Aldimines are conveniently metallated, at a position α to the functional group, by using very powerful bases i.e. activated lithium dialkylamides generated in situ from lithium and a secondary amine in benzene/hexamethylphosphoric triamide. The anions obtained are alkylated with various ω,ω′-dihalogenoalkanes to give, after aqueous acid hydrolysis, good yields of ω-halogenated aldehydes and dialdehydes
A yet-unexploited class of azomethine imines, C,N-cyclic azomethine imines, could be successfully employed in highly enantioselective1,3-dipolarcycloaddition with enals catalyzed by titanium-BINOLate to give pharmaceutically attractive tetrahydroisoquinoline and piperidine motifs.