Acid-Catalyzed Highly Enantioselective Synthesis of α-Amino Acid Derivatives from Sulfinamides and Alkynes.

An enantioselective difunctionalization of activated alkynes using chiral sulfinamide reagents is developed. It is an atom and chirality transfer process that allows for the modular synthesis of optically active α-amino acid derivatives under mild conditions. The reaction proceeds through an acid-catalyzed [2,3]-sigmatropic rearrangement mechanism with predictable stereochemistry and a broad scope.

Palladium-Catalyzed Defluorinative Coupling of Difluoroalkenes and Aryl Boronic Acids for Ketone Synthesis.

The transition-metal-catalyzed carbonylation reaction is a useful approach for ketone synthesis. However, it is often problematic to use exogenous carbonyl reagents, such as gaseous carbon monoxide. In this manuscript, we report a novel palladium-catalyzed coupling reaction of gem-difluoroalkenes and aryl boronic acids that yields bioactive indane-type ketones with an all-carbon α-quaternary center. Characterization and stoichiometric reactions of the key intermediates RCF2 PdII support a water-induced defluorination and cross-coupling cascade mechanism. The vinyl difluoromethylene motif serves as an in situ carbonyl precursor which is unprecedented in transition-metal-catalyzed coupling reactions. It is expected to raise broad research interest from the perspectives of ketone synthesis, fluoroalkene functionalization, and rational design of new synthetic protocols based on the unique reactivity of difluoroalkyl palladium(II) species.

Application of natural deep eutectic solvents to extract ferulic acid from Ligusticum chuanxiong Hort with microwave assistance.

In this study, a method using natural deep eutectic solvents (NADES) combined with microwave-assistance extraction (MAE) was researched for the first time to establish an environmentally-friendly method for extracting ferulic acid from Ligusticum chuanxiong Hort. 20 kinds of NADES were initially screened, then response surface methodology was performed to optimize the NADES-MAE extraction of ferulic acid in L. c on the basis of the results of single-factor experiments. The results demonstrated that NADES could provide better extraction yields of ferulic acid than conventional solvents, and the combination of choline chloride and 1,2-propanediol was the most effective. The optimal conditions were an extraction time of 20 min, an extraction temperature of 68 °C, and a solvent-to-solid ratio of 30 : 1 mL g-1. Under these conditions, the extraction yield of ferulic acid with NADES-MAE (2.32 mg g-1) was higher than that using traditional extraction methods. This research demonstrates that this approach, which adopts NADES as a green solvent and MAE as an assistant extraction technique, could be an excellent choice to design an environmentally-friendly method for extracting phenolic compounds in various materials.