Ivanov Reagents Are Carboxylate Enolates (enediolates, Or Carboxylic Acid Dianions) Derived From Phenyl Acetic Acid Or Substituted Analogs, And React With Aldehydes To Give β-hydroxy Acids, Similar To The Aldol Addition.
The Stereoselectivity Can Be Explained With The Zimmerman-Traxler Model, Which Predicts A Six-membered Cyclic Transition State Leading To Excellent Stereoselectivity For anti-substituted Products.