5468-97-3Relevant articles and documents
Synergistic Catalysis for the Umpolung Trifluoromethylthiolation of Tertiary Ethers
Xu, Wentao,Ma, Junyang,Yuan, Xiang-Ai,Dai, Jie,Xie, Jin,Zhu, Chengjian
supporting information, p. 10357 - 10361 (2018/08/06)
The first transition-metal-free, site-specific umpolung trifluoromethylthiolation of tertiary alkyl ethers has been developed, achieving the challenging tertiary C(sp3)–SCF3 coupling under redox-neutral conditions. The synergism of organophotocatalyst 4CzIPN and BINOL-based phosphorothiols can site-selectively cleave tertiary sp3 C(sp3)–O ether bonds in complex molecules initiated by a polarity-matching hydrogen-atom-transfer (HAT) event. The incorporation of several competing benzylic and methine C(sp3)?H bonds in alkyl ethers has little influence on the regioselectivity. Selective difluoromethylthiolation of C?O bonds has also been achieved. This represents not only an important step forward in trifluoromethylthiolation but also a promising means for site-selective C?O bond functionalization of unsymmetrical tertiary alkyl ethers.
Pd(II)-catalyzed hydroxyl-directed C-H olefination enabled by monoprotected amino acid ligands
Lu, Yi,Wang, Dong-Hui,Engle, Keary M.,Yu, Jin-Quan
supporting information; experimental part, p. 5916 - 5921 (2010/07/05)
A novel Pd(II)-catalyzed ortho-C-H olefination protocol has been developed using spatially remote, unprotected tertiary, secondary, and primary alcohols as the directing groups. Mono-N-protected amino acid ligands were found to promote the reaction, and an array of olefin coupling partners could be used. When electron-deficient alkenes were used, the resulting olefinated intermediates underwent subsequent Pd(II)-catalyzed oxidative intramolecular cyclization to give the corresponding pyran products, which could be converted into ortho-alkylated alcohols under hydrogenolysis conditions. The mechanistic details of the oxidative cyclization step are discussed and situated in the context of the overall catalytic cycle.
THE EFFECT OF ARYL SUBSTITUENTS ON ARYLCARBENE REACTIVITY
Tomioka, Hideo,Tabayashi, Kazuo,Ozaki, Yasuji,Izawa, Yasuji
, p. 1435 - 1440 (2007/10/02)
Substituted (p-MeO, p-Me, H, p-Cl, p-Br, m-Br, m-MeO, 3,4-Cl2, p-CO2Me, m-CN and p-CN) monophenylcarbenes are generated in a binary mixture of substrates (methanol, cis-4-methyl-2-pentene and cyclohexane) and the relative rate of O - H insertion into methanol to stereospecific cyclopropanation of the olefin to C - H insertion into cyclohexane are calculated from the ratios of products and substrates.It is found (i) that the reactivities of the substrates decrease in the order of methanol, olefin and cyclohexane and (ii) that electron-donating substituents generally lead to reaction with the more reactive substrates while the reaction with the less reactive substrates is favoured in the case of electron-withdrawing substituents.These results are interpreted in terms of the change in the electrophilicity of the singlet arylcarbene by the substituents rather than the change in the singlet-triplet equilibrium.