Scheme 3. Derivatization of dihydropyridine 5a. Ar = 4-fluorophenyl. Reagents and conditions: (a) Et₃SiH (1.05 equiv.), trifluoroacetic acid (20 equiv.), CH₂Cl₂, –10 °C, 45 s; (b) H₂ (1 atm), Lindlar catalyst (3 mol%), MeOH, rt, overnight; (c) N-iodosuccinimide (3 equiv.), DMF, rt, 2 h; (d) Buchwald precatalyst (2 mol%), XPhos (4 mol%), K₃PO₄ (2 equiv.), 4-MeO-PhB(OH)₂ (1.5 equiv.), THF, 80 °C, overnight; (e) OsO₄ (4 mol%), N-methylmorpholine-N-oxide (1.2 equiv.), THF : H₂O (2 : 1), rt, 3 h; (f) H₂ (100 psi), Pd/C (5 mol%), MeOH, rt, overnight; (g) n-BuLi (1.2 equiv.), THF, –50 °C, 30 min, then MeI (3 equiv.), THF, –78 °C, 2 h; (h) nitrosobenzene (2 equiv.), CH₂Cl₂, rt, 2 h; (i) CuCl (20 mol%), MeOH, rt, overnight; (j) LiAlH₄ (4 equiv.), THF, 50 °C, overnight, then HCl in Et₂O.