RESUMO
The chemical valorization of widespread molecules in renewable sources is a field of research widely investigated in the last decades. In this context, we envisaged that indole-3-carbinol, present in different Cruciferae plants, could be a readily available building block for the synthesis of various classes of indoles through a palladium-catalyzed Tsuji-Trost-type reaction with O and S soft nucleophiles. The regiochemical outcome of this high-yielding functionalization shows that the nucleophilic substitution occurs only at the benzylic position. Interestingly, with this protocol, the sulfonyl unit could be appended to the indole nucleus, providing convenient access to new classes of molecules with potential bioactivity.
RESUMO
The palladium-catalyzed reaction of N-protected 2-indolylmethyl acetates with soft carbon pronucleophiles is described. Besides the formation of the expected coupling reaction at the C1' position, unprecedented attack at the C3 position of the plausible η3-indolyl-palladium intermediate has been observed, and the selectivity control C1'/C3 seems to depend on the nature of the protecting group and ligand. The reactivity of 3-indolylmethyl acetates has also been also investigated. Quantum chemical calculations support the experimental results.