For the first time, a highly regioselective intermolecular sulfonylamidation unactivated secondary Csp(3) -H bond has been achieved using Ir(III) catalysts. The introduced N,N'-bichelating ligand plays a crucial role in enabling iridium-nitrene insertion into a secondary Csp(3) -H bond via an outer-sphere pathway. Mechanistic studies and density functional theory (DFT) calculations demonstrated that a two-electron concerted nitrene insertion was involved in this Csp(3) -H amidation process. This method tolerates a broad range of linear and branched-chain N-alkylamides, and provides efficient access to diverse γ-sulfonamido-substituted aliphatic amines.
We first report the direct ortho
C–H amidation of arenes
with azides by using a novel and inexpensive RuHCl(CO)(PPh3)3 catalyst. The reaction proceeds efficiently in high
yield over a broad range of substrates without requirement of any
additional silver salt or additive.
Copper(I)-catalyzed 5-sulfonation of quinolines via bidentate-chelation assistance has been developed. The reaction is compatible with a wide range of quinoline substrates and arylsulfonyl chlorides. Experimental and theoretical (DFT) investigation implicated that a single-electron-transfer process is involved in this sulfonylation transformation.
An efficient one-pot and transition-metal-free chlorocyclization cascade of 2-aminopyridines with aliphatic carboxylic acids is reported. This transformation provides a novel approach to 2-chloro- or 3-chloro-substituted imidazo[1, 2-α]pyridines with a broad range of substrate scopes.
A Rh(iii)-catalyzed cross-coupling/cyclization cascade of α-imino Csp(3)-H bonds with donor/acceptor α-acyl diazocarbonyl compounds has been developed. This novel transformation involves ligand-directed Csp(3)-H bond functionalization with carbenoids under the pyridine-chelation assistance, and offered an efficient access to synthetically versatile polysubstituted N-(2-pyridyl)pyrroles with a broad range of functional group tolerance.
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