Remote-Group-Assisted Facile Oxidative Arylation of Furans and Pyrroles

Abstract

A mild strategy for oxidative Csp2-H arylation of electron-rich furans and pyrroles has been achieved with the aid of remote carbonyl-containing groups. These groups enable the Pd-catalyzed oxidative Csp2-H arylation of furans to proceed under a warm temperature and O2 atmosphere, while distinctly promoting the yield of such a reaction for pyrroles. Supported by the experimental results and density functional theory calculation, an original concept, i.e., the remote-group-assisted Heck-type pathway, is proposed for these transformations. Moreover, the electron-rich substrates including the arylboronic acids as the arylating reagents were found to be well-tolerated, and the strategy has also been applied to the alternative route for synthesizing the skeleton of S-nitrosoglutathione reductase inhibitors.

Radical‐Dearomative Generation of Cyclohexadienyl Pd(II) toward the 3D Transformation of Nonactivated Phenyl Rings

“…[ 7 , 8 , 9 , 10 , 11 ] The current pathways for Pd‐catalyzed dearomatization of (hetero)arenes are mostly two‐electron processes, requiring harsh reaction conditions, such as high temperature, to overcome the energy barrier of the dearomative insertion step. The preference for more active (hetero)arenes and fused aromatic rings, [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ] instead of nonactivated phenyl rings, represents the present state of Pd‐catalyzed dearomatizations ( Scheme 1 a ). Recently, visible light‐induced radical pathways have provided benign methods for the dearomatization of a broader scope of (hetero)arenes including a few examples of nonactivated phenyl rings.…”

Carbon-doped boron nitride nanosheets as an efficient metal-free catalyst for the selective oxidation of H2S

“…1,2 With the increasingly strict environmental performance criteria, we need to work tirelessly to remove H 2 S. In recent years, the Claus process has become the most promising technology. 3 Nevertheless, on account of thermodynamic limitations, 3-5% of the H 2 S is left in the tail gas. 4 Therefore, there is an urgent need to develop an advanced approach to address this limitation.…”