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Cubitermes umbratus Williams, 1954 TANZANIA • 1 ♂ (alate), 1 soldier, 1 worker, paratypes; Usambara; 1 Apr. 1951; NHMUK • 1 ♀ (queen), 1 soldier, 1 worker, paratypes; Amani; 3 Jan. 1952; NHMUK. The above were collected in Central and East Africa (Fig. 20D)., Published as part of Josens, Guy & Deligne, Jean, 2019, Species groups in the genus Cubitermes (Isoptera: Termitidae) defined on the basis of enteric valve morphology, pp. 1-72 in European Journal of Taxonomy 515 on page 55, DOI: 10.5852/ejt.2019.515, http://zenodo.org/record/2638175, {"references":["Williams R. M. C. 1954. New East African Termitinae (Isoptera: Termitidae). Proceedings of the Royal Entomological Society of London B 23 (11 - 12): 215 - 227."]}

There are only 15 diterpenoids known sharing the rare cubitane skeleton (1,3-diisopropyl-6,10-dimethylcyclododecane, Fig. 1) named after the natural product (+)-cubitene ((+)-1) from the termite Cubitermes umbratus. Cubitane-type diterpenoids (“cubitanoids”) have since then been isolated from gorgonian corals and there are reports that cubitene also occurs in plants. The twelve-membered ring of the cubitanoids is an interesting feature for which we have developed a novel synthesis involving bicyclic precursors. In this review, we discuss the state-of-research regarding isolation, structure elucidation, biological activity, biosynthesis, and total synthesis of cubitane-type diterpenoids.

There are only 15 diterpenoids known sharing the rare cubitane skeleton (1,3-diisopropyl-6,10-dimethylcyclododecane, Fig. 1) named after the natural product (+)-cubitene ((+)-1) from the termite Cubitermes umbratus. Cubitane-type diterpenoids (“cubitanoids”) have since then been isolated from gorgonian corals and there are reports that cubitene also occurs in plants. The twelve-membered ring of the cubitanoids is an interesting feature for which we have developed a novel synthesis involving bicyclic precursors. In this review, we discuss the state-of-research regarding isolation, structure elucidation, biological activity, biosynthesis, and total synthesis of cubitane-type diterpenoids.

The total synthesis of (±)-biflora-4,10(19),15-triene is detailed which features a Diels-Alder strategy for elaboration of the four contiguous stereocenters at C(1), C(6), C(7), and C(11).

(1R, 6S, 7S, 11R)-(+)-Biflora-4, 10(19),15-triene was synthesized starting from (r)-(+)-citronellic acid. This enabled us to assign (1S), 6R, 7R, (11S)-stereochemistry to the naturally occurring (-)-enantiomer isolated from soldiers of the termite species Cubitermes umbratus.

Three families of termites have the ability to produce a sticky secretion that envelopes and immobilizes the enemy. In the family Termitidae the secretion contains the diterpenoid hydrocarbons, kempene I and kempene II. The molecular structure of kempene II from the termite, Nasutitermes kempae, is described in detail. Another species of termite, Cubitermes umbratus, contained the diterpenoid hydrocarbon biflora-4,10-19,15-triene in the secretion and this compound is described. Studies were also conducted on the mucous secretion of the pedal gland of the marine nudibranch, Tidachiella diomedea. Tridachione, a substituted ..gamma..-pyrone, was isolated in the pure state and its molecular structure is described in detail. (HLW)