Vanadium-Catalyzed Regioselective Oxidative Coupling of 2‑Hydroxycarbazoles
2016-01-15T12:06:19Z (GMT) by
The first regioselective oxidative coupling of 2-hydroxycarbazoles is described. With a vanadium catalyst and oxygen as the terminal oxidant, dimers with an ortho–ortho′ coupling pattern were obtained with high selectivity. Further oxidation led to ortho′–ortho′ coupling to generate a tetramer, which provided insight that the atropisomerization barriers of the unsymmetrical biaryl bonds are much lower than expected.
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