Thermal condensation of indoles with trifluoroacetaldehyde

Bis- and Trisindolylmethanes (BIMs and TIMs)

“…307 Synthesis of similar BIMs 43 has also been reported via condensation of 2-hydroxynaphthoquinone and 1-methylindole in protic media. 308 Gong and Kato 309,310 investigated the reaction of arenes and trifluoroacetaldehyde hemiaminals 45 catalyzed by BF 3 and ZnI 2 and found, for instance, that in the presence of BF 3 , indole and 45 (when R ) Me) gave compounds 46, 47, and 48 311 in 63.0%, 4.4%, and 32.6% yield, respectively (Scheme 17).…”

Crystal Structure of Diethyl 2-[2,2,2- trifluoro-1-(indole-3-yl)-ethyl]-2-acetamidomalonate

“…The target compound, 3-trifluoromethyltryptophan, could be prepared by hydrolysis and subsequent decarboxylation of diethyl 2-[2,2,2-trifluoro-1-(indol-3-yl)ethyl]-2-acetamidomalonate obtained from the replacement reaction of 2,2,2-trifluoro-1-(indole-3-yl)ethanol (MAKI, 1988) with diethyl acetamidomalonate in the presence of strong bases. Four stereoisomers were expected to be formed after the decarboxylation, but actually the product analysis showed clearly that two of the stereoisomers (a pair of enantiomers) were predominantly generated in the ratio of 97:3.…”

Synthesis of 3-Indolyl Perfluoroalkyl Carbinols by the Reaction of Indoles with Perfluorinated Aldehydes

“…Among the known methods of synthesis for these compounds, one should emphasize the reduction of 3-acylindoles [5][6][7], addition of Ruppert's reagent to indole-3-carboxaldehyde and its derivatives [8,9], addition of perfluoroaliphatic aldehydes and their derivatives to indole under the action of different catalysts with opportunity to obtain of enantimeric pure 3-indolyl carbinols [10][11][12], and hydroxylation of indoles with polyfluoroalkanols in the presence of radical initiators [13]. Several papers reported non-catalytic reaction of trifluoroacetaldehyde with indole at ambient temperature [14] or upon heating [15]. There are no examples in the literature for the reactions of indoles and aldehydes with long-chain perfluorocarbon fragments; therefore, the study of these reactions extends the possibility of synthetic use of perfluoroaliphatic carbonyl compounds.…”