LETTER
4-(1-Phenylethyl)benzene-1,3-diol (3a)
Synthesis of O-Heterocycles
1591
Typical Procedure for the Intramolecular Cyclization of
4-tert-Butyl-2-(1,3-diphenylallyl)phenol (29) with
Copper(II) Bromide
Yield 65%; thick oil. IR (neat): n = 3400, 3025, 2968, 2932,
1605, 1517, 1451, 1215, 1113, 972, 909, 758, 735, 701 cm–1.
1H NMR (200 MHz, CDCl3): d = 7.11–7.25 (m, 5 H), 6.98
(d, 1 H, J = 8.3 Hz), 6.32 (dd, 1 H, J = 8.3, 2.4 Hz), 6.17 (d,
1 H, J = 2.4 Hz), 4.61 (br s, 2 H), 4.20 (q, 1 H, J = 7.1 Hz),
1.50 (d, 3 H, J = 7.1 Hz). 13C NMR (50 MHz, CDCl3): d =
154.7, 154.0, 145.8, 128.7, 128.6, 127.4, 126.3, 124.8,
107.8, 103.5, 38.0, 21.1. Anal. Calcd for C14H14O2: C, 78.48;
H, 6.59. Found: 78.11; H, 6.38.
To a solution of 29 (0.342 g, 1 mmol) in dry MeCN (5 mL),
was added CuBr2 (0.536 g, 2.4 mmol) and stirred at ambient
temperature. After completion of the reaction (5 min,
checked by TLC) MeCN was removed under vacuo, and the
crude product was quenched with H2O, dissolved in EtOAc,
and the suspension was passed through Celite. The organic
layer was washed with brine and dried (Na2SO4). The
solvent was removed under vacuo, and the residue was
purified by chromatography (silica, eluant: hexane–EtOAc)
to get pure 33.
6-tert-Butyl-3-bromo-2,4-diphenyl chroman (33)
Single diastereomer; yield 96%; colorless solid; mp 240–
241 °C. IR (neat): n = 2955, 1497, 1238, 1005, 696 cm–1. 1H
NMR (200 MHz, CDCl3): d = 7.26–7.49 (m, 11 H), 6.86 (d,
1 H, J = 8.6 Hz), 6.67 (d, 1 H, J = 1.8 Hz), 5.17 (d, 1 H,
J = 9.8 Hz), 4.44–4.63 (m, 2 H), 1.14 (s, 9 H). 13C NMR (50
MHz, CDCl3): d = 152.4, 144.4, 141.9, 138.7, 129.3, 128.9,
128.5, 128.4, 127.9, 127.4, 126.7, 125.2, 124.1, 116.2, 82.6,
57.4, 53.9, 34.1, 31.3. ESI-MS: m/z = 421 [M+]. Anal. Calcd
for C25H25BrO: C, 71.26; H, 5.98. Found: 70.98; H, 5.73.
2-(Bromomethyl)-3,4-dihydro-7-methoxy-4-phenyl-2H-
chromene (34)
Mixture of syn and anti isomers; yield 86%; thick oil. IR
(neat): n = 2930, 1609, 1504, 1491, 1206, 1051, 752 cm–1. 1H
NMR (200 MHz, CDCl3): d = 7.13–7.34 (m, 7 H), 6.31 and
6.28 (2 s, 1 H), 4.36–4.48 (m, 1 H), 3.53–3.83 (m, 6 H),
2.85–2.98 (m, 1 H), 2.16–2.26 (m, 1 H). 13C NMR (50 MHz,
CDCl3): d = 155.3, 155.1, 154.0, 153.4, 142.8, 141.0, 132.6,
131.4, 128.9, 128.7, 128.1, 127.5, 127.2, 126.8, 124.1,
121.7, 102.5, 102.3, 101.7, 101.3, 56.3, 56.2, 50.9, 42.1,
41.8, 41.2, 41.1, 36.6, 36.5, 29.6. ESI-MS: m/z = 333 [M+].
Anal. Calcd for C17H17BrO2: C, 61.28; H, 5.14. Found:
60.91; H, 4.87.
4,6-Bis(1-phenylethyl)benzene-1,3-diol (3b)
Yield 14%; thick oil. IR (neat): n = 3522, 3025, 2968, 2932,
1605, 1517, 1506, 1451, 1215, 1113, 972, 909, 759, 735, 703
cm–1. 1H NMR (200 MHz, CDCl3): d = 7.10–7.28 (m, 10 H),
7.05 (s, 1 H), 6.11 (s, 1 H), 4.20 (q, 2 H, J = 7.2 Hz), 1.54 (d,
6 H, J = 7.2 Hz). 13C NMR (50 MHz, CDCl3): d = 152.4,
145.7, 128.6, 127.4, 127.2, 127.0, 126.3, 124.1, 104.3, 38.5,
21.2. Anal. Calcd for C22H22O2: C, 82.99; H, 6.96. Found:
82.64; H, 6.68.
4-tert-Butyl-2-(1,3-diphenylallyl)phenol (29)
Yield 67%; thick oil. IR (neat): n = 3447, 2963, 2928, 1491,
1261, 752, 698 cm–1. 1H NMR (200 MHz, CDCl3): d = 7.10–
7.37 (m, 12 H), 6.64–6.75 (m, 2 H), 6.35 (d, 1 H, J = 16.0
Hz), 5.07 (d, 1 H, J = 7.1 Hz), 1.23 (s, 9 H). 13C NMR (50
MHz, CDCl3): d = 151.2, 143.7, 142.2, 137.2, 131.8, 131.5,
128.7, 127.4, 126.7, 126.4, 124.7, 115.9, 114.8, 49.1, 34.2,
31.5. Anal. Calcd for C25H26O: C, 87.68; H, 7.65. Found:
87.31; H, 7.41.
5-Methoxy-2-(1-phenylbut-3-enyl)phenol (32)
Yield 68%; thick oil. IR (neat): n = 3420, 3026, 1614, 1597,
1200, 1150, 698 cm–1. 1H NMR (200 MHz, CDCl3): d =
7.19–7.37 (m, 5 H), 7.16 (d, 1 H, J = 8.5 Hz), 6.50 (dd, 1 H,
J = 8.5, 2.5 Hz), 6.34 (d, 1 H, J = 2.5 Hz), 5.70–5.78 (m, 1
H), 4.95–5.09 (m, 2 H), 4.21 (t, 1 H, J = 7.8 Hz), 3.76 (s, 3
H), 2.74–2.84 (m, 2 H). 13C NMR (50 MHz, CDCl3): d =
158.9, 154.2, 144.1, 136.9, 128.7, 128.4, 127.9, 126.2,
123.2, 116.1, 105.9, 102.3, 55.1, 43.7, 39.1. Anal. Calcd for
C17H18O2: C, 80.28; H, 7.13. Found: 79.91; H, 6.87.
(24) Castro, C. E.; Gaughan, E. J.; Owsley, D. C. J. Org. Chem.
1965, 30, 587.
Synlett 2011, No. 11, 1585–1591 © Thieme Stuttgart · New York