Nickel-catalyzed stereo-controlled 2,3-hydrosilylation of 1,1-disubstituted allenes.

Directing regioselectivity and stereoselectivity in allene reactions has long been a significant challenge due to the multiple reactive pathways available. In this study, we report the development of a Ni-catalyzed regio- and stereoselective 2,3-hydrosilylation of 1,1-disubstituted allenes. Stereoselectivity was precisely controlled through the strategic modulation of ligand-induced steric effects and non-covalent interactions.

Photosensitizer-Free Benzo[1,4]oxazin-2-one Synthesis by Continuous-Flow Photochemistry.

We report a photosynthetic method for producing 2H-benzo[b][1,4]oxazin-2-ones from aryl azides and α-ketoacids. This method is highly sustainable, requiring only visible light irradiation of the substrates and no external additives. Furthermore, we implemented a continuous-flow system to achieve efficient light irradiation and rapid mixing, significantly improving reaction efficiency and reducing reaction time compared to the batch process.

Dual Photoredox and Nickel Catalysis in Regioselective Diacylation: Exploring the Versatility of Nickel Oxidation States in Allene Activation.

We present a nickel-catalyzed regioselective radical diacylation of allenes with ketoacids to produce 1,4-dione products by dual photoredox and nickel catalysis. This integrated approach merges redox-active oxidative addition and reductive elimination steps with migratory insertion. The acyl radical generated in the photoredox cycle sequentially adds to Ni(I) and Ni(II) intermediates following a Ni(I)-Ni(II)-Ni(II)-Ni(III)-Ni(I) catalytic cycle.

Nickel-Catalyzed Enantioselective Synthesis of 2,3,4-Trisubstituted 3-Pyrrolines.

The development of synthetic methods to produce highly functionalized chiral 3-pyrrolines is of indisputable importance because of their prevalence in natural and synthetic bioactive molecules. Unfortunately, previous general cycloaddition approaches using allenoates, could not synthesize 3,4-disubstituted 3-pyrrolines. Herein, an original approach to yield 2,3,4-trisubstituted 3-pyrrolines with chirality at the 2-position is presented.

Nickel-Catalyzed -Carboamination across Internal Alkynes to Access Multifunctionalized Indoles.

A Ni-catalyzed reaction was developed for the synthesis of multifunctionalized indoles. The reaction proceeded through oxidative cyclization of the Ni(0)/P^N complex with an enyne system, 2-alkynyl anilinoacrylate, to provide a nickelacycle intermediate. The -carboamination around the internal alkyne was achieved by /-rotation of the Ni-carbenoid intermediate formed by C-N bond cleavage of the nickelacycle, and 3-alkenylated indoles were formed by C-N bond-forming reductive elimination.

Distinctive reactivity of -benzylidene-[1,1'-biphenyl]-2-amines under photoredox conditions.

A simple photocatalytic method was developed for the synthesis of unsymmetrical 1,2-diamines by the unprecedented reductive coupling of -benzylidene-[1,1'-biphenyl]-2-amines with an aliphatic amine. The presence of a phenyl substituent in the aniline moiety of the substrate was critical for the reactivity. The reaction proceeded via radical-radical cross-coupling of α-amino radicals generated by proton-coupled single-electron transfer in the presence of an Ir photocatalyst.

Eosin Y photoredox catalyzed net redox neutral reaction for regiospecific annulation to 3-sulfonylindoles via anion oxidation of sodium sulfinate salts.

An eosin Y photoredox catalyzed net redox neutral process for 3-sulfonylindoles via the anionic oxidation of sodium sulfinate salts and its radical cascade cyclization with 2-alkynyl-azidoarenes was developed with visible light as a mediator. The reaction offers metal and oxidant/reductant free, visible light mediated vicinal sulfonamination of alkynes to 2-aryl/alkyl-3-sulfonylindoles and proceeds via the generation of a sulfur-centered radical through direct oxidation of the sulfinate anion by an excited photocatalyst with a reductive quenching cycle. The mild conditions, use of an organic dye as photo-catalyst, bench stability and easily accessible starting materials make the present approach green and attractive.