Structures in solution of 1-azaallyllithium analogs

1-Azzaallyllithium reagents (lithium enamides) offer several advantages over the corresponding enolates in organic synthesis. In particular, they usually undergo monoalkylation and, furthermore, they have provided the basis of several methods for asymmetric syntheses which proceed with high enantioselectivity. Since it is known that the chemistry of lithium enolates in weakly polar aprotic solvents is intimately related to the phenomenon of ion pair aggregation it is reasonable to anticipate similar behavior for lithium enamides. For this reason, we have carried out an investigation of the structures in ether solvent of lithium anilides, indolinides, and tetrahydroquinolides which serve as close models for the more reactive lithium enamides.