A New and Efficient One-Pot Synthesis of 2-Fluoroalkyl Substituted Indoles

Abstract

A new simple and efficient one‐pot synthesis of 2‐fluoroalkyl substituted indoles from 2‐aminobenzyl alcohols with fluorine‐containing carboxylic acids in the presence of Ph3P, CCl4, and NEt3 is described. Various kinds of 2‐fluoroalkyl substituted indole derivatives can be conveniently prepared.

Trifluoroacetimidoyl halides: a potent synthetic origin

“…A simple approach for the formation of 2-fluoroalkyl indoles from 2-aminobenzyl alcohols with fluoroalkanoic acids in the presence of Ph 3 P, CCl 4 , and NEt 3 was developed by Wang and co-workers (Scheme 64). 82 A visible-light-induced intramolecular radical cyclization of N-[2-(alkynyl)phenyl]trifluoroacetimidoyl chlorides for the assembly of 2-trifluoromethyl indoles was established by Zhou and co-workers (Scheme 65). 83 In this transformation, imidoyl radical was generated through the irradiation with a 5 W blue LED in the presence of a visible-light photoredox catalyst, and a sequential C-C and C-O bond formation was involved.…”

An Efficient Approach to 2-CF3-Indoles Based on ortho-Nitrobenzaldehydes

“…Both radical and electrophilic trifluoromethylations was performed using bis(perfluoroalkanoyl) peroxides [ 48 ], difluorodiiodomethane [ 49 ], hypervalent iodine reagents [ 50 , 51 , 52 , 53 ], CF 3 I [ 54 , 55 , 56 , 57 , 58 ], Umemoto’s reagents [ 59 , 60 ], [(phen)CuCF 3 ] [ 61 ], and CF 3 SO 2 Na [ 62 , 63 , 64 , 65 ]. Cyclization approaches are based on formation of C2-C3 bond as a key step and deal with transformations of compounds having ortho -toluidine fragment [ 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 ]. One work reported transformation of 4- and 6-nitro-1-hydroxy indoles to NH indoles under treatment with bromoacetophenone ( Figure 2 ) [ 77 ].…”