Asymmetric Ni-catalyzed conjugate allylation of activated enones.
The nickel-catalyzed enantioselective addition of allylboronic acid pinacol ester, allylB(pin), is described. This reaction is highly effective with dialkylidene ketones and favors the allylation of the benzylidene site in nonsymmetric substrates. The reaction appears to proceed by conversion of the dialkylidene ketone substrate to an unsaturated pi-allyl complex (I), followed by reductive elimination. Enantioselectivities range from 91 to 94% ee for a range of substrates when chiral ligand 14 is employed.
Sieber
Joshua D
JD
Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA.
Morken
James P
JP
D000498:Allyl Compounds / Q000737:chemistry*; D001897:Boronic Acids / Q000737:chemistry*; D002384:Catalysis; D007659:Ketones / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D009532:Nickel / Q000737:chemistry*; D013237:Stereoisomerism
D000498:Allyl Compounds; D001897:Boronic Acids; D007659:Ketones; D009532:Nickel