An Improved Synthesis of Functionalized Biphenyl-Based Phosphine Ligands

Abstract

Functionalized dicyclohexyl- and di-tert-butylphosphinobiphenyl ligands are prepared by the reaction of arylmagnesium halides with benzyne, followed by the addition of a chlorodialkylphosphine. This one-pot procedure is considerably less expensive and time-consuming than the method used previously to prepare such ligands. The cost of introducing the dicyclohexylphosphine group can be decreased by preparing chlorodicyclohexylphosphine from PCl₃ and cyclohexylmagnesium chloride, and using the reagent without further purification. The new method is significant, as a variety of ligands can be produced in useful amounts by a procedure that is simple, with starting materials that are relatively inexpensive, and, in most cases, without chromatographic purification.