PCT No. PCT / EP97 / 06358 Sec. 371 Date Apr. 18, 1999 Sec. 102(e) Date Apr. 18, 1999 PCT Filed Nov. 14, 1997 PCT Pub. No. WO98 / 22484 PCT Pub. Date May 28, 1998Diphosphines of a mixed heteroarylic-arylic type, wherein the phosphine group carrying backbone is constituted by the interconnection of a five-atom heteroaromatic ring and a carbocyclic aromatic ring, forming an atropoisomeric chiral system with a C1 symmetry. Said chiral diphosphines are advantageously used as ligands for the formation of chiral complexes with transition metals, in particular Ru, Rh, Pd, Ir, Ni. The so-obtained chiral complexes are used as chiral complexes are used as chiral catalysts for stereocontrolled reactions, in particular diastereo and enantioselective reduction reactions, hydroformylation reactions, hydrosilylation reactions, hydrocyanation reactions, double-bond isomerisation reactions, other reactions of carbon-carbon bond formation.