( Z )‐4,7‐Octadiensäure‐äthylester und ( Z )‐Buttersäure‐3,5‐hexadienylester, zwei neue Aromastoffe der roten Passionsfrucht

Ethyl ( Z )‐4,7‐Octadienoate and ( Z )‐3,5‐Hexadienyl Butyrate, two New Aroma Components of the Purple Passionfruit The isolation of ethyl ( Z )‐4,7‐octadienoate ( 1 ) and ( Z )‐3,5‐hexadienyl butyrate ( 2 ), two new and important aroma constituents of the purple passionfruit ( Passiflora edulis S IMS ) is reported. Ester 1 was synthesized by two different routes: (1) via a Wittig reaction between the known 4‐oxobutyrate 4 and 3‐butenylidenephosphorane, and (2) by thermolysis of ( Z )‐8‐acetoxy‐4‐octenoate 7 which was readily accessible from ( Z , Z )‐1,5‐cyclooctadiene. Ester 2 was prepared from the known hex‐3‐yn‐5‐en‐1‐ol ( 8 ) by a stereoselective ( Z )‐reduction of the triple bond to 9 , using Rieke 's active metallic zinc, followed by esterification. The organoleptic properties and the taste threshold values of 1 and 2 are given.