The first diastereoselective synthesis of the antimicrobial and cytotoxic agent (−)-caulerpenynol 2 has been achieved in relatively few steps from the commercially available (S)-malic acid.
On exposure to daylight, caulerpenyne 1 in solution in the presence of oxygen and chlorophylls or pheophytins undergoes rapid, multifarious degradation involving a peculiar route through ynone 2, thus providing a model for detoxification from these and similar food web and seagrass potentially harmful terpenoids of caulerpalean green seaweeds in Mediterranean areas invaded by the tropical Caulerpa taxifolia.
The tropicalgreen seaweed Caulerpa taxifolia (VAHL) C. AGARDH (Caulerpales) which is invading the Mediterranean is shown to contain trace amounts of two further novel terpenes, 7,7-C-didehydro-6-hydroxy-6,7-dihydrocaulerpenyne (= (4S, 6S,1E)-3-[(Z)-acetoxymethylidene]-6-hydroxy-11-methyl-7-methylidenedodeca-1,10-dien-8-yne-1,4-diyl diacetate; 3a) and taxifolione (= 6-methylhept-5-en-3-yn-2-one; 4)
Caulerpenyne (1), the abundant sesquiterpene of the green seaweed Caulerpa taxifolia, has been epoxidized with dimethyldioxirane. The reaction proceeds with significant regioselectivity and moderate diastereoselectivity, the addition of oxygen occurring preferentially at the C(6)C(7) double bond thereby giving (6S,7S)- and (6R,7R)-epoxycaulerpenynes 10 and 12 in an approximately 2:1 molar ratio besides