合成路线1

Spiranic phenylsulfone intermediate (LXIII). The cyclization of the dithiane derivative (LIII) by means of HCL and Hg(ClO4)2/CaCO3 in acetonitrile/water gives a mixture of the desired spiroketal compound (LV) along with its isomer (LIV) that can be converted to (LV) by treatment with HClO4. The reaction of (LV) with Piv-Cl and TEA, followed by silylation with Tbdms-Cl and imidazole allows the selective silylation of the secondary OH group yielding (LVI). The cleavage of the Piv group of (LVI) by means of DIBAL in dichloromethane, followed by treatment with I2, PPh3 and imidazole in benzene affords the iodomethyl compound (LVII). The condensation of (LVII) with the dithiane intermediate (LII) by means of BuLi in THF/HMPA provides compound (LVIII), which is treated with Hg(ClO4)2 and CaCO3 and reduced with NaBH4 to cleave the dithiane auxiliary and yield alcohol (LIX). The protection of the OH group of (LIX) with Bom-Cl and DIEA affords compound (LX), which is reduced with DIBAL to cleave the cyclic ketal group and provide the primary alcohol (LXI). The reaction of (LXI) with I2, PPh3 and imidazole in benzene/acetonitrile gives the iodo derivative (LXII), which is finally treated with sodium phenylsulfinate in hot DMF to yield the desired spiranic phenylsulfone derivative (LXIII).