The development of rhodium-catalyzed diastereoselective N-sulfonylaminoalkenylation of azulenes using N-sulfonyltriazoles is described. This procedure can be successfully applied to rhodium-catalyzed diastereoselective N-sulfonylaminoalkenylation of azulenes starting from terminal alkynes and N-sulfonylazides via a three-component semi-one-pot process.

An efficient, one-pot synthetic method for producing functionalized indolizine derivatives was developed via a Rh-catalyzed [2 + 1]-cyclopropanation, Pd-catalyzed ring expansion, and subsequent oxidation using manganese dioxide from pyridotriazoles and 1,3-dienes.

Rhodium-catalyzed tandem oxidative alkenylation and an intramolecular oxy-Michael reaction were developed using arylphosphonic acid monoethyl esters and alkenes under aerobic conditions, which produced benzoxaphosphole 1-oxides in good to excellent yields.

Intramolecular hydroarylation using aryl alkynylphosphonates proceeds smoothly with a gold/silver catalyst in the presence of trifluoromethanesulfonic acid (TfOH) in the 6‐endo mode, thus affording a unique synthetic method for phosphacoumarins having various functional groups, which could be a privileged structure and prevalent scaffold in phosphorus heterocycles.magnified image

An efficient copper-TBAF-catalyzed C-N bond formation of sulfoximines with arylsiloxanes in dichloromethane at room temperature, affording the desired N-aryl sulfoximines in good to excellent yields under an oxygen atmosphere, is reported. This method complements the existing synthetic approaches due to some advantageous properties of arylsiloxanes such as availability, low toxicity, ease of handling, high stability, and environmental benignity under mild reaction conditions, thus opening a new approach to practical C-N bond formation.

We report aza-[4+3] annulation through sequential [3+2]-[2+1] cycloadditions-aza-Cope rearrangement for the synthesis of dihydroazepines. Aza-[3+2] annulation was achieved through [3+2]-[2+1]-aza-Cope rearrangement-1,3migration or [3+2]-[2+1]-Clock rearrangement, leading to the formation of dihydropyrroles. In addition, dihydroazepines thermally 1,3-migrated to give dihydropyrroles. This method affords a straightforward synthetic pathway from simple triazoles to produce dihydroazepines and dihydropyrroles together with N 2 as the single byproduct. This procedure can be successfully applied to a one-pot process starting from terminal alkynes, azides, and dienes.Azaheterocycles are a highly important class of compounds due to their biological activities and pharmaceutical applications. [1] In particular, dihydroazepines, dihydropyrroles, and pyrroles are constituents of a valuable privileged structure in organic chemistry. [2] For this reason, the development of efficient synthetic methods for producing multisubstituted azaheterocyclic compounds from simple and easily accessible starting materials has been continuously required. [3] Now, we report an efficient aza-[4+3] annulation and aza-[3+2] annulation starting from terminal alkynes, sulfonyl azides, and 1,3-dienes in one-pot (Scheme 1).Recently, 1-sulfonyl-1,2,3-triazoles, which are easily prepared from copper-catalyzed 1,3-dipolar cycloaddition of terminal alkynes with sulfonyl azides, have been extensively investigated as precursors of a-imino metal carbenes. [4] The high reactivity of a-imino metal carbenes toward nucleophiles is caused by the intrinsically electrophilic properties of the metal carbene species. In addition, a-imino metal carbenes can react with electrophiles because the nitrogen atom of the a-imino group is inherently nucleophilic. Accordingly, these amphiphilic a-imino metal carbenes smoothly react with nitriles, [5]

Ethyl α-(1-hydroxy-1-alkyl)methylallenoates and α-(1-hydroxy-1-aryl)methylallenoates containing not only electron-donating groups but also an electron-withdrawing group on the aryl group at the α-position have been shown to undergo an efficient and selective copper-catalyzed intramolecular hydroalkoxylation to give functionalized 3-ethoxycarbonyl-2-alkyl- and -aryl-2,5-dihydrofurans in good to excellent yields through a 5-endo mode.

Rhodium-catalyzed formal aza-[4 + 3] cycloaddition reaction of 3-diazoindolin-2-imines with 1,3-dienes was demonstrated for the synthesis of azepinoindoles in good to excellent yields in one-pot. First, rhodium-catalyzed [2 + 1] cycloaddition reaction smoothly took place to produce iminyl vinyl cyclopropane intermediate at room temperature in chlorobenzene for 1 h, which was thermally converted to azepinoindoles via aza-Cope rearrangement.