• Chemical structure of Me4tBuXPhos (2-di-tert-butylphosphino-3,4,5,6-tetramethyl-2',4',6'-triisopropyl-1,1'-biphenyl), CAS 857356-94-6, ≥98% — bulky electron-rich biaryl phosphine with four methyl groups on the phosphorus-bearing ring; ligand for palladium-catalysed amidation of aryl chlorides, synthesis of phenols from aryl halides and coupling of aryl halides with secondary alcohols. Supplied by NorrChemica with DDP shipping. CoA and SDS provided.
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NorrChemica™

Me4tBuXPhos

CAS 857356-94-6 ≥98%

Me4tBuXPhos | CAS 857356-94-6 | ≥98%

Pack sizes & prices

Pack size Excl. VAT
100 mg €29,64€296,40/g€37,20 incl. VAT
250 mg €45,58€182,32/g€57,20 incl. VAT
1.0 g €94,98€94,98/g€119,20 incl. VAT
5.0 g €421,67€84,33/g€529,20 incl. VAT

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Technical Specifications

CAS Number 857356-94-6
EC / EINECS Number 813-582-3
MDL Number MFCD09038436
SMILES CC1=C(C(=C(C(=C1C)C2=C(C=C(C=C2C(C)C)C(C)C)C(C)C)P(C(C)(C)C)C(C)(C)C)C)C
InChI InChI=1S/C33H53P/c1-19(2)26-17-27(20(3)4)30(28(18-26)21(5)6)29-24(9)22(7)23(8)25(10)31(29)34(32(11,12)13)33(14,15)16/h17-21H,1-16H3
InChIKey RCRYEYMHBHPZQD-UHFFFAOYSA-N
PubChem CID 11953610
Molecular Formula C₃₃H₅₃P
Molecular Weight 480.75 g/mol
Melting Point 168 - 172 °C
Solubility Insoluble in water, soluble in common organic solvents
Purity ≥98%
Physical Form White to off-white solid
HS Code 2931.49
Shelf Life Retest period: 36 months from date of manufacture
Storage Conditions Store under inert gas (N₂ or Ar) in a tightly sealed container at room temperature

Product Description & Scientific Applications

Me4tBuXPhos is tBuXPhos carrying four additional methyl groups on the phosphorus-bearing ring, and in practice the two ligands divide the substrate scope between them.

It is supplied and stored under inert gas at room temperature.

Applications and Reactions

  • Phenols from aryl halides: the founding application, and a demanding one. The catalyst has to overcome inhibition by free hydroxide, a difficult carbon–oxygen reductive elimination given how small the hydroxide group is, and over-arylation of the product phenol to the diaryl ether. The first hydroxylation of aryl bromides and chlorides with a hydroxide salt used a palladium catalyst supported by this ligand or by tBuXPhos, at 80–100 °C, with the optimal ligand chosen substrate by substrate. Palladium systems for this transformation offer wider scope, lower catalyst loadings and milder conditions.
  • Why the bulk matters: ligand bulk raises the rate of carbon–oxygen reductive elimination, and hydroxide attack on the arylpalladium intermediate outpaces phenoxide transmetalation.
  • Choosing between the two ligands: this one performed best on aryl chlorides without an ortho substituent, while tBuXPhos gave consistently excellent yields above 90% on ortho-substituted substrates. The source states this as a substrate-dependent optimum rather than one ligand being generally better.
  • Onward chemistry: the phenol need not be isolated. Tandem sequences convert it in the same pot to benzofurans, or alkylate it to alkyl aryl ethers.
  • Documented limits: in gold catalysis one cyclisation was sluggish on its gold chloride with silver triflate, where a triphenylphosphine gold chloride succeeded instead. In one solvent screen another ligand outperformed it alongside RockPhos, tBuBrettPhos and AdBrettPhos.

Further Reading

Practical guidance on choosing a phosphine ligand for palladium- and nickel-catalysed cross-coupling in NorrChemica's Lab Journal: Phosphine Ligands for Cross-Coupling.

Shipping Destinations

  • EU & UK: Priority delivery, 2–5 business days.
  • United States (DDP): 3–7 business days, duties and taxes prepaid.
  • EFTA Countries (DDP): 3–7 business days, duties and taxes prepaid.
  • Worldwide: 7–14 business days, selected locations.

Safety Information

Hazard Class Not regulated for transport
Transport Category Not classified as dangerous goods for transport (ADR/IATA/IMDG)

Documentation

Safety Data Sheet Download PDF
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