Twisted amide Xantphos ligands: wide bite angle, twist-controlled diphosphines

Area of Science:

• Organometallic Chemistry
• Homogeneous Catalysis

Background:

• Xantphos ligands are crucial in homogeneous catalysis.
• Twisted amides influence substituent geometry around amide linkages.

Purpose of the Study:

• To synthesize and characterize novel twisted amide Xantphos ligands.
• To investigate the impact of amide bond twist on ligand geometry and catalytic activity.

Main Methods:

• Synthesis of new twisted amide Xantphos ligands.
• Structural characterization including X-ray crystallography.
• Evaluation of catalytic performance in C-C, C-P, and C-B bond-forming reactions.

Main Results:

• Novel, accessible twisted amide Xantphos ligands were successfully synthesized.
• Ligand geometry, including P-P distances and P-M-P bite angles, was controlled by amide bond twist.
• *N-t*-BuC(O)-Xantphos demonstrated enhanced catalytic efficiency, particularly with significant amide nitrogen pyramidalization (χN = 32°).
• Coordination chemistry with Au(I), Cu(I), and Pd(II) was explored.

Conclusions:

• Controlling bis(phosphine) geometry via amide bond twist is a viable strategy.
• Twisted amide Xantphos ligands offer enhanced catalytic performance.
• This approach is expected to see widespread adoption in catalysis research.