The intermediate benzaldehyde (XII) has been obtained as follows: The reduction of 4-nitrobenzaldehyde (I) with NaBH4 and NiCl2 gives 4-aminobenzyl alcohol (II), which is treated with benzyl chloroformate to yield the carbamate (III). The protection of the OH group of (III) with Tbdms-Cl affords the silyl ether (IV). The cyclization of (IV) with glycidyl butyrate (V) by means of BuLi provides the hydroxymethyl oxazolidinone (VI), which is treated with MsCl and TEA to give the mesylate (VII). The reaction of (VII) with NaN3 yields the azidomethyl compound (VIII), which is condensed with thioacetic acid (IX) to afford the acetamide (X). The cleavage of the Tbdms protecting group of (X) by means of TBAF provides the benzyl alcohol (XI), which is oxidized with PDC to furnish the target benzaldehyde intermediate (XII)

3-Fluoroaniline (I) is condensed with benzyl chloroformate to give carbamate (II). Reaction of (II) with (R)-glycidol butyrate (III) in the presence of butyllithium affords oxazolidinone (IV). After conversion of alcohol (IV) to the corresponding mesylate, displacement with NaN3 provides azide (V). Reduction and acylation of (V) by means of thioacetic acid leads to acetamide (VI). Friedel-Crafts acylation of the aromatic ring of (VI) with acetic anhydride in the presence of methanesulfonic acid furnishes acetophenone (VII). Acidic hydrolysis of acetamide (VII) yields amine (VIII). This is then treated with thiophosgene, followed by methanol, to produce the thiocarbamate (IX). Finally, aldol condensation of the acetophenone (IX) with pyridine-2-carbaldehyde (X) gives rise to the target compound.