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.

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.