Domino Heck–Diels–Alder Reactions
ica gel (100 g, 3ϫ30 cm, light petroleum/ethyl acetate, 14:1), a mix-
ture of syn/anti-(E)-15d and/or syn/anti-(Z)-15d* along with some
unidentified impurities (214 mg, colorless oil) and tert-butyl 8-phen-
ylspiro[2.5]oct-7-ene-5-carboxylate* (26) (116 mg, 25%, yellowish
oil) was obtained. *These spirooctenes could not be isolated in
pure form, and their relative configurations could not be assigned.
5-tert-Butyl 1-Methoxycarbonyl-8-phenylspiro[2.5]oct-7-ene-5-car-
boxylate [syn/anti-(Z)-15e]: Rf = 0.46 (light petroleum/ethyl acetate,
10:1). IR (Film): ν = 3079, 3056, 3003, 2977, 2951, 2931, 2846,
˜
1729, 1492, 1479, 1441, 1392, 1368, 1335, 1316, 1258, 1212, 1192,
1170, 1152, 1070, 990, 904, 849, 829, 764, 705 cm–1. 1H NMR
(300 MHz, CDCl3): δ = 0.93–0.97 (m, 1 H, cPr-H), 1.13 (dd, J =
4.9, 8.1 Hz, 1 H, cPr-H), 1.19 (dd, J = 4.6, 6.0 Hz, 1 H, cPr-H),
1.28–1.32 (m, 1 H, cPr-H), 1.43 [s, 9 H, C(CH3)3], 1.44 [s, 9 H,
C(CH3)3], 1.55–1.60 (m, 1 H, cPr-H), 1.75 (dd, J = 6.0, 8.3 Hz, 1
H, cPr-H), 1.89–2.19 (m, 4 H, 4-H or 6-H), 2.34–2.44 (m, 4 H, 4-
H or 6-H), 2.48–2.60 (m, 1 H, 5-H), 2.68–2.78 (m, 1 H, 5-H), 3.65
(s, 3 H, OCH3), 3.67 (s, 3 H, OCH3), 5.59–5.64 (m, 2 H, 2ϫ7-H),
6.99–7.04 (m, 4 H, Ph), 7.19–7.29 (m, 6 H, Ph) ppm. 13C NMR
(50.3 MHz, CDCl3, DEPT): δ = 17.80 (–, cPr-C), 18.59 (–, cPr-C),
24.65 (+, 2ϫcPr-C), 28.03 [+, 2ϫC(CH3)3], 28.32 (–, C-4 or C-6),
28.60 (–, C-4 or C-6), 29.25 (Cquat, cPr-C), 29.90 (–, C-4 or C-6),
30.06 (Cquat, cPr-C), 30.99 (–, C-4 or C-6), 40.24 (+, C-5), 40.43
For the spectroscopic data of compound 26 see ref.[3]
.
Domino Heck–Diels–Alder Reaction of Methyl 1,1Ј-Bicyclopropyl-
idene-2-carboxylate (8e): According to GP-1, Pd(OAc)2 (20.3 mg,
90 µmol), triphenylphophane (71.3 mg, 271 µmol), K2CO3
(500 mg, 3.62 mmol), Et4NCl (300 mg, 1.81 mmol), iodobenzene
(9, 369 mg, 1.81 mmol), methyl bicyclopropylidenecarboxylate (8e,
500 mg, 3.62 mmol) and tert-butyl acrylate (13, 464 mg,
3.62 mmol) were stirred in anhydrous MeCN (2 mL) at 80 °C for 48
h. After work-up and column chromatography on silica gel (100 g,
3ϫ30 cm, light petroleum/ethyl acetate, 10:1) a mixture of syn- and
anti-(E)-15e (ratio 1.25:1 according to NMR, 427.5 mg, 69%, col-
orless solid) as well as a mixture of syn- and anti-(Z)-15e (ratio
1.1:1 according to NMR, 37 mg, 6%, yellowish oil) were obtained.
The diastereomers syn- and anti-(E)-15e were partially separated
from each other as crystals by slow evaporation of solvents from
an ethyl acetate/diethyl ether (1:1) solution of these compounds.
(+, C-5), 51.68 (+, OCH3), 51.72 (+, OCH3), 80.09 [Cquat
,
C(CH3)3], 80.21 [Cquat, C(CH3)3], 126.48 (+, C-7), 126.81 (+, C-7),
126.94 (+, Ph), 126.99 (+, Ph), 127.71 (+, 2ϫPh), 127.77 (+,
2ϫPh), 129.34 (+, 2ϫPh), 129.42 (+, 2ϫPh), 139.07 (Cquat),
139.48 (Cquat), 140.66 (Cquat), 140.87 (Cquat), 171.87 (Cquat, C=O),
172.09 (Cquat, C=O), 174.25 (Cquat, C=O), 175.50 (Cquat, C=O)
ppm. MS (DCI): m/z (%) = 702.7 (12) [2M + NH4+], 360 (100) [M
+ NH4+], 343 (14) [M + H+] 304 (61). HRMS-ESI for C21H26O4
(342.43): [M + H]+ 343.19047, calcd. 343.19039; [M + Na]+
365.17244, calcd. 365.17233. *For all measurements the pure mix-
ture of syn- and anti-diastereomers of (Z)-15e was used.
tert-Butyl 1-Methoxycarbonyl-8-phenylspiro[2.5]oct-7-ene-5-carbox-
ylate [syn/anti-(E)-15e]
Major Diastereomer [syn-(E)-15e]: Rf = 0.37 (light petroleum/ethyl
acetate, 10:1). IR (KBr): ν = 3064, 3027, 2997, 2977, 2956, 2919,
˜
2876, 1732, 1723, 1495, 1481, 1440, 1389, 1370, 1351, 1320, 1280,
1265, 1226, 1212, 1194, 1169, 1068, 1048, 946, 892, 846, 757, 696
CCDC-664722 [for syn-(E)-14b], -664723 [for syn-(E)-15e] and
-664724 [for anti-(E)-15e] contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
1
cm–1. H NMR (250 MHz, CDCl3): δ = 1.19 (dd, J = 5.2, 8.3 Hz,
1 H, cPr-H), 1.49 [s, 9 H, C(CH3)3], 1.58 (t, J = 5.6 Hz, 1 H, cPr-
H), 1.74–2.13 (AB system, δA = 2.08, δB = 1.78, JA = 7.9, 13.5, JB
= 5.3, 13.5 Hz, 2 H, 4-H or 6-H), 1.97–2.03 (m, 1 H, cPr-H), 2.47–
2.53 (m, 2 H, 4-H or 6-H), 2.64–2.75 (m, 1 H, 5-H), 3.36 (s, 3 H,
OCH3), 5.94 (t, J = 4.7 Hz, 1 H, 7-H), 7.13–7.32 (m, 5 H, Ph) ppm.
13C NMR (62.9 MHz, CDCl3, DEPT): δ = 18.27 (–, cPr-C), 27.49
Acknowledgments
(–, C-4 or C-6), 28.07 [+, C(CH3)3], 29.39 (+, cPr-C), 29.62 (Cquat
,
cPr-C), 37.42 (–, C-4 or C-6), 40.03 (+, C-5), 51.25 (+, OCH3),
80.50 [Cquat, C(CH3)3], 126.52 (+, Ph), 127.56 (+, 2ϫPh), 127.62
(+, 2ϫPh), 129.30 (+, C-7), 140.96 (Cquat), 141.70 (Cquat), 170.88
(Cquat, C=O), 174.53 (Cquat, C=O) ppm. MS (70 eV, EI): m/z (%)
= 342 (11) [M+], 327 (4) [M+ – CH3], 311 (6), 286 (26), 240 (48),
226 (46), 209 (17), 181 (100), 167 (22), 154 (11), 57 (26).
This work was supported by the Land Niedersachsen as well as
BAYER, BASF and Degussa AG (gifts of chemicals). The authors
are grateful to Reinhard Machinek for his technical support and
suggestions in measuring NOESY and other two-dimensional
NMR spectra.
Minor Diastereomer [anti-(E)-15e]: Rf = 0.37 (light petroleum/ethyl
[1] a) A. de Meijere, S. I. Kozhushkov, A. F. Khlebnikov, Top.
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acetate, 10:1). IR (KBr): ν = 3080, 3027, 2996, 2978, 2955, 2927,
˜
2867, 1733, 1723, 1494, 1481, 1437, 1387, 1370, 1351, 1318, 1280,
1258, 1226, 1212, 1192, 1170, 1068, 947, 893, 846, 829, 756, 697
cm–1. 1H NMR (250 MHz, CDCl3): δ = 1.29–1.36 (m, 2 H, cPr-H,
4-H or 6-H), 1.46 [s, 9 H, C(CH3)3], 1.63–1.68 (m, 1 H, cPr-H),
1.76–1.81 (m, 1 H, cPr-H), 2.23 (t, J = 12.7 Hz, 1 H, 4-H or 6-H),
2.39–2.67 (m, 2 H, 4-H or 6-H), 2.89–3.03 (m, 1 H, 5-H), 3.34 (s,
3 H, OCH3), 5.76 (t, J = 3.8 Hz, 1 H, 7-H), 7.06–7.10 (m, 2 H,
Ph), 7.20–7.31 (m, 3 H, Ph) ppm. 13C NMR (62.9 MHz, CDCl3,
DEPT): δ = 19.92 (–, cPr-C), 28.06 [+, C(CH3)3], 29.0 (–, C-4 or
C-6), 30.38 (Cquat, cPr-C), 30.50 (+, cPr-C), 38.80 (–, C-4 or C-6),
40.37 (+, C-5), 51.32 (+, OCH3), 80.38 [Cquat, C(CH3)3], 126.39 (+,
C-7), 127.40 (+, 2ϫPh), 128.07 (+, 2ϫPh), 130.16 (+, Ph), 138.97
(Cquat), 141.59 (Cquat), 170.90 (Cquat, C=O), 174.34 (Cquat, C=O)
ppm. MS (70 eV, EI): m/z (%) = 342 (4) [M+], 286 (22), 240 (42),
226 (44), 181 (100), 167 (24), 154 (16), 115 (9), 57 (82), 41 (39).
C21H26O4 (342.4): calcd. C 73.66, H 7.65; found C 73.56, H 7.43.
The elemental analysis was carried out with the purified mixture
of syn- and anti-diastereomers.
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© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
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