Titanium-Catalyzed Intermolecular Hydroaminoalkylation of Terminal Alkynes

Abstract

Terminal alkynes undergo intermolecular hydroaminoalkylation reactions with secondary amines in the presence of titanium catalysts and depending on the catalyst and the structure of the substrates, allylic amines and/or imines are formed as products in moderate yields. In addition, the desired allylamines can also be obtained from a convenient reaction sequence consisting of an initial hydroaminoalkylation of trimethylsilyl-protected alkynes and a subsequent protodesilylation that selectively delivers γ-unsubstituted allylamines.

Catalytic C–H Functionalization of Trimethylamine

“…Although terminal alkynes such as phenylacetylene were found to react unselectively under the reaction conditions (Scheme 3 ), the formal linear hydroaminoalkylation product of phenylacetylene with trimethylamine, ( E )- 8 , could be obtained by a two-step reaction sequence consisting of an initial regio- and stereoselective hydroaminoalkylation of (trimethylsilylethinyl)benzene and a subsequent HI-catalyzed protodesilylation. 12…”