ИСТИНА

Chiral organocatalysts have proven to be green, readily available, and cheap catalytic systems for various asymmetric transformations. However, one of the main problems in this case is the requirement of large catalyst loadings (up to 50 mol.%) in order to achieve a high asymmetric induction. Recently, as an alternative to classical organocatalysts, a new class of stereochemically inert transition metal complexes has been proposed. These metal template complexes showed high catalytic activity and enantiocontrol even at a loading of 0.001 mol% (ppm). We herein have developed a new class of octahedral cobalt(III) complexes of Λ- and Δ-configurations based on commercially available (1R,2R)-cyclohexanediamine or (1R,2R)-diphenylethylendiamine and different salicyl aldehydes (Figure). In the presented complexes, the amino groups become efficient hydrogen bond donors (or Brønsted acids) due to coordination with the metal ion. The obtained chiral complexes efficiently catalyzed various asymmetric reactions with enantioselectivity up to 96% ee.