Laurencia chamigrenes

Furusaki, A., Hashiba, N. and Kurosawa, E. 1979. The structures and absolute stereochemistry of two halogenated chamigrenes from the red alga Laurencia majuscula Harvey. Tetrahedron Lett. 879-882. 

A recent X-ray crystallographic study has resulted in a revised structure (98) for nidifocene, a minor metabolite of the Hawaiian marine alga Laurencia nidifica. In the previous structure (Vol. 7, p. 69) the positions of chlorine and bromine were reversed. An extension of previous work on the non-enzymic biogenetic cyclization of geranyl and farnesyl diphenylphosphates has shown that (Z)-monocyclo-farnesyl diethylphosphate (99) can be converted into ( )-a-chamigrene (100) in... 

Guella, G. Oztun, A. Mancini, I. Pietra, F. (1997A) Stereochemical features of sesquiterpene metabolites as a distinctive trait of red seaweeds in the genus Laurencia. Tetrahedron Lett., 38, 8261-4 Francisco M.E.Y. Turnbull, M.M. Erickson, K.L. Cartilagineoi, the fourth lineage of Laurencia-dsr neA polyhalogenated chamigrene. Ibid., 39, 5289-92. 

The halogenated spiro-chamigrene, and related metabolites represent a huge class of marine natural products, mainly from Laurencia seaweeds. The initial survey documented 85 examples (7). 

Francisco MEY, Turnbull MM, Erickson KL (1998) Cartilagineol, the Fourth Lineage of Laurencia-derived Polyhalogenated Chamigrene. Tetrahedron Lett 39 5289... 

Francisco MEY, Erickson KL (2001) Ma iliohydrin, a Cytotoxic Chamigrene Dibromohy-drin from a Philippine Laurencia Species. J Nat Prod 64 790... 

The red algal chamigrene sesquiterpene elatol (Structure 2.78) has been shown to deter feeding by reef fishes.93 Specimens of Laurencia elata from Southern Australia show a pronounced seasonal variation in elatol production. Incorporation studies using 14C acetate failed to confirm an acetate-mevalonate path for elatol production.125... 

Perforatone (46) and perforenones A (47 R = OH) and B (47 R = Cl) have been discovered in the marine alga Laurencia perforata.78 It is suggested that (46) and (47) are formed from a chamigrene cation (48), and this hypothesis provides a full rationale for the biosynthesis of the wide variety of sesquiterpenoids that have been isolated from Laurencia species. 

Full details of an earlier synthesis of chamigrene (161) have been published.95 Further work on the components of the red alga Laurencia nipponica Yamada has resulted in the isolation and structural elucidation (by Y-ray analysis) of the diol (162)96 and spironippol (164).97 The biogenesis of the latter compound can be viewed in terms of an intramolecular cyclization of the diol (163) derivable from the naturally occurring epoxide of 10-bromo-a-chamigrene. 

Further investigation of the seaweed species Laurencia perforata has revealed the presence of two new metabolites, perforenone (185) and perforenone-C (183) (c/. Vol. 6, p. 65 Vol. 7, p. 70). These compounds are further examples of a comparatively new structural type of sesquiterpenoid whose carbon skeleton is presumably derived by rearrangement of a chamigrene precursor (c/. Vol. 6, p. 65 Vol. 7 p. 70). Structures (183) and (185) were established by chemical correlation with perforatone (182), a previously reported constituent of L. perforata, and by the synthetic sequence outlined in Scheme 16. 

During our work on active metabolites from starfish we have isolated from Astropecten indicus three novel steroidal glycosides named as indicoside A (26). B (27) and C (28). The red alga Laurencia pinnatifida yielded three new halogenated sesquiterpenoids pinnatificine (29) pinnatifidone (30) and 1(1 4(3,10d tr ibromo-3-chloro-7(14)-ene-a-chamigrene (31). ... 

Francisco, M.E.Y. and Erickson, K.L. (2001) Ma iliohydrin, a cytotoxic chamigrene dibro-mohydrin from a Philippine Laurencia species. J. Nat. Prod. 64, 790-791... 

Gonzalez, A.G., Darias, J., Diaz, A., Fourneron, J.D., Martin, J.D., and Perez, C. (1976a) Evidence for the biogenesis of halogenated chamigrenes from the red alga Laurencia obtusa. Tetrahedron Lett., 17, 3051-3054. 

Wolinsky, L.E. and Eaulkner, D.J. (1976) A biomimetic approach to the synthesis of Laurencia metabolites. Synthesis of 10-bromo-a-chamigrene. y. Org. Chem., 41, 597-600. 

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