Serendipity strikes again-efficient preparation of lithium tetramethylcuprate(III) via rapid injection NMR

Lithium tetramethylcuprate(III), Me4CuLi, the Cu-III analog of the Gilman reagent, has been prepared in high yield from halo-Gilman reagents Me2CuLi center dot LiX (X = Cl, Br, I) and 2,3-dichloropropene and found to have surprising thermal stability. The cyano-Gilman reagent (X = CN) follows a different pathway.