反应详情

温度

20 °C

A solution of N-methyl-3-methoxyanilinochlorophenylborane (11 mmol) in dichloroethane was added dropwise to a mixture of (R)-(+)-citronellal (1.54 g, 10 mmol) and diisopropylethylamine (20 mmol) in dichloromethane at -20° C. The mixture was stirred at -20° C. for 2 h and at 20° C. for 0.5 hours, quenched with ammonium acetate and then faltered through a short pad of silica gel. The filtrate was concentrated and the residue was chromatographed on silica gel and eluted with EtOAc/Hexane (0-20%) to afford 32% of (3R)-1-(2-methoxy-6-methylamino-phenyl)-3,7-dimethyl-oct-6-en- 1-ol and 34% of (3R)-1-(2-methylamino-4-methoxy-phenyl)-3,7-dimethyl-oct-6-en- 1-ol. The former is an inseparable 1:1 mixture of diastereomers: 1H nmr (400 MHz, CD3COCD3), resolved signals: δ 0.91 (d, 3H, J=6.6 Hz), 0.95 (d, 3H, J=6.6 Hz), 1.56 (s, 3H), 1.60 (s, 3H), 1.63 (s, 3H), 1.66 (s, 3H), 2.76 (s, 3H, N--CH3), 2.77 (s, 3H, N--CH3), 3.72 (s, 3H, OCH3), 3.73 (s, 3H, OCH3), 4.32 (d, 1H, J=3.5 Hz, OH), 4.34 (d, 1H, J=3.6 Hz, OH), 5.05 (bt, 1H, J =7.1 Hz, CH=C), 5.12 (bt, 1H, J =7.1 Hz, CH=C), 5.50 (m, 2H, CHO), 6.05 (bs, 2H, NH), 6.23 (d, 2H, J=8.3 Hz), 6.25 (d, 4H, J=8.2 Hz), 7.00 (t, 1H, J=8.2 Hz); other resonances: δ 1.15 (m, 2H), 1.30 (m, 2H), 1.40 (m, 2H), 1.50 (m, 2H), 1.70 (m, 2H), 2.0 (m, 4H). Exact Mass calcd. for C18H30NO2 (M+1): 292.2276; found: 292.2276. The two diastereomers of (3R)-1-(2omethylamino-4-methoxy-phenyl)-3,7-dimethyl-oct-6-en-1-ol were separated by repeated chromatography. The less polar isomer: 1H nmr (400 MHz, CD3COCD3), δ 5 0.91 (d, 3H, J=6.6 Hz), 1.18 (m, 1H), 1.42 (m, 2H), 1.60 (s, 3H), 1.66 (s, 3H), 1.65 (m, 2H), 1.97 (m, 2H), 2.78 (d, 3H, J=5.2 Hz, N--CH3), 3.73 (s, 3H), 4.13 (d, 1H, J=4 Hz, OH), 4.72 (m, 1H, CHO), 5.12 (bt, 1H, J=7.2 Hz, CH=C), 5.48 (bs, 1H, NH), 6.11 (d, 1H, J=8.3 Hz), 6.88 (d, 1H, J=8.8 Hz); 13C nmr (100.6 MHz, CD3COCD3),: 17.7, 19.6, 25.9, 26.2, 30.4, 38.5, 55.1, 72.1, 97.7, 100.3, 122.5, 125.8, 131.3, 150.2, 161.1; the more polar isomer: 1H nmr (400 MHz, CD3COCD3), δ 0.94 (d, 3H, J=6.8 Hz), 1.13 (m, 1H), 1.40 (m, 1H), 1.48 (m, 1H), 1.56 (s, 3H), 1.63 (s, 3H), 1.65 (m, 2H), 1.80 (m, 1H), 1.95 (m, 1H), 2.78 (d, 3H, J=5.2 Hz, N--CH3), 3.73 (s,3H), 4.16 (d, 1H, J=3.9 Hz, OH), 4.70 (m, 1H, CHO), 5.05 (bt, 1H, J=7.2 Hz, CH=C), 5.48 (bs, 1H, NH), 6.10 (d, 1H, J=7.4 Hz), 6.12 (s, 1H), 6.86 (d, 1H, J=7.8 Hz); 13C nmr (100.6 MHz, CD3COCD3), δ 5 17.8, 20.6, 25.9, 26.1, 30.2, 30.4, 37.7, 43.3, 55.1, 72.9, 97.7, 100.3, 121.9, 125.8, 128.7, 131.2, 150.3, 161.2; Exact Mass calcd. for C18H30NO2 (M+1): 292.2276; found: 292.2276.

1. customquenched with ammonium acetate
2. concentrationThe filtrate was concentrated
3. customthe residue was chromatographed on silica gel
4. washeluted with EtOAc/Hexane (0-20%)