合成路线1

Dipolar cycloaddition of hydroxypyridinium betaine (I) with R-(+)-p-tolyl vinyl sulfoxide (II) furnished the chiral tropenone (III). Subsequent copper-catalyzed conjugate addition of phenyl-magnesium bromide on the beta-face of (III) provided the trans diaryltropanone (IV). Then, ketone reduction of (IV) with LiAlH4 gave alcohol (V), which was condensed with phenyl thionochloroformate (VI) to afford thiocarbonate (VII). This was reduced with tributyltin hydride and azobis(isobutyronitrile) to produce tropane (VIII). The sulfoxide group of (VIII) was further reduced to sulfide (IX) with PCl3 in DMF. Finally, Raney Nickel-promoted desulfurization in boiling EtOH yielded the title compound.