Bunnett indole synthesis

Scheme 13 General Mechanism for the Bunnett-Beugelmans Indole Synthesis...

In subsequent years, the Bunnett-Beugelmans indole synthesis has been pursued by Rossi and his coworkers [84-88]. A selection of Rossi s indole syntheses is in Scheme 11. The photostimulation of o-iodoaniline can be run in DMSO (equation 1), avoiding the use of ammonia. It can also be accompUshed with Fe(II) without irradiation. In all cases the dark reaction is sluggish and lower yielding. 

Rossi and colleagues extended the Bunnett-Beugelmans indole synthesis to carbazoles (Scheme 12) [87, 88]. The reaction may be run in liquid anunonia, DMSO, or THE For the process in equation 1, there is no reaction in the dark after 60 minutes, and an S l mechanism was implicated. The yields are generally very good to excellent, and the methodology was adapted to the synthesis of other benzo-fused heterocycles [88],... 

In 1970, Bunnett and Kim reported a new nucleophilic aromatic substimtion reaction the S l mechanism (substitution, radical-nucleophilic, first order) [77-80]. Nine years later, Bunnett [81] and Beugelmans [82,83] independently discovered the application of the S l reaction to the synthesis of indoles (Scheme 10). In Bunnett s work (equation 1) the aeetone enolate (and others) was generated from acetone and potassium tert-butoxide (tert-butyl alcohol) in the presence of potassium amide in liquid ammonia [81]. Indoles 16 to 18 were also prepared by Bard and Bunnett. Beugelmans and Roussi employed a similar... 

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