合成路线1

The reaction of the chiral oxazolopyridinone (I) with benzyl chloroformate and phenylselenium bromide by means of LHMDS in THF gives the intermediate (II), which is treated with O3 and oxygen to yield the unsaturated ester (III). The condensation of (III) with the arylcopper derivative (IV) in THF affords a mixture of cis- and trans-isomers that are separated by chromatography. The desired trans-isomer (V) is reduced with AlCl3 and LiAlH4 in THF, giving the carbinol (VI), which by elimination of the chiral auxiliary with H2 over Pd(OH)2 in ethyl acetate, followed by protection of the piperidine nitrogen with Boc2O, provides the carbamate (VII). The reaction of (VII) with MsCl in pyridine yields the corresponding mesylate (VIII), which is condensed with 1,3-benzodioxol-5-ol (IX) by means of NaH in refluxing THF to furnish the protected intermediate (X). Finally, this compound is deprotected with TFA in dichloromethane.