Phosphonium salts as chiral phase-transfer catalysts: asymmetric Michael and Mannich reactions of 3-aryloxindoles.
It's a PTC: A highly efficient reaction of 3-aryloxindoles in an asymmetric Michael addition was achieved by using a quaternary tetraalkylphosphonium salt as a chiral phase-transfer catalyst (PTC). The products were obtained in quantitative yields high ee values. The reaction of 3-aryloxindoles in an asymmetric Mannich reaction using the same catalyst also proved to be feasible.
He
Rongjun
R
Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto, 606-8502, Japan.
Ding
Changhua
C
Maruoka
Keiji
K