合成路线1

Displacement of the nosylate group of (XVI) with rubidium acetate in the presence of crown ether furnished the desired acetate ester (XVIII) accompanied by the elimination byproduct (XVII). Alcohol (XIX), obtained by basic hydrolysis of the acetate ester (XVIII), was protected as the silyl ether (XX) using triethylsilyl triflate. Hydrogenation of the lactam double bond of (XX) over PtO2 gave the saturated lactam (XXI). The azido group was introduced by reaction of the lithium enolate of lactam (XXI) with trisyl azide to afford a diastereomeric mixture from which the desired azide (XXII) was isolated by column chromatography. Simultaneous reduction of the lactam and azide functional groups of (XXII) with concomitant removal of the triethylsilyl protecting group was accomplished by treatment of (XXII) with LiAlH4. The resulting amine (XXIII) was then acylated with benzyl chloroformate to give carbamate (XXIV).