Scheme 4. General synthesis of 2-(piperidin-3-yl)-1H-benzimidazole analogues 5a–n, 6a–d and 7a–h. Reagents and conditions: (a) EtOH, 120 °C; (b) R¹CH₂Br, K₂CO₃, DMF, 80 °C; (c) TFA, CH₂Cl₂; (d) R²–( O)H, Na(OAc)₃BH or R₂X, Et₃N, THF; (e) separation of enantiomers by chiral SFC when chiral acids were not used.