A formal intramolecular vicinal 1,2-diamination of alkynes is achieved for the synthesis of indole-cyclic urea fused derivatives through a double cyclization process from readily available aminophenyl propargyl alcohols. This sequential triple C–N bond construction event was possible using isocyanate as urea precursor and Ag(I) catalyst as alkyne activating agent. Control experiments reveal that the
bicyclic core structures with up to three stereocenters within a single step. Herein, this concept is combined with the chemistry of chiral Brønsted acid bound ortho-quinonemethideimines to generate a range of interesting fused tetrahydroquinolines in a diastereo- and enantioselective manner.
Palladium(II)‐Catalyzed Sequential Aminopalladation and Oxidative Coupling with Acetylenes/Enones: Synthesis of Newly Substituted Quinolines from 2‐Aminophenyl Propargyl Alcohols
Palladium catalyzed conversion of 1‐(2‐aminophenyl)‐propargyl alcohols to 3‐alkynyl quinolines is realized via a cascade that involves aminopalladation, oxidative coupling with alkynes and dehydration. The method is shown to have a broad substrate scope with respect to propargyl alcohols as well as alkynes. Vinylketones as coupling partners in the same reaction afforded 3‐alkenyl quinolines with equal
Thermal Cyclization of Nonconjugated Aryl-Yne-Carbodiimide Furnishing a Dibenzonaphthyridine Derivative
作者:Hidenori Kimura、Kohei Torikai、Ikuo Ueda
DOI:10.1248/cpb.57.393
日期:——
The reagent-free C2–C7 thermal cyclization of a nonconjugated aryl–yne–carbodiimide yielded a dibenzo[b,g][1,8]naphthyridine derivative, whose congeners are known to possess fascinating pharmacological properties. This is the first heteroaromatic compound prepared by the thermal cycloaromatization of “nonconjugated” aryl–ynes.
Gold-Catalyzed Conversion of Aryl- and Alkyl-Substituted 1-(<i>o</i>-Aminophenyl)-2-propyn-1-ones to the Corresponding 2-Substituted 4-Quinolones
作者:Otto Seppänen、Mikko Muuronen、Juho Helaja
DOI:10.1002/ejoc.201402224
日期:2014.7
Gold-catalyzed cyclization of alkyl- or aryl-substituted 1-(o-aminophenyl)-2-propyn-1-ones to the corresponding2-substituted 4-quinolones was studied with various gold salts and complexes. Screening of the different catalysts showed highest performance with cationic AuI species. In particular PPh3AuNTf2 complex was the most efficient catalyst. Relative to classic quinolone synthesis that requires harsh