57606-65-2Relevant articles and documents
Transition-Metal-Free C-C, C-O, and C-N Cross-Couplings Enabled by Light
Liu, Wenbo,Li, Jianbin,Querard, Pierre,Li, Chao-Jun
supporting information, p. 6755 - 6764 (2019/05/06)
Transition-metal-catalyzed cross-couplings to construct C-C, C-O, and C-N bonds have revolutionized chemical science. Despite great achievements, these metal catalysts also raise certain issues including their high cost, requirement of specialized ligands, sensitivity to air and moisture, and so-called "transition-metal-residue issue". Complementary strategy, which does not rely on the well-established oxidative addition, transmetalation, and reductive elimination mechanistic paradigm, would potentially eliminate all of these metal-related issues. Herein, we show that aryl triflates can be coupled with potassium aryl trifluoroborates, aliphatic alcohols, and nitriles without the assistance of metal catalysts empowered by photoenergy. Control experiments reveal that among all common aryl electrophiles only aryl triflates are competent in these couplings whereas aryl iodides and bromides cannot serve as the coupling partners. DFT calculation reveals that once converted to the aryl radical cation, aryl triflate would be more favorable to ipso substitution. Fluorescence spectroscopy and cyclic voltammetry investigations suggest that the interaction between excited acetone and aryl triflate is essential to these couplings. The results in this report are anticipated to provide new opportunities to perform cross-couplings.
Reactions of Arylsulfonate Electrophiles with NMe4F: Mechanistic Insight, Reactivity, and Scope
Schimler, Sydonie D.,Froese, Robert D. J.,Bland, Douglas C.,Sanford, Melanie S.
, p. 11178 - 11190 (2018/09/12)
This paper describes a detailed study of the deoxyfluorination of aryl fluorosulfonates with tetramethylammonium fluoride (NMe4F) and ultimately identifies other sulfonate electrophiles that participate in this transformation. 19F NMR spectroscopic monitoring of the deoxyfluorination of aryl fluorosulfonates revealed the rapid formation of diaryl sulfates under the reaction conditions. These intermediates can proceed to fluorinated products; however, diaryl sulfate derivatives bearing electron-donating substituents react very slowly with NMe4F. Based on these findings, aryl triflate and aryl nonaflate derivatives were explored, since these cannot react to form diaryl sulfates. Aryl triflates were found to be particularly effective electrophiles for deoxyfluorination with NMe4F, and certain derivatives (i.e., those bearing electron-neutral/donating substituents) afforded higher yields than their aryl fluorosulfonate counterparts. Computational studies implicate a similar mechanism for deoxyfluorination of all the sulfonate electrophiles.
Suzuki-miyaura cross-coupling reactions in flow: Multistep synthesis enabled by a microfluidic extraction
Noal, Timothy,Kuhn, Simon,Musacchio, Andrew J.,Jensen, Klavs F.,Buchwald, Stephen L.
supporting information; experimental part, p. 5943 - 5946 (2011/08/02)
Continuous success: A continuous-flow Suzuki-Miyaura cross-coupling reaction starting from phenols was made possible through use of an efficient microfluidic extraction operation and a packed-bed reactor. Various biaryls were obtained in excellent yield (
