Novel heterobidentate ligands for asymmetric catalysis: Synthesis and rhodium-catalysed reactions of S-alkyl (R)-2-diphenylphosphino-1,1'- binaphthyl-2'-thiol

Atropisomerically pure S-alkyl (R)-2-diphenylphosphino-1,1'-binaphthyl- 2'-thiol derivatives have been synthesized through a multistep reaction sequence starting from (R)-binaphthol. Pd(II) and Rh(I) complexes containing the S-methyl derivative 14 as a chelate ligand have been prepared and characterized. Rh(I) complexes containing 14 or the S-iso-propyl derivative 15 effectively catalyse the asymmetric hydroformylation of styrene and the hydrogen transfer reduction of acetophenone.