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A Et3N-mediated Neber reaction of aryl/alkyl-2,2,2-trifluoroethylketoximes has been developed. This one-pot metal-free protocol enables the facile construction of an array of trifluoromethyl-substituted azirines in moderate to high yields under mild reaction conditions. Further transformations of azirines to CF3-containing pyrrole and amino-alcohol derivatives are also demonstrated.

A Et3N-catalyzed [3 + 2] cycloaddition reaction of allenoates with acceptor diazo compounds that include diazoesters, diazoketones, and diazoamides, has been developed. This transformation allows direct and regioselective synthetic route to a variety of pyrazoles from allenoates. 3-Alkynoates also participate in the cycloaddition reaction by isomerizing to the corresponding allenoates in situ.

Here we present a dipolar [3 + 2] cycloaddition transformation of diazoacetates with arenediazonium salts under silver catalysis, thus offering a straightforward approach for the regioselective construction of carboxylic tetrazoles. Several merits are accompanied with this reaction including readily available starting reagents, broad coupling scope, high yields, and friendly reaction conditions. The synthetic value is further showcased by one-pot conversion of commercially available primary arylamines to tetrazoles and successful transformations of the cycloadducts into valuable 5-fluoromethyltetrazoles and an analogue of P2X3 receptor antagonist.

A facile and effective enantioselective addition of terminal 1,3-diynes to acyclic α-CF 3 ketimine esters has been developed by using zinc/Binol complexes. The reaction works well with a variety of aromatic-, aliphatic- and silyl-substituted diynes, providing the desired products in up to 97% yield and 97% enantiomeric excess.