Trifluoromethyl derivatives of pentacyclo[5.4.0.0^2,6.0^3,10.0^5,9]undecane

Abstract

Three cage-like polycyclic compounds, viz. exo-8-(trifluoromethyl)pentacyclo[5.4.0.0(2,6).0(3,10).0(5,9)]undecan-endo-8-ol, C12H13F3O, 5-(trifluoromethyl)-4-oxahexacyclo[5.4.1.0(2,6).0(3,10).0(5,9).0(8,11)]dodecan-3-ol, C12H11F3O2, and N-[exo-11-(trifluoromethyl)-endo-11-(trimethylsilyloxy)pentacyclo[5.4.0.0(2,6).0(3,10).0(5,9)]undecan-8-ylidene]aniline methanol solvate, C21H24F3NOSi.CH4O, were obtained from the corresponding oxo derivatives by nucleophilic trifluoromethylation with (trifluoromethyl)trimethylsilane in 1,2-dimethoxyethane solution in the presence of CsF. The crystal structures show that the addition of trifluoromethanide occurs exclusively from the exo face of the polycyclic ketones. Further examination of the crystal structures, together with that of the starting pentacyclo[5.4.0.0(2,6).0(3,10).0(5,9)]undecane-8,11-dione, C11H10O2, showed that increasing substitution at the 8- and/or 11-positions in the cage molecules increases the non-bonded intramolecular C...C distances at the mouth of the cage and changes the puckering of the five-membered rings involving the 8- and 11-positions from an envelope towards a distorted half-chair conformation. Intermolecular co-operative O-H...O hydrogen bonds in the endo-8-ol compound link the molecules into tetramers.

Nucleophilic trifluoromethylation of some polycyclic ketones

“…ORTEP-plots for compounds 13 and 21. 13 Noteworthy, the transannular cyclization under trifluoromethylation conditions was previously reported for the reaction of a 1,5-dione (i.e. bicyclo[3.3.1]nonane-2,6-dione) but in this case the successful formation of the product of bis-trifluoromethylation was reported.…”

“…The transannular process has not been observed and even with an excess of 3 the C=N-group did not react. The X-ray analysis 13 showed that the CF 3 -group is placed at exo-position (Fig.1). …”

“…The IR-spectrum did not show the absorption band of the C=O group suggesting that a transannular process took place. In the 13 . Finally, the structure of trifluoromethylated hemiacetal 13 was unambiguously confirmed by the X-ray single crystal diffraction analysis (Fig.1 Figure 1.…”

“…As a result, the final product 8 contained the hydroxy group placed at the endo position as evidenced by the X-ray study. 13 The reaction of 3 with 9 was carried out under analogous conditions. Depending on the molar ratio of substrates dione 9 was expected to react either with one or two equivalents of CF 3 -SiMe 3 yielding mono-or bis-trifluoromethylated alcohols 10 or 11, respectively.…”

Benzyl 5-hydroxy-4-oxapentacyclo[5.4.1.02,6.03,10.08,11]dodecane-3-carboxylate

“…For examples of PCU cage structures that exhibit C-C bond lengths that deviate from the normal value, see: Flippen-Anderson et al (1991); Linden et al (2005). For similar structures, see: Kruger et al (2005Kruger et al ( , 2006; Karpoormath et al (2010).…”