Bis(2-diphenylphosphinoethyl)amine. A Flexible Synthesis of Functionalized Chelating Diphosphinesl

Chelat ing diphosphines are an important c lass of l igand in inorganic and organometall ic chemistry. Applications of these mater ia ls in areas uch as asymmetr ic synthesis and catalysis by polymer-bound metals increasingly require incorporation of diphosphine units into complicated organic structures. The most commonly used methods for synthesis of polydentate phosphines involve the introduction of multiple individual phosphine units into a precursor, ordinarily by displacement of halides or tosylates by diphenylphosphide ion or by addition of diphenylphosphine to activated olefins.2 These syntheses suffer from unpredictable yields and incompatibility with many funct ional groups. Here we out l ine an al ternat ive and widely applicable synthetic method in which the chelating diphosphine moiety is introduced as a unit, taking advantage of the highly reliable coupling of amines with carbonyl halides, anhydrides. active esters, and isocyanates (eq l)