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Enantioselective Nickel‐Catalyzed Hydrocyanation using Chiral Phosphine‐Phosphite Ligands: Recent Improvements and Insights
Author(s) -
Falk Anna,
Cavalieri Alberto,
Nichol Gary S.,
Vogt Dieter,
Schmalz HansGünther
Publication year - 2015
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201500644
Subject(s) - hydrocyanation , chemistry , phosphine , enantioselective synthesis , catalysis , nickel , cyclooctadiene , styrene , benzonitrile , tetrahydrofuran , ligand (biochemistry) , medicinal chemistry , acetylacetone , organic chemistry , solvent , copolymer , biochemistry , receptor , polymer
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‐ d 8 by means of 2 D NMR spectroscopy.