Palladium-promoted cyclization reactions of aminoalkenes

Abstract The trifluoromethanesulphonate salts of the aminoalkenes CH 2 CH(CH 2 ) 3 -NH 2 , its 2-methyl, 2,2-dimethyl and N -iso-propyl-derivatives, and CH 2 CH-(CH 2 ) 4 NH 2 cyclize in the presence of [PdCl 2 (PhCN) 2 ] and a nitrogen base to produce the corresponding C- or N-substituted 2-methylpyrrolidines and 2-methylpiperidine. E -CH 3 CHCH(CH 2 ) 3 NH 2 produces 2-ethylpyrrolidine and a small amount of 2-methylpiperidine. The regio-selectivity of these reactions differs from that observed for the cyclization of the same substrates promoted by [PtCl 4 ] 2- : (1) the palladium reaction with 2-methylpent-4-enylamine produces ca. a 4 : 6 ratio of cis - and trans -2, 4-dimethylpyrrolidine while with platinum the converse is true; (2) there is a more marked tendency for attack of the amine at the more substituted alkene carbon atom in the palladium than in the platinum reactions.