Efficient and selective synthesis of e-vinylamines via tungsten(0)-catalyzed hydroamination of terminal alkynes

Abstract

The hydroamination of terminal alkynes (RC≡CH=phenylacetylene, 4-methylphenylacetylene, 4-fluorophenylacetylene, 1-hexyne, methyl 2-propynyl ether, prop-2-yn-1-ol) with secondary amines (piperidine, pyrrolidine, morpholine, piperazine, methylpiperazine, 4-methylpiperidine and 3-methylpiperidine) was achieved in high yield (up to 99%), regioselectivity (only anti-Markovnikov product) and stereoselectivity (only E-isomers) within a maximum of 5 h in reactions catalyzed by the tungsten tetracarbonyl complex cis-[W(CO)4(piperidine)2] at 90°C without any additional solvent.