Condensation reactions of 4,5-dihydroimidazoles: Preparation and conjugate additions of 2-alkenyl-4,5-dihydroimidazoles

Abstract Whereas 1-benzyl-2-lithiomethyl-4,5-dihydroimidazole undergoes reversible 1,2-addition to aldehydes and ketones, the derived phosphonate salt, 1-benzyl-2-lithio(diethylphosphono)methyl-4,5-dihydroimidazole, affords the condensation products, 2-(1-alkenyl)-4,5-dihydroimidazoles; these latter undergo conjugate addition with carbon nucleophiles.