33945-86-7Relevant articles and documents
Niobium(V) oxido tris-carbamate as easily available and robust catalytic precursor for the selective sulfide to sulfone oxidation
Bresciani, Giulio,Ciancaleoni, Gianluca,Crucianelli, Marcello,Gemmiti, Mario,Marchetti, Fabio,Pampaloni, Guido
, (2021/11/01)
The oxidation of the sulfide function promoted by a variety of vanadium compounds has been largely explored, whereas the use of homogeneous catalytic systems based on the heavier group 5 metals remains less explored. We report the use of easily available niobium and tantalum carbamates, i.e. [M(O2CNMe2)5] (M = Nb, 1; M = Ta, 2), [Nb(O2CNMe2)4], 3, [NbO(O2CNEt2)3], 4, and [NbCl3(O2CNEt2)2], 5, as effective catalysts for the conversion of a series of alkyl aryl and aromatic sulfides into the corresponding sulfones. NMR investigations on the performant niobium catalyst 4 unexpectedly revealed the substantial stability of this compound in the protic catalytic environment, and a plausible catalytic cycle was obtained by DFT studies. The two active catalytic species, i.e. 4 and its minor mono-methoxide derivative, presumably interconvert to each other exploiting the versatile coordination of the carbamato ligand.
Para-coupling of phenols with C2/C3-substituted benzothiophene S-oxides
He, Zhen,Biremond, Tony,Perry, Gregory J.P.,Procter, David J.
supporting information, (2020/06/17)
C2 and C3 substituted benzothiophenes are common structures in medicinal and materials chemistry. The cross-coupling of phenols with benzothiophenes is a useful route towards these important molecules. In this report we reveal an efficient C–H/C–H-type cross-coupling of benzothiophenes, activated as their S-oxides, with phenols to give C2/C3 arylated benzothiophenes. Whereas previous reports describe cross-coupling at the ortho-position between phenols and sulfoxides, this procedure allows para-functionalization of phenols that typically have their ortho positions blocked.
Transition-Metal-Free Synthesis of C3-Arylated Benzofurans from Benzothiophenes and Phenols
Yang, Kevin,Pulis, Alexander P.,Perry, Gregory J. P.,Procter, David J.
supporting information, p. 7498 - 7503 (2018/11/25)
We report a transition-metal-free synthesis of benzofurans from benzothiophenes and phenols that exploits the unique reactivity of sulfoxides. Through a sequence involving an interrupted Pummerer reaction and [3,3] sigmatropic rearrangement, phenols can b
