Cu(I) β-Diketiminates for Alkene Aziridination: Reversible CuArene Binding and Catalytic Nitrene Transfer from PhINTs

β-Diketiminato Cu(I)−lutidine complexes [RMeNN]Cu(2,4-lutidine)
(R = Me (4a), iPr (4b)) were prepared in high yield from Tl[RMeNN]
and [CuBr(2,4-lutidine)2]2. Both 4a and 4b reversibly dissociate
lutidine base in toluene to give [RMeNN]Cu(toluene) solvento
complexes. A related base-free dicopper species {[Me2NN]Cu}2
(6) bridged via η2-binding of opposing N-aryl rings could be isolated
by the addition of Tl[Me2NN] to CuBr. The lutidine precursors serve
as precatalysts for the aziridination of alkenes with PhINTs.
Styrene, β-methylstyrene, and cyclooctene gave the highest yields
(59−96%) with a low olefin to PhINTs ratio (3:1) and 5 mol %
catalyst loading.