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

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
17. Ligand used for the Pd-catalyzed α-arylation of heteroaromatic ketones.
18. Ligand used for the Pd-catalyzed direct alkynlation of both azoles and azolines.
19. Ligand used for the Cu-catalyzed intermolecular coupling of alkynes with aryl iodides.
20. Ligand used for the Pd-catalyzed ene-type reaction of aldehydes with 1,3-diene.
21. Ligand used for the Ru-catalyzed intermolecular addition of 2-phenylbenzoic acid onto unactivated olefins.
22. Ligand used for the Pd/Cu-catalyzed direct arylation of heteroarenes.
23. Ligand used for the Pd-catalyzed reaction of propargyl-substituted malonate esters with aryl halides.
24. Ligand used for the Pd-catalyzed decarboxylative coupling of tertiary cyanoacetate salts with aryl halides and triflates.
25. Ligand used for the Pd-catalyzed hydroesterification of alkynes.
26. Ligand used for the Cu-catalyzed arylation of arylboronic acids with aldehydes.
27. Ligand used for the Ru-catalyzed oxidative synthesis of heterocycles from alcohols.
28. Ligand used for the Rh-catalyzed borylation of nitriles.
29. Ligand used in the Pd-catalyzed α-arylation of benzylic phosphine oxides.
30. Ligand used in the Pd-Catalyzed Oxidative Coupling of Enamides and Alkynes.
31. Ligand used in the Pd-catalyzed difunctionalization of enol ethers to amino acetals with aminals and alcohols.
32. Ligand used in the Pd-catalyzed alkoxycarbonylation of α-chloroketones.

19814-75-6

1079-66-9

161265-03-8

Example 2A Preparation of 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (Xantphos): To a 5L round bottom flask was added methyl tert-butyl ether (MTBE, 2.5L), 9,9-dimethylxanthene (131.4 g, 0.60 mol) and N,N,N',N'-tetramethylethylenediamine (TMEDA, 155 g, 1.32 mol). After degassing the solution, sec-butyl lithium (s-BuLi, 1.11 L, 1.3 M in cyclohexane, 1.44 mol) was loaded into a dropping funnel, and then slowly added dropwise over a period of 60 min while controlling the reaction temperature at 6-10 °C. After the dropwise addition, the mixture was stirred at room temperature for 14 hours. Subsequently, diphenylphosphonium chloride (Ph2PCl) was slowly added through the dropping funnel while controlling the reaction temperature at 10-20°C to maintain a mild exothermic reaction. About 60% diphenylphosphonium chloride (175 mL, 0.93 mol) was added over 0.5 hr. The mixture was stirred for 10 minutes and then the remaining diphenylphosphonium chloride (120 mL, 0.63 mol) was added. The reaction mixture was continued to be stirred at room temperature for 5 hours before the reaction was quenched with methanol (MeOH, 9.9 mL, 0.24 mol). Filtration yielded a pale yellow solid product, which was washed sequentially with methyl tert-butyl ether (MTBE, 250 mL), methanol (2 x 250 mL), water (2 x 300 mL), methanol (2 x 250 mL) and methyl tert-butyl ether (250 mL), and dried to give an off-white solid product (304.2 g, 88% yield).