Spectroscopic analysis of lithiated cyclic phosphonates belonging to the 1,3,2-dioxaphosphorinane 2-oxide class have been examined by NMR spectroscopy in THF and by single-crystal X-ray crystallography. Lithio P-benzyl-1,3,2-dioxaphosphorinane 2-oxide (Li+7-) and lithio P-isopropyl-1,3,2-dioxaphosphorinane 2-oxide (Li+8-) are characterized by freely rotating, sp2-hybridized onions devoid of lithium-carbon contacts. The anions are most likely dimers linked through oxygen-lithium bridges. The P-isopropyl compound crystallized from TMEDA/THF as a C-lithiated dimer in which each lithium bridges a carbon and an oxygen and is solvated by one TMEDA molecule.
|Original language||English (US)|
|Number of pages||10|
|State||Published - 1998|
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