I2 Catalyzed and TBHP/Ammonium-Promoted Conversion of Arylethanone to Nitriles via β-Scission of Iminyl Radicals

Herein, we report a general I2-catalyzed and TBHP/ammonium-promoted conversion of arylethanone to aromatic nitriles under air. This procedure proceeded with the β-scission of iminyl radical, which was facilitated via quenching the released alkyl radical by tert-butyl peroxyl radical leading to peroxide followed with Kornblum-DeLaMare rearrangement. A series of aryl methyl ketone and alkyl aryl ketone worked well with good functional group tolerance in high yields. As such, this metal-free procedure represents a facile, safe, green, and practical procedure in conversion of arylethanone to aromatic nitriles.

Fe-Catalyzed Direct Synthesis of Nitriles from Carboxylic Acids with Electron-Deficient N-Cyano-N-aryl-arylsulfonamide

Established carboxylic acids to nitriles conversion methods suffer from expensive catalysts, tedious steps, high temperatures (>200 °C), high pressure, or a narrow substrate range. Herein, we demonstrate a concise and efficient access to diverse nitrile compounds from ubiquitous carboxylic acids with electron-deficient N-cyano-N-aryl-arylsulfonamide (NCAS) in moderate to excellent yields. This strategy is promoted by an inexpensive iron catalyst and is generally compatible with primary, secondary, tertiary, and aryl carboxylic acids, as well as a variety of functional groups.

Cu2 O-Catalyzed Conversion of Benzyl Alcohols Into Aromatic Nitriles via the Complete Cleavage of the C≡N Triple Bond in the Cyanide Anion

Nitrogen transfer from cyanide anion to an aldehyde is emerging as a promising method for the synthesis of aromatic nitriles. However, this method still suffers from a disadvantage that a use of stoichiometric Cu(II) or Cu(I) salts is required to enable the reaction. As we report herein, we overcame this drawback and developed a catalytic method for nitrogen transfer from cyanide anion to an alcohol via the complete cleavage of the C≡N triple bond using phen/Cu₂ O as the catalyst. The present condition allowed a series of benzyl alcohols to be smoothly converted into aromatic nitriles in moderate to high yields. In addition, the present method could be extended to the conversion of cinnamic alcohol to 3-phenylacrylonitrile.

Mechanistic Insight into Pd(II)-Catalyzed Late-Stage Nondirected C(sp2)-H Cyanation of Toluene Using the Dual Ligands MPAA and Quinoxaline: A Density Functional Theory Investigation

Density functional theory (DFT) calculations were performed to investigate the mechanism of Pd(II)-catalyzed late-stage nondirected C(sp²)-H cyanation of toluene. We confirmed the resting state and catalytic active species of this stoichiometric reaction, and we calculated the full catalytic cycle to obtain a favorable reaction pathway. The DFT calculation results indicate that the morphology of the active species is essential for the observed concerted metalation/deprotonation step. Although C-H activation is reversible in principle, it is the regioselectivity- or product-determining step. Our calculation results show that the regioselectivity is not only influenced by the electron effects but also by the potential steric repulsion interactions between the substrates and the specific geometry of the catalyst. Interestingly, the transmetalation process involves the largest overall change in free energy; thus, transmetalation is defined as the rate-determining step and turnover-determining step.

Cleavage of carbon–carbon bonds by radical reactions

This review provides insights into the in situ generated radicals triggered carbon–carbon bond cleavage reactions.