Towards Substrate–Reagent Interaction of Lochmann–Schlosser Bases in THF: Bridging THF Hides Potential Reaction Site of a Chiral Superbase

Abstract

The metalation of N,N-dimethylaminomethylferrocene in THF by the superbasic mixture of nBuLi/KOtBu proceeds readily at low temperatures to afford a bimetallic Li2K2 aggregate containing ferrocenyl anions and tert-butoxide. Starting from an enantiomerically enriched ortho-lithiated aminomethylferrocene, an enantiomerically pure superbase can be prepared. The molecular compound exhibits superbasic behavior deprotonating N,N-dimethylbenzylamine in the α-position and is also capable of deprotonating toluene. Quantum chemical calculations provide insight into the role of the bridging THF molecule to the possible substrate–reagent interaction. In addition, a benzylpotassium alkoxide adduct gives a closer look into the corresponding reaction site of the Lochmann–Schlosser base that is reported herein.