Stereoselective Radical Acylfluoroalkylation of Bicyclobutanes via N-Heterocyclic Carbene Catalysis.

Cyclobutanes are prominent structural components in natural products and drug molecules. With the advent of strain-release-driven synthesis, ring-opening reactions of bicyclo[1.1.

Cooperative NHC and Photoredox Catalyzed Radical Aminoacylation of Alkenes to Tetrahydropyridazines.

Tetrahydropyridazines constitute an important structural motif found in numerous natural products and pharmaceutical compounds. Herein, we report an aminoacylation reaction of alkenes that enables the synthesis of 1,4,5,6-tetrahydropyridazines through cooperative N-heterocyclic carbene (NHC) and photoredox catalysis. This approach involves the 6-endo-trig cyclization of N-centered hydrazonyl radicals, generated via single-electron oxidation of hydrazones, followed by a radical-radical coupling step.

Synthesis of Pyrroloindolines via N-Heterocyclic Carbene Catalyzed Dearomative Amidoacylation of Indole Derivatives.

Pyrroloindoline is a privileged heterocyclic motif that is widely present in many natural products and pharmaceutical compounds. Herein, we report an amidyl radical-mediated dearomatization for synthesizing a series of pyrroloindolines via N-heterocyclic carbene catalysis. In this organocatalytic process, the Breslow enolate served as both a single electron donor and an acyl radical equivalent to assemble C3a-acyl pyrroloindolines with a broad substrate scope.

Silylacylation of Alkenes through N-Heterocyclic Carbene Catalysis.

The construction of silicon-containing molecules has received increasing attention in recent years. Herein, we report the generation of silyl radicals through NHC catalysis under mild reaction conditions. This methodology offers a novel and convenient route to a diverse range of β-silyl ketones with a broad substrate scope and good functional group compatibility.

Deoxygenation of oximes for the synthesis of pyrrolines hydroimination cyclization.

Herein, we report the generation of iminyl radicals through photocatalytic deoxygenation of oximes with trivalent phosphine. The hydroimination reaction proceeded β-scission of a phosphoranyl radical, followed by 5- cyclization of the resulting iminyl radical. This protocol transforms oximes, including alkyl oximes, into a variety of pyrrolines in moderate to good yields.

Diastereoselective Radical Aminoacylation of Olefins through N-Heterocyclic Carbene Catalysis.

There have been significant advancements in radical-mediated reactions through covalent-based organocatalysis. Here, we present the generation of iminyl and amidyl radicals via N-heterocyclic carbene (NHC) catalysis, enabling diastereoselective aminoacylation of trisubstituted alkenes. Different from photoredox catalysis, single electron transfer from the deprotonated Breslow intermediate to -aryl hydroxylamine generates an NHC-bound ketyl radical, which undergoes diastereocontrolled cross-coupling with the prochiral C-centered radical.

Visible-Light-Induced Aza-Pinacol Rearrangement: Ring Expansion of Alkylidenecyclopropanes.

A novel visible-light-induced aza-pinacol rearrangement was developed for the first time. In this approach, the addition of the N-centered radical to the C═C bond of alkylidenecyclopropanes delivers a variety of cyclobutanimines and γ-butyrolactones, with all-carbon quaternary centers via the ring expansion of the cyclopropyl group, in moderate to good yields under mild reaction conditions.