Photoinduced Cascade C-N/C═O Bond Formation from Bromodifluoroalkyl Reagents, Amines, and H2O via a Triple-Cleavage Process

Oxygen Migration-Defluorination Strategy Enables the Aminocarbonylation of Enaminones with o-Aminobenzamides and CF2Br2

The development of different concept approaches and user-friendly carbonyl surrogates for aminocarbonylation is highly desirable. Herein, we report the photocatalytic aminocarbonylation of enaminones with easily available o-aminobenzamides and CF2Br2 through an oxygen migration-defluorination strategy. The reaction features switchable transformation for the construction of carbamoyl-substituted enaminones and enol products and allows the expedient synthesis of fully substituted maleimides under mild reaction conditions.

Base-promoted triple cleavage of CCl2Br: a direct one-pot synthesis of unsymmetrical oxalamide derivatives

We present a novel, eco-friendly and one-pot approach for synthesizing unsymmetrical oxalamides with the aid of dichloroacetamide and amine/amides in the presence of CBr4 in a basic medium. The use of water as a potent supplement for the oxygen atom source and the detailed mechanism have been disclosed. Moreover, the protocol involves triple cleavage of CCl2Br and the formation of new C-O/C-N bonds, with the advantage of achieving selective bromination using CBr4 with good to excellent yield under mild conditions. The method also demonstrates promise for industrial use, as proven by its effective implementation in gram-scale synthesis conducted in a batch process, along with its utilization in a continuous-flow system.

TBHP Mediated C-N Bond Cleavage of Tertiary Amines toward the Synthesis of Oxalamides and α,β-Epoxy Amides

An efficient and convenient method for the synthesis of oxalamides by the reaction of β-ketoamides with tertiary amines and TBHP was developed. A variety of β-ketoamides and tertiary amines substrates were well-tolerated in this transformation. Based on the control experiments, a plausible mechanism for this reaction was proposed that involved the tandem oxidation/amination process. In addition, α,β-epoxy amides could be obtained by adjusting the reaction conditions.

Visible-Light-Mediated Synthesis of α-Ketoamides via Oxidative Amination of 2-Bromoacetophenones Using Eosin Y as a Photoredox Catalyst

An oxidative amination of 2-bromoacetophenones has been accomplished to provide α-ketoamides by using photoredox catalysis with air as oxidant. The reactants are readily accessible, and the method is endowed with broad substrate scope and good functional group tolerance. The practicality of the approach is also shown by a gram-scale reaction.

Visible-Light-Induced Desaturative β-Alkoxyoxalylation of N-Aryl Cyclic Amines with Difluoromethyl Bromides and H2O Via a Triple Cleavage Process

A visible-light-driven desaturative β-alkoxyoxalyation of N-aryl cyclic amines with difluoromethyl bromides and H2O has been reported. This tandem reaction is triggered by homolysis of the C-Br bond to produce the difuoroalkyl radical, which undergoes the subsequent defluorinated β-alkoxyoxalylation cascades to afford a wide range of β-ketoester/ketoamides substituted enamines. The prominent feature of this reaction contains photocatalyst-free, transition-metal free, and mild conditions. The 18O labeling experiment disclosed that H2O is the oxygen source of the carbonyl unit.

Photoredox-Catalyzed Tandem Radical Cyclization/Hydroxylation for the Synthesis of 4-Hydroxyalkyl-3,3-difluoro-γ-lactams

The photoredox-catalyzed radical difluoroalkylation/cyclization/hydroxylation cascade reaction of various 2-bromo-2,2-difluoro-N-arylacetamides containing unactivated alkene moieties has been developed, providing green and efficient access to various 4-hydroxyalkyl-3,3-difluoro-γ-lactams. Control experiments confirmed a radical process, and inexpensive air acted as the sole hydroxy resource. In addition, the highlights of this protocol include good tolerance for a variety functional groups, lower photocatalyst loading, and ease of operation.