Noncovalent Interactions in the Palladium-Catalyzed Diastereo- and Enantioselective Hydroalkylation of Alkoxyallenes with 2-Acylimidazoles.

A palladium-catalyzed diastereo- and enantioselective hydroalkylation of alkoxyallenes with 2-acylimidazoles has been developed featuring ()-DTBM-Garphos as a chiral ligand and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as an additive, providing access to enantiomerically pure carbonyl compounds bearing two vicinal acyclic stereogenic carbon centers with excellent stereocontrol (up to 20:1 dr and 97% ee).

Access to Chiral O,O-Acetals Enabled by Palladium-Catalyzed Asymmetric Addition of Oximes to Alkoxyallenes.

Enantiomerically pure acyclic O,O-acetal compounds (up to 97 % 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.

Irradiation-Induced Cobaloxime-Catalyzed C-H Monofluoroalkylation of Styrenes at Room Temperature.

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.

Visible-Light-Enabled Decarboxylative Mono- and Difluoromethylation of Cinnamic Acids under Metal-Free Conditions.

Several new mono- and difluoromethylation reactions of cinnamic acids using an Eosin Y catalytic system are reported. An efficient alkene fluoromethylation of α,β-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.