Wednesday, August 22, 2007

Indole synthesis

Fisher indole synthesis
started with N-substituted benzene, C-C bond is formed by an intramolecular rearrangement.
finished with elimination of NH3.

Neber-Taber indole synthesis
started with C-substituted benzene, C-N bond is formed by N* attack the benzene. finished with proton transfer from benzene to N.

The intermediate azirine is very stable and under elevated temp. or rt with some metal catalyst (rh dimer for example), the azirine smoothly rearranged to indole.

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