RESUMEN
Enantiomerically pure acyclic O,O-acetal compounds (up to 97 %â ee) have been accessed through chemo-, regio- and enantioselective palladium-catalyzed addition of oximes to alkoxyallenes. DFT calculations support that a protonative hydropalladation pathway is favourable, in which the hydrogen bonding interaction between the amide group of the diphosphine ligand and the alkoxyallene is critical for the highly stereoselective formation of the dioxygenated stereogenic center.
RESUMEN
A cobaloxime-catalyzed photochemical synthesis of allyl monofluorides from styrenes is described herein. This method is characterized by mild reaction conditions, low-cost catalyst, and broad substrate scope. Furthermore, this convenient method will provide a facile synthesis toward novel monofluoroalkylated natural product and pharmaceutical derivatives. Mechanistic investigations indicate that a monofluoroalkyl radical is involved in the catalytic cycle.
RESUMEN
Several new mono- and difluoromethylation reactions of cinnamic acids using an Eosin Y catalytic system are reported. An efficient alkene fluoromethylation of α,ß-unsaturated carboxylic acids was accomplished under ambient temperature and metal-free conditions, with a wide range of functional group tolerance. A mechanism that involves a radical process is proposed for this reaction.