Synthesis and derivative chemistry of 2-phosphabutadienes and the reactivity of a two-coordinate phosphine with organolithium reagents

Abstract

Since the first report of an iminophosphine that contained a trivalent, dicoordinate phosphorus atom with a (p-p)? P=N bond, there have been numerous papers on aminoiminophosphines, N-P=N-. In the past decades, phosphorus compounds containing other low-coordinate multiple bonded elements have received more attention. A wide range of species containing P?X and P=X bonds is now known. For many years, the chemistry of P III species has been limited to the reactivity of the lone pair as a nucleophilic center, e.g., the coordination of transition metal centers by the P lone pair. However, in 1992, the synthesis of a 2-phospha-3-methylbutadiene ( 1 , R = Me) via an ¿ene¿ reaction by Angelov and Neilson indicated that the 2-coordinate aminophosphine, (Me 3 Si) 2 N-P = NSiMe 3 ( III ), exhibits nucleophilic character as well. In this project by changing the R group, other 2-phosphabutadienes were synthesized and their derivative chemistry was studied. The compounds underwent a wide variety of reactions without disruption of the butadiene moiety, leading to the formation of novel P-functional derivatives and related compounds.* With normal phosphines or phosphoranimines, organolithium compounds are often used as addition or substitution reagents. Either way, the organolithium compound acts as a nucleophilic reagent towards phosphorus. By using different organolithium and quenching reagents to study the reactivity of aminoiminophosphine III , we were able to observe the various electronic and steric effects that influence these reactions.* The preparative details of these reactions as well as the structural characterization by multinuclear NMR spectroscopy of several representative products are presented. *Please refer to dissertation for diagrams.