Tunable coordination of a tropos phosphite for fine-tuning of the Rh catalyzed asymmetric addition of phenylboronic acid to cyclohexenone.

Using the deoxycholic acid derived tropos biphenylphosphite as a Rh(i) chiral ligand different complexes are obtained, depending on the Rh : L molar ratio, that give rise to the formation of different chiral products in the asymmetric addition of phenylboronic acid to cyclohexenone.

Stereochemical features making deoxycholic acid derived tropos biphenylphosphites efficient chiral ligands for rhodium: the asymmetric hydrogenation of dimethylitaconate as a case study.

Different deoxycholic acid derived biphenylphosphites, whose tropos nature was ascertained by NMR and CD measurements, were used in the rhodium-catalyzed asymmetric hydrogenation of dimethylitaconate achieving enantiomeric excesses up to 91%. The comparison of these results to those obtained using the corresponding atropoisomeric binaphthyl analogues, together with NMR and CD measurements on the rhodium complexes of some phosphites, allowed us to shed light on the nature of the active catalytic species and on the asymmetric induction process and hence to recognize the most appropriate stereochemical features to reach good levels of enantioselectivity.