Hydroamination of Dienes, Allenes, and Alkynes

Intermolecular hydroamination of alkynes, which is a process with a relatively low activation barrier, has not been used for the synthesis of chiral amines, since the achiral Schiff base is a major reaction product. However, protected aminoalkynes may undergo an interesting intramolecular allylic cyclization using a palladium catalyst with a chiral norbomene based diphosphine ligand (Eq. 11.9) [115]. Unfor tunately, significantly higher catalyst loadings were required to achieve better enantioselectivities of up to 91% ee. 

Equation 11.9. Palladium catalyzed asymmetric intramolecular hydroamination of aminoalkynes [115]. 

The unique counteranion effect was also crucial in analogous catalytic reactions of allenylsulfonamides using an achiral gold(I) precatalyst in the presence of the 

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