X-ray diffraction study of DL-1,4-dimethyl-2,5-dioxabicyclo[2.2.1]heptane-3,6-dione: the sense of twist and folding

Fluorocyclization of norbornenecarboxylic acids with F-TEDA-BF4

“…s, 1H, COOH). 13 For 2b: white crystals, yield 58%, R f 0.39, mp 89-91 °C. 1 H NMR (CDCl 3 ) d: 1.70 (m, 1H, 7-H anti , 2 J HH 11.4 Hz), 2.14 (m, 1H, 7-H syn , 2 J HH 11.4 Hz), 2.85 (dd, 1H, 2-H, 3 J HH 10.6, 4.5 Hz), 2.88-2.92 (m, 1H, 1-H), 3.12 (m, 1H, 3-H, 3 J HH 10.6, 5.1 Hz), 3.34-3.38 (m, 1H, 4-H), 3.73 (s, 3H, Me), 4.71 (dd, 1H, 6-H, 3 J HF 20.4 Hz, 3 J HH 5.1 Hz), 5.19 (d, 1H, 5-H, 2 J HF 49.8 Hz).…”

“…The extract was washed with water and 10% aqueous NaHCO 3 , dried (Na 2 SO 4 ), concentrated, and separated by column chromatography on silica gel using diethyl ether-hexane (2:1) as an eluent. The 1 H, 13 C and 19 F NMR spectra were taken on a Varian VXR-300 spectrometer at 299.9, 75.3 and 282.2 MHz, respectively, using TMS and CCl 3 F as internal standards. The IR spectra were measured on a Specord IR-75 spectrophotometer in KBr disks.…”

“…1 H NMR (CDCl 3 ) d: 1.70 (m, 1H, 7-H anti , 2 J HH 11.4 Hz), 2.14 (m, 1H, 7-H syn , 2 J HH 11.4 Hz), 2.85 (dd, 1H, 2-H, 3 J HH 10.6, 4.5 Hz), 2.88-2.92 (m, 1H, 1-H), 3.12 (m, 1H, 3-H, 3 J HH 10.6, 5.1 Hz), 3.34-3.38 (m, 1H, 4-H), 3.73 (s, 3H, Me), 4.71 (dd, 1H, 6-H, 3 J HF 20.4 Hz, 3 J HH 5.1 Hz), 5.19 (d, 1H, 5-H, 2 J HF 49.8 Hz). 13 C NMR (CDCl 3 ) d: 33.58 (7-C), 41.30 (1-C), 44.73 (d, 4-C, J 22.8 Hz), 46.80 (2-C), 47.52 (d, 3-C, J 9.1 Hz), 52.91 (Me), 84.08 (d, 6-C, J 28.1 Hz), 93.38 (d, 5-C, J 186.9 Hz), 170.95 (9-C), 179.91 (8-C). 19 F NMR (CDCl 3 ) d: -184.7 (dd, CHF, 2 J FH 49.9 Hz, 3 J FH 21.2 Hz).…”

“…IR (n/cm -1 ): 1790 and 1730 (COO). MS, m/z (%): 214 (4) [M + ], 183 (13) 19 F NMR (CDCl 3 ) d: -211.3 (dd, CHF, 2 J FH 58.1 Hz, 3 J FH 6.5 Hz). IR (n/cm -1 ): 1740 and 1700 (COO).…”

“…IR (n/cm -1 ): 1740 and 1700 (COO). MS, m/z (%): 214 (18) [M + ], 183 (45) [M + -MeO], 155 (28) [M + -COOMe], 111 (16) [M + --COOMe -CO 2 ], 98 (20), 79 (11), 66 (100), 59 (13) of its fluorine substituent (Figure 1). ‡ All geometric parameters of 2b are unexceptional.…”