合成路线1

The indenone intermediate (XIII) has been obtained as follows: The silylation of 3-methyl-1-pentyn-3-ol (I) with Tes-Cl and DMAP in DMF gives the silyl ether (II), which is condensed with paraformaldehyde and n-BuLi in THF to yield the propargyl alcohol (III). Partial reduction of (III) with Red-Al in THF affords the allyl alcohol (IV), which is treated with Ts-Cl and DMAP in dichloromethane to provide the allyl chloride (V). The condensation of (V) with the unsaturated ester (VI) (obtained by Wittig condensation of perhydroindanone (VII) with triethyl phosphonoacetate (VIII) by means of EtONa) by means of BuLi and dicyclohexylamine in HMPA gives the octenoic ester (IX), which is reduced with LiAlH4, yielding the corresponding primary alcohol (X). The reaction of (X) with TsCl and pyridine affords the tosylate (XI), which is reduced with LiBEt3H in THF with simultaneous opening of the epoxide ring to provide the hexahydroindenol (XII). Finally, this compound is oxidized with pyridinium dichromate (PDC), yielding the target hexahydroindenone intermediate (XIII).