Synthesis of Nitrile-Bearing Quaternary Centers by an Equilibrium-Driven Transnitrilation and Anion-Relay Strategy.

The efficient preparation of nitrile-containing building blocks is of interest due to their utility as synthetic intermediates and their prevalence in pharmaceuticals. As a result, significant efforts have been made to develop methods to access these motifs which rely on safer and non-toxic sources of CN. Herein, we report that 2-methyl-2-phenylpropanenitrile is an efficient, non-toxic, electrophilic CN source for the synthesis of nitrile-bearing quaternary centers by a thermodynamic transnitrilation and anion-relay strategy. This one-pot process leads to nitrile products resulting from the gem-difunctionalization of alkyl lithium reagents.

Cyclic Hypervalent Iodine Reagents for Azidation: Safer Reagents and Photoredox-Catalyzed Ring Expansion.

Azides are building blocks of increasing importance in synthetic chemistry, chemical biology, and materials science. Azidobenziodoxolone (ABX, Zhdankin reagent) is a valuable azide source, but its safety profile has not been thoroughly established. Herein, we report a safety study of ABX, which shows its hazardous nature. We introduce two derivatives, tBu-ABX and ABZ (azidobenziodazolone), with a better safety profile, and use them in established photoredox- and metal-mediated azidations, and in a new ring-expansion of silylated cyclobutanols to give azidated cyclopentanones.

Divergent Access to (1,1) and (1,2)-Azidolactones from Alkenes using Hypervalent Iodine Reagents.

A versatile synthesis of azidolactones through azidation and cyclization of carboxylic acids onto alkenes has been developed. Based on either photoredox or palladium catalysis, (1,1) and (1,2) azido lactones can be selectively synthesized. The choice of catalyst and benziodoxol(on)e reagent serving as azide source was essential to initiate either a radical or Lewis acid mediated process with divergent outcome. These transformations were carried out under mild conditions using a low catalyst loading and gave access to a large scope of azido lactones.

Superacid-Catalyzed Trifluoromethylthiolation of Aromatic Amines.

Upon activation under superacid conditions, functionalized tailor-made N-SCF3 sulfenamides served as reagents for the trifluoromethylthiolation of aromatic amines. This method has a broad substrate scope and can be used for the late-stage functionalization of complex molecules such as alkaloids or steroids. Mechanistic studies based on in situ low-temperature NMR spectroscopy revealed the involvement of dicationic superelectrophilic intermediates.

Copper-Catalyzed Perfluoroalkylthiolation of Alkynes with Perfluoroalkanesulfenamides.

Copper-catalyzed direct perfluoroalkylthiolation of alkynes by using the corresponding perfluoroalkanesulfenamide reagent is reported. The selective mono- and bis-perfluoroalkylthiolation of alkynes can be conducted under very mild conditions (no base, room temperature) in very good to excellent yields. This approach, which uses a low toxicity, inexpensive copper catalyst that incorporates a commercially available ligand, is applied in the absence of any additional base. Preliminary mechanistic investigations shed some light on the nature of the unprecedented reactivity observed.

Mild and Soft Catalyzed Trifluoromethylthiolation of Boronic Acids: The Crucial Role of Water.

The most reactive 2nd generation of trifluoromethanesulfenamides undergoes a copper-catalyzed cross-coupling reaction with boronic acids to afford CF3 S-molecules. Contrary to the previous methods in the literature, no base addition, no heating, and no large excess of reagents are required to obtain good results. Furthermore, a crucial role of a small amount of water to favor this reaction has been demonstrated. This constitutes the mildest described conditions for such a reaction.

Electrophilic trifluoromethylthiolation of carbonyl compounds.

A general method for the α-trifluoromethylthiolation of carbonyl compounds, without prefunctionalization, has been developed. Aldehydes, ketones, esters, amides, keto-esters, alkaloids, and steroids have been trifluoromethylthiolated with good yields. This work, proposing a new reagent for electrophilic trifluoromethylthiolation, provides a route towards the original synthesis of various trifluoromethylthiolated molecules for further applications.

Direct electrophilic N-trifluoromethylthiolation of amines with trifluoromethanesulfenamide.

The CF3SN moiety is a substituent with interesting properties. However, there is no easy synthetic access to molecules bearing this group. The trifluoromethanesulfenamide is a new reagent for the electrophilic trifluoromethylthiolation which reacts easily with amines to obtain trifluoromethylsulfanylamines with good yields.