合成路线1

Condensation of protected ketone (I) with 2-benzyloxy-1-trimethylsilyloxyphenoxyethane (II) by means of Sn(OTf)2 and chiral amine (III) in propionitrile affords aldolic reaction product (IV), which is then dehydroxylated by treatment with thiocarbonyl diimidazole (A) in THF followed by reduction with Bu3SnH in refluxing toluene to provide the protected hydroxyester (V). Reduction of the ester group of (V) with DIBAL in CH2Cl2 followed by Swern oxidation with (COCl)2, DMSO and Et3N in dichloromethane yields aldehyde (VI), which is then condensed with 2-methoxypropene (VII) and 2-methoxyaniline (VIII) in the presence of yterbium triflate (Yb(OTf)3) in THF/H2O to furnish a mixture of diastereoisomers from which anti-(IX) is separated. Derivative anti-(IX) is treated with HF in THF for TBS removal and cyclization is induced by reaction with PPh3 and CBr4 in CH2Cl2, affording piperidine (X). Next, treatment of (X) with cerium ammonium nitrate (CAN) in acetonitrile/H2O allows N-protecting group removal, giving piperidine derivative (XI). Alternatively, (XI) can be obtained as follows: Treatment of aldehyde (VI) with 2-methoxyaniline (VIII) and PMB-protected 2-methoxypropene (XII) in the presence of scandium trisdodecylsulfate (STDS) in THF/H2O yields a mixture of diastereoisomers from which anti-(XIII) is separated. Derivative anti-(XIII) is then converted into (XI) by following the same procedure as for the conversion of anti-(IX) into (XI). Derivative (XI) is then subjected to: (i) N-protection by means of Boc2O; (ii) treatment with lithium hexamethyl disilazide (LHMDS) followed by trimethylsilyl chloride (TMSCl); (iii) oxidation of the silylenol ether by means of MCPBA; and (iv) bromination with PPh3 and CBr4. After all these steps bromo derivative (XIV) is obtained. Finally, coupling of (XIV) with 4-hydroxyquinazoline (XV) using KOH followed by Boc removal by treatment with refluxing HCl furnishes the target compound.