4,5-Bis(diphenylphosphino)-9,9-dimethylxanthene

Xantphos is an organophosphorus compound derived from the heterocycle xanthene. It is used as a bidentate diphosphine ligand and is noteworthy for having a particularly wide bite angle (108°). Such ligands are useful in the hydroformylation of alkenes. Illustrative of its wide bite angle, it forms both cis and trans adducts of platinum(II) chloride. In the latter context, xantphos is classified as a trans-spanning ligand. A related bidentate ligand with a greater bite angle is spanphos.

The ligand is prepared by double directed lithiation of 9,9-dimethylxanthene with sec-butyllithium followed by treatment with chlorodiphenylphosphine.

Xantphos is a ligand used in a synthesis of heterocycles by palladium-catalyzed C-N cross coupling of 3-bromothiophenes with 2-aminopyridines. Also used in a ruthenium-catalyzed alkylation of active methylene compounds with alcohols. Metal chelating ligand for catalysis. 4,5-Bis(diphenylphosphino)-9, 9-dimethylxanthene is used as a bidentate ligand, which finds application in hydroformylation of alkenes.

Examples of 9,9-Dimethyl-4,5-bis(diphenylphosphino)xanthene, min. 98% XANTPHOS:

1. Ligand used for the hydroformylation of alkenes.

2. Ligand used in the intermolecular coupling of amides and hydrazones with aryl halides.

3. Ligand used in the intermolecular coupling of amides with aryl halides or triflates.

4. Ligand used in the coupling of heteroarylamines and aryl halides.

5. Ligand used in the hydrophosphinylation of alkenes and alkynes.

6. Ligand used for the Au(I)-catalyzed dehydrogenative silation of alcohols.

7. Ligand used for the sulfinylation of aryl iodides.

8. Ligand used for the Pd-catalyzed carbonylation reaction of aryl bromides and amines.

9. Ligand used for the Ni-cataltzed alkynylcyanation of alkynes.

10. Ligand used for the Pd-catalyzed N-arylation of 3-amino-1H-pyrazole.

11. Ligand used for the Rh-catalyzed dehydrogenation borylation of cyclic alkenes.

12. Ligand used for the Pd-catalyzed intermolecular coupling of H-Phosphonate diesters with benzyl halides.

13. Ligand used for the Pd-catalyzed one pot synthesis of 4-aryl-1H-1,2,3-triazoles.

14. Ligand used for the Pd-catalyzed intermolecular addition of formamides to alkynes.

15. Ligand used for the Pd-catalyzed decarboxylative couplings of 2-(2-azaaryl)acetates with aryl halides and triflates.

16. Ligand used for the Pd-catalyzed benzylic arylation of 2-methyl azaarenes

The Xantphos/Pd-catalyzed intermolecular coupling of aryl halides and amides displays good functional group compatibility, and the desired C-N bond forming process proceeds in good to excellent yields. The arylation of sulfonamides, oxazolidinones, and ureas was found to be highly dependent on reaction concentrations and catalyst loadings.