TY - JOUR
T1 - Enantioselective Nickel-Catalyzed Hydrocyanation using Chiral Phosphine-Phosphite Ligands
T2 - Recent Improvements and Insights
AU - Falk, Anna
AU - Cavalieri, Alberto
AU - Nichol, Gary S.
AU - Vogt, Dieter
AU - Schmalz, Hans Günther
PY - 2015/10/1
Y1 - 2015/10/1
N2 - The asymmetric hydrocyanation of vinylarenes was investigated using hydrogen cyanide (HCN) in the presence of 5 mol% of a catalyst prepared from a phenol-derived chiral phosphine-phosphite ligand and bis(cyclooctadiene)nickel [Ni(cod)2]. The reactions were performed in tetrahydrofuran (THF) at room temperature to give exclusively the branched nitriles with superior enantioselectivities of 88-99% ee for vinylarenes and 74-94% ee for vinylheteroarenes, respectively. Using styrene as a model substrate it was shown that the catalyst loading could be decreased to 0.42 mol% without any loss of selectivity (88% ee). The structure of the pre-catalyst, i.e., a tetrahedral Ni(0)(P,P-chelate)(cod) complex, was proven by X-ray and NMR analysis. Additional insight into the reaction course was gained by monitoring the hydrocyanation of styrene-d8 by means of 2D NMR spectroscopy.
AB - The asymmetric hydrocyanation of vinylarenes was investigated using hydrogen cyanide (HCN) in the presence of 5 mol% of a catalyst prepared from a phenol-derived chiral phosphine-phosphite ligand and bis(cyclooctadiene)nickel [Ni(cod)2]. The reactions were performed in tetrahydrofuran (THF) at room temperature to give exclusively the branched nitriles with superior enantioselectivities of 88-99% ee for vinylarenes and 74-94% ee for vinylheteroarenes, respectively. Using styrene as a model substrate it was shown that the catalyst loading could be decreased to 0.42 mol% without any loss of selectivity (88% ee). The structure of the pre-catalyst, i.e., a tetrahedral Ni(0)(P,P-chelate)(cod) complex, was proven by X-ray and NMR analysis. Additional insight into the reaction course was gained by monitoring the hydrocyanation of styrene-d8 by means of 2D NMR spectroscopy.
KW - asymmetric synthesis
KW - hydrocyanation
KW - hydrogen cyanide (HCN)
KW - nickel
KW - phosphine-phosphites
UR - http://www.scopus.com/inward/record.url?scp=84944930756&partnerID=8YFLogxK
U2 - 10.1002/adsc.201500644
DO - 10.1002/adsc.201500644
M3 - Article
AN - SCOPUS:84944930756
SN - 1615-4150
VL - 357
SP - 3317
EP - 3320
JO - Advanced Synthesis & Catalysis
JF - Advanced Synthesis & Catalysis
IS - 14-15
ER -