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Scheme 1.
Reagents and conditions: (a) [Cp∗RhCl2]2, NaBArF4, CH3COOH, 100 °C, 8 h, 20.0%–87.0%; (b) 1 M NaOH (aq.), CH3OH, 50 °C, 2 h, 37.0%–99.0%.