COMMUNICATIONS
Jos e´ Barluenga et al.
odienes does not require harsher conditions or longer sis. The mixture was allowed to cool to room temperature, tak-
en up in dry pentane or hexanes (15 mL), and filtered through
reaction times than with bromodienes. Moreover, 1-
celite. The solvents were evaporated under reduced pressure.
chlorodienes are readily available through several
The residue was redissolved in dry hexanes (15 mL), filtered
methods, among them various cross-coupling protocols
again through celite, concentrated under reduced pressure
and dried under high vacuum to afford a residue which consist-
involving commercially available 1,2-dichloroethy-
[20]
lene; therefore, the present methodology may repre-
sent a very simple entry into structurally diverse 1-ami-
no-1,3-butadienes.
ed of the essentially pure 1-aminodiene 3.
-[(1E)-2-Cyclohexenylvinyl]morpholine (3a): HRMS:
4
1
calcd. for C H ON: 193.1461; found: 193.1460; H NMR
1
2
19
In conclusion, we have reported a new methodology, (CDCl , 300 MHz): d¼1.61–1.68 (m, 4H), 2.09–2.12 (m,
3
3
which represents a fairly general method for the syn- 4H), 2.87–2.93 (m, 4H), 3.72–3.77 (m, 4H), 5.26 (d, J
¼
trans
3
thesis of 1-amino-1,3-butadienes from readily available 14.2 Hz, 1H), 5.48 (s, 1H), 6.03 (d,
J
trans ¼14.2 Hz, 1H);
1
3
C NMR (CDCl , 75 MHz): d¼23.05 (CH ), 23.14 (CH ),
substrates, 1-bromo- and 1-chloro-1,3-butadienes. Giv-
en the usefulness of 1-amino-1,3-butadienes in cycload-
dition processes, we believe that the reaction presented
herein may be of great applicability in synthetic organic
chemistry.
3
2
2
2
5.25 (CH ), 26.06 (CH ), 49.49 (CH ), 66.77 (CH ), 106.88
2 2 2 2
(
CH), 122.27 (CH), 134.70 (C), 136.82 (CH).
N-[(1E,3E)-Deca-1,3-dienyl]-N-methylbenzenamine (3k):
HRMS: calcd. for C H N: 243.1981; found: 223.1980;
1
7
25
1
H NMR (CDCl , 300 MHz): d¼0.92–0.94 (m, 3H), 1.32–
3
1
2
1
.37 (m, 8H), 2.08–2.13 (m, 2H), 3.19 (s, 3H), 5.44–5.53 (m,
3
3
3
H), 6.10 (dd, J ¼15.0 Hz, J¼10.4 Hz, 1H), 6.82 (d, J
¼
trans
trans
3.5 Hz, 1H), 6.92–7.03 (m, 3H, arom. H), 7.28–7.31 (m, 2H,
Experimental Section
1
3
arom. H); C NMR (CDCl , 75 MHz): d¼14.06 (CH ), 22.60
3
3
(CH ), 28.86 (CH ), 29.89 (CH ), 31.75 (CH ), 32.87 (CH ),
2 2 2 2 2
General Remarks
35.03 (CH
), 104.95 (CH), 117.04 (CH), 120.62 (CH), 126.62
3
(
CH), 129.06 (CH), 129.12 (CH), 134.84 (CH), 147.34 (C).
All reactions were carried out under nitrogen atmosphere in an
RR98030 12 place Carousel Reaction Station from Radleys
TM
Discovery Technologies, equipped with gas-tight threaded
caps with a valve, cooling reflux head system, and digital tem-
perature controller. Toluene, pentane and hexanes were con-
tinuously refluxed and freshly distilled from sodium/benzo-
phenone under nitrogen. Pd (dba) and Pd(OAc) were pur-
Acknowledgements
Financial support of this work by the DGI (Grant BQU-2001-
2
3
2
3
853) and the FICYT (Grant PR-01-GE-09).
chased from Strem Chemical co. and used without further pu-
rification. All phosphane ligands used are commercially avail-
able from Strem or Aldrich and were used without further
purification. NaO-t-Bu was purchased from Aldrich Chemical
Co., stored in a flask purged with nitrogen and weighted in the
air. Bromodienes 1a and 1b were prepared as described in the
Supplementary Information. The synthesis of 1-bromo-3-
methyl-4-phenyl-1,3-butadiene 1c and 1-bromo-4-phenylbuta-
References and Notes
[1] a) The Chemistry of Enamines, (Ed.: Z. Rappaport), Wi-
ley, New York, 1994; b) Enamines: Synthesis, Structure
and Reactions, 2nd edn., (Ed.: A. G. Cook), Marcel Dek-
ker, New York, 1998.
[2] For reviews on Diels–Alder reactions of amino-substitut-
ed dienes, see: a) D. Enders, O. Meyer, Liebigs Ann.
[17]
diene 1d was adapted from a known procedure and is de-
tailed in the Supplementary Information. GC analysis were
performed with a GC Agilent Technologies 6890N instrument.
1
NMR spectra were recorded at 300 or 200 MHz for H and 75
13
or 50.3 MHz for C, with tetramethylsilane as internal stand-
1
996, 1023–1035; b) J. Barluenga, A. Su a´ rez-Sobrino,
1
13
ard for H and the residual solvent signals as standard for C.
Chemical shifts are given in ppm. Mass spectra were obtained
by EI (70 eV).
L-A. L o´ pez, Aldrichimica Acta 1999, 32, 4–15.
3] L. E. Overman, G. F. Taylor, K. N. Houk, L. N. Domel-
smith, J. Am. Chem. Soc. 1978, 100, 3182.
[
[
4] a) S. A. Kozmin, V. H. Rawal, J. Am. Chem. Soc. 1997,
1
19, 7165–7166; b) R. Robiette, K. Cheboub-Benchaba,
D. Peeters, J. Marchand-Brynaert, J. Org. Chem. 2003,
8, 9809–9812 and references cited therein.
[5] P. Wipf, X. Wang, Tetrahedron Lett. 2000, 41, 8747–8751.
General Procedure for the Cross-Coupling of 1-
Halodienes 1a–d with Secondary Amines 2; Synthesis
of 1-Aminodienes 3a–k
6
[
6] a) L. E. Overman, P. J. Jessup, J. Am. Chem. Soc. 1978,
00, 5179; b) S. A. Kozmin, T. Iwama, Y. Huang, V. H.
Rawal, J. Am. Chem. Soc. 2002, 124, 4628–4641.
7] For reviews on the synthesis and reactivity dienamines,
see: a) P. W. Hickmott, Tetrahedron 1984, 40, 2989–
A carousel reaction tube under nitrogen atmosphere was
charged with XPHOS (0.01 mmol, 1 mol %), tris(dibenzyli-
deneacetone)dipalladium(0) (0.005 mmol, 1 mol %), sodium
tert-butoxide (1.4 mmol) and toluene (4 mL). After 1 minute,
the halodiene 1 (1 mmol) was added and the reaction mixture
was stirred for 2 additional minutes, when the amine 2
1
[
3
051; b) O. Cervinka, in: The Chemistry of Enamines.
(
1 mmol) was added. The system was heated (808C for bromo-
Part 1, (Ed.: Z. Rappoport), Wiley, New York, 1994,
dienes or 908C for chlorodienes) with stirring until the starting
chap. 9, p. 467.
halide had been completely consumed as judged by GC analy-
[8] S. Hünig, H. Kahanek, 1957, Chem. Ber. 90, 238.
1700
ꢁ 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
Adv. Synth. Catal. 2004, 346, 1697–1701