Chiraphos

Structural formula
General
Surname	Chiraphos
other names	(2 S , 3 S ) - (-) - Bis (diphenylphosphino) butane; (2 R , 3 R ) - (+) - Bis (diphenylphosphino) butane;
Molecular formula	C 28 H 28 P 2
Brief description	white, granular powder
External identifiers / databases
EC number	623-476-7
ECHA InfoCard	100.152.152
PubChem	10113249
ChemSpider	8288775
Wikidata	Q412641
properties
Molar mass	426.47 g mol −1
Physical state	firmly
Melting point	104-109 ° C
safety instructions
GHS labeling of hazardous substances Caution
H and P phrases	H: 315-319-335
	P: 261-305 + 351 + 338
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Chiraphos is a chiral bidentate chelating ligand . It belongs to the group of bidentate chiral phosphine ligands . The name is made up of the words chiral and phosphino .

presentation

Chiraphos can be produced enantiomerically pure from commercially available enantiomerically pure tartaric acid . For this purpose, the carboxy groups of the tartaric acid are first reduced to methyl groups , which results in chiral 2,3-butanediol . The hydroxyl groups are then tosylated with p -toluenesulfonic acid chloride (TosCl) and thus to better leaving groups . In the last step, elemental lithium and triphenylphosphine are used to exchange the tosyl functions by means of nucleophilic substitution by diphenylphosphino groups (Ph = phenyl).

properties

( S , S ) - and ( R , R ) -Chiraphos are chiral molecules that have C ₂ symmetry . The meso forms ( R , S ) and ( S , R ) are achiral. The rotation value of a 1.5 molar solution of ( S , S ) -chiraphos in chloroform at 22 ° C is −191 °.

use

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

Individual evidence

↑ ^a ^b Chiraphos data sheet at Acros, accessed on February 20, 2010.
↑ ^a ^b ^c data sheet (2S, 3S) - (-) - bis (diphenylphosphino) butane from Sigma-Aldrich , accessed on March 16, 2011 ( PDF ).
↑ MD Fryzuk, B. Bosnich: Asymmetric synthesis. Production of optically active amino acids by catalytic hydrogenation , in: J. Am. Chem. Soc. , 1977 , 99 , pp. 6262-6267; doi : 10.1021 / ja00461a014 .

[acros-1] Chiraphos data sheet at Acros, accessed on February 20, 2010.

[Sigma-2] ta sheet (2S, 3S) - (-) - bis (diphenylphosphino) butane from Sigma-Aldrich , accessed on March 16, 2011 ( PDF ).

[3] MD Fryzuk, B. Bosnich: Asymmetric synthesis. Production of optically active amino acids by catalytic hydrogenation , in: J. Am. Chem. Soc. , 1977 , 99 , pp. 6262-6267; doi : 10.1021 / ja00461a014 .