Crystal structure of enol benzoate ( [formula omitted]) obtained from conjugate addition of phenylmagnesium bromide to benzalacetomesitylene ( [formula omitted]); (z)-α-(2,2-diphenylethylidene)-2,4,6-trimethylbenzenemethanol benzoate ( [formula omitted

Abstract

The title compound ( 1 ) is shown to have a (Z) configuration confirming a previous assignment based on 1H nmr vinyl shielding constants. Bond distances, bond angles, and selected torsion angles are reported. The benzoyl ester grouping is s-trans in accord with the usual conformation for alkyl benzoates in solution. A torsion angle of 6.6° (average) involving the ester grouping for C 8-0 2-C 7-0 1 (or C 8-0 2-C 7-C 1 ) was found. The cyclic mechanism of Lutz and Reveley involving reaction of an s-cis conformation of the α,β-unsaturated ketone with the Grignard reagent explains the (Z)-stereochemlstry observed.