Several enantiopure spiroisoxazoline amides were prepared from tert-butylester 22, which is obtained via an enantiotopic groups differentiating high pressure Diels–Alder cycloaddition. Treatment of these amides with an isoxazoline-splitting enzyme, which is involved in an injury induced defense reaction of the sponge Aplysina cauliformis, proves the bromoatoms in the cyclohexenone moiety to be important