Bis(oxazoline)-copper complexes as chiral catalysts for the enantioselective aziridination of olefins

The Chemistry of Vicinal Diamines

“…2) The regioselectivity observed in the opening of a disubstituted aziridine may not be good, especially when the substituents are structurally close. It must also be pointed out that although ways to obtain chiral, non-racemic aziridines have been described [109b, c] (from chiral epoxides, [111a, b] from chiral diols, [111c] or by using catalytic asymmetric aziridination of alkenes [58,112] ), none as yet are very general. Of the numerous examples described in the literature, only some significant ones will be detailed here.…”

Copper-catalyzed aziridination of allylglycine derivatives

“…In order to improve this diastereoselectivity, asymmetric coppercatalyzed aziridination was performed in the presence of chiral bis(oxazolines). 17 Among the ligands tested, the tert-butyl derivative 14 appeared to give the highest excess (d.e. = 50%) when the reaction was run at -20°C (scheme 3).…”

α-Functionalization of Carbonyl Compounds Using Hypervalent Iodine Reagents

“…An enantioselective version of this reaction was developed, where bis(oxazoline)-copper complexes were employed as catalysts to give aziridinated products in good yields and high enantiomeric excess (Scheme 79). [149] Template for SYNLETT and SYNTHESIS © Thieme Stuttgart · New York Jacobsen and co-workers reported a similar catalytic system, employing bifunctional Schiff bases derived from trans-1,2-diaminocyclohexane. [150] Other groups have also developed ligands useful for asymmetric aziridination of α,β-unsaturated esters under similar conditions.…”