No abstract

Asymmetricc atalytic multistep reactions enable the formation of structurally complexc ompounds from simple starting materials.E nantioselective Cu-catalyzed 1,4-additionso fG rignard reagents to Michaela cceptors form reactive chiral enolates. We show here that these chiral enolates react in ao ne-pot fashion with naked carbenium ions,s uch as tropylium, 1,3-benzodithiolium, andd ianisylmethylium ions.T he corresponding productsw ereo btained in good yields,w ith enantioselectivitiesu pt o 96% ee andhigh diastereomeric purities.

Enantioselective conjugate addition of Grignard reagents to enones, catalyzed by Cu-Taniaphos or Josiphos complex, affords chiral enolates. Ensuing one-pot Mannich reaction with TiCl(4)-generated imine leads to aminocarbonyl compounds with benzyloxycarbonyl-protected nitrogen. Both diastereomers of these compounds are isolated in moderate yields but high enantiomeric purities (up to er 97.5:2.5).

Copper(I) complexes of TADDOL‐based phosphane–phosphite ligands catalyze enantioselective conjugate additions of various Grignard reagents to cyclic enones. Through trapping of the resulting chiral magnesium enolates with N‐benzylidene‐4‐methylbenzenesulfonamide (as an imine) in one‐pot procedures, the corresponding Mannich products (i.e., β‐aminocarbonyl compounds) were obtained in good yields and high enantiomeric purities, although with only low diastereoselectivities.

Interactions of phosphinoferrocene oxazolines with Group 11 metals were elucidated. The differences dictated by the metal ions are discussed.