A high temperature investigation using microwave synthesis for electronically and sterically disfavoured substrates of the Newman–Kwart rearrangement
作者:Jonathan D. Moseley、Philip Lenden
DOI:10.1016/j.tet.2007.02.101
日期:2007.5
Electronically deactivated and/or sterically hindered substrates undergo the Newman–Kwartrearrangement (NKR) at around 300 °C, beyond the range of most convenient and safe, small-scale laboratory equipment. We report here the convenient conversions of several difficult substrates using modern microwave technology, which has proven ideal for investigating this high temperature reaction in all but the most
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 Tandem Olefination–Intramolecular Sulfuration of Two <i>Ortho</i> C–H Bonds: Application to Synthesis of a COX-2 Inhibitor
作者:Wendong Li、Yingwei Zhao、Shaoyu Mai、Qiuling Song
DOI:10.1021/acs.orglett.8b00089
日期:2018.2.16
A palladium-catalyzed dual ortho C–H bond activation of aryl thiocarbamates is developed. This tandem reaction initiates by thiocarbamate-directed ortho C–H palladation, which leads to favorable olefin insertion rather than reductive elimination. The oxidative Heck reaction followed by another C–H activation and sulfuration affords the dual-functionalized products. This reaction provides a concise
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