Copper-Catalyzed Cross Dehydrogenative Coupling of<i>N</i>,<i>N</i>-Disubstituted Formamides and Phenols: A Direct Access to Carbamates
作者:Wajid Ali、Saroj K. Rout、Srimanta Guin、Anju Modi、Arghya Banerjee、Bhisma K. Patel
DOI:10.1002/adsc.201400659
日期:2015.2.9
AbstractAn efficient copper‐catalyzed protocol has been developed for the synthesis of carbamates from dialkylformamides and phenols possessing directing groups such as benzothiazole, quinoline and formyl at the ortho‐position. In this chelation assisted approach, CO bond formation takes place via a cross dehydrogenative coupling (CDC) between the formyl CH of dialkylformamide and phenolic OH in the presence of copper(II)acetate/aqueous tert‐butyl hydroperoxide. Under identical reaction conditions, salicylic acid derivatives underwent amidation with the carboxylic group rather than formamidation of the phenolic OH. The use of a cheap and environmentally benign catalyst along with the tolerance of a wide range of functional groups makes this an easy, phosgene‐free route to carbamates.magnified image
Copper
<scp>porphyrin‐catalyzed</scp>
C(sp
<sup>2</sup>
)
<b>—</b>
O bond construction via coupling phenols with formamides
作者:Shuang Yang、Xiao‐Yan Chen、Ming‐Feng Xiong、Hao Zhang、Lei Shi、Dong‐Zi Lin、Hai‐Yang Liu
DOI:10.1002/jccs.202100046
日期:2021.8
construction of C(sp2)—Obond via coupling formamides with phenols was achieved firstly. A broad range of substrates afforded various carbamates in moderate to good yields with good functional group tolerance at low catalyst loading. Intermolecular competing kinetic isotope effect experiment indicated that the generation of formamide radical is the rate-determining step of current cross-dehydrogenative coupling