3991-61-5Relevant articles and documents
Ligand- and Counterion-Assisted Phenol O-Arylation with TMP-Iodonium(III) Acetates
Kikushima, Kotaro,Miyamoto, Naoki,Watanabe, Kazuma,Koseki, Daichi,Kita, Yasuyuki,Dohi, Toshifumi
, p. 1924 - 1928 (2022/03/27)
High reactivity of trimethoxyphenyl (TMP)-iodonium(III) acetate for phenol O-arylation was achieved. It was first determined that the TMP ligand and acetate anion cooperatively enhance the electrophilic reactivity toward phenol oxygen atoms. The proposed method provides access to various diaryl ethers in significantly higher yields than the previously reported techniques. Various functional groups, including aliphatic alcohol, boronic ester, and sterically hindered groups, were tolerated during O-arylation, verifying the applicability of this ligand- and counterion-assisted strategy.
Preparation and characterization of Cu based on 5,5'-bistetrazole as a recyclable metal-organic framework and application in synthesis of diaryl ether by the Ullmann coupling reaction
Noorpoor, Zeinab,Tavangar, Saeed
, p. 1651 - 1662 (2021/05/10)
Cu based on 5,5′-bistetrazole ([Cu2BT · 2H2O] n) as a recyclable metal-organic framework (MOF) heterogeneous catalyst was characterized by FT-IR, 13C NMR, XRD, SEM, EDX, BET, BJH, and ICP-AES analysis. The catalytic activity of the catalyst was probed through the Ullmann reaction for synthesis of diaryl ether derivatives from two component reactions of aromatic arylhalides and phenol derivatives in DMSO. Simple procedure, high yields, short reaction time, and environmentally benign methods are advantages of this protocol. The catalyst was readily separated by simple filtration and reusable without significant loss of its catalytic efficiency.
Radical and ionic mechanisms in rearrangements of o-tolyl aryl ethers and amines initiated by the Grubbs-stoltz reagent, et3SiH/KOtbu
Kolodziejczak, Krystian,Murphy, John A.,Stewart, Alexander J.,Tuttle, Tell
, (2021/12/04)
Rearrangements of o-tolyl aryl ethers, amines, and sulfides with the Grubbs-Stoltz reagent (Et3SiH + KOtBu) were recently announced, in which the ethers were converted to o-hydroxydiarylmethanes, while the (o-tol)(Ar)NH amines were transformed into dihydroacridines. Radical mechanisms were proposed, based on prior evidence for triethylsilyl radicals in this reagent system. A detailed computational investigation of the rearrangements of the aryl tolyl ethers now instead supports an anionic Truce-Smiles rearrangement, where the initial benzyl anion can be formed by either of two pathways: (i) direct deprotonation of the tolyl methyl group under basic conditions or (ii) electron transfer to an initially formed benzyl radical. By contrast, the rearrangements of o-tolyl aryl amines depend on the nature of the amine. Secondary amines undergo deprotonation of the N-H followed by a radical rearrangement, to form dihydroacridines, while tertiary amines form both dihydroacridines and diarylmethanes through radical and/or anionic pathways. Overall, this study highlights the competition between the reactive intermediates formed by the Et3SiH/KOtBu system.
