53587-16-9Relevant academic research and scientific papers
Catalytic activation of unstrained C(aryl)–C(aryl) bonds in 2,2′-biphenols
Zhu, Jun,Wang, Jianchun,Dong, Guangbin
, p. 45 - 51 (2018/11/23)
Transition metal catalysis has emerged as an important means for C–C activation that allows mild and selective transformations. However, the current scope of C–C bonds that can be activated is primarily restricted to either highly strained systems or more polarized C–C bonds. In contrast, the catalytic activation of non-polar and unstrained C–C moieties remains an unmet challenge. Here we report a general approach for the catalytic activation of the unstrained C(aryl)–C(aryl) bonds in 2,2′-biphenols. The key is to utilize the phenol moiety as a handle to install phosphinites as a recyclable directing group. Using hydrogen gas as the reductant, monophenols are obtained with a low catalyst loading and high functional group tolerance. This approach is also applied to the synthesis of 2,3,4-trisubstituted phenols. A further mechanistic study suggests that the C–C activation step is mediated by a rhodium(i) monohydride species. Finally, a preliminary study on breaking the inert biphenolic moieties in lignin models is illustrated.
Selective catalytic conversion of guaiacol to phenols over a molybdenum carbide catalyst
Ma, Rui,Cui, Kai,Yang, Le,Ma, Xiaolei,Li, Yongdan
supporting information, p. 10299 - 10301 (2015/06/25)
An activated carbon supported α-molybdenum carbide catalyst (α-MoC1-x/AC) showed remarkable activity in the selective deoxygenation of guaiacol to substituted mono-phenols in low carbon number alcohol solvents. Combined selectivities of up to 85% for phenol and alkylphenols were obtained at 340°C for α-MoC1-x/AC at 87% conversion in supercritical ethanol. The reaction occurs via consecutive demethylation followed by a dehydroxylation route instead of a direct demethoxygenation pathway.
Access to 3-arylindoles through a tandem one-pot protocol involving dearomatization, a regioselective michael addition reaction, and rearomatization
Chittimalla, Santhosh Kumar,Bandi, Chennakesavulu,Putturu, Sireesha,Kuppusamy, Rajesh,Boellaard, Kevin Christopher,Tan, David Chu Aan,Lum, Demi Ming Jie
, p. 2565 - 2575 (2014/05/06)
A facile, general and rapid protocol for the introduction of oxygenated aryls at the 3-position of indoles is described. This approach consists of a tandem dearomatization, a regioselective Michael addition reaction, and rearomatization in a one-pot three-step sequence to obtain 3-arylindoles in good yields. A non-metal mediated detour method for installing oxygenated aryls at the 3-position of indoles is described. Copyright
Anodic coupling of guaiacol derivatives on boron-doped diamond electrodes
Kirste, Axel,Schnakenburg, Gregor,Waldvogel, Siegfried R.
supporting information; experimental part, p. 3126 - 3129 (2011/08/03)
The anodic treatment of guaiacol derivatives on boron-doped diamond electrodes (BDD) provides a direct access to nonsymmetrical biphenols, which would require a multistep sequence by conventional methods. Despite the destructive nature of BDD anodes they
Zirconia-modified superacid UDCaT-5: An efficient and versatile catalyst for alkylation reactions under solvent-free conditions
Yadav, Ganapati D.,Pathre, Ganesh S.
, p. 2684 - 2691 (2008/12/22)
UDCaT-5, a modified version of zirconia, efficiently catalyzes alkylation of phenols with alcohols under environmentally safe, heterogeneous reaction conditions with high selectivity and in excellent yields. The high content present in UDCaT-5 with preservation of tetragonal phase of zirconia was responsible for the superactivity. Several phenolic compounds carrying either electron-sulfer releasing or electron-withdrawing substituents in the ortho, meta, and para positions afforded high yields of the products. Copyright Taylor & Francis Group, LLC.
Tobacco smoke chemistry. 2. Alkyl and alkenyl substituted guaiacols found in cigarette smoke condensate.
Arnarp,Bielawski,Dahlin,Dahlman,Enzell,Pettersson
, p. 44 - 50 (2007/10/02)
A series of alkyl and alkenyl substituted guaiacols, which comprise a group of biologically and organoleptically active compounds, have been synthesized. Mass spectra and GC retention times for these have been recorded and compared with those obtained for constituents of a weakly acidic fraction of smoke condensate derived from American blend type cigarettes. On the basis of these results, 25 guaiacols have been identified, 18 of which have not been detected in tobacco smoke condensate previously.
