A new type of nucleophile, a 3‐imino nitrile carbanion generated in situ by Thorpe reaction of acetonitrile with a base, was developed successfully and applied in a Pd‐catalyzed asymmetric allylic alkylation with mono‐substituted allyl reagents under Pd/SIOCPhox catalysis, affording β‐enaminonitrile products in high yields with excellent regio‐ and enantioselectivities.
imidazole, which then reacts with a π-allyl palladium electrophile generated from an allylalcohol derivative by a palladium-based catalyst. A broad scope of substrates was suitable for this reaction. The utility of this method was demonstrated by a gram-scale reaction and subsequent elaboration of the allylation products.
Enantioselective Copper-Catalyzed Allylic Substitution Reaction with Aminohydroxyphosphine Ligand
作者:Naohiko Yoshikai、Kotaro Miura、Eiichi Nakamura
DOI:10.1002/adsc.200900054
日期:2009.5
Abstractmagnified imageA proline‐derived aminohydroxyphosphine ligand induced excellent regio‐ and enantioselectivities (SN2′:SN2>94:6, 94–97% ee) in the copper‐catalyzed substitution reaction of cinnamyl phosphates with Et2Zn. A computational modelling study of the reaction pathway suggests that the displacement of the leaving group takes place in an ordered, anti‐fashion through simultaneous copper–olefin and zinc–oxygen interactions, which is critical for the enantioselection.