X-Ray Structure of a Heterochiral, Sulfoximine-Stabilized Dilithiomethane Derivative

A distorted Li₆O octahedron in the center and four geminal dilithiated sulfoximine units characterize a tetrameric aggregate of the chiral sulfoximine-stabilized dilithiomethane derivative 3, a previously unknown reaction intermediate in asymmetric dianion chemistry. A comparison with the crystal structure of the monolithiated parent 2, formed by the treatment of 1 with nBuLi, allows a rationalization of the second lithiation.