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CYTOP® Secondary Phosphines – The Building Blocks of Catalysis

Commercial ligand building blocks available at all scales

Changes in industry present tremendous opportunities for innovation and sustainable reinvention. Homogeneous catalysts are integral in the development of modern solutions for a variety of industries including petrochemical, pharmaceutical, agrochemicals and many more. The advancement of these industries relies on the development of new ligands and catalysts constantly. Having the ability to quickly alter the structure and electronic properties of a system is critical. Solvay offers a wide range of CYTOP® secondary phosphines that are commercially available at scale – giving you confidence that the phosphines you screen in the lab, are the phosphines that will arrive for your homogeneous process.

Cross coupling is a critical reaction for the pharmaceutical, agrochemical and fine chemical industries. CYTOP® 216X (Strem Catalog # 97-1310) is a bulky secondary phosphine that can be employed to create bidentate ligands for cross coupling catalytic reactions (DalPhos ligand family) (1-5). This ligand family has been demonstrated to be incredibly versatile for nickel-catalyzed cross coupling for C-N and C-O bond forming reactions, with large scope and mild reaction conditions (for example, they can occur at room temperature).


In particular, these ligands can promote nickel-catalyzed cross coupling of a wide variety of primary and secondary amines, along with ammonia. This work builds nicely on a field that is traditionally dominated by other metals, such as the electron-rich palladium chemistry of Buchwald-Hartwig aminations. In these cases, the repurposing of ligands from palladium to nickel is not sufficient, rather new ligands must be developed. The DalPhos ligand family has shown excellent versatility with significant breadth demonstrated in the literature. Representative examples are shown below.


Nickel is an attractive metal for these reactions as it has the propensity to engage electrophilic reaction partners where C-X oxidative addition can be challenging (for example, C-Cl in heteroaryl chlorides). Nickel is also an attractive alternative metal for these reactions from an industrial perspective due to its low cost and high abundance. Secondary phosphines are an integral component to the rational design of ligands and catalysts globally – Solvay’s CYTOP® series of secondary phosphines are produced at commercial volumes and have a diverse array of structural and electronic properties. These secondary phosphines can be built into any ligand design program with the added confidence of material being representative of commercial supply.


CYTOP® phosphines are readily available in high-purity at commercial and lab scales.  Custom packaging and logistics support is available at commercial scale. To learn more about other ligands for catalysis, please refer to the Solvay offering at Strem or the Solvay website.



  1.    Nature Comm,2016, 11073.
  2.    ACS Catalysis, 2017, 7, 6048-6059.
  3.    Angew. Chem. Int. Ed. 2019, 58, 2485-2489.
  4.    Angew. Chem. Int. Ed. 2019, 58, 6391-6395.
  5.    J. Am. Chem. Soc. 2018, 140, 5023-5027.


Featured Product:

97-1310: 2,4,6-Trioxa-1,3,5,7-tetramethyl-8-phosphaadamantane (~32% in xylene) [CYTOP® 216X ORGANOPHOSPHINE] (26088-25-5)


Related Products:

CYTOP Products

Phosphorus Ligands and Compounds Booklet

All products sold in collaboration with Solvay




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