title: Palladium-catalyzed asymmetric Heck arylation of 2,3-dihydrofuran--effect of prolinate salts.
abstract: Chiral ionic liquids (CILs) containing L-prolinate and L-lactate anions and non-chiral quaternary ammonium cations were employed in the palladium catalyzed enantioselective Heck arylation of 2,3-dihydrofuran with aryl iodides (iodobenzene, 4-iodotoluene, 2-iodoanisole, 4-iodoanisole, 4-iodoacetophenone). In all the reactions 2-aryl-2,3-dihydrofuran (3) was obtained as the main product with the yield up to 52% at the total conversion reaching 83%. Product 3, 2-phenyl-2,3-dihydrofuran, was obtained with excellent enantioselectivity (>99% ee) in a 6 h reaction with tetrabutylammonium L-prolinate. In the proposed homogeneous reaction Pd(0) nanoparticles are considered as a resting state of the catalyst and a source of soluble palladium species catalyzing the Heck reaction. The yield and stereoselectivity of the Heck reaction are strongly influenced by the kind of non-chiral cations present in CILs.
authors.affiliation: Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie St., 50-383 Wrocław, Poland.
authors.forename: Adam
authors.initials: A
authors.lastname: Morel
authors.forename: Ewelina
authors.initials: E
authors.lastname: Silarska
authors.forename: Anna M
authors.initials: AM
authors.lastname: Trzeciak
authors.forename: Juliusz
authors.initials: J
authors.lastname: Pernak