Enantiodivergent Chemoenzymatic Synthesis of (S)- and (R)-(Z)-9-Dodecyl-4,5,8,9-tetrahydro-3H-oxonin-2-one as Analogues of Topsentolides

(Z)-4,5,8,9-Tetrahydro-3H-oxonin-2-one is the core of naturally occurring topsentolides, cytotoxic oxylipins isolated from a marine sponge of the genus Topsentia. An enantiodivergent approach to topsentolide analogues was worked out with a lipase-catalyzed kinetic resolution of a secondary alcohol and a ring-closing metathesis giving the unsaturated nine-membered lactone as key steps.