for the preparation of 3-substituted isocoumarins via palladium-catalyzed nucleophilic addition/oxidative annulation of bromoalkynes with benzoic acids has been developed. Remarkably, preliminary mechanistic studies indicated that the transformation might proceed via a stereo- and regioselective nucleophilic addition and C–H functionalization procedure.
Convenient Synthesis of 3-Glycosylated Isocoumarins
作者:Kasireddy Sudarshan、Indrapal Singh Aidhen
DOI:10.1002/ejoc.201601264
日期:2017.1.3
A new route for the synthesis of 3-substituted and 8-hydroxy-3-substituted isocoumarins has been developed by using modified Julia olefination for initial C-C bond formation between aldehydes and benzylic-sulfones. Palladium-catalyzed Meinwald rearrangement was used as a key step for the obtainment of ketone intermediates, which on base promoted intramolecular cyclization afforded the desired isocoumarins
通过使用改良的 Julia 烯化在醛和苄基砜之间形成初始 CC 键,开发了一种合成 3-取代和 8-羟基-3-取代异香豆素的新途径。钯催化的 Meinwald 重排被用作获得酮中间体的关键步骤,其在基础上促进了分子内环化,得到了所需的异香豆素。所开发的方法首次为迄今为止未知的 3- 糖基异香豆素和特别是其中葡糖基部分连接到异香豆素骨架的吡喃酮环的 3- 糖基异香豆素铺平了道路。
Palladium complexes with an annellated mesoionic carbene (MIC) ligand: catalytic sequential Sonogashira coupling/cyclization reaction for one-pot synthesis of benzofuran, indole, isocoumarin and isoquinolone derivatives
作者:Akshi Tyagi、Noor U Din Reshi、Prosenjit Daw、Jitendra K. Bera
DOI:10.1039/d0dt02918a
日期:——
Two Pd(II) complexes (1 and 2) featuring a fused π-conjugated imidazo[1,2-a][1,8]naphthyridine-based mesoionic carbene ligand have been synthesized and structurally characterized. Both complexes effectively catalyze the one-pot synthesis of benzofuran starting from phenylacetylene and 2-iodophenol under mild conditions. Complex 1 is found to be an excellent catalyst for the straightforward access to
合成了两个Pd(II)配合物(1和2),这些配合物具有基于π-共轭咪唑并[1,2- a ] [1,8]萘啶基的介电卡宾配体的稠合结构。两种络合物在温和条件下均能有效地催化苯乙炔和2-碘苯酚的一锅法合成苯并呋喃。通过末端炔烃与苯酚,N-甲基苯胺,苯甲酸和N的2-碘衍生物的反应,发现配合物1是直接访问苯并呋喃,吲哚,异香豆素和异喹诺酮衍生物库的极佳催化剂。-甲基苯甲酰胺。使用多种不同取代的末端炔烃证明了催化方法的通用性,并以良好或优异的收率获得了相应的所需产物。在对照实验的基础上,提出了一种二循环机理,该机理涉及2-碘衍生物与炔烃的Sonogashira偶联以及随后的相应2-炔基化合物的环化。
Modular synthesis of 3-substituted isocoumarins <i>via</i> silver-catalyzed aerobic oxidation/<i>6-endo</i> heterocyclization of <i>ortho</i>-alkynylbenzaldehydes
作者:Hao Wu、Yi-Chun Wang、Andrey Shatskiy、Qiu-Yan Li、Jian-Quan Liu、Markus D. Kärkäs、Xiang-Shan Wang
DOI:10.1039/d1ob01065d
日期:——
A method involving silver-catalyzed aerobic oxidation/6-endo heterocyclization of ortho-alkynylbenzaldehydes to yield 3-substituted isocoumarins is described. The developed protocol allows convenient access to a range of synthetically useful 3-substituted isocoumarins and related fused heterocyclolactones in good to high yields, using silver tetrafluoroborate as the catalyst, and atmospheric oxygen
Cu-catalyzed coupling-cyclization in PEG 400 under ultrasound: a highly selective and greener approach towards isocoumarins
作者:R. Gangadhara Chary、G. Rajeshwar Reddy、Y. S. S. Ganesh、K. Vara Prasad、S. K. Phani Chandra、Soumita Mukherjee、Manojit Pal
DOI:10.1039/c3ra40969d
日期:——
The combination of CuI–K2CO3-PEG 400 facilitated the coupling-cyclization of o-iodobenzoic acid with terminal alkynes under ultrasound, affording a greener and practical approach towards 3-substituted isocoumarins with remarkable regioselectivity. This inexpensive and Pd and ligand free methodology gave rise to various isocoumarins of potential pharmacological interest.