Commercially available pyridine ligands can significantly enhance the rate, yield, substrate scope, and site selectivity of arene C-H olefination (Fujiwara-Moritani) reactions. The use of a 1:1 ratio of Pd/pyridine proved critical to maximize reaction rates and yields.

Less is more: The rational optimization and general applicability of the catalytic system Pd(OAc)2/pyridine is described (see scheme). The catalyst shows excellent reactivity in the CH oxygenation of simple aromatic substrates. The Pd/pyridine ratio is critical as the use of one equivalent of pyridine per Pd center leads to dramatic enhancements in both reactivity and site selectivity in comparison to Pd(OAc)2 alone.

De novo syntheses of amides often generate stoichiometric amounts of waste. Thus, recent progress in the field has focused on precious metal catalyzed, oxidative protocols to generate such functionalities. However, simple tertiary alkyl amines cannot be used as starting materials in these protocols. The research described herein enables the oxidative synthesis of amides from simple, noncyclic tertiary alkyl amines under synthetically useful, mild conditions through a biologically inspired approach: Fe-catalyzed Cα-H functionalization. Mechanistic investigations provide insight into reaction intermediates and allow the development of a mild Cα-H cyanation method using the same catalyst system. The protocol was further applied to oxidize the drug Lidocaine, demonstrating the potential utility of the developed chemistry for metabolite synthesis.

This paper describes the development and mechanistic studies of a general, high-yielding amine C-H cyanation protocol via photoredox catalysis. Inexpensive NaCN is employed as the cyanide source and air is the external oxidant, resulting in mild and highly functional group tolerant conditions. Notably, efficient C-H cyanations of secondary and tertiary aliphatic amines and of complex, biologically active compounds (drugs) can be performed using the established methodology. Mechanistic studies suggest that the carboxylic acid additive has three effects: formation of a stabilizing hemiaminal intermediate, prevention of catalyst decomposition by protonating the substrate, and modulation of fluorescence quenching of the photoexcited catalyst species.

Cationic catalysts in HD: Palladium(II) and platinum(II) complexes of pyridinium‐substituted bipyridine ligands are highly active and stable catalysts for H/D exchange and oxidation of aromatic CH bonds (TONs up to 3200, TOFs up to 0.1 s−1; see scheme, EWG=electron‐withdrawing group, EDG=electron‐donating group).

This work presents a detailed structure–activity analysis of a polymeric solid acid catalyst used in cellulose hydrolysis. In contrast to previous work, our studies show that the high catalytic activity is likely not due to hydrogen bonding between C–Cl moieties at the polymer surface and cellulose fibers. Instead, we report that such C–Cl bonds hydrolyze readily under polymer functionalization conditions to produce C–OH groups on the exterior of the solid acid beads. Furthermore, continued C–Cl to C–OH substitution under cellulose or cellobiose hydrolysis conditions releases HCl from the resin, which contributes to cellulose hydrolysis. Overall, the presented studies stress the need for detailed, quantitative analysis of polymer structures and spatial distribution of functional groups in order to correctly interpret the catalytic results obtained with polymer-based solid acids.

This report describes the use of an oxidant and a ligand to control site selectivity in the Pd(OAc)2-catalyzed C-H acetoxylation of simple arenes. The use of MesI(OAc)2 as the terminal oxidant in combination with acridine as the ligand results in primarily sterically controlled selectivity. In contrast, with Pd(OAc)2 as the catalyst and PhI(OAc)2 as the oxidant, electronic effects dominate the selectivity of arene C-H acetoxylation.

In order to facilitate the development of recycling technologies for rare earth magnets from postconsumer products, we present herein an analysis of the neodymium (Nd) content in shredder scrap. This waste stream has been chosen on the basis of current business practices for the recycling of steel, aluminum, and copper from cars and household appliances, which contain significant amounts of rare earth magnets. Using approximations based on literature data, we have calculated the average Nd content in the ferrous shredder product stream to be between 0.13 and 0.29 kg per ton of ferrous scrap. A value analysis considering rare earth metal prices between 2002 and 2013 provides values between $1.32 and $145 per ton of ferrous scrap for this material, if recoverable as pure Nd metal. Furthermore, we present an analysis of the content and value of other rare earths (Pr, Dy, Tb).