Junzo Nokami, Masahiro Osafune, Kazuhiro Shiraishi, Shin-ichi Sumida and Nobuyuki Imai
(11E)-13-Hydroxy-10-oxooctadec-11-enoic acid 1 is conveniently synthesized via a Knoevenagel-type reaction of isopropyl 11-phenylsulfinyl-10-oxoundecanoate 2a (itself easily derived from undec-10-enoic acid) with heptanal to form the γ-hydroxyenone functionality together with carbon chain elongation.