G. P. Pollini

Synthetic studies towards forskolin

Abstract A model tricyclic system incorporating the complete array of oxygenated functions of the AB portion of forskolin has been synthetized. The highly substituted decalin unit of the natural target has been in turn assembled in a convenient way utilizing an intramolecular nitrile oxide cycloaddition reaction as key step.

Methyl 4-oxothiolane-3-carboxylate and methyl 2-methyl-4-oxothiolane-3-carboxylate anions as synthetic equivalents of α-acrylate and α-crotonate anions. Formal synthesis of integerrinecic acid

The base-promoted fragmentation of the C-alkylation products (6a–h) and (8a–e) of methyl 4-oxothiolane-3-carboxylate (4) and methyl 2-methyl-4-oxothiolane-3-carboxylate (5) gave good yields of the α-substituted acrylates (7a–h) and α-substituted crotonates (9a–e); thus the corresponding heterocyclic anions (1a) and (1b) could be considered to be synthetic equivalents of α-acrylate and α-crotonate anions respectively. A formal synthesis of integerrinecic acid (10) is reported, demonstrating the usefulness of this strategy in natural product chemistry.

Isoxazoles-mediated synthesis of geiparvarin and dihydrogeiparvarin

Abstract A new synthesis of geiparvarin 1 and its dihydroderivative 2 two naturally occurring antitumor agents, possessing the 3(2H)-furanone ring system central structural feature, is described. The synthetic design is based on the use of suitably substituted isoxazole derivatives, the heterocyclic ring acting as masked 1,3-diketone moiety.