Preferential crystallization of (±)-pinenyllithium·TMEDA

Authors

• Alexander N. Erickson, College of Arts & Sciences
• Curtis Haltiwanger, University of Colorado Boulder
• Masoumeh Rahim, College of Arts & Sciences
• Charles M. Garner, College of Arts & Sciences

Abstract

(±)-Pinenyllithium.TMEDA or (tetramethylethylenediamine-к²N,N^')(η³-6,6-dimethyl-2-methylenebicyclo[3.1.1]heptyl)lithium, [Li(C10H15)(C6H16N2)], is readily prepared from β-pinene, butyllithium and TMEDA, and the racemic material preferentially crystallizes even from 96:4 (92% ee) mixtures of (‒)- and (+)-β-pinene, respectively. The structure is monomeric, with the geminal-dimethyl bridge of the bicyclic structure shielding one face of the allyl system, restricting the lithium to the opposite face and preventing the Li-allyl-Li aggregation observed with some other allyllithium systems. The symmetry of the allyl system, bond lengths, bond angles and out-of-plane deviations are compared to existing structures. In addition, a much older structure of this complex is compared to this very recent one.

Publication Title

Acta Crystallographica Section C Structural Chemistry

Recommended Citation

Erickson, A., Haltiwanger, C., Rahim, M., & Garner, C. (2024). Preferential crystallization of (±)-pinenyllithium·TMEDA. Acta Crystallographica Section C Structural Chemistry, 80 (Pt 7), 297-301. https://doi.org/10.1107/S2053229624004662