Oxidative Rearrangement of Internal Alkynes To Give One-Carbon-Shorter Ketones via Manganese Porphyrins Catalysis

Oxidative rearrangement of internal alkynes catalyzed by manganese­(III) porphyrin is described, which opens a new access to one-carbon-shorter ketones using molecular oxygen. Under the standard conditions, a variety of alkynes including diarylalkynes and arylalkylalkynes rearranged smoothly to the corresponding ketones in high yields. Based upon experimental observations, a plausible reaction mechanism is proposed

Metal-Free Synthesis of Oxindoles via (NH₄)₂S₂O₈‑Mediated Halocarbocyclization of Alkenes in Water

A metal-free synthesis of oxindoles was achieved through the (NH₄)₂S₂O₈-mediated halocarbocyclization of alkenes. This protocol provides a practical and environmentally benign method for the construction of halo-containing oxindoles in water. The advantages of this reaction are its good functional group tolerance and mild reaction conditions. On the basis of experimental observations, a plausible reaction mechanism is proposed

Highly efficient and green esterification of carboxylic acids in deep eutectic solvents without any other additives

<p>A protocol that carboxylic acids esterifies with the quaternary ammonium salt of deep eutectic solvent (DES) is presented, which opens a new access to ester using DES as alkylating agent, solvent, and catalyst. The reaction runs smoothly in DES without any other additives. Substituted cinnamic acids, aromatic acids, and aliphatic acids can be esterified in moderate to good yields. The advantages of this reaction include excellent functional group compatibility and simple reaction procedure.</p