Synthesis of atropisomeric chiral MeOBIPHEP analogues via Pd-catalyzed P–C coupling — applications to asymmetric Rh-catalyzed C–C bond formations in water
•Preparation of water-soluble MeOBIPHEP analogues via Pd-catalyzed reaction•13P NMR spectroscopic monitoring of the Pd-catalyzed P–C coupling reaction•Asymmetric Rh-catalyzed 1,4-addition reactions in water (ee up to 96%)
The preparation and catalytic applications of water-soluble MeOBIPHEP-based atropisomeric chiral congener ligands are described. The optimization of the catalytic system to promote the key P–C coupling revealed the superiority of palladium catalysts versus nickel or copper. Spectroscopic studies of the Pd-catalyzed reaction medium showed the presence of phosphorylated intermediates. The asymmetric Rh-catalyzed 1,4-addition of boronic acids to enones in water was described in the presence of water-soluble MeOBIPHEP derivatives. The 4-CO2Na-, 3-CO2Na- and 3,5-(CO2Na)2-substituted MeOBIPHEP analogues showed high and complementary reactivities and enantioselectivities, considering either the enone or the boronic acid.
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Journal: Catalysis Communications - Volume 69, 5 September 2015, Pages 129–132