Metal-Template Electrophilic Substitution on Phenols: Synthesis and Crystal Structure of Bromomagnesium Phenolate and Its Reactive Complex with para-IsopropylbenzaldehydeDedicated to the memory of Professor Giuseppe Casnati on the 4th anniversary of his death
electrophilic aromatic substitutions
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
The crystal structures of the bromomagnesium phenolate 5 and its complex 7 with para-isopropylbenzaldehyde are reported; for the first time it has been possible to demonstrate that the reactive complex 7, responsible for the complete ortho-regioselective control in the alkylation of phenoxymagnesium bromides with aldehydes, is not obtained by simple replacement of the ethereal ligand but by expansion of the metal coordination sphere from 4 (usual tetrahedral configuration) to 5. We infer from 1H NMR studies that the magnesium coordination of complex 7 in solution is analogous to that shown in the solid state, with a complexed ethereal molecule.
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