1364
T. Voigt et al.
LETTER
temperature overnight. The reaction was quenched by
carefully adding 5 mL of water, the mixture was exposed to
air until it had turned light yellow or colorless and then
filtered. The solids on the filter were washed with diethyl
ether (3 20 mL). The combined filtrates were concentrated
in vacuo, and the light yellow residue was subjected to
column chromatography (column 2 25 cm, 40 g of silica
gel) eluting with pentane/diethyl ether/triethylamine
90:9.5:0.5.
CH3), 2.14 2.27 (m, 1 H, 6-H), 2.30 2.37 (m, 1 H, 5-H*),
5.01 (dd, 2J = 1.6 Hz, 3J = 17.4 Hz, 1 H, 2 -H), 5.02 (dd,
2J = 1.6 Hz, 3J = 11.1 Hz, 1 H, 2 -H), 5.67 (dd,
3J = 11.1 Hz, 3J = 17.4 Hz, 1 H, 1 -H). 13C NMR
(62.9 MHz, CDCl3, DEPT): = 27.0 ( , C-2*), 29.4 ( ,
C-3*), 30.8 ( , C-6), 32.4 ( , C-4*), 32.5 ( , C-5*), 33.8 (+,
C-7), 34.7 (Cquat, C-1), 45.2 (+, 2 C, CH3), 64.8 (+, C-8),
111.1 ( , C-2 ), 142.4 (+, C-1 ). MS (70 eV, EI): m/z (%) =
179 (30) [M+], 164 (21), 150 (18), 136(100), 122 (39) [M+
C4H9], 108 (80) [M+ C5H11], 84 (62), 71(45), 42 (100),
41 (49). Anal. Calcd for C12H21N (179.3): C, 80.38;
H, 11.81; N, 7.81. Found: C,80.18; H, 11.74; N, 7.74.
(2,4,5,6,7,7a-Hexahydro-1H-inden-1-yl)dimethylamine
(7c): 1H NMR (250 MHz, CDCl3): = 0.93 1.38 (m, 3 H,
4-H*, 5-H*), 1.69 1.80 (m, 2 H, 6-H*), 1.80 1.98 (m, 1 H,
7-H*), 1.98 2.17 (m, 1 H, 7-H*), 2.17 2.45 (m, 4 H, 1-H,
2-H, 4-H), 2.23 (s, 6 H, CH3), 2.55 2.64 (m, 1 H, 7a-H),
5.15 (mc, 1 H, 3-H). 13C NMR (62.9 MHz, CDCl3, DEPT):
= 26.1 ( , C-6), 26.9 ( , C-5), 29.2 ( , C-4), 35.4 ( ,
C-2), 35.5 ( , C-7), 43.3 (+, 2 C, CH3), 48.5 (+, C-7a), 73.2
(+, C-1), 118.3 (+, C-3), 144.8 (Cquat, C-3a). MS (70 eV, EI):
m/z (%) = 165 (100) [M+], 150 (42), 136 (51), 122 (23),
108 (15), 91 (24), 84 (41), 70 (33), 58 (19), 42 (26). Anal.
Calcd for C11H19N (165.3): C, 79.94; H, 11.59; N, 8.47.
Found: C, 79.85; H, 11.57; N, 8.35.
exo-5-Dibenzylaminobicyclo[2.1.0]pentane (3a):
According to GP, 962 mg (12 mmol) of 1-ethenylcyclo-
butene (2a) with N,N-dibenzylformamide (5.63 g, 25 mmol),
methyltitanium triisopropoxide (2.88 g, 12 mmol) and 15.8
mL (30 mmol) of cyclohexylmagnesium bromide solution
(1.90 M in diethyl ether) gave 2.20 g (63%) of 3a as a
light yellow oil. 1H NMR (250 MHz, CDCl3): = 1.42
(ddd, 2J = 11.0, 3J = 6.5, 3J = 3.9 Hz, 1 H, 3-Hendo), 1.55
(ddd, 2J = 11.0, 3J = 6.5, 3J = 4.6 Hz, 1 H, 2-Hendo), 1.79
(d, 3J = 4.6 Hz, 1 H, 4-H), 2.01 (dddd, 2J = 11.0, 3J = 11.0,
3J = 4.6, 3J = 4.6 Hz, 1 H, 3-Hexo), 2.31 (ddd, 2J = 11.0,
3J = 11.0, 3J = 3.9 Hz, 1 H, 2-Hexo), 2.36 (s, 1 H, 5-H),
3.61 (AB, d, 2J = 14.0 Hz, 2 H, NCH2Ph), 3.80 (AB, d,
2J = 14.0 Hz, 2 H, NCH2Ph), 5.09 (dd, 2J = 1.9,
3Jtrans = 17.5 Hz, 1 H, 7-H), 5.17 (dd, 2J = 1.9,
3Jcis = 10.8 Hz, 1 H, 7-H), 6.20 (dd, 3Jtrans = 17.5,
3Jcis = 10.8 Hz, 1 H, 6-H), 7.25–7.47 (m, 10 H, Ph-H).
13C NMR (62.9 MHz, CDCl3, additionally DEPT): = 19.2
(–, C-3), 22.9 (–, C-2), 31.3 (+, C-4), 36.0 (Cquat, C-1), 56.9
(–, 2 C, NCH2Ph), 57.7 (+, C-5), 112.3 (–, C-7), 126.9 (+,
2 C, Ph-C), 128.1 (+, 4 C, Ph-C), 129.3 (+, 4 C, Ph-C), 137.4
(+, C-6), 137.9 (Cquat, 2 C, Ph-C). MS (70 eV): m/z (%) =
289(16) [M+], 288(12) [M+ – H], 262(3) [M+ – C2H3],
224(11), 198(29) [M+ – C7H7], 170(5) [M+ – C7H7 – C2H4],
4,5,6,7-Tetrahydro-1H-indene(11c) and 4,5,6,7-
Tetrahydro-2H-indene (12c): 11c: 1H NMR see ref.11.
13C NMR (62.9 MHz, CDCl3, DEPT): = 23.1 ( , C-4*),
23.3 ( , C-5*), 24.4 ( , C-6*), 25.3 ( , C-7*), 34.1 ( , C-1),
129.8 (+, C-2), 134.5 (+, C-3), 137.9 (Cquat, C-3a*), 139.2
(Cquat, C-7a*). 12c: 1H NMR (250 MHz, CDCl3): = 1.58
1.80 [m, 4 H, 5(6)-H], 2.47 2.58 [m, 4 H, 4(7)-H], 2.72
2.80 (m, 2 H, 2-H), 5.97 [mc, 2 H, 1(3)-H]. 13C NMR
(62.9 MHz, CDCl3, DEPT): = 24.4 [ , C-4(7)], 25.7 [ ,
C-5(6)], 39.7 ( , C-2), 125.1 [+, C-1(3)]. The signals of the
quaternary carbon atoms C-3a and C-7a were not visible
because of the low concentration of 12c.
+
144(20) [M+ – C7H7 – C4H6], 106(8) [HNC7H7 ], 91(100)
+
[C7H7 ]. C21H23N: 289.1830 (correct HRMS). Anal. Calcd
for C20H23N (289.4): C, 87.15; H, 8.01; N, 4.84. Found; C,
86.88; H, 7.90; N, 4.97.
(10) All new compounds were fully characterized by
spectroscopic techniques (1H and 13C NMR, MS), and bulk
purities – except for the quaternary ammonium salts 9 and N-
oxides 10 – were established by elemental analyses.
Spectroscopic data of representative examples: exo-N,N-
Dimethyl-(1-ethenylbicyclo[4.1.0]hept-7-yl)amine (3c):
1H NMR (500 MHz, CDCl3): = 1.03 (ddd, 3J = 1.8,
3J = 8.0 Hz, 3Jtrans = 4.3 Hz, 1 H, 6-H), 1.08–1.24 (m, 3 H,
3-H*, 4-H), 1.27–1.37 (m, 1 H, 4-H), 1.45 (d,
(11) Dané, L. M.; de Haan, J. W.; Klosterziel, H. Tetrahedron
Lett. 1970, 9, 2755.
(12) (a) Hudlicky, T.; Becker, D. A.; Fan, R. L.; Kozhushkov, S.
I. Methods in Organic Chemistry (Houben-Weyl), Vol. E
17c; de Meijere, A., Ed.; Thieme: Stuttgart, 1997, 2538.
(b) Hudlicky, T.; Reed, J. W. In Comprehensive Organic
Synthesis, Vol. 5; Trost, B. M.; Fleming, I., Eds.; Pergamon
Press: Oxford, 1991, 899.
(13) (a) Richey, H. G.; Shull, D. W. Tetrahedron Lett. 1976, 575.
(b) Williams, C. M.; de Meijere, A. J. Chem. Soc., Perkin
Trans. 1 1998, 3699.
3Jtrans = 4.3 Hz, 1 H, 7-H), 1.52 1.63 (m, 2 H, 2-H, 5-H),
1.87 1.98 (m, 2 H, 2-H, 5-H), 2.20 (s, 6 H, CH3), 4.99 (dd,
2J = 1.6, 3J = 10.8 Hz, 1 H, 2 -H), 5.03 (dd, 2J = 1.6,
3J = 17.6 Hz, 1 H, 2 -H), 5.82 (dd, 3J = 10.8, 3J = 17.6 Hz,
1 H, 1 -H). 13C NMR (62.9 MHz, CDCl3, DEPT): = 21.1
( , C-3*), 22.7 ( , C-4*), 22.1 ( , C-5**), 25.8 ( , C-2**),
27.7 (+, C-6), 28.5 (Cquat, C-1), 45.0 (+, 2 C, CH3), 58.4 (+,
C-7), 110.4 ( , C-2 ), 143.7 (+, C-1 ). MS (70 eV, EI):
m/z (%) = 165 (100) [M+], 150 (42), 136 (62), 122 (30),
108 (23), 84 (57), 70 (38), 58 (30), 42 (48). Anal. Calcd for
C11H19N (165.3): C, 79.94; H, 11.59; N, 8.47. Found:
C, 79.66; H, 11.35; N, 8.53.
(14) The structure of the by-products could not unambiguously
be determined.
(15) (a) The necessity of relatively high temperatures for the
rearrangement of 3b–d is consistent with the fact that the
dimethylamino and the ethenyl group in each of them are
cis-oriented with respect to each other. It is known that the
direct ring enlargement of a cis-2-donor-substituted
ethenylcyclopropane to a cyclopentene is much slower than
that of the trans isomer, and the cis to trans isomerization of
3b–d, which would correspond to an exo to endo
exo-N,N-Dimethyl-(1-ethenylbicyclo[5.1.0]oct-8-
yl)amine (3d): 1H NMR (500 MHz, CDCl3): = 0.89 1.14
(m, 4 H, 2-H*, 6-H, 7-H), 1.20 1.31 (m, 1 H, 3-H*), 1.40 (d,
3Jtrans = 3.8 Hz, 1 H, 8-H), 1.48 1.56 (m, 1 H, 3-H*), 1.58
1.72 (m, 2 H, 4-H*), 1.74 1.83 (m, 1 H, 5-H*), 2.19 (s, 6 H,
isomerization, is retarded due to the bulk of the
dimethylamino group. (b) Cf. ref.13 and ref.14 and see also:
McGaffin, G.; Grimm, B.; Heinecke, U.; Michaelsen, H.; de
Meijere, A.; Walsh, R. Eur. J. Org. Chem. 2001, 3559.
(16) Pauli, A.; Meier, H. Chem. Ber. 1987, 120, 1617.
Synlett 2002, No. 8, 1362–1364 ISSN 0936-5214 © Thieme Stuttgart · New York