secondary amines as well as aniline to methacrylonitrile and crotonitrile (Scheme
40) [74].
The Togni group developed a new nickel pincer complex 40 based on the
Pigiphos ligand [75]. This complex showed good activity in the hydroamination of
α,β-unsaturated nitriles (Scheme 41). Even the challenging substrate aniline did react
with crotonitrile catalysed by 40 at rt. giving the aminated product in up to 91% yield
with 22% ee. Aliphatic amines (morpholine and piperidine) were also evaluated in
reactions with methacrylonitrile/crotonitrile leading to the products in excellent
yields. The highest ee (69%) was obtained in the hydroamination of
Scheme 40 Aza-Michael
addition on α,β-unsaturated
nitriles catalysed by
palladium pincer complexes
Scheme 41 Asymmetric aza-Michael addition catalysed by a Ni Pigiphos complex
Catalytic Conversion of Nitriles by Metal Pincer Complexes
359
40) [74].
The Togni group developed a new nickel pincer complex 40 based on the
Pigiphos ligand [75]. This complex showed good activity in the hydroamination of
α,β-unsaturated nitriles (Scheme 41). Even the challenging substrate aniline did react
with crotonitrile catalysed by 40 at rt. giving the aminated product in up to 91% yield
with 22% ee. Aliphatic amines (morpholine and piperidine) were also evaluated in
reactions with methacrylonitrile/crotonitrile leading to the products in excellent
yields. The highest ee (69%) was obtained in the hydroamination of
Scheme 40 Aza-Michael
addition on α,β-unsaturated
nitriles catalysed by
palladium pincer complexes
Scheme 41 Asymmetric aza-Michael addition catalysed by a Ni Pigiphos complex
Catalytic Conversion of Nitriles by Metal Pincer Complexes
359