Integrating Olefin Carboamination and Hofmann-Löffler-Freytag Reaction by Radical Deconstruction of Hydrazonyl N-N Bond.

As a type of elementary organic compounds containing N-N single bond, hydrazone involved chemical conversions are extremely extensive, but they are mainly limited to N2-retention and N2-removal modes. We report herein an unprecedented protocol for the realization of division utilization of the N2-moiety of hydrazone by a radical facilitated N-N bond deconstruction strategy. This new conversion mode enables the successful combination of alkene carboamination and Hofmann-Löffler-Freytag reaction by the reaction of N-homoallyl mesitylenesulfonyl hydrazones with ethyl difluoroiodoacetate under photocatalytic redox neutral conditions. Mechanism studies reveal that the reaction undergoes a radical relay involving addition, crucial remote imino-N migration and H-atom transfer. Consequently, a series of structurally significant ϵ-N-sulphonamide-α,α-difluoro-γ-amino acid esters are efficiently produced via continuous C-C bond and dual C-N bonds forging.

Radical 1,4/5-Amino Shift Enables Access to Fluoroalkyl-Containing Primary ß(γ)-Aminoketones under Metal-Free Conditions.

A novel radical 1,4/5-amino shift from the oxygen center of alkene-tethered diphenyl ketoxime ethers to the carbon center to achieve high value-added fluoroalkyl-containing primary ß(γ)-amino-ketones is reported. Mechanism studies reveal that the migration is triggered by the alkene addition of fluoroalkyl radical derived from the electron donor-acceptor (EDA) complex of Togni's reagent II or fluoroalkyl iodides and quinuclidine, and involves a unique 5(6)-exo-trig cyclization of the carbon-centered radical onto the N-atom of ketoxime ethers followed by a cascade sequence of N-O bond cleavage and dehydrogenation. Notably, besides Togni's reagent II and fluoroalkyl iodides, this protocol is also compatible with other radical precursors to provide various functionalized primary aminoketones.

Visible-Light-Driven Aryl Migration and Cyclization of α-Azido Amides.

This paper reports two new visible-light-promoted radical reactions of α-azido amides. By catalysis of [Ir(ppy)2(dtbbpy)]PF6 with i-Pr2NEt as the reducing agent, N-aryl α-azido tertiary amides were first converted to the corresponding aminyl radicals through reduction of the azido group; the aminyl radicals then underwent N-to-N aryl migration to give α-anilinyl-functionalized amides. α-Azido secondary amides, on the other hand, reacted with the solvent ethanol and i-Pr2NEt to afford the imidazolinone products.

Decarboxylative Borylation of mCPBA-Activated Aliphatic Acids.

A decarboxylative borylation of aliphatic acids for the synthesis of a variety of alkylboronates has been developed by mixing m-chloroperoxybenzoic acid (mCPBA)-activated fatty acids with bis(catecholato)diboron in N,N-dimethylformamide (DMF) at room temperature. A radical chain process is involved in the reaction which initiates from the B-B bond homolysis followed by the radical transfer from the boron atom to the carbon atom with subsequent decarboxylation and borylation.