Cyclopentenones are synthetically versatile structures, and their straightforward construction from alkynone substrates by employing synthetically streamlining C-H insertion is conceptually appealing and of high synthetic potential. But, its implementation is very limited. Herein we report a Au-catalyzed version, which affords 2-bromocyclopent-2-en-1-ones with a broad scope and synthetically desirable
环戊烯酮是合成通用的结构,它们通过合成流线型 CH 插入从炔酮底物直接构建在概念上具有吸引力且具有高合成潜力。但是,它的实施非常有限。在此我们报告了一种 Au 催化的版本,它提供了具有广泛范围和合成所需的非对映选择性的 2-bromocyclopent-2-en-1-ones。所提出的能够插入未活化 CH 键的关键中间体是一种完全功能化的金亚乙烯基,它是通过一种新的分子间策略产生的。这种可能的金亚乙烯基的灵活获取为探索其多功能反应性提供了各种机会。
Cyclopropanation and Carbonyl Olefination Utilizing 2-(Alk-1-yn-1-yl)-2-(trialkylsilyl)-1,3-dithianes via Regioselective Generation of Titanium Alkynylcarbene Complexes
Cp2Ti[P(OEt)3]2-promoted reactions of 2-(alk-1-yn-1-yl)-2-(trialkylsilyl)-1,3-dithianes (RS)2C(Si)C⋮CR with terminal olefins and carbonyl compounds produced (trialkylsilylethynyl)cyclopropanes and 1-(trialkylsilyl)alk-3-en-1-ynes, respectively. These compounds were suggest to be produced via the formation of intermediary titanium α-(trialkylsilylethynyl)carbene complexes Cp2TiC(R)C⋮CSi in preference to their
Cp 2 Ti [P(OEt)3 ] 2促进了2-(alk-1-yn-1-yl)-2-(trialksilsilyl )-1,3-dithianes(RS)2 C(Si)C⋮的反应具有末端烯烃和羰基化合物的CR分别产生(三烷基甲硅烷基乙炔基)环丙烷和1-(三烷基甲硅烷基)alk-3-en-1-ynes。这些化合物被认为是通过形成中间体钛α-(三烷基甲硅烷基乙炔基)碳烯络合物Cp 2 Ti C(R)C⋮C Si而不是其区域异构体,α-(三烷基甲硅烷基)炔基碳烯络合物Cp 2 Ti C(Si C⋮CR。
Enantioselective Total Synthesis of the Putative Biosynthetic Intermediate Ambruticin J
作者:Kathryn Trentadue、Chia‐Fu Chang、Ansel Nalin、Richard E. Taylor
DOI:10.1002/chem.202100975
日期:2021.8.2
synthase pathway proceeds via a diol intermediate, known as ambruticin J. Herein, we report the first enantioselective totalsynthesis of the putative PKS product, ambruticin J, according to a triply convergent synthetic route featuring a Suzuki-Miyaura cross-coupling and a Julia-Kocienski olefination for fragment assembly. This synthesis takes advantage of synthetic methodology previously developed by our
Dative Directing Group Effects in Ti-Catalyzed [2+2+1] Pyrrole Synthesis: Chemo- and Regioselective Alkyne Heterocoupling
作者:Hsin-Chun Chiu、Xin Yi See、Ian A. Tonks
DOI:10.1021/acscatal.8b04669
日期:2019.1.4
found to play a key role in controlling the regioselectivity of alkyne insertion and [2+2] cycloaddition in Ti-catalyzed [2+2+1] pyrrole synthesis and Ti-catalyzed alkyne hydroamination. TMS-protected alkynes with pendent Lewis basic groups can invert the regioselectivity of TMS-protected alkyne insertion, leading to the selective formation of highlysubstituted 3-TMS pyrroles. The competency of various
Total Synthesis of (±)-Lysergic Acid, Lysergol, and Isolysergol by Palladium-Catalyzed Domino Cyclization of Amino Allenes Bearing a Bromoindolyl Group
Ergotalkaloids and their synthetic analogs have been reported to exhibit broad biological activity. We investigated direct construction of the C/D ring system of ergotalkaloids based on palladium-catalyzed domino cyclization of amino allenes. With this biscyclization as the key step, total synthesis of (+/-)-lysergic acid, (+/-)-lysergol, and (+/-)-isolysergol was achieved.