6380-21-8Relevant articles and documents
Ruthenium Removal Using Silica-Supported Aromatic Isocyanides
Gregg, Zackary R.,Glickert, Elise,Xu, Ruoshui,Diver, Steven T.
supporting information, (2021/05/13)
New silica gel scavengers containing aromatic isocyanides have been synthesized and evaluated for Ru removal. A thiol-ene click reaction was used to attach the isocyanide precursor to a thiol-containing siloxane. Conventional methods for grafting to silica gel at elevated temperature resulted in significant hydrolysis of the isocyanide. A novel cleavage reaction was developed to quantitate the amount of surface-loaded isocyanide. Binding by the new materials was comparatively evaluated for a variety or Ru carbene catalysts. The optimal conditions were extended to two ring-closing metatheses (RCM). The residual Ru was determined by inductively coupled plasma mass spectrometry (ICP-MS). For facile RCM reactions, the UV data agreed with the ICP-MS results. However, more difficult RCM did not correlate well with the UV data. This was interpreted in terms of varying extent of catalyst decomposition. In all cases, isocyanide scavenger reagents were found to be superior to commonly used, silica gel-based metal scavengers.
Cascade Claisen and Meinwald Rearrangement for One-Pot Divergent Synthesis of Benzofurans and 2 H-Chromenes
Song, Liyan,Su, Qian,Lin, Xi,Du, Zhihui,Xu, Huiyou,Ouyang, Ming-An,Yao, Hongliang,Tong, Rongbiao
, p. 3004 - 3009 (2020/04/20)
A new cascade approach has been developed for the one-pot four-step divergent synthesis of polysubstituted benzofurans and 2H-chromenes, featuring a novel cascade aromatic Claisen rearrangement/Meinwald rearrangement/dehydrative or oxidative cyclization. This new method was demonstrated with 39 examples tolerating different substitutions at an epoxide, allylic ether, and aromatic ring, and we showcased its utility with the first total synthesis of natural product liparacid A in seven steps.
Selective Synthesis of Primary Anilines from NH3 and Cyclohexanones by Utilizing Preferential Adsorption of Styrene on the Pd Nanoparticle Surface
Koizumi, Yu,Jin, Xiongjie,Yatabe, Takafumi,Miyazaki, Ray,Hasegawa, Jun-ya,Nozaki, Kyoko,Mizuno, Noritaka,Yamaguchi, Kazuya
supporting information, p. 10893 - 10897 (2019/07/12)
Dehydrogenative aromatization is one of the attractive alternative methods for directly synthesizing primary anilines from NH3 and cyclohexanones. However, the selective synthesis of primary anilines is quite difficult because the desired primary aniline products and the cyclohexanone substrates readily undergo condensation affording the corresponding imines (i.e., N-cyclohexylidene-anilines), followed by hydrogenation to produce N-cyclohexylanilines as the major products. In this study, primary anilines were selectively synthesized in the presence of supported Pd nanoparticle catalysts (e.g., Pd/HAP, HAP=hydroxyapatite, Ca10(PO4)6(OH)2) by utilizing competitive adsorption unique to heterogeneous catalysis; in other words, when styrene was used as a hydrogen acceptor, which preferentially adsorbs on the Pd nanoparticle surface in the presence of N-cyclohexylidene-anilines, various structurally diverse primary anilines were selectively synthesized from readily accessible NH3 and cyclohexanones. The Pd/HAP catalyst was reused several times though its catalytic performance gradually declined.
