Acetogenins of annonaceae. Part 86: synthesis of a highly functionalized precursor of (-)-4-deoxygigantecin, an annonaceous acetogenin

A highly functionalized precursor of(-)-4-deoxygigantecin possessing six st ereogenic centers has been prepared in 14 steps from tridecanal. The key st eps are (i) enantioselective aldolization, (ii) diastereoselective C-glycos ylation and (iii) diastereoselective aldolization reactions, all of them us ing 2-trimethylsilyloxyfuran as nucleophile. This strategy would allow us t o prepare squamostatin D as well, another acetogenin of Annonaceae possessi ng two nonadjacent tetrahydrofuran rings and a closely related tetrahydrofu ran pattern.