Hydroamination of non-activated alkenes with ammonia: a holy grail in catalysis

Alkyl amines represent an important class of chemicals with multiple applications in our daily life. Among the different routes to alkyl amines, the catalytic hydroamination of alkenes with amines is of high interest mainly because it occurs in a 100% atom-economical fashion. To circumvent thermodynamic limitations, activated alkenes or activated amines are essentially employed in such reactions. To date, the catalytic hydroamination of cheap and abundant non-activated (linear) alkenes with ammonia, the simplest amine, remains an unsolved reaction by catalysis. This tutorial review covers the advances reported so far in the intermolecular hydroamination of non-activated linear alkenes with simple alkyl amines, with special interest in ammonia. Focusing on thermodynamics, catalysis and emerging technologies, we aim at providing new perspectives to look at this challenging reaction from a different point of view. In particular, we highlight that the generation of amino radicals from NH3 using "physics activation" is a potential source of inspiration to (i) reduce energy barriers and (ii) reverse the regioselectivity to complete anti-Markovnikov addition.