General
1H- and 13C-NMR spectra were obtained using a Bruker AMX 500 NMR and were recorded at 500 and 125 MHz respectively. All reagents and chemicals were obtained from Aldrich Chemical Company (Canada) and were used as received unless otherwise noted.
Preparation of 3a and 3b: Compound 1 (10.5 mg, 0.0335 mmol) was treated with triphenylantimony (23.7 mg, 0.067 m mol, 2 eq.), 3-iodo-N-Boc-aniline (16.0 mg, 0.0503 mmol), Pd(OAc)2 (0.8 mg, 3.5 μmol), and triethylamine (1 mL), and refluxed for 5 hours. The reaction mixture was evaporated under reduced pressure, and the residue chromatographed on silica gel, using 4:1 hexane-ethyl acetate as eluent, giving 14.7 mg (94%) of a colorless oily semi-solid. 1H-NMR showed it to be a 1:1 mixture of the 2',3'- and the 3',3'-disubstituted isomers. An excess of 3-iodo-N-Boc-aniline was used since this reaction was intended to provide Heck coupling, thus requiring stoichiometric amounts of the aryl halide. Spectral Data: MS (ESI) for C27H30O7 : 467 (M+H); 3a: 1H-NMR (CDCl3) δ: 7.4-7.0 (10H, m, Ar-H), 6.75 (1H, s, H-3'), 5.26 (1H, dd, J1,2 = 8.8 Hz, J2,3 = 10.3 Hz, H-2), 5.15 (1H, dd, J3,4 = 3.3 Hz, J4,5 = 0.8 Hz, H-4), 5.05 (1H, dd, J2,3 = 10.3 Hz, J3,4 = 3.4 Hz, H-3), 4.21 (1H, m, H-1), 4.02 (1H, dq, J- 4,5 = 0.8 Hz, J5,6 = 6.4 Hz, H-5), 3.10 (1H, dd, J1,1' = 10.6 Hz, 2J1',1' = 14.7 Hz, H-1'), 2.85 (1H, dd, J1,1' = 3.6 Hz, 2J1', 1' = 14.8 Hz, H-1'), 2.12, 1.95, 1.91 (9H, 3s, CO-CH3), 1.13 (3H, d, J5,6 = 6.4 Hz) (Note: certain assignments may be reversed); 13C-NMR (CDCl3) δ: 170.5, 170.0, 169.9 (C=O), 144.0, 142.1, 139.7 (4° C=C), 130.9 (C-3'), 129.6, 128.5, 128.4, 127.3, 127.2, 126.0 (Ar-C), 73.2 (C-1), 70.7 (C-2), 70.6 (C-4), 70.4 (C-3), 65.9, (C-5), 26.5 (C-1'), 20.8, 20.6, 20.6 (COCH3), 16.1 (C-6); 3b: 1H-NMR (CDCl3) δ: 7.4-7.0 (10H, m, Ar-H), 6.2-6.0 (1H, m, H-2'), 5.26 (1H, dd, J1,2 = 8.7 Hz, J2,3 = 10.3 Hz, H-2), 5.15 (1H, dd, J3,4 = 3.3 Hz, J4,5 = 0.8 Hz, H-4), 5.05 (1H, dd, J2,3 = 10.3 Hz, J3,4 = 3.4 Hz, H-3), 4.33 (1H, m, H-1), 3.63 (1H, dq, J4,5 = 0.8 Hz, J5,6 = 6.4 Hz, H-5), 2.7-2.4 (2H, m, H-1'), 2.03, 1.92, 1.88 (9H, 3s, CO-CH3), 1.09 (3H, d, J5,6 = 6.4 Hz); 13C-NMR (CDCl3) δ: 170.4, 170.0, 169.6 (C=O), 142.9, 139.8, 137.7 (4° C=C), 128.5, 128.4, 128.1, 127.2, 126.9, 125.4 (Ar-C), 124.4 (C-2'), 71.9 (C-1), 68.5 (C-3), 68.4 (C-2), 68.1 (C-4), 65.6 (C-5), 25.9 (C-1'), 20.7, 20.6, 20.5 (COCH3), 15.2 (C-6).
1-Phenyl-1-cyclohexene (
4): A screw-cap test tube was charged with cyclohexene (0.5 mL), diisopropylethylamine (0.5 mL), triphenylantimony (63.3 mg, 0.179 mmol, 0.537 mmol phenyl groups), palladium acetate (10.1 mg, 0.045 mmol), and 3-iodo-
N-Boc-aniline (17.1 mg, 0.0535 mmol). The tube was sealed and heated at 70° C on a water bath for ten hours. The resulting black suspension was then carefully evaporated under reduced pressure, and the residue brought up in pentane (20 mL). The pentane phase was then washed with 6 N HCl (2 x 20 mL), dried over sodium sulfate, filtered and carefully evaporated to a yellow oil. The oil was then chromatographed on silica gel using pentane as eluent to give
4 (83 mg, 97 % based on triphenylantimony) as a clear, colorless oil. The NMR and mass spectra of this oil matched those published in the literature for
4 [
7]