Asymmetric Aziridination by Using Optically Active (Salen)manganese(III) Complexes

Magnetic assemblies based on Mn(III) salen analogues

“…The current outstanding development in the coordination chemistry of manganese (Mn) is largely a result of the following three research subjects: (i) the design of models of Mn-containing biological systems [1][2][3][4] (e.g., photosystem II of green plants [5,6], manganese catalase [7,8], superoxide dismutase [9], ribonucleotide reductase [10], and acid phosphatase of sweet potato [11]), (ii) the development of catalysts for oxidations of organic substrates [12,13] (e.g., epoxidation [14,15] and aziridination of olefins [16,17], oxidation of sulfides [18,19]), and (iii) study on magnetism of Mn complexes and Mn-containing hetero-metallic assemblies [20]. The design (and/or search) for key ligands to suit respective needs is the most important process to advance this research.…”

Polymer-supported salen complexes for heterogeneous asymmetric synthesis: Stability and selectivity

“…These reactive centers are analogues of homogeneous salen complexes based on the [N,NЈ-bis-(3,5-di-t-butylsalicylidene)]-(1,2-diaminocyclohexane) ligand (1) (Scheme 1). This homogeneous ligand has demonstrated exceptional versatility for enantioselective synthesis as the incorporation of various transition metal ions produces asymmetric catalysts for epoxidation, 3,16 -25 aziridination, 26,27 cyclopropanation, 28 hydroxylation, 29 and the kinetic resolution of racemic epoxides. 30 In addition, the enantioselectivity for these reactions has been demonstrated to be sensitive to changes in the ligand structure.…”

Rhodium(II)-catalyzed aziridinations and CH insertions with [N-(p-nitrobenzenesulfonyl)imino]phenyliodinane

“…The stereospecificity of the addition may be rationalized either by a concerted reaction of the cis-olefin 14 with the metal-complexed nitrene to afford the cis-aziridine 17. However, a stepwise mechanism involving a radical intermediate (16), in which the rate of ring closure is faster than that for rotation around the single bond, could in principle also result in a stereospecific a~iridination. "~'~ A dipolar intermediate would be more difficult to reconcile with the p-value, however.…”