Aplysia brasiliana

Panacene (61) is a metabolite of the sea hare Aplysia brasiliana and acts as a fish antifeedent [61]. The synthesis of the racemic natural product, published by Feldman et al. [77] in 1982, takes advantage of the anti-selective SN2 -substitution of the propargylic mesylate 67 with LiCuBr2 (Scheme 18.21). In contrast, the later attempted biomimetic synthesis by treatment of the enyne 68 with NBS or 2,4,4,6-tetrabromocyclohexadienone did not proceed stereoselectively and led to a 1 1 mixture of the target molecule 61 together with its allenic epimer [78]. 

One of the antifeedants isolated from the marine mollusk Aplysia brasiliana, which is distasteful to fish and rejected by sharks, is the bromoallene panacene (142) [113]. 

Further additions to the ever-increasing number of marine sesquiterpenoids of unusual structure are brasilenol (672) and epibrasilenol (673). These two compounds were isolated from the digestive glands of the sea hare Aplysia brasiliana. It has been established that they are also metabolites of the alga... 

Aspey, W.P. and Blankenship, J.E., 1976. Aplysia behavioural biology. II. Induced burrowing in swimming Aplysia brasiliana by burrowed conspecifics. Behav. Biol., 17 301-312. 

Other defense allomones isolated from marine mollusks include panacene (102) from Aplysia brasiliana 391), onchidal (103) from On-chidela binneyi 392), navanones A-C (104-106) from Navanax inermis 393,394), pu lenal (107) from Chromodoris albonotato 398), spiniferin-2... 

Kinnel, R., A.J. Duggan, T. Eisner, J. Meinwald, and I. Miura Panacene An Aromatic Bromoallene from a Sea Hare Aplysia brasiliana). Tetrahedron Lett. 3913-3916(1977). 

Feldman and co-workers have outlined two syntheses of the interesting bromoallene metabolite penacene (211), found in the sea hare Aplysia brasiliana one of the syntheses, shown in Scheme 10, is based on biomimicry. 

In the synthesis of the allenyl bromide moiety of panacene 65 (isolated from Aplysia brasiliana ) and isolaurallene 38, a Sn2 strategy was applied (Scheme 42.20). LiCuBra was used to provide the nucleophilic Br source. For instance, alkynyl O-mesylate 64 was converted into the... 

Greene, A.E., Coelho, F., Barreiro, E.J., and Costa, P.R.R. (1986) A selective synthesis of brasilenol, a novel sesquiterpene from the sea hare Aplysia brasiliana and the red alga Laurencia obtusa. J. Org. Chem., 51, 4250-4253. 

Dieter, R.K., Kinnel, R., Meinwald, J., and Eisner, T. (1979) Brasudol and isobrasudol two bromo-sesquiterpenes from a sea hare Aplysia brasiliana). Tetrahedron Lett., 20,1645-1648. 

Stallard, M.O., Fenical, W., and Kittredge, J.S. (1978) The brasilenols, rearranged sesquiterpene alcohols isolated from the marine opisthobranche Aplysia brasiliana. Tetrahedron, 34, 2077-2081. 

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