Synthesis of primary amines via linkage of hydroaminomethylation of olefins and splitting of secondary amines

Abstract

An elegant method capable of synthesising primary amines from olefins is presented by a new orthogonal tandem amination reaction. Rh/Ru-catalysed bis-hydroaminomethylation of dienes towards secondary amines 10 and primary amines 13 is implemented. The obtained secondary amines 10 intermediates are then converted in a second reaction step to primary amines 13via splitting of amines through subsequent addition of ammonia. Influences on the orthogonal catalytic system towards the formation of primary amines are discussed and point towards a novel N-dealkylation and alkylation mechanism. For the model substrate dicyclopentadiene (tricyclo[5.2.1.02,6]deca-3,8-diene, dcpd 1) yields of up to 29% of the primary diamine (3(4),8(9)-bis(aminomethyl)tricycle-[5.2.1.02,6]decane, TCD-diamine 13) were achieved under optimized conditions, with a primary amine 13 to secondary amine 10 ratio of 5.8. The reverse reaction towards secondary amines was revealed as the limiting factor in the selective reaction towards primary amines 13 caused by the equilibrium of the reaction. In this equilibrium, however, a slight tendency towards the primary amine 13 was identified.