合成路线1

The reaction of the acetonide of (R)-3,4-dihydroxybutanal (I) with the silylated 4-bromobenzyl alcohol (II) by means of n-BuLi in THF gives the corresponding carbinol (III), which is oxidized to the ethanone (IV) by means of tetrapropylammonium perruthenate (TPAP) and NMO in dichloromethane. The enantioselective reduction of the ketone (IV) by means of LiAlH4 and an excess of LiI in ethyl ether gives the (R,S)-enantiomer (V), which is mesylated with MsCl/TEA in dichloromethane and treated with NaN3 in hot DMF to yield the azide (VI). The reduction of (VI) with triphenylphosphine in THF/water affords the amine (VII), which is treated with allyl chloroformate and TEA in THF providing the carbamate (VIII). The desilylation of (VIII) with TBAF in THF gives the benzyl alcohol (IX), which is mesylated with MsCl and TEA in dichloromethane yielding the mesyl ester (X). The reaction of (X) with NaN3 in DMF affords the azide (XI), which is reduced as before to the benzylamine (XII). The reaction of (XII) with allyl chloroformate provides the bis carbamate (XIII).