An Efficient Synthesis of 2-CF3-3-Benzylindoles

Abstract

The reaction of α-CF3-β-(2-nitroaryl) enamines with benzaldehydes afforded effectively α,β-diaryl-CF3-enones having nitro group. Subsequent reduction of nitro group by NH4HCO2-Pd/C system initiated intramolecular cyclization to give 2-CF3-3-benzylindoles. Target products can be prepared in up to quantitative yields. Broad synthetic scope of the reaction was shown. Probable mechanism of indole formation is proposed.

Synthesis and Reactions of 3-Halogenated 2-CF3-Indoles

“…Mono-and di-bromo derivatives were prepared in 58% and 56% yields calculating on two steps (Scheme 1). rated convenient approaches towards α-CF3-phenethylamines [48], CF3-enones [49][50][51], CF3-β-carbolines [52], 2-CF3-3-arylindoles [52], 2-CF3-3-benzylindoles [53] and unsubstituted 2-CF3-indoles [54,55]. We have also examined several electrophilic reagents for modification of 2-CF3-indoles at C-3 atom [55].…”

“…Recently we have proposed the synthesis of α-CF 3 -β-aryl enamines [44][45][46], which have been shown to be potent CF 3 -building blocks for the synthesis of various fluorinated compounds. Using α-CF 3 -β-aryl enamines, we have elaborated convenient approaches towards α-CF 3 -phenethylamines [47], CF 3 -enones [48][49][50], CF 3 -β-carbolines [51], 2-CF 3 -3arylindoles [51], 2-CF 3 -3-benzylindoles [52] and unsubstituted 2-CF 3 -indoles [53,54]. We have also examined several electrophilic reagents for modification of 2-CF 3 -indoles at C-3 atom [54].…”