Chelated aryllithium reagents: ring size and chelating group effects.
[figure: see text] Chelation and aggregation in phenyllithium reagents with potential 5-, 6-, and 7-ring chelating ether and amine ortho substituents have been examined utilizing variable-temperature 6Li and 13C NMR spectroscopy, 6Li and 15N isotope labeling, and the effects of solvent additives. Both ether and amine form strong 5-ring chelates; 6-ring ether chelates compete well with THF, but 6-ring amine chelates barely do, and 7-ring amine chelates do not. o-Methoxymethylphenyllithium (4) forms an open dimer (9) and a pentacoordinate monomer with PMDTA (10).
Reich
H J
HJ
Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, USA. Reich@chem.wisc.edu
Goldenberg
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Sanders
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Tzschucke
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