合成路线1

The condensation of benzaldehyde (I) with thiazolidine-2,4-dione (II) by means of piperidine in ethanol gives the benzylidene-thiazolidinedione (III), which is reduced with H2 over Pd/C in methanol to yield the benzyl derivative (IV). The cleavage of the cyclic ketal group of (IV) with HCl affords the piperidone (V), which is finally reductocondensed with the chiral ethanolamine (VI) by means of sodium triacetoxyborohydride in DMF to provide the target compound. The intermediate ethanolamine (VI) has been obtained as follows: The reaction of 3-amino-4-(benzyloxy)acetophenone (VII) with Ms-Cl and pyridine in dichloromethane gives the expected sulfonamide (VIII), which is brominated with CuBr2 in chloroform to yield the phenacyl bromide (IX). Enantioselective reduction with the Corey's chiral oxazaborolidine catalyst affords the (R)-bromoethanol derivative (X), which is treated with NaN3 in DMSO to provide the azido compound (XI). Finally, this compound is reduced and debenzylated by hydrogenation with H2 over Pd/C in methanol to furnish the desired ethanolamine intermediate (VI).