Chamigrene

Bromo-a-chamigrene, a compound isolated from marine algae, is... 

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... 

Syntheses have been reported for several other natural products related structurally to carotenoids, viz. dihydroactinidiolide (123) and tetrahydroactinidiolide (124), trans- and cis-a-damascone (125), dihydroedulans I and II, (51) and (52), bicyclodamascenones A and B, (53) and (54), the diastereoisomeric caparrapi oxides (126), ( )-a-chamigrene (127), and the novel passion-fruit ionone derivatives (47) and (48). ... 

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. 

Where there is an electron-rich olefinic double bond in the diazoketone as in the 2-substituted 3,4-dihydropyran derivative 47, the intramolecular cyclopropanation produces oxatricyclic ketones, e.g. 48 (equation 57)86 87. Rhodium(II) acetate is the catalyst of choice for this transformation. An interesting application of this method is found in a stereoselective synthesis of ( )-/ -chamigrene 49 (equation 5S)88. 

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... 

Kaiser CR, Pitombo LF, Pinto AC (1998) C-13 and H-l NMR Assignments of the Chamigrenes Prepacifenol and Dehydroxyprepacifenol Epoxides. Spectroscopy Lett 31 573... 

Guella G, Chiasera G, Pietra F (1992) Conformational Studies of Marine Polyhalogenated a-Chamigrenes Using Temperature-Dependent NMR Spectra. Inverted Chair and Twist-Boat Cyclohexane Moieties in the Presence of an Axial Halogen Atom at C(8). Helv Chim Acta 75 2026... 

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. 

Spiroannelatwn of phenolic a-diazoketones (8, 118-119). The Cu(I) decomposition of the phenolic a-diazo ketone 1 has been used for a synthesis of a-chamigrene (3). ... 

Another collection of A. dactylomela collected from Kohoma Island, Okinawa, on the other hand was found to contain (42) cuparene-related sesquiterpenes — cyclolaurene [33], laurinterol [34], cyclolaurenol [35], cyclolaurenol acetate [36], cupalaurenol [37] and cupalaurenol acetate [3 8]. The authors failed to comment on the presence or absence of chamigrenes in these samples. 

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