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

摘要

Treatment of β-fluoroalkylated-α,β-unsaturated ketones with 1.2 equiv. of various arylboronic adds in the presence of 5 mol% of [Rh(COD)_2]BF_4 and 6 mol% of (S)-BINAP in toluene/H_2O (v/v = 4/1) at the reflux temperature for 3 h gave the corresponding Michael adducts in high yields with over 90% enantioselec-tivity. 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.