Sequential hydroaminomethylation/Pd-catalyzed hydrogenolysis as an atom efficient route to valuable primary and secondary amines

A Cooperative Rh/Co‐Catalyzed Hydroaminomethylation Reaction for the Synthesis of Terpene Amines

“…This latter approach seems a better option from a sustainable perspective, despite the lack of efficiency obtained in our initial attempts using terpenes substrates (results shown in Table 1). In the literature, pressures higher than 60 bar or the addition of a supplementary catalyst are necessary to reduce the enamine intermediate in the synthesis of terpene amines by HAM (for selected contributions see: [6a,7a,11,19] ).…”

“…In contrast to the alkenes coming from fossil resources, few examples regarding HAM have been reported with bio‐sourced substrates, in particular using terpenes as raw materials in combination with mainly primary and secondary amines, [5,7] or ammonia under biphasic conditions [8] . Generally, high syngas pressures (more than 60 bar) and high temperatures (80‐130 °C) are required principally using homogeneous monometallic Rh‐based catalysts (under tandem [9] or two‐step processes), [10] and also combining Rh and Pd catalysts [11] …”

“…[8] Generally, high syngas pressures (more than 60 bar) and high temperatures (80-130 °C) are required principally using homogeneous monometallic Rh-based catalysts (under tandem [9] or two-step processes), [10] and also combining Rh and Pd catalysts. [11] With the aim of enhancing the activity and selectivity of the HAM processes, homogeneous bimetallic Rh/Ir catalytic systems have been efficiently employed by Beller's group involving alkyl α-olefins [12] and Hartwig's group using both alkyl and aryl αolefins also including the natural compound methyl eugenol. [13] Given the scarcity of both metals, the quest of more sustainable approaches led our group to boost the enamine hydrogenation step of monometallic Rh-catalyzed HAM reactions using glycerol as solvent taking advantage of the reducing behavior of the latter, as an eco-friendly alternative to iridium.…”

Phosphorus-free nitrogen-containing catalytic systems for hydroformylation and tandem hydroformylation-based reactions

“…Further, the sequence of hydroaminomethylation in the presence of complex 67a and hydrogenolysis on Pd/C [148] enabled one to convert benzylamine and various unsaturated substrates to a number of primary and secondary amines with high yields (Scheme 41).…”