Dehydroaromatization of Indolines and Cyclohexanones with Thiol Access to Aryl Sulfides under Basic Conditions.

Aryl sulfides are common and ubiquitous motifs in natural products and pharmaceuticals. Presented herein is the first example of the synthesis of diaryl sulfide derivatives via dehydroaromatization under simple basic conditions. Dehydroaromatization reactions between indolines or cyclohexanones with aryl thiols are performed in an environmentally benign manner by the use of air (molecular oxygen) as the oxidant, with producing water as the only byproduct. The methodology provides a simple and practical route to diaryl sulfides with wide functional groups in good to excellent yields. Preliminary mechanistic studies suggest that a radical process is involved in the transformation.

Four-Component Reaction Access to Nitrile-Substituted All-Carbon Quaternary Centers.

A four-component reaction strategy for access to acyclic nitrile-substituted all-carbon quaternary centers is disclosed. In the presence of a DABCO-based ionic liquid catalyst, the reactions proceed smoothly with a wide range of substrates efficiently to deliver nitrile-substituted all-carbon quaternary centers under mild reaction conditions. This protocol is further demonstrated as an efficient method for the construction of contiguous all-carbon quaternary centers. All the reactions are easily operated in a green manner, producing water as the only byproduct. Some of the products show excellent activity against specific fungi.

Aerobic Cross-Dehydrogenative Coupling Reactions for Selective Mono- and Dithiolation of Phenols.

A highly efficient strategy for the direct thiolation of phenols under transition metal-free and solvent-free conditions has been developed. These reactions are operationally simple with employing air (molecular oxygen) as an ideal oxidant and can selectively provide mono- and dithiolation products in good to excellent yields under basic conditions. The reaction tolerates a broad range of aryl thiols and arenes and is especially applicable for large-scale synthesis.

Iron-Catalyzed Direct Oxidative Alkylation and Hydroxylation of Indolin-2-ones with Alkyl-Substituted N-Heteroarenes.

Presented herein is the first direct alkylation and hydroxylation reaction between two different C(sp3 )-H bonds, indolin-2-ones and alkyl-substituted N-heteroarenes, through an oxidative cross-coupling reaction. The reaction is catalyzed by a simple iron salt under mild ligand-free and base-free conditions. The reaction is environmentally benign, employs air (molecular oxygen) as the terminal oxidant and oxygen source for the synthesis of O-containing compounds, and produces only water as the byproduct.

Iron-Catalyzed Oxidative Coupling of Indoline-2-ones with Aminobenzamides via Dual C-H Functionalization.

We describe an unprecedented dual C-H functionalization of indolin-2-one via an oxidative C(sp3)-H/N-H/X-H (X = N, C, S) cross-coupling protocol, which is catalyzed by a simple iron salt under mild and ligand-free conditions and employs air (molecular oxygen) as the terminal oxidant. This method is readily applicable for the construction of tetrasubstituted carbon centers from methylenes and provides a wide variety of spiro N-heterocyclic oxindoles.