Photoinduced Acetylation of Anilines under Aqueous and Catalyst-Free Conditions.

A green and efficient visible-light induced functionalization of anilines under mild conditions has been reported. Utilizing nontoxic, cost-effective, and water-soluble diacetyl as photosensitizer and acetylating reagent, and water as the solvent, a variety of anilines were converted into the corresponding aryl ketones, iodides, and bromides. With advantages of environmentally friendly conditions, simple operation, broad substrate scope, and functional group tolerance, this reaction represents a valuable method in organic synthesis.

Total synthesis of absinthin.

(+)-Absinthin, a structurally unique triterpene, has been efficiently constructed in nine reaction steps and in 18.6% overall yield from O-acetylisophotosantonic lactone. The synthesis features Mitsunobu arylselenylation, oxidative elimination of allylic arylselenides, biomimetic dimerization via regio- and stereospecific Diels-Alder reaction, and a four-step stereochemical inversion of a highly sterically congested tertiary alcohol. This approach has not only tackled the formidable synthetic challenges in assembling structurally complex (+)-absinthin but also paved an efficient synthetic route to a series of medicinally attractive absinthin analogues.