Steric Tuning of Sulfinamide/Sulfoxides as Chiral Ligands with C 1 , Pseudo- meso , and Pseudo- C 2 Symmetries: Application in Rhodium(I)-Mediated Arylation.

A new family of sulfinamide/sulfoxide derivatives was synthesized as chiral bidentate ligands by stereoselective additions of methylsulfinyl carbanions to N-tert -butylsulfinylimines. The new ligands, with C ₁ , pseudo- meso , and pseudo- C ₂ symmetries, were successfully assayed in Rh-catalyzed additions of arylboronic acids to activated ketones. The sterically dissymmetric C ₁ ligand ( R _S , S _C , R _S )- N -[1-(phenylsulfinyl)-3-methylbut-2-yl] tert -butylsulfinamide turned out to be the optimal one, allowing the 1,4-additions of diverse arylboronic acids, on different α,β-unsaturated cyclic ketones with high chemical yields and enantioselectivities up to >99% ee.