2.36–2.42 (2H, m), 2.65–2.70 (2H, m), 6.51 (1H, dd, J = 2.4, 15.7 Hz), 7.31–7.49 (5H, m), 7.54 (1H, d, J = 15.7 Hz), 12.92 (1H, br s). 13C NMR (68 MHz, CDCl3): d 20.52, 25.48, 37.99, 111.14, 119.76, 127.76, 128.86, 129.68, 135.46, 138.97, 163.81, 210.54. .max (KBr): 1619, 1652 cm-1. m/z (EI): 214 (M+, 47%), 196 (34), 157 (51), 131 (100), 104 (72). Anal. Calcd. for C14H14O2: C, 78.48; H, 6.59. Found: C, 78.39; H, 6.35.
(2Z,2'E)-2-(1-Hydroxy-3-phenylprop-2-enylidene)cyclohexanone (3). Prepared from LDA (1.02 x 10-1 mol), cyclohexanone (10.0 g, 1.02 x 10-1 mol) in dry THF (80 mL) and cinnamoyl chloride (5.66 g, 3.4 x 10-2 mol) in dry THF (60 mL), cinnamoyl cyclohexanone 3 was obtained as a yellow solid (6.67 g, 86%). The spectroscopic data matched those previously reported.
(2Z,2'E)-2-(1-Hydroxybut-2-enylidene)cyclohexanone (7). Prepared from LDA (1.02 x 10-1 mol), cyclohexanone (10.0 g, 1.02 x 10-1 mol) in dry THF (80 mL) and 2-butenoyl chloride (3.52 g, 3.4 x
10-2mol) in dry THF (50 mL), the diketone 7 was obtained as a pale yellow solid (4.57 g, 81%) mp 46– 48 °C (Lit., 46–48 °C). 1H NMR (270 MHz, CDCl3): d 1.67–1.78 (4H, m), 1.94 (3H, dd, J = 1.3, 6.7 Hz), 2.34–2.47 (4H, m), 6.34 (1H, dd, J = 1.3, 14.7 Hz), 6.98 (1H, dq, J = 6.7, 14.7 Hz), 16.72 (1H, br s). 13C NMR (68 MHz, CDCl3): d 18.47 (CH3), 21.73, 22.99, 23.71, 33.66, 106.06, 124.47, 141.60, 182.14, 191.76. .max (CHCl3): 1602, 1651 cm-1. m/z (EI): 166 (M+, 9%), 151 (63), 138 (5), 123 (15), 95 (52), 69 (100). Anal. Calcd. for C10H14O2: C, 72.26; H, 8.49. Found: C, 71.99; H, 8.38.
(2Z,2'E)-2-(1-Hydroxy-3-phenylprop-2-enylidene)cycloheptanone (8). Prepared from LDA (5.35 x 10-2 mol), cycloheptanone (6.0 g, 5.35 x 10-2 mol) in dry THF (50 mL) and cinnamoyl chloride (2.97 g, 1.78 x 10-2 mol) in dry THF (40 mL). Cinnamoyl cycloheptanone 8 was obtained as a yellow solid (3.5 g, 83%), mp 94–95 °C. 1H NMR (270 MHz, CDCl3): d 1.61–1.80 (6H, m), 2.53–2.66 (4H, m), 6.95 (1H, dd, J = 1.1, 16.5 Hz), 7.29–7.58 (5H, m), 7.65 (1H, d, J =16.5 Hz), 16.10 (1H, d, J = 1.1 Hz). 13C NMR (68 MHz, CDCl3): d 24.96, 26.26, 29.53, 31.40, 42.50, 112.72, 119.16, 129.50, 128.82, 127.77, 135.75, 139.42, 170.53, 207.47. .max (KBr): 1583, 1632 cm-1. m/z (EI): 242 (M+, 14%), 224 (12), 165 (22), 131 (100), 103 (57). Anal. Calcd. for C16H18O2: C, 79.31; H, 7.49. Found: C, 79.26; H, 7.51.
2-Cinnamoyl a-tetralone (9). Prepared from LDA (4.1 x 10-2 mol), a-tetralone (6.0 g, 4.1 x 10-2 mol) in the dry THF (60 mL) and cinnamoyl chloride (2.28 g, 1.37 x 10-2 mol) in dry THF (30 mL). 2-Cinnamoyl a-tetralone 9 was obtained as a yellow solid (3.25 g, 88%), mp 104–106 °C. 1H NMR (270 MHz, CDCl3): d 2.79–2.98 (4H, m), 7.05 (1H, d, J = 15.7 Hz), 7.19–7.60 (8H, m), 7.72 (1H, d, J = 15.7 Hz), 8.01 (1H, dd, J = 1.5, 7.7 Hz), 16.76 (1H, s, br). 13C NMR (68 MHz, CDCl3): d 22.57, 28.29, 107.12, 119.01, 126.53, 126.87, 127.62, 127.93, 128.82, 129.78, 132.52, 132.65, 135.43, 140.24, 141.82, 174.96. .max (KBr): 1626, 1640 cm-1. m/z (EI): 276 (M+, 72%), 258 (53), 199 (54), 144(48), 131 (100), 115 (85). Anal. Calcd. for C19H16O2: C, 82.58; H, 5.84. Found: C, 82.49; H, 5.86.
General procedure for the a-methylation of a,ß-unsaturated 1,3-diketones
Tetrabutylammonium fluoride (3 molar equiv 1.6 M solution in THF) was added to the diketone at 0 °C and the solvent was removed under reduced pressure. The resulting orange solid was dissolved in dry dichloromethane (25 mL), iodomethane (4 molar equiv.) was added, and the
