Transition-metal-free iterative two-fold reductive coupling and 1,3-borotropic shift to form 1,4-skipped dienes.

We report herein a transition-metal-free two-fold reductive coupling between prenal (allyl) tosylhydrazone and boronic acids/1,3-borotropic shift cascade to furnish 1,4-skipped dienes. In this work, a single batch operation produces (,)-1,4-skipped dienes by undergoing a second reductive coupling of the transient boronic acid, which developed following the first reductive allylation and a cascade 1,3-boron migration. Remarkably, the protocol is compatible with various aryl- and alkyl-substituted boronic acids, is scalable and has demonstrated on 61 substrates with yields up to 98%.

Organophotoredox-Catalyzed Synthesis of Unnatural α/β Amino Acids and Peptides via Deaminative Three-Component Coupling.

Herein, we disclose an expedient visible-light-mediated, organophotoredox-catalyzed multicomponent synthesis of unnatural amino acids using a Katritzky salt, glyoxal derivatives, and substituted anilines. Mechanistically, an alkyl radical is generated from the Katritzky salt via a deaminative process that undergoes addition to the -generated imine to furnish α-amino acids in a moderate diastereoisomeric ratio. For the first time, we have demonstrated this deaminative protocol to access substituted β-amino acids from α-amino acid-derived Katritzky salts.

Shining light on the nitro group: distinct reactivity and selectivity.

The nitro moiety is an indispensable functional group in organic synthesis due to its facile introduction and reduction to the corresponding amines for a plethora of organic transformations. Owing to its distinct electronegative and conventional properties, it has been used for activated aromatic nucleophilic substitution (SAr) reactions, Smiles reactions, Henry reactions, acyl anion equivalents, Recently, the excellent photochemical properties of nitroarenes have been rediscovered by several groups, and their untapped potential in organic synthesis under UV or visible light irradiation has been exploited. Photoexcited nitroarenes can undergo facile reduction to amines, azo-coupling, metal-free reductive C-N coupling with boronic acids a 1,2-boronate shift, hydrogen atom transfer (HAT), oxygen atom transfer for anaerobic oxidation of organic molecules, molecular editing nitrene intermediates, denitrative coupling of β-nitrostyrene, radical α-alkylation of nitroalkanes, They have also been used as a photolabile protecting group in medicinal chemistry and chemical biology applications.

An HFIP-assisted, cobalt-catalyzed three-component electrophilic C-H amination/cyclization/directing group removal cascade to naphtho[1,2-d]imidazoles.

A concise and efficient method has been developed herein for the synthesis of valuable naphtho[1,2-d]imidazole derivatives. It involves an earth-abundant cobalt-catalyzed electrophilic C-H amination/cyclization/directing group removal cascade with -benzoloxyamines using paraformaldehyde as a one carbon synthon. Picolinamide has been utilized as a traceless directing group.