The first total synthesis of (-) and (+)-2-hydroxy-24-oxooctacosanolide using an effective lactonization.

[structure: see text] An effective method for the total synthesis of 2-hydroxy-24-oxooctacosanolide, a defensive salivary secretion of the African termite Pseudacanthotermes spiniger, has been developed. The key lactonization to form a 29-membered ring lactone core is performed using 2-methyl-6-nitrobenzoic anhydride with a catalytic amount of 4-(dimethylamino)pyridine N-oxide.