合成路线1

Asymmetric Robinson annulation of 2-methylcyclopentane-1,3-dione (II) with (phenylsulfanyl)methyl vinyl ketone (I) using R-(+)-phenylalanine as the catalyst afforded the chiral bicyclic dione (III). Oxidation of the sulfide group of (III) by means of m-chloroperbenzoic acid gave sulfone (IV). This was reduced with LiAlH4 to the trans-hydrindane derivative (V), which was further oxidized to ketone (VI) with Jones reagent. The indaneacetic ester (VII) was obtained by Horner-Emmons condensation of ketone (VI) with triethyl phosphonoacetate, followed by catalytic hydrogenation. Treatment of (VII) with bromide (VIII) in the presence of LDA provided an inseparable mixture (IX and X) of alkylated compounds at the alpha position of the ester and sulfone functions, respectively. Ester reduction of this mixture by means of DIBAL afforded the mixture of alcohols (XI) and (XII), which were separated by chromatography. The desired alcohol (XI) was reduced to the methyl derivative (XIII) via conversion to the corresponding mesylate, which was then reduced by treatment with lithium triethyl borohydride.