Selective Heck arylation of cyclohexene with homogeneous and heterogeneous palladium catalysts.
Palladium catalysts containing Pd(II) supported on Al2O3 and alumina-based mixed oxides, Al2O3-ZrO2, Al2O3-CeO2, and Al2O3-Fe2O3, are very effective in the Heck coupling of iodobenzene with cyclohexene in DMF solution. The best results, up to 81% of monoarylated products with a selectivity to 4-phenylcyclohexene (3) close to 90% were obtained with KOH as a base. The catalytic activity of palladium supported on alumina-based oxides was compared with that of homogeneous precursors, such as Pd(OAc)2 and PdCl2(PhCN)2, used in [Bu4N]Br as the reaction medium. Under such conditions homogeneous systems were more selective and produced up to 60% of monoarylated products with a selectivity to 3 close to 60%.
Mieczyńska
Ewa
E
Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, Wrocław, Poland. gosia@wchuwr.pl
Trzeciak
Anna M
AM
D000085:Acetates / Q000737:chemistry*; D000537:Aluminum Oxide / Q000737:chemistry; D002384:Catalysis; D003510:Cyclohexanes / Q000737:chemistry*; D053138:Cyclohexenes / Q000737:chemistry*; D007462:Iodobenzenes / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*
D000085:Acetates; D003510:Cyclohexanes; D053138:Cyclohexenes; D007462:Iodobenzenes; D009942:Organometallic Compounds; C516071:palladium(II) acetate; C052568:cyclohexene; D010165:Palladium; C031905:iodobenzene; C080904:4-phenylcyclohexene; D000537:Aluminum Oxide; C008756:palladium chloride