Journal of the American Chemical Society 2008-11-05

Lithiation of TMEDA and its higher homologous TEEDA: understanding observed alpha- and beta-deprotonation.

Viktoria H Gessner, Carsten Strohmann

Index: J. Am. Chem. Soc. 130(44) , 14412-3, (2008)

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Abstract

TMEDA and its ethyl-substituted analogue, TEEDA, show a different behavior toward the deprotonation with lithiumalkyls. While TMEDA mainly undergoes alpha-lithiation of its methyl group, TEEDA shows selective beta-lithiation with following elimination of ethene. The crystal structure of the monomeric intermediate of this beta-lithiation, tBuLi.TEEDA, and theoretical studies indicate kinetic favoritism for the beta-lithiation.