Lithium Cation-Catalyzed Wittig Reactions

Article abstract of DOI:10.1021/jo00084a034

The condensation of stabilized phosphorane 1 with benzaldehyde is catalyzed by Li(+) ion.In the presence of a large quantity of Li(+), ylide 1 adds slowly to ketones with which it does not react under the usual reaction conditions.On the other hand, pretreatment of the ylide solution with trace amounts of BuLi tends to slow the reactions with aldehydes, probably by removing any traces of water and conjugate acid, the sources of protons that catalyzed these condensations.