O
R
O
R
1
250 refined parameters and 3030 reflections. A Chebychev polynomial
O
O
with three coefficients was used in the weighting scheme. There are four
independent molecules in the asymmetric unit and, although this is rather
rare, no significant difference between these molecules was evidenced.
CCDC 182/1253. See http://www.rsc.org/suppdata/cc/1999/1143/ for crys-
tallographic data in .cif format.
i
1
+
R′
NMeAc
R
R′
‡
The analoguous isoquinolin-3-ol is reported to give a head-to-tail exo
photodimer (ref. 19).
All new compounds were fully characterized by H, 13C NMR and HRMS
except for adducts 9a and 9b which could not be separated by
chromatography. Selected data for 9a: d 1.70 (ddd, J 14.2, 5.1 and 2.7,
1H), 2.03 (s, 3H), 2.18 (s, 3 H), 2.72 (ddd, J 14.2, 10.6 and 2.8), 5.58 (ddd,
J 10.6, 5.1 and 2.5). For 9b: d 1.85 (ddd, J 14.2, 5.4 and 2.5), 2.14 (s, 3 H),
2.22 (s, 3 H), 2.76 (ddd, J 14.2, 10 and 2.5), 4.67 (ddd, J 10, 5.4 and 2.5).
8
a
b
R = OEt, R′ = H
R = H, R′ NMeAc
R = NMeAc, R′ = H
9c
9
9
1
§
10
R = p-MeOC6H4, R′ = H
1
1
1a R = OMe, R′ = Me
1b R = Me, R′ = OMe
H
H
Scheme 2 Reagents and conditions: i, NaIO
4
(1.1 equiv.), dienophile (5
equiv.), MeOH–H O, 2–12 h, rt.
2
H
For 9c: d 2.13 (s, 3 H), 2.24 (m, 2 H), 2.90 (s, 3 H), 5.17 (ddd, J 9.6, 7.9
and 2.5).
The p-facial selectivity of the reduction observed here is not
controlled by the epoxide group, but this may be due to steric
hindrance from the remote phenylene group rather than
stereoelectronic control by the nearest phenyl ring.
Then, in situ cycloaddition of dienone 1 was attempted by
carrying out the oxidation step in presence of 5 equiv. of
dienophile (Scheme 2). Ethoxyethene and N-methyl-N-vinyl-
acetamide add to 1 to give 8 (82%) and 9a–c (70%) without
notable dimer formation, unlike the less reactive 4-methoxy-
styrene, which gave 10 (42%) together with 3 (30%), and
1
E. Adler, S. Brasen and H. Miyake, Acta Chem. Scand., 1971, 25, 2055;
H.-D. Becker, T. Bremholt and E. Adler, Tetrahedron Lett., 1972,
4
205.
2
3
E. Adler and K. Holmberg, Acta Chem. Scand., 1974, B28, 465.
(a) V. Singh and B. Thomas, J. Chem. Soc., Chem. Commun., 1992,
1211; (b) J.-P. Gesson, L. Hervaud and M. Mondon, Tetrahedron Lett.,
1993, 34, 2941; (c) V. Singh and M. Porinchu, Tetrahedron, 1996, 52,
7087; (d) C. Bachmann, V. Bonnarme, A. Cousson, M. Mondon and
J.-P. Gesson, Tetrahedron, 1999, 55, 433.
M. Tius and N. K. Reddy, Synth. Commun., 1994, 24, 859.
J.-P. Gesson, M. Mondon and N. Pokrovska, Synlett, 1997, 1395.
Y. Tanoue, A. Terada, I. Seto, Y. Umezu and O. Tsuga, Bull. Soc. Chim.
Jpn., 1988, 61, 1221.
4
5
6
2
-methoxyprop-2-ene, which gave 11a (25%), 11b (4%) and 3
(44%). As expected, syn-endo cycloadition is observed in most
cases, except for the enamide which exhibits low selectivity,
giving syn-exo (9a), syn-endo (9b) and anti-exo (9c)§ adducts in
a 2:1:1 ratio (a high syn-exo selectivity has been observed with
7
C. W. G. Fishwick and D. W. Jones, in The Chemistry of the Quinonoid
Compounds, ed. S. Patai and Z. Rappoport, Wiley, 1988, vol. 2, part 1,
pp. 403–453; J. L. Charlton and M. M. Alaudin, Tetrahedron, 1987, 43,
2873.
3d
enamides for a related spirocyclohexadienone and for a
1
4
pyrone ).
8 D. A. Bleasdale, D. W. Jones, G. Maier and H. P. Reisenauer, J. Chem.
Soc., Chem. Commun., 1983, 1095.
In summary, oxidation of 3-hydroxymethyl-2-naphthol af-
9
G. Simig and M. Schlosser, Tetrahedron Lett., 1994, 35, 3081.
0 C. H. Chou and W. S. Trahanovsky, J. Am. Chem. Soc., 1986, 108,
138.
2
fords chiral dimer 3 possessing C symmetry in a rigid
1
1
1
framework, and trapping of the unstable dienone 1 is possible
at room temperature with electron-rich dienophiles. Such
adducts may serve as useful templates for the preparation of
4
1 P. Chautemps and J.-L. Pierre, Tetrahedron, 1976, 32, 549; P. A.
Bartlett, Tetrahedron, 1980, 36, 2.
2 (a) T .W. Hart and B. Vacher, Tetrahedron Lett., 1992, 33, 3009; (b)
M. J. Brienne, D. Varech and J. Jacques, Tetrahedron Lett., 1974,
15
rigid phenethylamine derivatives or of tetrahydronaphthalene
derivatives after cleavage of the a,b-epoxy ketone moiety.16
1
233.
3 K. Okada, S. Tomita and O. Masaji, Tetrahedron Lett., 1986, 27,
645.
1
Notes and references
2
†
2
5
7
Selected data for 4: mp 190 °C; d
.50 (AB q, J 6, 4 H, CH O), 3.14 (s, 2 H, ArCH), 3.89 (d, J 2, 2 H, ArCH),
.12 (d, J 2, 2 H, CHOAc), 7.30 (m, 8 H); d 20.4, 46.0, 51.4, 55.0, 58.7,
0.4, 127.0, 127.4, 129.1, 130.1, 138.9, 139.1, 170.2.
Crystal data for 4: C28 , M = 1729.89, monoclinic, a = 16.578(7),
b = 25.37(1), c = 20.826(8) Å, b = 105.99(7)°, V = 8420(2) Å , space
H
(300 MHz, CDCl
3
) 1.81 (s, 6 H, Ac),
14 K. Afarinkia, N. T. Daly, S. Gomez-Farnos and S. Joshi, Tetrahedron
Lett., 1997, 38, 2369.
15 J. C. Barrish, S. H. Spergel, S. Moreland and S. A. Hedberg, Bioorg.
Med. Chem. Lett., 1992, 2, 95.
16 K. Holmberg, H. Kirudd and G. Westin, Acta Chem. Scand., 1974, B28,
913.
17 G. M. Sheldrick, SHELXS86, Program for the solution of crystal
structures, 1986, University of Göttingen, Germany.
18 D. J. Watkin, J. R. Carruthers and P. W. Betteridge, CRYSTALS
Software, 1985, Chemical Crystallography Laboratory, University of
Oxford, England.
2
C
H
O
24 6
r
3
= 1.36 g cm2 , F(000) = 3659.166, colourless
3
group P2
1
/n, Z = 16, D
c
21
prismatic crystal stable in air, m(Cu-Ka) = 0.754 mm , 3030 independent
reflections with I 4 3s(I) were used in the structural analysis. The structure
was solved using direct methods (ref. 17) and refined using least-squares
calculations (ref. 18). Positional and anisotropic thermal parameters of all
atoms except hydrogen were refined. Hydrogen atom positions were
calculated, an equivalent isotropic thermal parameter was given for
19 D. W. Jones, J. Chem. Soc. (C), 1969, 1729.
hydrogen atom groups. Finally R = 9.39%, R
w
= 10.53% and S = 1.53 for
Communication 9/01914F
1144
Chem. Commun., 1999, 1143–1144