Experimental and molecular orbital calculational study of the stereoselective Horner—Wittig reaction with phosphine oxides: Control of stereoselectivity by lithium

Abstract Ab initio calculations have been used to determine the possible structure of lithium derivatives of phosphine oxides in THF: extension of these calculations to the docking of a carbonyl compound onto such a lithium derivative suggests an explanation for the anti selectivity of the Horner—Wittig reaction.