SYNTHESIS OF 11CIS 15CIS- AND 10CIS 15CIS-OCTADECADIENOIC ACID PROBABLE PRECURSORS OF 4CIS-HEPTENAL IN AUTOXIDIZED BUTTERFAT

11 cis,15 cis- and 10 cis,15 cis-Octadecadienoic acid are considered to be precursors of 4 cis-heptenal occurring in autoxidized butterfat. The synthesis of these acids was carried out as follows. In liquid ammonia, 1-sodio-1,5-octadiyne was coupled with 1-chloro-9-iodononane and 1-sodio-1,6-nonadiyne with 1-chloro-8-iodooctane. The 1-chloro-10,14-and -9,14-heptadecadiynes thus obtained were converted into 11,15- and 10,15-octadecadiynoic acid. Stereospecific partial hydrogenation of the 11,15-diynoic acid, or of the methyl 10,15-diynoate, and subsequent saponification, yielded the acids desired. © 1969 AOCS Press.