Syntheses of Bimetallic Zwitterionic Complexes Containing Stereogenic Bifunctionalized Phosphine through Stepwise Insertion and Hydration Reactions

A class of bifunctionalized phosphine complexes bearing a stereogenic center at phosphorus have been synthesized through stepwise insertion and hydration of the two alkynyl groups of a prochiral dialkynylphosphine complex, [RU(eta(6)-benzene){PPh(C CCH3)(2)}Cl-2]. One of the two alkyric moieties of this complex inserted into the Pd-C bond of cyclopalladated benzylamine complexes to yield bimetallic complexes containing two stereogenic centers at ruthenium and phosphorus with high stereoselectivity and yield. Subsequently, the remaining free alkynyl group underwent hydration in a mixed solvent system of DCM/acctone/H2O (2:10:1), which resulted in the formation of bimetallic zwitterions bearing anionic palladium(II) and cationic ruthenium(II) centers. The carbon-carbon triple bond was converted into a ketonyl group during the hydration, and the absolute configuration at phosphorus was observed to remain unchanged in the products. All Structures of the insertion and hydration products have been identified by X-ray analyses or 2D ROESY NMR Studies.