作者:Thibault Gendron、Raul Pereira、Hafsa Y. Abdi、Timothy H. Witney、Erik Årstad
DOI:10.1021/acs.orglett.9b04280
日期:2020.1.3
Herein, we report that iron(II)/ammonium persulfate in aqueous acetonitrile mediates the Newman-Kwart rearrangement of O-aryl carbamothioates. Electron-rich substrates react rapidly under moderate heating to afford the rearranged products in excellent yields. The mild conditions, rapid reaction rates, and suitability for scale up offers immediate practical benefits to access functionalized thiophenols
Thiocarbamate‐Directed
<i>ortho</i>
C−H Bond Alkylation with Diazo Compounds
作者:Shengnan Jin、Zhan Chen、Yingwei Zhao
DOI:10.1002/adsc.201900804
日期:2019.10.22
We herein report a rhodium catalysed insertion of C(sp2)−H bond into diazo derived carbenes directed by a thiocarbamate group. This reaction provides a direct and efficient pathway to the ortho alkylation of phenol derivatives with a broad substrate scope. The C−H activation process is accomplished through a reversible electrophilic rhodation.
An Electrocatalytic Newman–Kwart-type Rearrangement
作者:Timo Broese、Arend F. Roesel、Adrian Prudlik、Robert Francke
DOI:10.1021/acs.orglett.8b03257
日期:2018.12.7
An electrochemical approach toward rearrangement of O-aryl thiocarbamates to the corresponding S-aryl thiocarbamates is presented. The protocol requires only catalytic amounts of electric charge and allows for operation at room temperature. The electrolysis can be carried out with the simplest equipment, i.e., under galvanostatic conditions in an undivided cell. Furthermore, it is demonstrated that
Inverting the Selectivity of the Newman–Kwart Rearrangement via One Electron Oxidation at Room Temperature
作者:Stephan K. Pedersen、Anne Ulfkjær、Madeleine N. Newman、Sarangki Yogarasa、Anne U. Petersen、Theis I. Sølling、Michael Pittelkow
DOI:10.1021/acs.joc.8b01800
日期:2018.10.5
The discovery that the Newman–Kwartrearrangement can be performed at room temperature by action of a simple and readily available oxidant, cerium ammonium nitrate, is described. The conditions give clean conversion when using electron-rich aromatic substrates, and the reactions are often quantitative. Computational studies support a reaction mechanism where the O-thiocarbamate is first oxidized to
We herein establish a multicomponent annulation method for the synthesis of valuable iminocoumarins using aryl thiocarbamates, internal alkynes, and sulfonamides as starting materials, which are safe and readily available. The key step is a Rh-catalyzed and sulfur-directed C—H bondactivation. Preliminary mechanistic investigations suggested that the nucleophilic attack of the sulfonamide on an active