Intermolecular Rhodium‐Catalysed Hydroamination of Non‐Activated Olefins: Effect of Olefin, Amine, Phosphine and Phosphonium Salt

Abstract

Abstract The catalytic system RhCl 3 ⋅3H 2 O/2P( p ‐CH 3 C 6 H 4 ) 3 /65 n Bu 4 PI/2I 2 , which was discovered recently in our research group, allows the highest catalytic activity ever reported for the intermolecular hydroamination of ethylene, 1‐butene, and 1‐hexene with aniline‐type amines (0.3 mol % catalytic precursor) to give the expected N ‐alkyl‐ ( N ‐ethyl‐, 1 ) and N,N ‐dialkyl‐anilines ( N,N ‐diethyl‐, 2 ) along with 2‐methyl quinolines ( 3 ; in the case of ethylene). The effects of time and temperature, as well as the nature of the phosphonium salt, phosphine, and amine on the catalytic activity of this reaction have been studied. This system is particularly efficient for the hydroamination of ethylene with aniline in the presence of 2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl (CE*=460) and tri( p ‐tolyl)phosphine (CE*=520). Good to excellent activities were also found by combining Wilkinson’s catalysts (Rh I complexes) with n Bu 4 PI and I 2 . The simple association of PPh 3 and I 2 has been shown to be a very efficient “in‐situ generated” source of I − promoters. *CE (catalytic efficiency)=TON 1 +2TON 2 +2TON 3 .