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- Title
Rogiolenyne A, B, and C: The First Branched Marine C<sub>15</sub> Acetogenins. Isolation from the Red Seaweed Laurencia microcladia or the Sponge Spongia zimocca of II Rogiolo.
- Authors
Guella, Graziano; Pietra, Francesco
- Abstract
It is shown here that the red seaweed Laurencia microcladia, collected off the torrent II Rogiolo, south of Livorno, contains rogiolenyne A (= (−)-(1R*, 2S*, 3R*, 5S*, 7S* )-2-(bromomethyl)-5-[(Z )-1-chlorohex-3-en-5-ynyl]-3-ethyl-4,8-dioxabicyclo[5.1.0]octane; (−)- 1) while the sponge Spongia zimocca, which grows in the same small area, contains rogiolenyne B (= (−)-(2R *3R *,4R *,5R *,7S *)-3-(bromomethyl)-5-chloro-7-[(Z )-1-chlorohex-3-en-5-ynyl]-2-ethyloxepan-4-ol; (−)- 4a) and its acetate, rogiolenyne C((−)- 4b). These structures, which are based on extensive NMR and MS data and on chemical transformation, are the first examples of branched marine C15 acetogenins. Biogenesis of (−)- 1 in L. microcladia is thought to involve C(12) extrusion form a C15 linear tetraen-1-yne precursor via H+-induced cyclopropane ring closure, followed by Br+-induced cyclopropane ring opening, aided by C-O− attack ( Scheme 2). It is also proposed that transfer of (−)- 1 to S. zimocca is followed by epoxide ring opening by Cl− to give (−)- 4a and acetylation to give (−)- 4b.
- Publication
Helvetica Chimica Acta, 1991, Vol 74, Issue 1, p47
- ISSN
0018-019X
- Publication type
Article
- DOI
10.1002/hlca.19910740107