A Selective and General Cobalt‐Catalyzed Hydroaminomethylation of Olefins to Amines

Abstract

A new cobalt catalyst is presented for the domino hydroformylation-reductive amination reaction of olefins. The optimal Co-tert-BuPy-Xantphos catalyst shows good to excellent linear-to-branched (n/iso) regioselectivity for the reactions of aliphatic alkenes with aromatic amines under mild conditions. This system is far more selective than traditional cobalt(I) catalysts and even better than most known rhodium catalysts.

Structures and Oxidation Properties of Phenylene-Bridged Diazacycloalkanes: Ring Size Effects on Structures and Properties

“…The signals of the methylene groups in C10 were observed separately. In particular, signals assignable to γ-, δ-, and ε-CH 2 showed upfield shift compared to 1.26–1.30 ppm; these are the shifts for the inner methylene (from γ- to ζ-CH 2 ) protons of N , N -dimethyl- N , N -diphenyl-1,14-tetradecanediamine . These shifts are influenced by the ring current of the benzene ring, which has been reported in NMR studies of cyclophanes .…”

“…In particular, signals assignable to γ-, δ-, and ε-CH 2 showed upfield shift compared to 1.26−1.30 ppm; these are the shifts for the inner methylene (from γto ζ-CH 2 ) protons of N,N-dimethyl-N,N-diphenyl-1,14-tetradecanediamine. 11 These shifts are influenced by the ring current of the benzene ring, which has been reported in NMR studies of cyclophanes. 12 The benzene-ring current effects on shielding of protons located near the ring were first calculated based on Pauling's free electron model by Johnson and Bovey at 1958.…”

An Intramolecular Hydroaminomethylation-Based Approach to Pyrrolizidine Alkaloids under Microwave-Assisted Heating

“…Although characterized by high atom economy, HF and HAM are featured by harsh reaction conditions in terms of temperature (>100 °C), syngas pressure (50 bar) and time (24 h) [ 26 , 27 , 28 , 29 , 30 ]. However, many reactions that require very harsh conditions, such as aminocarbonylation, hydrogen borrowing, reductive amination, HF, and HAM itself, can benefit from MW assistance [ 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ].…”

Selective and stable tetraphosphite for Rh-catalyzed linear hydroaminomethylation of aliphatic and aromatic terminal olefins

“…In comparison, transition metal-catalyzed hydroaminomethylation (HAM), discovered by Walter Reppe 5 in 1949, represents an elegant one-pot process for converting cheap alkenes to value-added amines in the presence of syngas and an amine source via hydroformylation, condensation and hydrogenation cascade reactions (Scheme 1A). 6…”

“…To achieve useful chemoselectivity, regioselectivity and activity for applications, various transition metal catalysts such as iron, 5 a ,7 cobalt, 6 b , f manganese, 8 nickel, 5 b ruthenium 9 and rhodium 6 a – e ,10 have been developed. Among the abovementioned metals, rhodium based catalysts show promising control in activity and selectivity as pioneered by Elibracht, 10 a , c , d Vorholt, 11 Beller, 6 a , e ,9 d ,12 Vogt, 13 and Zhang, 14 among others, 15 and thus has received considerable attention. Although large bite angle diphosphine ligands are well-known for linear selective hydroformylation reactions, they are unfortunately less active and selective for such complex transformations (Scheme 1B).…”