2-Dicyclohexylphosphino-2′,6′-dimethoxybiphenyl

Name: 2-Dicyclohexylphosphino-2′,6′-dimethoxybiphenyl
English Other Names: S-Phos; Dicyclohexyl-[2-(2,6-dimethoxyphenyl)phenyl]phosphane; Dicyclohexyl(2′,6′-dimethoxy-[1,1'-biphenyl]-2-yl)phosphane; SPhos, ≥98%
CAS No.: 657408-07-6
EINECS No.: 613-838-2
Chemical Formula: C₂₆H₃₅O₂P
Molecular weight 410.53
InChI InChI=1S/C26H35O2P/c1-27-23-17-11-18-24(28-2)26(23)22-16-9-10-19-25(22)29(20-12-5-3-6-13-20)21-14-7-4-8-15-21/h9-11,16-21H,3-8,12-15H2,1-2H3
Density -
Boiling point 513.3±40.0°C (predicted value)
Flash point -
Water solubility Soluble in chloroform; slightly soluble in DMSO and methanol (heating required)
Vapor pressure -
Refractive index -
Storage conditions Store at room temperature under an inert atmosphere; or freeze at -20°C, protected from moisture.

Sensitivity: Air-sensitive

Appearance: White crystalline powder/crystals

Specific Gravity: -

Color: White to off-white

BRN: -

MDL No.: MFCD05861611

Hazard Symbol: Xn (Hazardous)

Risk Terms: R40 (May have irreversible effects)

Safety Terms: S24/25 (Avoid contact with skin and eyes); S36/37 (Wear appropriate protective clothing and gloves)

Customs Code: 2931499090

I. Properties
SPhos is an air-stable, electron-rich, bis(arylphosphine) ligand developed by the Buchwald group. This compound is a white crystalline solid with a melting point of 164-166°C. Its molecular structure contains two cyclohexylphosphine groups and two methoxy groups, giving it unique electronic properties and steric hindrance characteristics. This ligand is relatively stable in air, but long-term storage under an inert atmosphere is recommended.

II. Applications
SPhos is primarily used as a ligand in palladium-catalyzed cross-coupling reactions, with applications including:
Suzuki-Miyaura coupling reaction: suitable for coupling aryl chlorides, heteroaryl chlorides, and boric acids
Buchwald-Hartwig amination reaction: used for C-N bond formation
Kumada-Corriu cross-coupling reaction
Boronization of aryl halides
[4+2] cycloaddition reaction
In drug synthesis, it is used to construct C-C and C-N bonds, essential for synthesizing complex molecules (such as riccardin). Key Reagents for C and Other Natural Products
III. Preparation
SPhos can be synthesized by the following method:
From 2-bromo-2′,6′-dimethoxybiphenyl
Reaction with dicyclohexylphosphine under alkaline conditions
The reaction mixture is heated, filtered, and washed
The filtrate is concentrated by rotary evaporation
Recrystallization in acetone yields a white crystalline product
Yield is approximately 36%, melting point 163-165°C (literature value 162.0-162.5°C)
IV. Safety Information
Hazard Class: Hazardous Substance (Xn)
Main Risk: R40 (potential risk of irreversible action)
Protective Measures:
S24/25: Avoid contact with skin and eyes
S36/37: Wear appropriate protective clothing and gloves
Storage Requirements: Store in a sealed container under an inert atmosphere at room temperature or -20°C
Handling Precautions: Although this ligand has some air stability, it is still recommended to handle it under an inert gas atmosphere and avoid prolonged exposure to air.