Design, synthesis, application and recovery of a minimally fluorous diaryl diselenide for the catalysis of stannane-mediated radical chain reactions

Recent Advances in Dearomative Partial Reduction of Benzenoid Arenes

Dearomative partial reduction is an extraordinary approach for transforming benzenoid arenes and has been well-known for many decades, as exemplified by the dehydrogenation of Birch reduction and the hydroarylation of Crich addition. Despite its remarkable importance in synthesis, this field has experienced slow progress over the last half-century. However, a revival has been observed with the recent introduction of electrochemical and photochemical methods. In this Minireview, we summarize the recent advancements in dearomative partial reduction of benzenoid arenes, including dihydrogenation, hydroalkylation, arylation, alkenylation, amination, borylation and others. Further, the intriguing utilization of dearomative partial reduction in the synthesis of natural products is also emphasized. It is anticipated that this Minireview will stimulate further progress in arene dearomative transformations.

Catalysis of stannane-mediated radical chain reactions by benzeneselenol

The discovery and development of the catalysis of stannane-mediated radical chain reactions by benzeneselenol, generated in situ by reduction of diphenyl diselenide with tributyltin hydride, are described. The catalytic sequence is discussed in terms of polarity reversal catalysis of radical chain reactions, and applications to synthesis are presented. These include the prevention of numerous radical rearrangement reactions, the ability to intervene in certain multistep radical rearrangements, especially aryl and vinyl radical cyclizations, at intermediate stages with advantages to the product profile, and the effective trapping of allyl-, benzyl-, and cyclohexadienyl-type radicals, permitting inter alia the isolation of aryl cyclohexadienes and their application in synthesis.

Catalytic Oxidation Adjacent to Carbonyl Groups and at Benzylic Positions with a Fluorous Seleninic Acid in the Presence of Iodoxybenzene

In conjunction with iodoxybenzene as oxidant, perfluorooctylseleninic acid serves as a catalyst for the oxidation of aryl alkyl ketones to the corresponding ketoacids. Benzylic methylene groups are also oxidized by this reagent combination to the corresponding ketones.

Synthesis of new diselenide compounds as anti-inflammatory agents

Many diselenide compounds are used as antioxidants, enzyme inhibitors and cytokine inducers. Three new diselenide compounds, bis-(2-hydroxyphenyl) diselenide, bis-(3-hydroxyphenyl) diselenide and bis-(4-hydroxyphenyl) diselenide were designed and synthesized as anti-inflammatory agent. All of them were found to have strong in vitro activity in anti-inflammatory assays.

Catalytic Allylic Oxidation with a Recyclable, Fluorous Seleninic Acid

In conjunction with iodoxybenzene as reoxidant perfluorooctylseleninic acid catalyzes the allylic oxidation of alkenes to enones in trifluoromethylbenzene at reflux in moderate to good yield. After a reductive workup with sodium metabisulfite, the catalyst is recovered by fluorous extraction in the form of bis(perfluorooctyl) diselenide, which, itself, serves as a convenient catalyst precursor. [reaction: see text]

Efficient conversion of vicinal diols to alkenes by treatment of the corresponding dimesylates with a catalytic, minimally fluorous, recoverable diaryl diselenide and sodium borohydride

In conjunction with sodium borohydride as stoichiometric reagent a catalytic quantity of bis(4-perfluorohexylphenyl) diselenide converts vicinal dimesylates to the corresponding alkenes in good yield on warming in ethanol. The diselenide is recovered in high yield by continuous fluorous extraction.

Efficient one-pot conversion of carbonyl compounds to their alpha,beta-unsaturated derivatives using a recoverable, minimally fluorous organoselenium reagent

A protocol for the preparation of a fluorous arylselenenyl chloride is described. This selenenyl chloride may be used for the direct alpha-selenation of ketones and, following oxidation and syn-elimination, formation of alpha,beta-unsaturated carbonyl compounds. Treatment of the crude reaction mixtures with sodium metabisulfite reduces the various selenium species to the diaryl diselenide, which is then recovered in high yield by continuous fluorous extraction.