Synthesis of α‐(2‐Hydroxyphenyl)‐α‐Aminoketones by Rhodium‐Catalyzed Tandem Reaction of 1‐Sulfonyl‐1,2,3‐Triazoles and Benzoquinone‐Derived Alcohols

Amine-Directed Regioselective Pyridyl Csp2-H Aminovinylation

A Rh-catalyzed amine-directed cross-coupling of 2-aminopyridines with 1-sulfonyl-triazoles has been developed. The method provides an efficient approach to access 5-aminovinylpyridines with wide functional group tolerance.

Synthesis of Benzofuran Derivates via a Gold-Catalyzed Claisen Rearrangement Cascade

A novel method toward a facile synthesis of diverse benzofuran derivates from easily obtained quinols and alkynyl esters has been reported. A gold-catalyzed intermolecular alkoxylation/Claisen rearrangement/condensation cascade was involved. The introduction of difluorodiphenylsilane as a water-trapping reagent in the reaction leads to a higher yield.

Rhodium(II)-Catalyzed Highly Selective 1,3-Insertion Reactions Using N-Sulfonyl-1,2,3-Triazoles with Heteroaryl Ethers or Heteroaryl Alcohols

The transformation of N-sulfonyl-1,2,3-triazoles via insertion/rearrangement is achieved using 2-hydroxybenzimidazole or 2-alkoxybenzothiazole over 3 mol % Rh₂(Oct)₄ for the synthesis of α-((1H-benzo[d]imidazol-2-yl)amino) ketones or (Z)-2-alkoxy-2-phenylethenamines. This regio- and stereoselective reaction proceeds under mild conditions, is tolerant of functional groups, and has a broad substrate scope. Notably, while the general rhodium-catalyzed reaction involves sigmatropic rearrangement from an allyl vinyl ether, the present synthetic methodology prevents rearrangement owing to the benzimidazole group, allowing access to (Z)-olefins.

Base-Induced Highly Regioselective Synthesis of N2-Substituted 1,2,3-Triazoles under Mild Conditions in Air

We developed a highly regioselective base-induced synthesis of N²-substituted 1,2,3-triazoles from N-sulfonyl-1,2,3-triazoles and alkyl bromides/alkyl iodides at room temperature. We propose an S_N2-like mechanistic pathway to explain the high N²-regioselectivity. The protocol features a broad substrate scope and generates products in good to excellent yields (72-90%).

Cycloaddition of N-sulfonyl and N-sulfamoyl azides with alkynes in aqueous media for the selective synthesis of 1,2,3-triazoles

The cycloaddition of N-sulfonyl and N-sulfamoyl azides with terminal alkynes generally produces amide derivatives via ketenimine intermediates. We herein delineate a Cu(I) catalyzed method using a prolinamide ligand that selectively generate N-sulfonyl and sulfamoyltriazoles in aqueous media by inhibiting the cleavage of the N1-N2 bond of 5-cuprated triazole intermediates. The present method is mild and tolerant to air, moisture and a wide range of functional groups thereby providing an easy access to a variety of triazole products.

Doyle-Kirmse reaction using 3,3-difluoroallyl sulfide and N-sulfonyl-1,2,3-triazole: an efficient access to gem-difluoroallylated multifunctional quaternary carbon

A Doyle-Kirmse reaction of N-sulfonyl-1,2,3-triazole with 3,3-difluoroallyl sulfide through a Rh(ii)-catalyzed [2,3]-sigmatropic rearrangement has been developed, which provides an efficient access to multifunctional quaternary centers containing aryl, imino, thio, and brominated gem-difluoroallyl groups. The reaction features broad substrate scope with moderate to excellent yields. The applicability of the method is confirmed by gram-scale synthesis and further transformations.

Grob-type fragmentation of an oxonium ylide generated from α-imino rhodium carbene

A Grob-type fragmentation of an oxonium ylide generated from α-imino rhodium carbene and tethered tetrahydrofuran was realized, leading to functionalized acroleins.

Rh(ii)-Catalyzed denitrogenative 1-sulfonyl-1,2,3-triazole-1-alkyl-1,2,3-triazole cross-coupling as a route to 3-sulfonamido-1H-pyrroles and 1,2,3-triazol-3-ium ylides

The reaction of 1-alkyl-1H-1,2,3-triazoles with rhodium(ii) azavinyl carbenes, generated from 1-sulfonyl-1H-1,2,3-triazoles, was utilized to prepare 3-sulfonamido-1H-pyrroles and 1,2,3-triazol-3-ium ylides in good yields.