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. 2024 Jul 1;80(Pt 7):297-301.
doi: 10.1107/S2053229624004662. Epub 2024 Jun 19.

Preferential crystallization of (±)-pinenyllithium·TMEDA

Alexander N Erickson  1 , Curtis Haltiwanger  2 , Masoumeh Rahim  1 , Charles M Garner  1
Affiliations

Preferential crystallization of (±)-pinenyllithium·TMEDA

Alexander N Erickson et al. Acta Crystallogr C Struct Chem. .

Abstract

(±)-Pinenyllithium·TMEDA or (tetramethylethylenediamine-κ2N,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.

Keywords: TMEDA; allylic metalation; allyllithium; crystal structure; pinene.

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Figures

Figure 1
Figure 1
Metalation of α-pinene and β-pinene.
Figure 2
Figure 2
Other reported allyl­lithium structures.
Figure 3
Figure 3
The crystal structure of pinenyllithium·TMEDA (1). Displacement el­lip­soids are drawn at the 50% probability level. H atoms have been omitted for clarity.
Figure 4
Figure 4
Deviations in pinenyllithium·TMEDA (1) from the C3—C2—C10 allyl plane; a negative sign denotes a deviation away from the Li atom.
See this image and copyright information in PMC

References

    1. Bauer, W., Winchester, W. & Schleyer, P. R. (1987). Organometallics, 6, 2371–2379.
    1. Begley, M. J., Gill, G. B. & Wallace, B. (1978). J. Chem. Soc. Perkin Trans. 1, pp. 93–97.
    1. Boche, G., Etzrodt, H., Marsch, M., Massa, W., Baum, G., Dietrich, H. & Mahdi, W. (1986). Angew. Chem. Int. Ed. Engl.25, 104–105.
    1. Boche, G., Fraenkel, G., Cabral, J., Harms, K., Van Eikema Hommes, N. J. R., Lohrenz, J., Marsch, M., Schleyer, P. & v, R. (1992). J. Am. Chem. Soc.114, 1562–1565.
    1. Brown, C. A. (1978). Synthesis (Stuttg), pp. 754–755.

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