Iridium-Catalyzed Direct C–H Sulfamidation of Aryl Nitrones with Sulfonyl Azides at Room Temperature

Ir­(III)-catalyzed direct C–H sulfamidation of aryl nitrones has been developed to synthesize various sulfamidated nitrones in moderate to excellent yields with excellent regioselectivity and broad functional group tolerance. This transformation could proceed smoothly at room temperature with low catalyst loading in the absence of external oxidants, acids, or bases. Molecular nitrogen was released as the sole byproduct, thus providing an environmentally benign sulfamidation process. And this protocol could efficiently apply to synthesize the substituted benzisoxazoline via one-step transformation from the product

Iridium-Catalyzed Direct C–H Sulfamidation of Aryl Nitrones with Sulfonyl Azides at Room Temperature

Ir­(III)-catalyzed direct C–H sulfamidation of aryl nitrones has been developed to synthesize various sulfamidated nitrones in moderate to excellent yields with excellent regioselectivity and broad functional group tolerance. This transformation could proceed smoothly at room temperature with low catalyst loading in the absence of external oxidants, acids, or bases. Molecular nitrogen was released as the sole byproduct, thus providing an environmentally benign sulfamidation process. And this protocol could efficiently apply to synthesize the substituted benzisoxazoline via one-step transformation from the product

Transition Metal-Controlled Divergent Annulations of Azomethine Imines with Iodonium Ylides <i>via C</i>-Centered [1,2]-Rearrangement

Transition metal-controlled divergent annulation reactions of azomethine imines with iodonium ylides via C-centered [1,2]-rearrangement have been developed. The azomethine imino group, as a switchable and transient directing group (DG), underwent intramolecular nucleophilic addition and in situ generated bicyclic diaziridine, which facilitated the C-centered [1,2]-rearrangement and subsequent divergent annulations in the presence of different metal complexes as the catalysts. The benzo[c]chromen-1-one and pyrano[de]isochromene scaffolds could be independently constructed with Rh(III) and Ru(II), respectively. It was worth noting that the azomethine imino group was employed first as the switchable DG through rearrangement progress

Iridium(III)-Catalyzed C–H Amidation of Nitrones with Dioxazolones

Various amidated nitrones were efficiently achieved through Ir­(III)-catalyzed direct C–H amidation of nitrones with good to excellent yields and tolerance of broad functional groups. This reaction smoothly proceeded at room temperature in the absence of acid or base in a short reaction time. Carbon dioxide was generated as the sole byproduct, thus providing an environmentally benign amidation process. The title products could be efficiently transformed to substituted benzisoxazoline

Rhodium(III)-Catalyzed [4 + 2] Annulation of <i>N</i>‑Arylbenzamidines with Propargyl Alcohols: Highly Regioselective Synthesis of 1‑Aminoisoquinolines Controlled by Noncovalent Interaction

A highly regioselective synthesis of 1-aminoisoquinolines has been explored via rhodium­(III)-catalyzed C–H bond activation/annulation reactions of propargyl alcohols with N-arylbenzamidines. The imidamide was used as the directing group and the nitrogen source of the heterocycle and for regulating the regioselective migratory insertion of propargyl alcohol through a hydrogen bond. In this transformation, a specific isomer was obtained that would provide a new strategy for the synthesis of 1-aminoisoquinolines with biological activity

Lewis Acid-Catalyzed [3 + 2]-Cyclization of Iodonium Ylides with Azadienes: Access to Spiro[benzofuran-2,2′-furan]-3-ones

A highly regioselective synthesis of spiro­[benzofuran-2,2′-furan]-3-ones has been explored via Lewis acid-catalyzed [3 + 2] cyclization of iodonium ylides with azadienes. The acidity of the Lewis acid was significantly strengthened with strong hydrogen bond donors, thereby promoting the enolization isomerization of iodonium ylides for the subsequent cycloaddition. This reaction was compatible with a broad range of substrates under the mild reaction conditions, and efficiently delivered spiro-heterocycles with excellent stereoselectivity

2‑Butyne Biscarbonate as a “Bridge” in Rhodium(III)-Catalyzed [4 + 2] Cyclization and Diels–Alder Reaction

Described herein is the development of an unprecedented approach to construct multiple heterocycles with high selectivity through Rh(III)-catalyzed two- or three-component cyclization reaction from simple and readily available starting materials: N-methoxybenzamides, 2-butyne biscarbonate, and maleimides. This methodology provides an efficient strategy for the synthesis of diverse and complicated heterocycles in a one-pot manner and displays excellent features of extremely mild reaction conditions, easy operation, excellent regioselectivity, and good functional group compatibility