TfOH-promoted cyclocondensation reaction of 2-arylacetonitriles

Nucleophilic Substitution of Tertiary Sulfonamides: Construction of Sulfonate Esters

Under the combined action of trichloroisocyanuric acid (TCCA) and triflic acid (TfOH), tertiary sulfonamides are efficiently activated, leading to the in situ generation of electrophilic sulfonamide salts. These electrophilic salts subsequently undergo nucleophilic substitution by alcohols, resulting in the formation of sulfonate esters under mild conditions. Other advantages of this method include the absence of transition-metal catalysts, broad substrate applicability, and high functional-group tolerance.

Synthesis of Isoxazoles via One-Pot Oxidation/Cyclization Sequence from Propargylamines

A facile strategy for the synthesis of isoxazoles has been efficaciously developed, which involves oxidation of propargylamines to the corresponding oximes followed by CuCl-mediated intramolecular cyclization of the latter. This protocol shows a straightforward way to construct a series of isoxazole cores with a wide range of functional group compatibility. Meanwhile, a gram-scale experiment and synthetic applications can be successfully operated.