An improved synthesis of functionalized biphenyl-based phosphine ligands

Functionalized dicyclohexyl- and di-tert-butylphosphinobiphenyl Ligands are prepared by the reaction of arylmagnesium halides with benzyne, followed b y the addition of a chlorodialkylphosphine. This one-pot procedure is consi derably less expensive and time-consuming than the method used previously t o prepare such ligands. The cast of introducing the dicyclohexylphosphine g roup can be decreased by preparing chlorodicyclohexylphosphine from PCl3 an d cyclohexylmagnesium chloride, and using the reagent without further purif ication. The new method is significant, as a variety of ligands can be prod uced in useful amounts by a procedure that is simple, with starting materia ls that are relatively inexpensive, and, in most cases, without chromatogra phic purification.