Chiral P,N-bidentate N-pyrrolylphophines as ligands with remarkable electronic properties

Previously unknown chiral P,N-bidentate N-pyrrolylphosphines and their chelate complexes Rh(η²-P,N)(CO)Cl] and Pd(Allyl)(η²-P,N)]BF₄ were synthesized by phosphorylation of (E,1R,2R,3R,5S)-2-(2,6,6-trimethylbicyclo3.1.1]heptyl-3-)iminomethyl]-1H-pyrrole. The composition and structures of the novel compounds were determined by the ¹H, ¹³C, and ³¹P NMR, IR, mass spectrometry (electrospray), and elemental analysis methods. N-pyrrolylphosphines were found to have unusual electronic properties, being simultaneously more strong π-acids and σ-bases as compared to phosphites.