N,S-chelating triazole-thioether ligand for highly efficient palladium-catalyzed Suzuki reaction
作者:Qiong Yan、Lei Zheng、Miaomiao Li、Yunfeng Chen
DOI:10.1016/j.jcat.2019.07.004
日期:2019.8
1,2,3-Triazole-thioether compounds could serve as efficient ligands for Pd-catalyzed Suzuki reactions of various aryl iodides, bromides and chlorides. The reactions feature wide substrate scope and mild reaction conditions. Besides, shorter reaction time, lower catalyst loadings and quantitative yields with a turnover-frequency (TOF) value of up to 11,880 h−1 are other advantageous of this attractive
1,2,3-三唑-硫醚化合物可以用作钯催化的各种芳基碘化物,溴化物和氯化物的Suzuki反应的有效配体。该反应具有广泛的底物范围和温和的反应条件。此外,更短的反应时间,更低的催化剂载量和定量产率(TOF)值高达11,880 h -1的定量收率是该引人注目的方案的其他优点。晶体结构分析和计算研究表明,相应的螯合钯配合物的较高催化活性归因于较低的能隙和较低的氧化还原电势。
Visible-Light-Promoted, Catalyst-Free Gomberg–Bachmann Reaction: Synthesis of Biaryls
作者:Juyoung Lee、Boseok Hong、Anna Lee
DOI:10.1021/acs.joc.9b00557
日期:2019.7.19
Biaryls were synthesized via a novel visible-light-promoted Gomberg–Bachmann reaction that does not require a photosensitizer or any metal reagents. The formation of an electron donor–acceptor complex between aryl diazonium salts and pyridine allows, under visible-light irradiation, the synthesis of biaryls in moderate-to-high yields.
A method for practical preparation of pinacolborane from borane-diethylaniline and pinacol was newly developed. Aromatic C–H borylation of arenes with pinacolborane or bis(pinacolato)diboron catalyzed by 1/2[Ir(OMe)(COD)]2-(4,4′-di-tert-butyl-2,2′-bipyridine) at 25 °C in hexane to give arylboronic esters was directly followed by cross-coupling with aromatic bromides at 60 °C in the presence of PdCl2(dppf)
新开发了一种由硼烷-二乙基苯胺和频哪醇实际制备频哪醇硼烷的方法。1/2 [Ir(OMe)(COD)] 2-(4,4'-二叔丁基-2,2'-联吡啶)催化的芳烃与频哪醇硼烷或双(频哪醇)二硼烷的芳烃C氢硼化在25℃下于己烷中在20℃下得到芳基硼酸酯,然后直接在60℃在PdCl 2(dppf)(3.0mol%)和K 3 PO 4在DMF中的存在下与芳族溴化物交叉偶联。这种一锅两步的方法以高收率提供了多种不对称的联芳基。