Facile Synthesis and Isolation of Secondary Amines via a Sequential Titanium(IV)-Catalyzed Hydroamination and Palladium-Catalyzed Hydrogenation.

An atom economical and catalytic route for the synthesis of aryl- and alkyl-substituted secondary amines has been developed. Using a bis(amidate)bis(amido)titanium(IV) precatalyst, the hydroamination of terminal alkynes with a range of amines results in the selective formation of the anti-Markovnikov product. The crude enamine/imine mixtures are effectively hydrogenated using palladium on carbon (Pd/C) and H2 to afford the corresponding secondary amine in excellent yields. Simple work-up procedures allow for the isolation of pure compounds while avoiding purification via column chromatography. [ABSTRACT FROM AUTHOR]