Nucleophilic attack of intramolecular hydroxyl groups on electron-rich aromatics using hypervalent iodine(III) oxidation
作者:Kayoko Hata、Hiromi Hamamoto、Yukiko Shiozaki、Simon B. Cämmerer、Yasuyuki Kita
DOI:10.1016/j.tet.2007.02.118
日期:2007.5
The hypervalent iodine(III) reagent, phenyliodine bis(trifluoroacetate) (PIFA)-mediated oxidative nucleophilic substitution of electron-rich aromatics involving aromatic cation radical intermediates was utilized in the direct aromatic carbon–oxygen bond formation reaction, and a novel and simple synthetic method for chroman derivatives was developed. As an extension of this methodology, a facile access
Phenyl trimethyl ammonium tribromide mediated robust one-pot synthesis of spiro-oxacycles – an economic route – stereoselective synthesis of oxaspirohexacyclodieneones
作者:Debayan Sarkar、Manoj Kumar Ghosh、Nilendri Rout
DOI:10.1039/c6ob01116k
日期:——
This paper entails the first recognition of PhenylTrimethylAmmonium Tribromide (PTAB) as an effective reagent for spiro-cyclizations proceeding via oxidative dearomatization. The experiment exhibits economical, metal and ligand free one-pot accomplishment of these significant transformations. The described protocol presents the first generalised methodology of spiro-oxacycle synthesis which can be
Ruthenium(VIII)-Catalyzed <i>ipso</i>-Dearomative Spiro-Etherification and Spiro-Amidation of Phenols
作者:Debayan Sarkar、Nilendri Rout
DOI:10.1021/acs.orglett.9b01322
日期:2019.6.7
An open air ruthenium(VIII)-catalyzed oxidative spiro-etherification as well as spiro-amidation of phenols has been performed. The transformation works satisfactorily with both phenols and naphthols and thus exhibits a wide range of flexibility. The catalysis is performed in open air at room temperature with a yield of ≤95%.
We developed a chemoselective oxidative dearomative spiroetherification and spiroamination of arenols using I+/oxone catalysis. The intramolecular dearomative C-O and C-N couplings proceeded much more efficiently under slightly acidic conditions to give the corresponding spiro adducts in higher yields compared with previous methods using transition metal or hypervalent iodine catalysts. Control experiments