Leached nickel promotes catalysis using supported Ni(II) complex precatalysts in Kumada-Corriu reactions

Ni(II) acetate is immobilized onto diamine ligands anchored to (i) a cross-linked poly(styrene) support and (ii) a mesoporous silica support. These anchored Ni(II) materials are successfully used to promote Kumada-Corriu reactions of 4-bromoanisole with phenylmagnesium chloride. Leaching studies utilizing filtration tests, analysis of recycle kinetics, elemental analysis, selective poisoning tests, and “three phase tests” indicate that an active catalytic species is associated with leached, soluble nickel. The cause of leaching is associated with the presence of the Grignard reagent. The use of anchored 3-iodopropyl groups for “three phase testing” of heterogeneity in Kumada-Corriu reactions is demonstrated. Polymer bound triphenyl phosphine is presented as a material for selective poisoning of soluble nickel in Kumada-Corriu reactions.

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