A Highly Diastereoselective Route to Dinaphtho[<i>c</i>,<i>e</i>][1,2]oxaphosphinines and Their Application as Ligands in Homogeneous Catalysis

Abstract

Abstract A new and facile method for the synthesis of 6 H ‐dinaphtho[ c , e ][1,2]oxaphosphinines starting from dinaphthol (BINOL) is described. The ring‐opening of an intermediary dinaphtho[2,1‐ b ;1′,2′‐ d ]furan proceeds with extremely high diastereoselectivity and forms the thermodynamically most stable product. The stereochemistry was elucidated by 31 P NMR spectroscopy and X‐ray structural analysis. Epimerization at the stereogenic P‐centre did not take place. DFT calculations were performed to determine the dihedral angles of several dinaphtho[ c , e ][1,2]oxaphosphinines and to explain the observed loss of stereochemistry during the total synthesis from the starting enantiopure BINOL. The synthetic potential of 6‐chloro‐6 H ‐dinaphtho[ c , e ][1,2]oxaphosphinine was corroborated in its reactions with phenols to afford the corresponding phosphonites. These were successfully applied as ligands in the Rh‐catalysed hydroformylation of three terminal olefins.