Silver-Catalysed Hydroarylation of Highly Substituted Styrenes

Coupling Titanium and Chromium Catalysis in a Reaction Network for the Reprogramming of [BH4 ]- as Electron Transfer and Hydrogen Atom Transfer Reagent for Radical Chemistry

We describe a unique catalytic system with an efficient coupling of Ti- and Cr-catalysis in a reaction network that allows the use of [BH4 ]- as stoichiometric hydrogen atom and electron donor in catalytic radical chemistry. The key feature is a relay hydrogen atom transfer from [BH4 ]- to Cr generating the active catalysts under mild conditions. This enables epoxide reductions, regiodivergent epoxide opening and radical cyclizations that are not possible with cooperative catalysis with radicals or by epoxide reductions via Meinwald rearrangement and ensuing carbonyl reduction. No typical SN 2-type reactivity of [BH4 ]- salts is observed.

Direct Regioselective Hydro(hetero)arylation/Cyclocondensation Reactions of β-(2-Aminophenyl)-α,β-ynones by Means of Transition-Metal Catalysis/Brønsted Acid Synergism: Experimental Results and Computational Insights

Experimental results and computational insights explain the key role of transition-metal catalysis/Brønsted acid synergism in the achievement of the sequential regioselective direct heteroarylation/cyclocondensation reactions of β-(2-aminophenyl)-α,β-ynones with a variety of electron-rich aromatic heterocyclic/arenes to afford quinoline-(hetero)aromatic hybrids. The first approach to the synthesis of 4-(1H-pyrrol-2-yl)quinolines is described. The effectiveness of various transition metals is compared.

Synthesis of β,β-Disubstituted Styrenes via Trimethylsilyl Trifluoromethanesulfonate-Promoted Aldehyde-Aldehyde Aldol Coupling-Elimination

In the presence of trimethylsilyl trifluoromethanesulfonate (TMSOTf) and 2,6-lutidine, α,α-disubstituted aldehydes condense with electron-rich aromatic aldehydes to yield β,β-disubstituted styrenes. More electron-rich aromatic aldehydes react more rapidly and in higher yield. Preliminary results suggest that the reaction may proceed via the ionization and formal deformylation of an aldol intermediate.

Transition-metal-catalyzed C-H bond alkylation using olefins: recent advances and mechanistic aspects

Transition metal catalysis has contributed immensely to C-C bond formation reactions over the last few decades, and alkylation is no exception. The superiority of such methodologies over traditional alkylation is evident from minimal reaction steps, shorter reaction times, and atom economy while also allowing control over regio- and stereo-selectivity. In particular, hydrocarbonation of alkenes has grabbed increased attention due its fundamental ability to effectively and selectively synthesise a wide range of industrially and pharmaceutically relevant moieties. This review attempts to provide a scientific viewpoint and a systematic analysis of the recent developments in transition-metal-catalyzed alkylation of various C-H bonds using simple and activated olefins. The key features and mechanistic studies involved in these transformations are described briefly.

Electrochemically-mediated C–H functionalization of allenes and 1,3-dicarbonyl compounds to construct tetrasubstituted furans

We reported an electrocatalytic C–H activation method to construct novel highly functionalized tetrasubstituted furan derivatives, which uses allenes and 1,3-dicarbonyl compounds as substrates.

Iron-catalyzed alkylation of carbazole derivatives via hydroarylation of styrenes

The first direct and selective 3,6-di-alkylation of carbazoles via iron-catalyzed hydroarylation of styrenes is demonstrated. This simple, general and efficient method could deliver a wide range of di-benzyl-carbazoles with high chemo- and regio-selectivity at room temperature in up to 96% yield with no need for a noble-metal catalyst, directing group or additives.

Silver-catalyzed tandem 5- and 6-endo-cyclizations via concomitant yne-ol-imine activation: selective entry to 2-aryldihydrofuroquinolines

Ag(i)-catalyzed domino imination-intramolecular bi-heterocyclization-aromatization cascade has been developed to construct 2-aryldihydrofuroquinolines from aldehyde and unprotected 4-(2-aminophenyl)but-3-yn-1-ol via tandem 5-endo-dig and 6-endo-trig cyclization.