合成路线1

Addition of 3-lithiopyridine (I) to methyl 4-formylbenzoate (II) in Et2O at low temperature provided carbinol (III), which was oxidized to ketone (IV) with MnO2 in refluxing THF. Then, saponification of the methyl ester of (IV) gave acid (V). Alternatively, acid (V) was obtained by Jones oxidation of silyloxymethyl compound (VI). Serinamide (IX) was prepared by coupling of N-Boc-L-serine (VII) with 4-cyclohexylbutylamine (VIII) using EDC and HOBt, followed by deprotection of the Boc group with trifluoroacetic acid in cold CH2Cl2. Compound (IX) was then coupled with acid (V) to provide amide (X), whose cyclization in the presence of PPh3, CCl4 and i-Pr2NEt produced the oxazoline (XI). Subsequent nickel peroxide oxidation yielded oxazole (XII). Finally, Wittig reaction of (XII) with phosphonate (XIII) in the presence of KO-t-Bu furnished the title compound.