Expedient Synthesis of Alkyl and Aryl Thioethers Using Xanthates as Thiol-Free Reagents.

Thioethers are critical in the fields of pharmaceuticals and organic synthesis, but most of the methods for synthesis alkyl thioethers employ foul-smelling thiols as starting materials or generate them as by-products. Additionally, most thiols are air-sensitive and are easily oxidized to produce disulfides under atmospheric conditions; thus, a novel method for synthesizing thioethers is necessary. This paper reports a simple, effective, green method for synthesizing dialkyl or alkyl aryl thioether derivatives using odorless, stable, low-cost ROCSK as a thiol surrogate.

Access to Thienopyridine and Thienoquinoline Derivatives via Site-Selective C-H Bond Functionalization and Annulation.

To develop of an effective synthetic methodology for biologically relevant thienopyridines, a concise and efficient protocol is described for the synthesis of a series of substituted thienopyridine and thienoquinoline derivatives with high selectivity using EtOCSK as the sulfur source. The reaction proceeds via metal-free, site-selective C-H bond thiolation and cyclization of the alkynylpyridine and alkynylquinoline substrates.

Selective Synthesis of Substituted Pyridines and Pyrimidines through Cascade Annulation of Isopropene Derivatives.

Diverse substituted pyridines and pyrimidines with high selectivity were obtained using a concise and efficient protocol developed herein. The reaction proceeds via metal-free cascade annulation of isopropene derivatives. Using isopropene derivatives as C3 synthons, NHI as the "N" source, and formaldehyde or dimethyl sulfoxide as the carbon source, this reaction realizes the efficient formation of intermolecular C-N and C-C bonds.

Synthesis of Deuterated ()-Alkene through Xanthate-Mediated Hydrogen-Deuterium Exchange Reactions.

Herein we have developed a reversible hydrogen-deuterium exchange reaction of nonactivated olefins. By using EtOCSK as a mediator, the H/D exchange reaction was realized through repeated addition and elimination reactions, demonstrating reversible H/D exchange between ordinary olefins and deuterated olefins. Using the lowest cost DO without precious metal catalysts and ligands, a broad spectrum of compatibility of functional groups was achieved.

Metal-Free Oxidative Esterification of Ketones and Potassium Xanthates: Selective Synthesis of α-Ketoesters and Esters.

A novel and efficient oxidative esterification for the selective synthesis of α-ketoesters and esters has been developed under metal-free conditions. In the protocol, various α-ketoesters and esters are available in high yields from commercially available ketones and potassium xanthates. Mechanistic studies have proven that potassium xanthate not only promotes oxidative esterification but also provides an alkoxy moiety for the reaction, which involves the cleavage and reconstruction of C-O bonds.

NHI-Promoted and HO-Controlled Intermolecular Bis-sulfenylation and Hydroxysulfenylation of Alkenes via a Radical Process.

An NHI-promoted and HO-controlled intermolecular difunctionalization of alkenes for the synthesis of bis-methylsulfane and β-hydroxysulfides is presented. Mechanistic investigation revealed the reaction proceeds via methylthiyl radical addition to C═C of alkenes to give a carbon-centered radical and immediately cyclize to a thiiranium ion, followed by combination with HO to afford β-hydroxysulfides in 52-89% yields with chemo- and regioselectivities. In the absence of water, 1,2-disulfenylation takes place to give bis-methylsulfane in moderate to good yields.