Marine diterpenoids

Shimomura M, Miyaoka H, Yamada Y (1999) Absolute Configuration of Marine Diterpenoid Kalihinol A. Tetrahedron Lett 40 8015... 

Miyaoka H, Shida H, Yamada N, Mitome H, Yamada Y (2002) Total Synthesis of Marine Diterpenoid Kalihinene X. Tetrahedron Lett 43 2227... 

Palominol. Corey has reported the application of an intramolecular titanium-mediated pinacol coupling reaction to the synthesis of a 15-membered ring, en route to palominol, a marine diterpenoid that displays cytotoxicity toward the human colon cell line (Eq. 3.10) [28]. Slow addition of the keto aldehyde (32 h) to the titanium reagent furnished the cyclized product in 53% yield as a mixture of diastereomers (2.1 1). 

Miyaoka, H., Baba, T., Mitome, H., and Yamada, Y., Total synthesis of marine diterpenoid stolonidiol. Tetrahedron Lett., A l, 9233, 2001. 

Look, S. A., Fenical, W., Vanengen, D., Clardy, J., Erythrolides Unique Marine Diterpenoids Interrelated by a Naturally occurring Di 71 methane Rearrangement, 7. Am. Chem. Soc. 1984, 106, 5026 5027. 

An interesting synthesis of the marine diterpenoid dictyolene (139) pro-ceeded " via the lactone (138) in which the diene and cis ring junction were set up in a rational manner early iu the synthesis. 

Steroidal Alkaloids from Solanum umbelliferum Marine Diterpenoids from Eunicea toumeforti Limonoids from Trichilia emetica... 

Corey and Kania later prepared the bicyclic marine diterpenoid (+)-dolabellatrie-none via the Ireland-Claisen rearrangement (Scheme 4.132) [125]. Ring contraction of the 15-membered ring lactone occurred with both high diastereo- and enantioselectivity via the Z-(0)-B-ketene acetal. The alkene and carboxyhc acid group were manipulated in several steps to form the isopropylidene cyclopenta-... 

In order to test this principle, Enquist and Stoltz submitted compound 107, which consisted of a 1 1 mixture of the racemate and the weso-compound to the standard decarboxylative allylic alkylation protocol. The reaction resulted in a mixture of chiral diketone 108 and the wteso-diastereomer 109 in a ratio of 81 19, the total yield amounting to 78%. More remarkably, the enantiomeric excess of the major product R,R)-108 was found to be 99% ee. The result indicates that, after the two stereogenic centers of the starting material have been subsequently bulldozed, the chiral catalyst exerts stereocontrol in the allylation of the enolate. The main diastereomer 108 was separated and served as a key intermediate in a total synthesis of the marine diterpenoid cyanthiwigin F along with the lower homolog (R = H) (Scheme 5.34) [57]. 

The usefulness of this reaction was highlighted in the total synthesis of marine diterpenoid (—)-cyanthiwigin, which was isolated from the sea sponge Myrmekioderma Styx and shown to exhibit cytotoxic activity against human primary tumor cells (with a half-maximal inhibitory... 

Ge, Y, Kondo, S., Katsumura, S., Nakatani, K., and Isoe, S. (1993b) Absolute configuration of novel marine diterpenoid udoteatrial hydrate synthesis and cytotoxicities of ent-udoteatrial hydrate and its analogues. Tetrahedron, 49,10555-10576. 

Asao, K., lio, H., and Tokoroyama, T. (1989) Total synthesis of (+)-agelasidine C, a physiologically active marine diterpenoid with hypotaurocyamine group. Chem. Lett., 1813-1814. 

Harvis, C.A., Burch, M.T, and Fenical, W. (1988) New marine diterpenoids, including a unique hydroperoxide, from a Caribbean gorgonian coral of the genus Pseudopterogorgia. Tetrahedron Lett., 29, 4361 364. 

Ito, H., Iwasaki, J., Sato, Y., Aoyagi, M., Iguchi, K., and Yamori, T. (2007) Marine diterpenoids with a briarane skeleton from the Okinawan soft coral Pachyclavularia violacea. Chem. Pharm. Bull, 55, 1671-1676. 

Iwasaki, J., Ito, H., Nakamura, M., and Iguchi, K. (2006) A synthetic study of briarane-type marine diterpenoid, pachydavulide B. Tetrahedron Lett., 47,1483-1486. 

Johnson, T.W. and Corey, E.J. (2001) Enantiospedfic synthesis of the proposed structure of the antitubercular marine diterpenoid pseudopteroxazole revision of stereochemistry. J. Am. Chem. Soc., 123, 4475-4479. 

In studies directed at the synthesis of the furanocembranoids, marine diterpenoid natural products, investigation on the use of an intramolecular oxidative coupling strategy for ring closure led to an interesting result whereby the desired macrocyclic product or its dimer could be obtained... 

A tetracyclic core of marine diterpenoid was obtained by a Diels-Alder reaction of l,3,3-trimethyl-2-viityl-l-cyclohexene withchromones under microwave irradiation with and without TiCl (Rajesh et al., 2010). 

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