合成路线1

The functionalized glucosamine building block (XI) is prepared as follows. Allyl 2-amino-2-deoxy-4,6-O-isopropylidene-beta-D-glucopyranoside (I) is converted into azide (II) upon treatment with trifluoromethanesulfonyl azide and DMAP. Alkylation of the free hydroxyl group of (II) with mesylate (III) in the presence of NaH gives ether (IV). The O-allyl group of (IV) is then removed by iridium-catalyzed double bond isomerization, followed by oxidative hydrolysis with iodine and pyridine, to afford (V). Condensation of (V) with trichloroacetonitrile produces imidate (VI), which is further displaced with trimethylsilyl cyanide, yielding nitrile (VII). Reduction of the azido group of (VII) by means of triphenylphosphine affords amine (VIII). This is acylated by (R)-3-(benzyloxy)tetradecanoic acid (IX) in the presence of DCC and DMAP, yielding amide (X). Acidic hydrolysis of the cyano group, followed by reaction of the resultant carboxylic acid with diphenyldiazomethane, leads to the benzhydryl ester (XI).