Solution and Solid-State Structures of Lithiated Phenyloxazolines

The structures of three ortho-lithiated phenyloxazolines, the parent (1), the para-tert-butyl analogue (2), and the para-chloro analogue (3), were studied in solution. All three compounds are mixtures of monomers and dimers in THF/ether mixed solvents, with 2 the most aggregated and 3 the least. They are converted to monomers with HMPA and PMDTA. In the PMDTA complexes, the lithium appears to still be chelated to the oxazoline ring. Single-crystal X-ray structures were obtained for 1 and 2. Both are centrosymmetric dimers of B-type (each lithium coordinated to one oxazoline ring).