BINAP

Use as ligand in asymmetric catalysis

BINAP is used in organic synthesis for enantioselective transformations catalyzed by its complexes of ruthenium, rhodium, and palladium. As pioneered by Ryōji Noyori and his co-workers, rhodium complexes of BINAP are useful for the synthesis of (–)-menthol.

Silver complexes are also important; BINAP-AgF can be used to enantioselectively protonate silyl enol ethers.

Subsequent studies revealed that related diphosphines with a narrower dihedral angle between the aromatic faces give catalysts that are more enantioselective. One such ligand is SEGPHOS.

Preparation

BINAP is prepared from BINOL via its bistriflate derivatives. Both the (R)- and (S)-enantiomers, as well as the racemate, are commercially available. One of the wide applications include chemoselective hydrogenation, where BINAP is conjugated to rhodium.

References

References

1. (2009). "Bite angle effects of diphosphines in C–C and C–X bond forming cross coupling reactions". Chemical Society Reviews.
2. Kitamura, Masato. (1998). "Asymmetric hydrogenation of 3-oxo carboxylates using BINAP-ruthenium complexes". [[Org. Synth.]].
3. Akutagawa, S. (1992). "A practical synthesis of (−)-menthol with the Rh-BINAP catalyst". [[Chirality Ind.]].
4. Kumobayashi, Hidenori. (1997). "Industrial asymmetric synthesis by use of metal-BINAP catalysts". [[Nippon Kagaku Kaishi]].
5. (2005). "Enantioselective Protonation of Silyl Enolates Catalyzed by a Binap⋅AgF Complex". Angewandte Chemie International Edition.
6. (2007). "Developments in Asymmetric Hydrogenation from an Industrial Perspective". [[Acc. Chem. Res.]].
7. "BINAP: An industrial approach to manufacture". [[Rhodia (company).
8. Cai, Dongwei. (1999). "(''R'')-(+)- and (''S'')-(−)-2,2′-bis(diphenylphosphino)-1,1′-binapthyl (BINAP)".