Steric Tuning of the Amidomonophosphane-Rhodium(I) Catalyst in Asymmetric Addition of Arylboroxines to N-Phosphinoyl Aldimines
摘要:
Highly enantioselective rhodium-catalyzed addition of arylboroxines to N-phosphinoylaldi mines was realized by the steric tuning of a cliphenylphosphorus moiety to a di(o-tolyl) phosphorus moiety of a chiral amidomonophosphane. The presence of MS 4 A in a 5:1 solvent mixture of dioxane-propanol was essential to afford the corresponding diarylmethylamines in high yield.
Steric Tuning of the Amidomonophosphane-Rhodium(I) Catalyst in Asymmetric Addition of Arylboroxines to N-Phosphinoyl Aldimines
摘要:
Highly enantioselective rhodium-catalyzed addition of arylboroxines to N-phosphinoylaldi mines was realized by the steric tuning of a cliphenylphosphorus moiety to a di(o-tolyl) phosphorus moiety of a chiral amidomonophosphane. The presence of MS 4 A in a 5:1 solvent mixture of dioxane-propanol was essential to afford the corresponding diarylmethylamines in high yield.
Examination of the rhodium-catalyzedasymmetricarylation of benzaldehyde-imines bearing ethoxy, isopropoxy, phenyl, cyclohexyl, 3,5-xylyl, and 2,4,6-mesityl N-phosphorus activating/protecting groups revealed that bulky N-phosphorus groups retarded the arylation and at the same time prevented the competitive hydrolysis of an imine. Although the level of enantioselectivity was dependent favorably on