Reactivity patterns of benzhydryl(mesityl)phosphane oxide – a potential intermediate in carbonyl-carbonyl coupling reactions?

Abstract

Benzhydryl(mesityl)phosphane oxide 2-H is prepared and its deprotonation and nucleophilicity behavior investigated. Treatment of lithium salts of 2-H with MeI results in methylation at the Pcenter while the benzyl carbon is not affected. Only upon double lithiation, it is possible to methylate also the benzyl carbon. Di-anion 2-2Li is reactive towards benzaldehyde to afford moderate amounts of triphenylethene after basic work.