5-BROMINATION OF AN ETA(2)-8-QUINOLYL LIGAND BOUND TO OSMIUM(II) AND SUBSEQUENT LITHIATION AND DERIVATIZATION OF THIS FUNCTIONALIZED LIGAND

Bromination of the 8-quinolyl ligand in the complex Os(eta(2)-8-quinol yl)Cl(CO)(PPh3)(2) (1) occurs selectively in, the 5-position, para to the osmium-carbon bond. Treatment of the brominated product, Os(eta(2) -8-quinolyl-Br-5)Cl(CO)(PPh3)(2) (2a), with BuLi gives an intermediate lithiated quinolyl species Os(eta(2)-8-quinolyl-Li-5)Cl(CO)(PPh3)(2) (3), which undergoes further reactions typical of aryllithium reagents . Treatment with the representative electrophiles n-BuBr, Bu3SnCl, and Me2NC{O}Me produces Os(eta(2)-8-quinolyl-Bu-5)Cl(CO)(PPh3)(2) (4), Os (eta(2)-8-quinolyl-SnBu3-5)Cl(CO)(PPh3)(2) (5), and Qs(eta(2)-8-quinol yl-C{O}Me-5)Cl(CO)(PPh3)(2) (6), respectively. Crystal structures of O s(eta(2)-8-quinolyl-Br-5)I(CO)(PPh3)(2) (2b) and Os(eta(2)-8-quinolyl- [C{O}Me]-5)Cl(CO)(PPh3)(2) (6) have been determined.