Gold Meets Selenium: Dual Activation of Selenium-Containing Propargyl Alcohols Towards the Synthesis of 2H-Chromenes
Eric F Lopes1,2, Martin C Dietl2, Benjamin Ziegler2
1Instituto de Química, Universidade Federal do Rio Grande do Sul, UFRGS, Av. Bento Gonçalves 9500, 91501-970, Porto Alegre, RS, Brazil.
Abstract:
Herein, we report the synthesis of seleno-substituted chromenes from selenoalkynes and phenols. In this cascade reaction, the applied gold catalyst not only functions as a π-acid, but also as a Lewis acid, enabling the propargylic substitution in the first step to connect the oxygen carbon bond. Under the optimal reaction condition a total of 26 chromenes were accessible by this modular access. During scale up experiments, the hydrolysis of the vinylselenium substructure to the corresponding chromenones was observed. By revisiting the electron-rich starting materials, four chromenones were produced following a one-pot reaction using a single gold catalyst. To better understand the interaction of gold and selenium, a series of nuclear magnetic resonance studies and high-resolution mass spectrometry studies were performed, which led to the proposal of a mechanism for this transformation.
More Related Videos
10:17Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
07:36Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy
Published on: November 9, 2019
Related Concept Videos
Formation of Halohydrin from Alkenes
Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Halogenation of Alkenes
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Preparation and Reactions of Sulfides
Radical Substitution: Allylic Bromination
