Rhodium(III)-Catalyzed Enantiotopic C-H Activation Enables Access to P-Chiral Cyclic Phosphinamides

Abstract

Compounds with stereogenic phosphorus atoms are frequently used as ligands for transition-metal as well as organocatalysts. A direct catalytic enantioselective method for the synthesis of P-chiral compounds from easily accessible diaryl phosphinamides is presented. The use of rhodium(III) complexes equipped with a suitable atropochiral cyclopentadienyl ligand is shown to enable an enantiodetermining C-H activation step. Upon trapping with alkynes, a broad variety of cyclic phosphinamides with a stereogenic phosphorus(V) atom are formed in high yields and enantioselectivities. Moreover, these can be reduced enantiospecifically to P-chiral phosphorus(III) compounds.

Keywords: C−H activation; P-chirality; asymmetric catalysis; chiral Cp ligands; rhodium.