2-Di-tert-butylphosphino-2′,4′,6′-triisopropylbiphenyl

Name: 2-Di-tert-butylphosphino-2′,4′,6′-triisopropylbiphenyl

Other Names: tBuXPhos; t-Bu XPhos; tert-Butyl X-Phos; 2-Di-t-butylphosphino-2′,4′,6′-tri-i-propyl-1,1′-biphenyl; di-tert-butyl(2′,4′,6′-triisopropylbiphenyl-2-yl)phosphine

CAS Number: 564483-19-8
EINECS No. 639-817-8
Chemical Formula C₂₉H₄₅P
Molecular Weight 424.64
InChI InChI=1S/C₂₉H₄₅P/c1-19(2)22-17-24(20(3)4)27(25(18-22)21(5)6)23-15-13-14-16-26(23)30(28(7,8)9)29(10,11)12/h13-21H,1-12H3
Boiling Point 493.5±45.0 °C (Predicted); 493.479°C at 760 mmHg
Flash Point 267.742°C
Vapor Pressure 0 mmHg at 25°C
Storage Conditions: 2-8°C, protected from light, nitrogen protection
Sensitivity: Sensitive to air (but air-stable)
Appearance: Crystalline powder
Color: White to pale yellow
Properties: 2-Di-tert-butylphosphine-2′,4′,6′-triisopropylbiphenyl is an organophosphine compound belonging to the Buchwald ligand series. This compound is an electron-rich biarylphosphine ligand with good air stability. It has a melting point of 148-151°C and is soluble in organic solvents such as toluene. The ligand’s significant steric hindrance and electron-donating ability give it excellent performance in transition metal catalytic reactions.

Applications

tBuXPhos is an important organophosphine ligand, primarily used in palladium-catalyzed cross-coupling reactions:
* C-N bond formation: used in palladium-catalyzed coupling reactions of aryl halides with amines, amides, sulfinamides, etc.
* C-O bond formation: used in palladium-catalyzed coupling reactions of aryl halides with alcohols and phenols
* C-C bond formation: used in Suzuki-Miyaura coupling, cyanation reactions, trifluoromethylation reactions, etc.
* Tsuji-Trost reaction: used for substitution and cross-coupling of allyl fluorides
* Other applications: can be used to prepare the gold catalyst [tBuXPhosAu(MeCN)]BAr₄F for [2+2] cycloaddition reactions.
* Preparation: tBuXPhos was developed by the Buchwald research group and is typically synthesized via the following method: It is prepared by nucleophilic substitution of 2-bromo-2′,4′,6′-triisopropylbiphenyl with di-tert-butylphosphine chloride in the presence of a strong base (such as n-butyllithium). The reaction needs to be carried out under anhydrous and oxygen-free conditions, typically involving lithium halide exchange at low temperature (-78°C), followed by reaction with a phosphine reagent to obtain the target product.

Safety Information

Storage Conditions: Store at 2-8°C, protected from light, under a nitrogen atmosphere.

Stability: Will not decompose if used and stored according to regulations.

Handling Precautions: As an organophosphine compound, it should be handled in a fume hood to avoid inhaling dust.

Protective Measures: It is recommended to wear protective eyewear and gloves, and avoid contact with skin and eyes.