Acid-Catalysed Rearrangments of 1-Arylindoles

Suggest a mechanism for the 1 — 2 transformation consistent with these observations. 

Conversion of 2 ,4, 6 -trihydroxyacetophenone to the tricarbonate proceeded smoothly in 87% yield on treatment with 3.3 equivalents of methyl chloroformate and triethylamine in THF at 0°C. Treatment of this tricarbonate with 4 equivalents of sodium borohydride in a 1 1 THF/water mixture at 0°C to ambient temperature gave the phenol 1 in 83% yield. 

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