One-pot synthesis of functionalized indenols from 2-bromoalkenyl trifluoromethyl ketones

Stereoelectronic structure of α-bromoalkenyl trifluoromethyl ketones

“…Polyfunctionality and accessibility of haloalkenyl trifluoromethyl ketones makes them undoubtedly advantageous as intermediate products for the preparation of various biologically active substances and analogs of natural compounds. For example, we recently reported on unexpected one-pot transformation of 4-aryl-3-bromo-1,1,1-trifluoromethylbut-3-en-2-ones into indenols by the action of secondary amines [7,8].With a view to understand specific reactivity of alkenyl trifluoromethyl ketones having a halogen atom in the α-position, it is necessary to thoroughly analyze their structure and the nature of electronic interactions in their molecules. In the present work we examined the stereoelectronic structure of α-haloalkenyl trifluoromethyl ketones in comparison with their nonfluorinated analogs on the basis of the results of DFT quantum-chemical calculations (B3LYP/6-311G**) and IR spectral data.…”

“…Polyfunctionality and accessibility of haloalkenyl trifluoromethyl ketones makes them undoubtedly advantageous as intermediate products for the preparation of various biologically active substances and analogs of natural compounds. For example, we recently reported on unexpected one-pot transformation of 4-aryl-3-bromo-1,1,1-trifluoromethylbut-3-en-2-ones into indenols by the action of secondary amines [7,8].…”

“…α-Bromo enones IIIa-IIId were synthesized according to a classical procedure implying bromination of initial enones Ia-Id and subsequent dehydrobromination of dibromo derivatives IIa-IId thus obtained [7,8] (Scheme 1). α-Haloalkenyl trifluoromethyl ketones are typical captodative alkenes, which can exist as several stereoisomers A-D arising from cis-trans isomerism about the C=C bond and rotation of the trifluoroacetyl group about the C-C bond.…”

“…α-Haloalkenyl trifluoromethyl ketones are typical captodative alkenes, which can exist as several stereoisomers A-D arising from cis-trans isomerism about the C=C bond and rotation of the trifluoroacetyl group about the C-C bond. According to the 1 H and 13 C NMR data, α-bromo enones DOI: 10.1134/S1070428009100017 IIIa-IIId have Z configuration with respect to the C=C bond with s-cis orientation with respect to the single C-C bond in the C=C-C=O fragment [8].…”

“…The corresponding differences in the experimental IR spectra range from 110 to 120 and from 70 to 90 cm -1 , respectively. EXPERIMENTAL Enones IIIa-IIId were synthesized according to the procedure described in [8]. Enone IV was prepared by successive bromination-dehydrobromination of benzylideneacetone as described in [13].…”