Search

A catalyst-controlled acylation reaction of β-ketoesters was developed for the first time by combining visible-light photoactivation with Lewis acid or base catalysis. By employing a NiCl2·glyme complex with a bis(oxazoline) ligand as the Lewis acid catalyst, C-acylation products are exclusively achieved, while utilizing pyridine or DABCO as the Lewis base catalyst affords O-acylation products with complete regioselectivity. A range of β-ketoesters with satisfactory structural diversity were suitable for this transformation, demonstrating the functional group compatibility of the method, which was attributed to the mild reaction conditions. This success is heavily built upon the visible-light-induced Wolff rearrangement and the unique catalytic activation modes, and thus, this work significantly expands the applications of ketene chemistry.

Efficient and enantioselective radical difluoroalkylation and perfluoroalkylation reactions of β-ketoesters were successfully developed through an asymmetric photoredox and nickel catalysis cascade. This protocol provides Rf-containing quaternary stereocenters in up to 67% yield and 95:5 er with ethyl iododifluoroacetate and perfluoroalkyl iodides (C3F7I and C4F9I) as radical sources under extremely mild conditions.

A dual visible light photoredox and nickel-catalyzed cross-coupling reaction of 2-arylaziridines and potassium benzyltrifluoroborates is described for the first time. This strategy features high functional group tolerance, exclusive regioselectivity for reaction at the more hindered C-N bond, easily accessible substrates, and mild redox-neutral reaction conditions. A variety of diversely substituted β-substituted amines are obtained in generally good yields.