(hexane–ethyl acetate)] which contained small amounts of the
formate of 2a as well as uncharacterized compounds. Further
purification (hexane–ethyl acetate) afforded pure 3-phenylbut-
3-en-1-ol 2a as a colourless oil (348.3 mg, 2.35 mmol, 47%
isolated yield), which was identified upon the basis of spectral
results: δH (270 MHz) 2.06 (1H, s, br, OH), 2.75 (2H, td, J 6.4,
0.99, CH2), 3.68 (2H, t, J 6.4, CH2OH), 5.12 (1H, dt, J 1.49,
0.99, C᎐CH ), 5.38 (1H, d, J 1.49, C᎐CH ) and 7.20–7.41
catalyst was then rinsed with diethyl ether (10 cm3). Evapor-
ation of combined filtrate and the ethereal washings under
reduced pressure left a colourless oil, which was subjected to
silica-gel column chromatography (Wakogel C-300; eluents,
hexane, hexane–ethyl acetate = 95:5 and then ethyl acetate).
Concentration of the fractions of hexane–ethyl acetate afforded
a colourless oil of methylisopulegol 4 (833.0 mg, 4.95 mmol,
99%) which was identified upon the basis of spectral results.25
Compounds 6 and 7 obtained from citronellal 5 were simi-
larly isolated by silica-gel column chromatography (Wakogel
C-300; hexane–ethyl acetate = 95:5 as eluent) as a mixture: the
᎐
᎐
2
2
(5H, m, ArH); δC(67.8 MHz) 38.5 (t), 60.9 (t), 114.4 (t), 126.1
(d), 127.6 (d), 128.4 (d), 140.5 (s) and 144.8 (s); m/z 148 (Mϩ,
26%), 133 (20), 117 (35), 103 (29), 91 (30), 78 (100) and 51
(40).
1
ratio of the two compounds was measured by H NMR spec-
The recovered Zr4ϩ-mont was regenerated by stirring it
magnetically with 50% aqueous acetone (10 cm3) at room
temperature for 24 h after which it was filtered and dried at
120 ЊC in an electric oven for 24 h.
troscopy:15 compound 6: δH 0.938 (d, J 6.75, CH3CH), 3.455
(td, J 10.0 and 4.0, CHOH); compound 7: δH 0.880 (d, J 6.75,
CH3CH) and 3.710 (td, J 10.0 and 4.0, CHOH). Since chemical
shift and coupling constant values are slightly different from
those reported in the literature,15 we cannot exclude the possi-
bility that the minor compound 7 tentatively assigned here
might be iso-isopulegol where both isopropenyl and methyl
groups are in a trans disposition to a hydroxy group. The prod-
ucts of a 10-fold scale reaction using 5 (7.70 g, 50 mmol) and
Zr4ϩ-mont (3.406 g) in acetonitrile (100 cm3) were isolated by
distillation as a colourless oil (6.545 g, 42.5 mmol, 85% yield):
bp 75–76 ЊC (7 mmHg); lit.,30 88 ЊC (10 mmHg).
3-(4-Methoxyphenyl)but-3-en-1-ol 2b. A white solid: mp
42.5–44.0 ЊC; δH (270 MHz) 1.82 (1H, s, br, OH), 2.76 (2H, td, J
6.4, 1.1, CH2), 3.72 (2H, t, J 6.4, CH2OH), 3.81 (3H, s, CH3O),
5.07 (1H, dt, J 1.4, 1.1, C᎐CH ), 5.34 (1H, d, J 1.4, C᎐CH ),
᎐
᎐
2
2
6.86 (2H, d, J 8.79, ArH, AAЈXXЈ type) and 7.35 (2H, d, J 8.79,
ArH, AAЈXXЈ type); δC(67.8 MHz) 38.6 (t), 55.3 (q), 61.0 (t),
76.5 (t), 77.5 (d), 127.2 (d), 132.7 (s), 144.0 (s) and 159.3 (s); m/z
178 (Mϩ, 61%), 163 (19), 148 (17), 135 (100), 115 (26), 108 (44),
91 (30), 77 (35), 55 (29) and 51 (25) (Found: C, 73.5; H, 8.0.
C11H14O2 requires C, 74.12; H, 7.92%).
3-(4-Methylphenyl)but-3-en-1-ol 2c. A colourless oil; δH (270
MHz) 2.16 (1H, s, br, OH), 2.34 (3H, s, CH3), 2.77 (2H, td, J
6.3, 1.1, CH2), 3.72 (2H, t, J 6.3, CH2OH), 5.11 (1H, d, J 1.4,
Estimation of the number of active acid sites on Zr4؉-mont with
triethylamine-doped acetonitrile (Fig. 1)
Following a literature method,7,8 we stirred magnetically a mix-
ture of freshly prepared triethylamine-doped acetonitrile (10.0
2
2
cm3; containing various amounts of triethylamine) and Zr4ϩ
-
C᎐CH ), 5.38 (1H, d, J 1.4, C᎐CH ), 7.13 (2H, d, J 8.24, ArH,
᎐
᎐
AAЈBBЈ type) and 7.31 (2H, d, J 8.24, ArH, AAЈBBЈ type);
δC(67.8 MHz) 20.7 (q), 38.1 (t), 60.7 (t), 113.0 (t), 125.6 (d),
128.8 (d), 136.9 (s), 137.3 (s) and 143.3 (s); m/z 162 (Mϩ, 61%),
147 (57), 129 (38), 115 (68), 105 (27), 92 (100), 77 (22), 65 (32)
and 51 (28).
mont (340.6 mg) at room temperature for 3 h. To the mixture
were added paraformaldehyde (300.4 mg, 10.0 mmol) and α-
methylstyrene 1a (590.9 mg, 5.0 mmol). The mixture was stirred
first at room temperature for 5 min and then at 80 ЊC for 24 h.
After it had been cooled, the reaction mixture was suction-
filtered to remove the catalyst which was then rinsed with
diethyl ether (10 cm3). Acetophenone was added to a mixture of
the filtrate and the washings as an internal standard and the
amount of 2a produced was estimated by GLC analysis.
3-(4-Bromophenyl)but-3-en-1-ol 2d. A colourless oil; δH (270
MHz) 2.17 (1H, s, br, OH), 2.75 (2H, td, J 6.2, 1.0, CH2), 3.72
(2H, t, J 6.2, CH OH), 5.18 (1H, d, J 1.1, C᎐CH ), 5.40 (1H, d,
᎐
2
2
J 1.1, C᎐CH ), 7.28 (2H, d, J 8.5, ArH, AAЈBBЈ type) and 7.46
᎐
2
(2H, d, J 8.5, ArH, AAЈBBЈ type); δC(67.8 MHz) 38.2 (t), 60.8
(t), 114.9 (t), 121.5 (s), 127.7 (d), 131.4 (d), 139.3 (s) and 143.7
(s); m/z 226 (Mϩ, 26%), 211 (17), 196 (12), 183 (26), 169 (5), 156
(16), 147 (23), 129 (30), 115 (100), 102 (31), 91 (21), 77 (21), 63
(21) and 51 (34).
Acknowledgements
We thank Kunimine Industries Co. Ltd. for the gift of Kunipia
G.
3-(4-Chlorophenyl)but-3-en-1-ol 2e. A colourless oil; δH (400
MHz) 2.12 (1H, s, br, OH), 2.72 (2H, t, J 6.8, CH2), 3.68 (2H, t,
J 6.4, CH OH), 5.14 (1H, d, J 0.9, C᎐CH ), 5.38 (1H, d, J 0.9,
᎐
2
2
References
C᎐CH ) and 7.27–7.33 (4H, m, ArH); δ (67.8 MHz) 38.3 (t),
᎐
2
C
1 J. Tateiwa and S. Uemura, J. Jpn. Pet. Inst., in press.
2 Recent review of solid (mont and supported reagent)-catalysed
organic reactions: A. Cornélis, P. Laszlo and M. W. Zettler, in
Encyclopedia of Reagents for Organic Synthesis, ed. L. A. Paquette,
Wiley, Chichester, 1995, vol. 5, pp. 3667–3671; J. H. Clark and
D. J. Macquarrie, Chem. Soc. Rev., 1996, 303.
60.8 (t), 114.9 (t), 127.4 (d), 128.5 (d), 133.4 (s), 138.9 (s) and
143.7 (s); m/z 182 (Mϩ, 46%), 167 (41), 151 (39), 139 (44), 129
(39), 112 (100), 101 (28), 75 (45), 62 (35) and 51 (54).
3-(4-Trifluoromethylphenyl)but-3-en-1-ol 2f. A colourless oil;
δH (270 MHz) 2.06 (1H, s, br, OH), 2.77 (2H, td, J 6.3, 1.0,
CH2), 3.74 (2H, t, J 6.3, CH2OH), 5.27 (1H, d, J 1.3,
3 J. Tateiwa, K. Hashimoto, T. Yamauchi and S. Uemura, Bull. Chem.
Soc. Jpn., 1996, 69, 2361.
C᎐CH ), 5.47 (1H, d, J 1.3, C᎐CH ), 7.51 (2H, d, J 8.24,
᎐
᎐
2
2
4 J.-F. Roudier and A. Foucaud, Tetrahedron Lett., 1984, 25, 4375.
5 J. A. Ballantine, in Solid Supports and Catalysts in Organic Synthesis,
ed. K. Smith, Ellis Horwood, London, 1992, part 2, ch. 4, p. 106.
6 J. Tateiwa, H. Horiuchi, K. Hashimoto, T. Yamauchi and
S. Uemura, J. Org. Chem., 1994, 59, 5901.
7 M. Kawai, M. Onaka and Y. Izumi, Bull. Chem. Soc. Jpn., 1988, 61,
1237; K. Higuchi, M. Onaka and Y. Izumi, Bull. Chem. Soc. Jpn.,
1993, 66, 2016.
8 J. Tateiwa, H. Horiuchi, M. Suama and S. Uemura, Bull. Chem. Soc.
Jpn., 1994, 67, 2883; J. Tateiwa, H. Horiuchi and S. Uemura, J. Org.
Chem., 1995, 60, 4039.
9 J. Tateiwa, H. Horiuchi and S. Uemura, J. Chem. Soc., Perkin
Trans. 2, 1995, 2013.
ArH, AAЈBBЈ type) and 7.59 (2H, d, J 8.24, ArH, AAЈBBЈ
type); m/z 216 (Mϩ, 45%), 201 (58), 185 (56), 166 (35), 165
(49), 146 (56), 133 (19), 115 (91), 109 (14), 89 (10), 75 (22), 63
(18) and 51 (40).
General procedure for metal cation-exchanged montmorillonite-
(Mnϩ-mont)-catalysed intramolecular carbonyl-ene reaction of
citronellals
A typical experimental procedure was as follows (Table 2, run
3). To a mixture of 3-methylcitronellal 3 (841.4 mg, 5.0 mmol)
and dry acetonitrile (10 cm3) was added Zr4ϩ-mont (340.6 mg,
0.25 mmol as acid sites estimated by NH3-TPD analysis) at
25 ЊC. The resulting mixture was stirred magnetically at 80 ЊC
for 1.5 h after which it was cooled and suction-filtered to
recover the catalyst (Toyo, quantitative filter paper No. 4A); the
10 M. Marthy, H. Stoeckli-Evans and R. Neier, Tetrahedron, 1996, 52,
4645.
11 M. Fuentes, J. Magraner, C. de las Pozas, R. Roque-Malherbe,
J. Pérez Pariente and A. Corma, Appl. Catal., 1989, 47, 367.
12 T. K. Sarker and S. K. Nandy, Tetrahedron Lett., 1996, 37, 5195.
J. Chem. Soc., Perkin Trans. 1, 1997
2173