## 3 Results and Discussion
### Synthesis
We then attempted a similar strategy with \(\beta\)-tetralone (**3a**) to ascertain whether this ditrifluoroacetylation methodology could be generalized to other ketones with two acidic \(\alpha\)-hydrogen sets. Sequential treatment of **3a** with two equivalents of ethyl trifluoroacetate followed by neutralization at room temperature led to a mixture of the 3- and 1-trifluoroacetyl-2-tetralone endocyclic enols **3b** and **3c**, respectively; the formation of 1,3-ditrifluoroacetyl-2-tetralone was not observed. Assignment of the endocyclic enolic structures was based on the observation of a single \({}^{19}\)F NMR resonance at \(-\)70.6 ppm for **3b** and \(-\)67.7 ppm for **3c**. When the reaction workup conditions were modified by subjecting the enols **3b** and **3c** to an additional equivalent of base and ethyl trifluoroacetate followed by _in vacuo_ removal of solvent at elevated temperature, we were surprised to find that aromatization occurred to give the trifluoroacetylated naphthol **3d** in moderate overall yield. Figure 3 depicts a plausible route to naphthol **3d**. We surmise that deprotonation of the less sterically hindered \(\alpha\)-hydrogen enroute to **3b** occurs rather than abstraction of the more acidic, benzylic \(\alpha\)-hydrogen. Detrifluoroacetylation of triketone **I** followed by tautomerization of diketone **II** under acidic workup provides naphthol **3d**. Application of [PERSON]'s method to **4a** and **5a** produced the cross-conjugated, dienoic 1,3,5-triketones **4b** and **5b** in modest yields [17]. Assignment of the enolic structures was based on a combination of resonances found in their NMR spectra--**(4b)**\({}^{1}\)H: an alkene proton signal _@_ 6.76 ppm (1H), a broad, unresolvable singlet corresponding to the enol protons _@_ 15.68 ppm (2H) and \({}^{19}\)F: a  
Figure 3: Formation of 3-trifluoroacetyl-2-tetralone (**3b**) and 3-trifluoroacetyl-2-naphthol (**3d**). Figure 2: Formation of 1,3-ditrifluoroacetyl-2-indanone (**2c**). singlet \(a\) -72.0 ppm (3F); for **(5b)**\({}^{1}\)H: an alkene proton signal \(a\) 6.90 ppm (1H), a singlet corresponding to the phenolic enol proton \(a\) 14.44 (1H), a broader singlet \(a\) 15.68 ppm (1H) corresponding to the enol adjacent to the CF\({}_{3}\) group and \({}^{19}\)F: a singlet \(a\) -71.6 ppm (3F). Addition of D\({}_{2}\)O to the NMR samples of **4b** and **5b** resulted in rapid diminuation of the exchangeable enolic protons in the \({}^{1}\)H NMR. Increasing the molar ratio of ethyl trifluoroacetate:diketone to \(>\)2:1, although necessary for triketone product formation, also led to \(O\)-trifluoroacetylated by-products. Fortunately, these were easily separated by chromatography from the desired 1,3,5-triketones. Additionally, we found that when **4a** was subjected to standard Claisen reaction conditions, an unintended acetyl-trifluoroacetyl group exchange occurred to give 2-trifluoroacetyl-1-tetralone (**4c**) in good yield along with, to our surprise, naphthol **5a**. A process similar to the detrifluoroacetyllation depicted in Figure 2 may be operating in these cases as well. Treatment of **5a** with Selectfluor(r) demonstrated the fluorination preference of activated aromatic substrates over acetyl groups [19, 20, 21]. The fluorinated naphthols **5c** and **5d** were achieved in good overall yield and a 5:1 ratio of the _para:meta_ isomers, respectively. Ring fluorination was confirmed by the observation of resonances in the \({}^{19}\)F NMR spectra as singlets: \(-\)134.0 ppm (1F) and \(-\)134.2 ppm (1F) for **5c** and **5d**, respectively. Preferential _para_ fluorination is in accord with the _o-p_ directing ability of the hydroxyl group. Use of up to 5 equivalents of Selectfluor(r) to effect fluorination at the acetyl carbon provided only the monofluorinated naphthols **5c** and **5d**.