The catalytic hydroamination of alkynes

Abstract

Catalytic additions of ammonia or primary and secondary amines to non-activated alkenes and alkynes are called hydroaminations. These reactions of fundamental simplicity represent the most atom efficient processes for the formation of amines, enamines and imines, which are important bulk and fine chemicals or building blocks in organic synthesis. Consequently, the development of corresponding hydroamination reactions has received much attention and great progress has been achieved in the case of catalytic hydroaminations of alkynes over the past four years. To illustrate this progress, this tutorial review will mostly focus on recent developments in the field of intermolecular hydroamination of alkynes that appeared in the literature between the end of 2002 and October 31, 2006.

Well‐Defined Regioselective Iminopyridine Rhodium Catalysts for Anti‐Markovnikov Addition of Aromatic Primary Amines to 1‐Octyne

“…In contrast, alkynes are generally more reactive in hydroamination reactions. [3] A wide variety of catalysts have successfully been employed in the catalytic cyclization of aminoalkynes, although intermolecular amination reactions with alkynes are much more difficult. Pioneering work was carried out by Barluenga et al, who employed mercury and thallium salts for the Markovnikov hydroamination of alkynes with anilines.…”

Recent Innovative Strategies for the Synthesis of Amines: From CN Bond Formation to CN Bond Activation

“…Important examples include the seminal development of palladium-and copper-catalyzed aminations of aryl halides (Buchwald-Hartwig amination, Scheme 1 A), [2] the reductive amination of carbonyl compounds (Scheme 1 B), [3] and the hydroaminomethylation of olefins (Scheme 1 C). [4] The latter reaction and the direct hydroamination of unsaturated carbon-carbon bonds (Scheme 1 D) [5] might result in two regioisomeric products: the Markovnikov (branched) and the corresponding anti-Markovnikov (linear) isomer. [6] Obviously, the intermolecular reaction between amines and olefins perfectly fulfils today's need of "green catalysis"; however, despite significant efforts no general methodology is available.…”

Zinkvermittelte Hydrohydrazinierung von terminalen Alkinen – eine effiziente Dominosynthese von Indolen

“…[8] Später beschrieben Odom und Mitarbeiter die erste titankatalysierte intermolekulare Hydroaminierung von Arylhydrazinen mit Alkinen. [9,10] Die erhaltenen Arylhydrazone wurden nachfolgend in einer Fischer-Indol-Reaktion in hohen Ausbeuten zu N-Alkyl-und N-Arylindolen umgesetzt. Auf der Grundlage dieses Ansatzes entwickelten wir titankatalysierte Synthesen von funktionalisierten Tryptaminen und Tryptaminhomologen ebenso wie von Tryptophol und Tryptopholderivaten, wobei wir von kommerziell erhältlichen Arylhydrazinen und Alkinen ausgingen.…”