Synthesis of Acyl Alkenylindium Reagents and Their Application in the Synthesis of (<i>Z</i>)‑α,β-Unsaturated Ketones <i>via</i> Palladium-Catalyzed Cross-Coupling Reaction

A synthetic method for the preparation of acyl alkenylindium reagents was developed involving the hydroindation reaction of allenyl ketones with indium and indium chloride in methanol under mild conditions. Their synthetic applications were demonstrated from Pd-catalyzed cross-coupling reactions with aryl bromides and iodides and alkenyl and aryl triflates for the synthesis of (<i>Z</i>)-α,β-unsaturated ketones

Ruthenium-Catalyzed C–H Activation/Cyclization for the Synthesis of Phosphaisocoumarins

An efficient and cost-effective ruthenium-catalyzed oxidative cyclization of phosphonic acid monoesters or phosphinic acids with alkynes has been developed for the synthesis of a wide range of phosphaisocoumarins in good to excellent yields under aerobic conditions. A multitude of arylphosphonic acid monoesters and arylphosphinic acids having electron-donating and -withdrawing groups were oxidatively cyclized. Various diarylacetylenes, dialkylacetylenes, and alkylarylacetylenes effectively underwent the ruthenium-catalyzed oxidative cyclization. A substrate possessing benzoic acid as well as a phenylphosphonic monoester moiety was smoothly cyclized with hex-3-yne to afford a compound having both isocoumarin and phosphaisocoumarin moieties. Alkenylphosphonic monoester afforded phosphorus 2-pyrone through oxidative cyclization with alkyne. Competition experiments between diaryl- and dialkylalkynes and between diarylacetylenes having <i>p</i>-methoxy and <i>p</i>-chloro groups gave results which showed that the present oxidative cyclizations were not affected by the electronic effects of alkynes. Mechanistic studies revealed C–H bond metalation to be the rate-limiting step

Synthesis of 2‑Aryl‑2<i>H</i>‑benzotrizoles from Azobenzenes and <i>N</i>‑Sulfonyl Azides through Sequential Rhodium-Catalyzed Amidation and Oxidation in One Pot

An efficient synthetic method of 2-aryl-2<i>H</i>-benzotriazoles from nonprefunctionalized azobenzenes and <i>N</i>-sulfonyl azides via sequential Rh-catalyzed amidation (C–N bond formation) and oxidation (N–N bond formation) with PhI­(OAc)₂ in one pot is reported

ICl-Mediated Intramolecular Twofold Iodoarylation of Diynes and Diynyl Diethers and Amines: Synthesis of Bis(2<i>H</i>‑hydronaphthalene and chromene) and 2<i>H</i>‑Quinoline Bearing an Alkenyl Iodide Moiety

Electrophilic intramolecular twofold iodoarylation was developed from the reaction of diynes and diynyl diethers and amines with iodine monochloride under mild conditions, which produced bis­(2<i>H</i>-hydronaphthalene and chromene) and 2<i>H</i>-quinoline bearing an alkenyl iodide moiety in good to excellent yields. These compounds underwent Pd-catalyzed cross-coupling reactions with arylboronic acid and indium tris­(arylthiolate) to produce the functionalized styrene derivatives