Tandem Conjugate Addition-Aldol Cyclization to give Optically Active 1-Aryl-1H-indenes via Asymmetric Pd2+-Catalyzed 1,4-Addition of Aryl-boronic Acids

An asymmetric 1,4-addition of arylboronic acids to β-(2-acylaryl)enones was carried out in aqueous isopropanol in the presence of a dicationic palladium(II) complex and HBF 4 . The palladium complexes of (S,S)-chiraphos gave optically active 1-aryl-1H-indenes of up to 97% ee via tandem 1,4-addition-aldol condensation.