Imidazoline-aminophenol ligands

In 2013, chiral imidazoline-aminophenol ligands 138 combined with copper salts were successfully applied by the same group in the AFC reaction of indoles with isatin-derived nitroalkenes 139. By employing the appropriate catalyst, CuOTf/138a or Cu(OTf)2/138a, the reaction of isatin-derived nitroalkene with indole proceeded smoothly to afford 3,3 -bisindole derivatives 140 in up to 99% yield with 92% ee. l,l,l,3,3,3-Hexafluoro-2-propanol (HFIP) was found to be crucial to this transformation, with a positive effect on catalyst activity (Scheme 6.61). 

In 2014, Arai and Yamamoto described asymmetric nickel-catalysed domino Michael/Henry reactions between 2-sulfanylbenzaldehydes and aromatic nitroalkenes to give the corresponding chiral 2-aryl-3-nitrochroman-4-ols, in most cases in almost quantitative yields and with good to high diastereo- and enantioselectivities of up to >98% de and 95% ee, respectively (R = H, Scheme 4.4). These reactions were promoted by an in situ generated catalyst from 10-11 mol% of chiral imidazoline-aminophenol ligand 1 and... 

The imidazoline-aminophenol-ligand complex (34) has been developed for the 3 + 2-cycloaddition reaction of methyleneindolinones (32) with iminoesters (33) to produce exo-spiro[pyrrolidin-3,3 -oxindole]s (35) as stable isomers. The reaction proceeds in a stepwise Michael-Mannich reaction sequence (Scheme 12). ... 

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