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Abstract BulkyN,N’‐bidentate ligands can furnish catalysts with enhanced catalytic activity compared to commercially available ligands. Straightforward methods to effectively synthesize a broad range of these ligands, however, are uncommon. In this work, a simple and efficient method is developed for the synthesis of bulkyN,N’‐bidentate ligands, including 2,2’‐bipyridines and enantioenriched pyridine‐oxazolines. The Pd/NIXANTPHOS catalyst system enabled synthesis of a series of bulky 2,2’‐bipyridine‐based ligands and (S)‐pyridine oxazoline‐based enantioenriched ligands with good to excellent yields. The ligands have been benchmarked in the aminofluorination of styrene. magnified image
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Monosubstituted, Anionic Imidazolyl Ligands from N−H NHC Precursors and Their Activity in Pd‐Catalyzed Cross‐Coupling Reactions
Abstract We report that treatment of several 2‐diphenylphosphinoimidazoles with Pd(II) salts generates monosubstituted N−H NHC−Pd complexes via insertion into the C−P bond. Removal of the N−H proton in situ leads to anionic (X‐type) or imidazolyl‐Pd complexes that are highly stable and catalytically active, achieving up to 340,000 turnovers at 1 ppm catalyst loading in Suzuki‐Miyaura reactions. DFT‐calculated Tolman electronic parameters for the sterically small ligands suggest that these ligands are significantly more donating than traditional NHCs, which provides a rationale for rapid cross‐coupling catalysis. Excellent reactivity is also demonstrated in Sonogashira reactions. magnified image
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- PAR ID:
- 10163724
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Synthesis & Catalysis
- Volume:
- 362
- Issue:
- 14
- ISSN:
- 1615-4150
- Format(s):
- Medium: X Size: p. 2876-2881
- Size(s):
- p. 2876-2881
- Sponsoring Org:
- National Science Foundation
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