Chiraphos

• (2S, 3S) - (-) -bis (diphenylphosphino ) butane
• (2R, 3R) - ( ) -bis (diphenylphosphino ) butane

• 74839-84-2 (R, R - enantiomer)
• 64896-28-2 (S, S - enantiomer)

White granular powder

Fixed

104-109 ° C

Attention

Template: Infobox chemical / molecular formula search available

Chiraphos is a chiral bidentate chelate ligand. It belongs to the group of the bidentate chiral phosphine ligands. The name comes from the words together and chiral phosphino.

Representation

Chiraphos enantiopure can be prepared from commercially available enantiomerically pure tartaric acid. For this purpose, first the carboxyl groups of tartaric acid are reduced to methyl groups, thus chiral 2,3- butanediol is produced. Subsequently, the hydroxyl groups with p- toluenesulfonyl ( Tos = ) be tosylated, which they can now act as leaving groups. In the last step is by nucleophilic substitution Tosylfunktionen replaced with diphenylphosphino groups (Ph = phenyl ) with elemental lithium and triphenylphosphine.

Properties

For (S, S ) - and ( R, R) - chiraphos are chiral molecules possessing C2 - symmetry. The meso- forms of (R, S) and ( S, R) are achiral. The optical rotation of a 1.5 molar solution of (S, S)- chiraphos in chloroform at 22 ° C -191 °.

Use

Chiraphos is used as a chiral phosphine ligand in transition-metal- mediated enantioselective catalysis. This can be achieved with very high enantiomeric excesses chiraphos.