Mechanistic and Synthetic Investigations on the Dual Selenium-π-Acid/Photoredox Catalysis in the Context of the Aerobic Dehydrogenative Lactonization of Alkenoic Acids
作者:Stefan Ortgies、Rene Rieger、Katharina Rode、Konrad Koszinowski、Jonas Kind、Christina M. Thiele、Julia Rehbein、Alexander Breder
DOI:10.1021/acscatal.7b02729
日期:2017.11.3
efficiency and practicality, good functional group tolerance, and high sustainability, since ambient air and visible light are adequate for the clean conversion of alkenoicacids into their respective lactones. The title method has been used as a case study to elucidate the general mechanistic aspects of the dual selenium-π-acid/photoredox catalysis. On the basis of NMR spectroscopic, mass spectrometric, and
Direct Catalytic Asymmetric Vinylogous Additions of α,β‐ and β,γ‐Butenolides to Polyfluorinated Alkynyl Ketimines
作者:Barry M. Trost、Chao‐I. (Joey) Hung、Manuel J. Scharf
DOI:10.1002/anie.201806249
日期:2018.8.27
We report a Zn‐ProPhenol catalyzed asymmetric Mannich reaction between butenolides and polyfluorinated alkynyl ketimines to obtain vinylogous products featuring two contiguous tetrasubstituted stereogenic centers. Notably, this is the first successful use of ketimines in the ProPhenol Mannich process, and the reaction offers a new approach for the preparation of pharmaceutically relevant products possessing
Gold-Catalyzed Intramolecular Oxidative Cross-Coupling of Nonactivated Arenes
作者:Matthew N. Hopkinson、Arnaud Tessier、Andrew Salisbury、Guy T. Giuffredi、Lorraine E. Combettes、Antony D. Gee、Véronique Gouverneur
DOI:10.1002/chem.201000322
日期:2010.4.26
An (Au)some coupling! Gold‐catalyzed cascade CO cyclizations of benzyl‐substituted allenoate esters followed by intramolecular oxidative CC cross‐coupling involving aryl CH functionalization were performed with Selectfluor as the oxidant (see scheme). This operationally simple and mild procedure benefits from complete axis‐to‐center chirality transfer and allows for the preparation of surprisingly
Abstract The combination of dimethylsulfoxide and oxalyl bromide was used to accomplish the cyclization of 3-alkenoic acids with the aid of a base to afford γ-butenolides, in which bromodimethylsulfonium salt generated in situ was proposed to serve as a Br+ source. GRAPHICAL ABSTRACT