Novel and Convenient Routes to Functionalized Alkynyl Ketones from 1-(Benzotriazol-1-yl)propargyl Ethyl Ethers
摘要:
1-(Benzotriazol-1-yl)propargyl ethyl ethers, readily accessible from propargyl aldehyde diethyl acetals and benzotriazole, undergo smooth Lithiation at the methine carbon and subsequent reactions with alkyl halides, aldehydes, ketones, imines, esters, trialkylsilyl chlorides, dialkyl carbonates, and isocyanates to yield the corresponding substituted ethers. Hydrolysis of these intermediates under acidic conditions affords a wide variety of alkynyl ketones bearing hydroxy, amino, acyl, trimethylsilyl, alkoxycarbonyl, and (alkylamino)carbonyl substituents at the alpha-position in good to excellent overall yields.
Enantioselective Addition of Alkynyl Ketones to Nitroolefins Assisted by Brønsted Base/H‐Bonding Catalysis
作者:Teresa E. Campano、Igor Iriarte、Olatz Olaizola、Julen Etxabe、Antonia Mielgo、Iñaki Ganboa、José M. Odriozola、Jesús M. García、Mikel Oiarbide、Claudio Palomo
DOI:10.1002/chem.201805542
日期:2019.3.21
sets of enolizable alkynyl ketones (including methyl ynones with α‐aryl, α‐alkenyl, and α‐alkoxy groups) were able to react smoothly with nitroolefins with the assistance of bifunctional Brønsted base/H‐bond catalysts to provide adducts with two consecutive tertiary stereocenters in a highly diastereo‐ and enantioselective fashion. Further transformation of the obtained adducts into optically active acyclic
Phosphine-Catalyzed α-Umpolung–Aldol Reaction for the Synthesis of Benzo[<i>b</i>]azapin-3-ones
作者:Kui Zhang、Lingchao Cai、Sooji Hong、Ohyun Kwon
DOI:10.1021/acs.orglett.9b01749
日期:2019.7.5
serves as a conduit for the construction of benzo[b]azepin-3-ones in good to excellent yields under mild conditions. The resulting 2-benzylidene moieties are formed exclusively in the E-configuration. Mechanistically, this unusual annulation occurs through a phosphine-catalyzed α-umpolung addition, followed by an aldol reaction. One of the benzo[b]azepin-3-one products was converted to the core structure
报道了一种新型膦催化的 2-磺酰胺苯甲醛和炔酮之间的分子间环化。该方法可作为在温和条件下以良好至优异的产率构建苯并[ b ]氮杂-3-酮的渠道。所得的2-亚苄基部分仅以E-构型形成。从机制上讲,这种不寻常的环化是通过膦催化的 α-umpolung 加成,然后是羟醛反应发生的。其中一种苯并[ b ]氮杂卓-3-酮产品被转化为3-氨基-[ a ]苯并氮杂卓-2-一-1-链烷酸的核心结构,其中许多充当血管紧张素转换酶抑制剂。
α-Amino Acid Sulfonamides as Versatile Sulfonylation Reagents: Silver-Catalyzed Synthesis of Coumarins and Oxindoles by Radical Cyclization
作者:Kyalo Stephen Kanyiva、Daisuke Hamada、Sohei Makino、Hideaki Takano、Takanori Shibata
DOI:10.1002/ejoc.201800901
日期:2018.11.25
silver‐catalyzed sulfonylation strategy using sulfonamides derived from α‐amino acids is described. The reaction proceeded via decarboxylation, N–S bond cleavage and radical cyclization to provide a variety of coumarins. The reaction was suitable for the synthesis of 2‐oxindoles and an isoquinolinedione by the capturing of the sulfonyl radical with an alkene moiety and cyclization.
A phosphine-free, atom-efficient cross-coupling reaction of triorganoindiums with acyl chlorides catalyzed by immobilization of palladium(0) in MCM-41
作者:Jiankang Miao、Bin Huang、Haiyi Liu、Mingzhong Cai
DOI:10.1039/c7ra08355f
日期:——
first phosphine-free heterogeneous palladium(0)-catalyzedcross-coupling of triorganoindiums with acyl chlorides has been developed that proceeds smoothly in THF at 68 °C and provides a general and powerful tool for the synthesis of various valuable aryl ketones and α,β-acetylenic ketones with high atom-economy and high yield. This phosphine-free heterogeneous palladium(0) catalyst can be easily prepared
Simple and General Procedure for the Synthesis of α,β-Alkynyl Ketones from Nitriles Using Alkynyldimethylaluminum Reagents
作者:Sang-Hyeup Lee、Balaji Korbad
DOI:10.1055/s-0033-1339482
日期:——
the synthesis of α,β-alkynyl ketones from nitriles and alkynyldimethylaluminum reagents, derivedfrom trimethylaluminum and alkynes, is described. This methodology provides access to a wide range of α,β-alkynyl ketones with aliphatic, aromatic, and heteroaromatic substituents in moderate to high yield (53–90%). In the cases of aryl-substituted nitriles, the product can also be obtained as α,β-alkynyl