Effects of HMPA on the Structure and Reactivity of the Lithium Enolate of Cyclopentanone in THF: The Dimer is Responsible for Alkylation and Proton Exchange Reactions by Masaaki Suzuki and others (2004)

Bulletin of the Chemical Society of Japan 77, 259–268. Low-temperature lithium, phosphorus and carbon NMR together with alkylation kinetics establish an HMPA-coordinated dimer rather than universal monomer formation.