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

The metalation of N,N-dimethylaminomethylferrocene in THF by the superbasic mixture of (BuLi)-Bu-n/(KOBu)-Bu-t 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 alpha-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.

Automated summary

This article investigates the metalation of N,N-dimethylaminomethylferrocene by superbase and the preparation of enantiomerically pure superbase. Quantum chemical calculations provide insights into the mechanism of substrate-reagent interaction, and a closer look at the reaction site is presented through experimental studies.