Heterogeneous and homogeneous chiral Cu(II) catalysis in water: enantioselective boron conjugate additions to dienones and dienoesters.
It was proved that a judicious choice of counteranion played a prominent role in Cu(II) catalysis for enantioselective boron conjugate additions in water; the use of Cu(OH)2 renders heterogeneous catalysis, whereas Cu(OAc)2 renders homogeneous catalysis; cyclic dienones underwent a remarkable switch of regioselectivity between 1,4- and 1,6-modes of the additions through these catalyses.
Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Taku
T
Kitanosono
Pengyu
P
Xu
Shū
S
Kobayashi