaldehyde and an amine with a phenyl-substituted compound selected from the group consisting of phenyl alkanals and phenyl alkenyl bromides in order to produce a phenyl-substituted Schiff base and treating said phenyl-substituted Schiff base with an acid, or (ii) comprising the steps of first admixing phenyl propionaldehyde with a tri-substituted formyl methylene phosphorane in a non-reactive solvent and then heating the resulting mixture.

Abstract: 4- and 5-Phenyl pentenal acetals having the structure: ##STR1## wherein one of X and Y is phenyl and the other of X and Y is hydrogen and A is the moiety: ##STR2## WHEREIN R.sub.b and R.sub.b ' are separately the same or different lower alkyl or R.sub.b and R.sub.b' taken together form a lower alkylene group. The compounds are used to impart flavors and fragrances to consumable materials.