Diastereoselectivity in Addition of Methylmagnesium Halide to Benzoylformate of Chiral 1,1'-Binaphthalene-2,2'-diol.

Abstract

The Grignard reactions of mono-benzoylformate ester of 1, 1'-binaphthalene-2, 2'-diol were examined to investigate the complex-induced proximity effect of the phenolic hydroxyl a+ C-2' under different reaction conditions. This hydroxyl group exerted a significant neighboring group participation in the reaction. The nucleophilic addition reaction proceeded with higher diastereoselectivity than that of a series of sterically similarly sized binaphtyl esters recently reported. The halogen ligand in methyl Grignard reagents plays a crucial role in controlling the degree and sense of diastereoselectivity. A plausible mechanism is also proposed.