Reissert indole synthesis Mechanism

The mechanism of the formation of 4-nitroindole parallels the Reissert indole synthesis and is discussed in references 2 and 3. 

The ester products we have been using so far can be hydrolysed and decarboxylated by the mechanism described in the last chapter if a free indole is required. In any case, it is not necessary to use diethyl oxalate as the electrophilic carbonyl compound. The strange antibiotic chuangxinmycin (which you met in Chapter 32) was made by a Reissert synthesis using the acetal of DMF as the electrophile. Here is part of the synthesis. 

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