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A highly modular method for the synthesis of (Z)-3-[amino(phenyl/methyl)methylidene]-1,3-dihydro-2H-indol-2-ones starting from easily available 3-bromooxindoles or (2-oxoindolin-3-yl)triflate and thioacetamides or thiobenzamides is described. A series of 49 compounds, several of which have previously been shown to possess significant tyrosin kinase inhibiting activity, was prepared in yields varying mostly from 70 to 97% and always surpassing those obtained by other published methods. The method includes an Eschenmoser coupling reaction, which is very feasible (even without using a thiophile except tertiary amides) and scalable. The (Z)-configuration of all products was confirmed by NMR techniques.

This review covers all known examples of [3 + 2]-cycloaddition between sydnones and both terminal as well as internal alkynes/cycloalkynes taken from literature since its discovery by Huisgen in 1962 up to the current date. Except enumeration of synthetic applications it also covers mechanistic studies, catalysis, effects of substituents and reaction conditions influencing reaction rate and regioselectivity.

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Reactions catalyzed by palladium(II) acetate and trifluoroacetic acid (TFA) have a clear preactivation phase.However, the structure of real catalytic species remains unclear. We show that the key species are cyclic trinuclear complexes of composition [Pd 3 (OAc) 6−x (OTFA) x ] (x = 1-6) formed by a sequential ligand exchange from [Pd 3 (OAc) 6 ]. Furthermore, we prove that the trinuclear palladium backbone of the precatalyst remains preserved during the first phase of the C-H activation reaction of acetanilides. In other words, the reaction pathway including the trinuclear species should be taken into account in discussion about mechanisms of the reactions catalyzed by palladium acetates.