Hydroaminomethylation of n‐Alkenes in a Biphasic Ionic Liquid System

Abstract

Hydroaminomethylation reactions were performed successfully in an imidazolium-based ionic liquid using a rhodium/sulfoxantphos system by reacting piperidine with different n-alkenes, affording yields higher than 95 % of the resulting amine with turnover frequencies of up to 16,000 h À1, along with high regioselectivity for the linear amines with l/b ratios up to 78. Additionally, facile quantitative catalyst recovery was accomplished and recycling of the catalyst and product separation was achieved by a fast phase separation after the reaction. The product distribution was monitored over time at different temperatures both in an organic solvent and in the ionic liquid in order to investigate and compare the course of the formation of (side) products and intermediates in these reactions. Furthermore, it was shown that the nature of the rhodium precatalyst has a profound effect on the activity and selectivity. Protic organic solvents and ionic liquids containing a C À H acidic bond in the imidazolium part have a beneficial effect on the hydrogenation activity of the catalyst systems.

Fast and Selective Hydroaminomethylation Using Xanthene‐Based Amino‐Functionalized Ligands

“…[7] High yields and selectivities in HAM can be obtained by using similar catalyst-ligand systems to hydroformylation. Recently, we demonstrated the importance of protic solvents in this reaction and accomplished efficient catalyst recovery combined with excellent activity and selectivity by carrying out the reaction in ionic liquids.…”

Catalysis in Non-conventional Reaction Media

“…The resulting amines were obtained in more than 95% yield with TOF of up to 16 000 h À1 , along with high regioselectivity for the linear amines, with n/i ratios up to 78, and quantitative catalyst recovery. 128 Analogous hydroaminomethylation reactions were also reported to be catalysed by Rh(CO) 2 acac/BISBIS in [bmim][p-CH 3 -C 6 H 4 -SO 3 ] with high conversions and n/i ratios ranging from 5 to 36. 129 The known cobaltocenium complexes 48 and 49 were proposed as ligands for rhodium (Table 1.5).…”

Hydroaminomethylation of Isoprene: Recycling of the Homogeneous Rhodium Catalyst in Aqueous Biphasic Systems

“…Untersucht wurde bislang die Hydroaminomethylierung in organisch/wässrigen Systemen [10,11], in ionischen Flüssigkeiten [12,13], in thermomorphen Lösungs-mittelsystemen [8] und bei überkritischen Bedingungen [14].…”