Rhodium(I)-catalyzed 1,4-conjugate arylation toward β-fluoroalkylated electron-deficient alkenes: a new entry to a construction of a tertiary carbon center possessing a fluoroalkyl group

Treatment of beta-fluoroalkylated-alpha,beta-unsaturated ketones with 1.2 equiv. of various arylboronic acids in the presence of 5 mol% of [Rh(COD)(2)]BF4 and 6 mol% of (S)-BINAP in toluene/H2O (v/v = 4/1) at the reflux temperature for 3 h gave the corresponding Michael adducts in high yields with over 90% enantioselectivity. Though other electron-deficient alkenes, such as vinylsulfone and vinylphosphonate, were found to be much less reactive in the rhodium-catalyzed conjugate addition with arylboronic acids, the reaction of various arylstannanes toward such electron-deficient alkenes took place very smoothly to afford the corresponding adducts in high yields.