1130808-88-6Relevant articles and documents
Ligand-Less Iron-Catalyzed Aromatic Cross-Coupling Difluoromethylation of Grignard Reagents with Difluoroiodomethane
Motohashi, Hirotaka,Kato, Miki,Mikami, Koichi
, p. 6483 - 6490 (2019)
Iron-catalyzed cross-coupling difluoromethylations of the Grignard reagents with difluoroiodomethane provide various aromatic difluoromethyl products in good yields, not employing sterically demanding ligands. Difluoromethylations proceed within 30 min at -20 °C with 2.0 equiv of the Grignard reagents and FeCl3 or Fe(acac)3 (2.5 mol %). Mechanistic investigations clarify difluoromethyl radical intervention; Fe(0) ate is initially generated. Single-electron transfer from Fe(0) ate to difluoroiodomethane takes place. Recombination with aryl groups gives Ar-CF2Hs. The catalyst can be regenerated by the Grignard reagents.
Precatalyst Effects on Pd-Catalyzed Cross-Coupling Difluoromethylation of Aryl Boronic Acids
Hori, Kaishi,Motohashi, Hirotaka,Saito, Daichi,Mikami, Koichi
, p. 417 - 421 (2019)
The Pd-catalyzed difluoromethylation of aryl boronic acids with difluoroiodomethane is shown to provide the difluoromethyl compounds in high to moderate yields by Pd(PPh3)2/DPEphos catalyst in H2O/toluene. Mechanistic studies show that the oxidative addition by Pd(PPh3)4 rather than Pd2(dba)3 precatalyst to difluoroiodomethane provides a square-planar trans-(PPh3)2Pd(II)(CF2H)I complex defined by X-ray crystallographic analysis. The trans-(PPh3)2Pd(CF2H)I complex is transformed to cis-(PPh3)2Pd(CF2H)Ph detected by low temperature NMR analysis, via transmetalation with phenylboronic acids. The reductive elimination occurs via ligand exchange to DPEphosPd(CF2H)Ph to give Ph-CF2H (t1/2 = 144.7 min at 20 °C) with formation of the Pd(0)(PPh3)2/DPEphos catalyst.
Two Ligands Transfer from Ag to Pd: En Route to (SIPr)Pd(CF2H)(X) and Its Application in One-Pot C-H Borylation/Difluoromethylation
Herbert, Simon,Kinzel, Tom,Shen, Qilong,Zhang, Wei,Zhao, Haiwei
, p. 3596 - 3604 (2020/03/23)
A process for the concurrent transfer of both the NHC ligand and the difluoromethyl group from [(SIPr)Ag(CF2H)] to PdX2 (X = Cl, OAc, and OPiv) for the preparation of [(SIPr)Pd(CF2H)X] complexes is described. These complexes were air-stable and easily underwent transmetalation with aryl pinacol boronate/reductive elimination to generate ArCF2H in high yields. Based on this discovery, the first one-pot C-H borylation and difluoromethylation process for the preparation of difluoromethylated (hetero)arenes was developed.
Controllable catalytic difluorocarbene transfer enables access to diversified fluoroalkylated arenes
Fu, Xia-Ping,Xue, Xiao-Song,Zhang, Xue-Ying,Xiao, Yu-Lan,Zhang, Shu,Guo, Yin-Long,Leng, Xuebing,Houk, Kendall N.,Zhang, Xingang
, p. 948 - 956 (2019/11/05)
Difluorocarbene has important applications in pharmaceuticals, agrochemicals and materials, but all these applications proceed using just a few types of reaction by taking advantage of its intrinsic electrophilicity. Here, we report a palladium-catalysed strategy that confers the formed palladium difluorocarbene (Pd=CF2) species with both nucleophilicity and electrophilicity by switching the valence state of the palladium centre (Pd(0) and Pd(ii), respectively). Controllable catalytic difluorocarbene transfer occurs between readily available arylboronic acids and the difluorocarbene precursor diethyl bromodifluoromethylphosphonate (BrCF2PO(OEt)2). From just this simple fluorine source, difluorocarbene transfer enables access to four types of product: difluoromethylated and tetrafluoroethylated arenes and their corresponding fluoroalkylated ketones. The transfer can also be applied to the modification of pharmaceuticals and agrochemicals as well as the one-pot diversified synthesis of fluorinated compounds. Mechanistic and computational studies consistently reveal that competition between nucleophilic and electrophilic palladium difluorocarbene ([Pd]=CF2) is the key factor controlling the catalytic difluorocarbene transfer.