P-Stereogenic bisphosphines with a hydrazine backbone: from N-N atropoisomerism to double nitrogen inversionElectronic supplementary information (ESI) available: Experimental procedures, characterization data and NMR spectra for new compounds; crystallographic data file in CIF format. CCDC 1533430-1533432. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7cc01944k

The synthesis of P-stereogenic bisphosphine ligands starting from a phosphinous acid chiral synthon and hydrazine is reported. The dialkylation of the hydrazine backbone yielded atropo- and nitrogen inversion isomers which are in slow exchange. The crystallization of one of the isomers allowed us to study the reaction kinetics of the equilibria. The new ligands were tested in the Rh catalysed asymmetric hydrogenation of various benchmark substrates attaining up to 99% ee. P-Stereogenic C 2 diphosphine ligands with a hydrazine backbone are reported. The ligands exist as a mixture of atropo- and nitrogen inversion isomers in slow exchange.