Trifer/ChenPhos

Both ligands were developed by groups that included Weiping Chen; Trifer at StylaCats Ltd and ChenPhos at Solvias. These are P-P ligands for which a secondary interaction of the dimethylamino group  with the substrate (electrostatic or hydrogen bonding) is invoked to account for the selectivity and activity observed. ChenPhos is a C1 symmetric variant of Trifer, the dicyclohexylphosphine (giving greater d-σ* interaction) imparting improved activity without loss of enantioselectivity. Applications to date resulting in >80% ee are principally with Rh, with one example of Ir catalysis.

Trifer_ChenPhos-Ligands

Rhodium

Hydrogenation Angew07-46-4141

PP-Trifer_Angew07-46-4141

 

Angew13-52-8652

PP-Chenphos_Angew13-52-8652

CC14-50-978

PP-Chenphos_CC14-50-979

Methodology also applied to geraniol to give (S)-citronellol, and nerol to give (R)-citronellol.

CC16-52-2273

PP-Chenphos_CC16-52-2273_1

 

Iridium

Hydrogenation CC16-52-2273

PP-Chenphos_CC16-52-2273_Ir

Absolute configuration not stated but assumed to be the same as Rh.