1682
A. M. Seayad et al. / Tetrahedron Letters 44 (2003) 1679–1683
Table 3. Hydroaminomethylation of 2-pentenea
Entry
Solvent
Conv. %
Amine Sel.,%
n:iso
Enamine Sel.,%
n:iso
1
2
Toluene
THF
95
43
89
29
10:90
0:100
8
49
0:100
0:100
a Reaction conditions: 2-pentene (15 mmol), piperidine (15 mmol), THF (30 ml), 0.1 mol%, Rh(Imes)(cod)Cl, CO (10 bar), H2 (50 bar),
temperature (85°C), time (12 h).
conditions. A high degree of regioselectivity (n/iso
selectivity) is obtained in the case of substituted styre-
nes. Terminal aliphatic olefins gave mixtures of linear
and branched products. The procedure is environmen-
tally friendly (i.e. water is the only by-product) and the
starting materials are both inexpensive and readily
available.
Briel, O.; Karch, R.; Beller, M. Angew. Chem., Int. Ed.
2002, 41, 986–989; (b) Selvakumar, K.; Zapf, A.; Span-
nenberg, A.; Beller, M. Chem. Eur. J. 2002, 8, 3901–3906.
9. To a solution of [Rh(cod)Cl]2 (0.5 mmol) in THF (20 ml)
was added slowly a THF solution (10 ml) of 1,3-dime-
sitylimidazol-2-ylidene (1.0 mmol) at room temperature.
The clear solution was stirred for 2 h and the solvent was
evaporated. The residue was triturated with pentane. The
yellow solid obtained was analytically pure. It can be
recrystallized from CH2Cl2/pentane. Yield=450 mg,
Acknowledgements
1
82%. H NMR (CDCl3): 1.54 (m, 4H), 1.83 (m, 4H), 2.10
(s, 6H), 2.34 (s, 6H), 2.38 (s, 6H), 3.30 (s, 2H), 4.40 (s,
2H), 6.96 (s, 2H), 7.03 (s, 4H); 13C NMR (CDCl3): 18.5,
20.0, 21.4, 28.9, 33.2, 68.7 (d, 1JRhC=14.3 Hz), 96.3 (d,
1JRhC=7.6 Hz), 124.3, 128.8, 129.8, 135.1, 137.0, 137.9,
A.S. and K.S. thank the Alexander-von-Humboldt-
Stiftung for their fellowships. This work has been
financed by the State of Mecklenburg-Western Pom-
merania and the Bundesministerium fu¨r Bildung und
Forschung (BMBF).
1
139.2, 183.5 (d, JRhC=52.5 Hz); MS (EI): 550 (M+, 13),
404 (21), 303 (100); Anal. calcd for C29H36ClN2Rh
(550.98): C, 63.22; H, 6.58; N, 5.08; Found: C, 63.08; H,
6.34; N, 5.05.
10. General procedure: In a typical experiment (Table 1, entry
9), 1-pentene (15 mmol), piperidine (15 mmol),
Rh(cod)(Imes)Cl (0.1 mol%) and freshly distilled THF
(30 ml) were charged under argon atmosphere into a 100
ml stainless steel autoclave provided with an overhead
stirrer and temperature controlled heating. The autoclave
was closed and pressurized to 60 bar (CO/H2=1:5) and
the reaction was carried out for 12 h at a temperature of
95°C (total pressure at 95°C was ca. 66 bar). After the
reaction, the autoclave was cooled slowly to 0–5°C and
slowly depressurized. The reaction mixture was analyzed
by gas chromatography with bis(methoxyethyl)ether as
an internal standard. N-Hexylpiperidine and (2-methyl-1-
pentyl)piperidine were identified by comparison with
authentic samples by GC (HP5890 series; column: HP5
(Crosslinked 5% PH ME Siloxane) 30 m, 0.25 mm, 0.25
mm). The products were also confirmed by GC MS and
NMR.
References
1. Reviews: Mu¨ller, T. E.; Beller, M. Chem. Rev. 1998, 98,
675–703; (b) Yamamoto, Y.; Radhakrishnan, U. Chem.
Soc. Rev. 1999, 28, 199–207; (c) Beller, M.; Breindl, C.;
Eichberger, M.; Hartung, C. G.; Seayad, J.; Thiel, O. R.;
Tillack, A.; Trauthwein, H. Synlett 2002, 1579–1594.
2. Review: Eilbracht, P.; Ba¨rfacker, L.; Buss, C.; Hollmann,
C.; Kitsos-Rzychon, B. E.; Kranemann, C. L.; Rische, T.;
Roggenbuck, R.; Schmidt, A. Chem. Rev. 1999, 99, 3329–
3365.
3. Gross, T.; Seayad, A.; Ahmed, M.; Beller, M. Org. Lett.
2002, 4, 2055–2058.
4. Zimmermann, B.; Herwig, J.; Beller, M. Angew. Chem.,
Int. Ed. 1999, 38, 2372–2375.
5. Seayad, A.; Ahmed, M.; Klein, H.; Jackstell, R.; Gross,
T.; Beller, M. Science 2002, 297, 1676–1678.
6. Reviews: (a) Jafarpour, L.; Nolan, S. P. Adv. Organomet.
Chem. 2001, 46, 181–222; (b) Herrmann W. A., Angew.
Chem., Int. Ed. 2002, 41, 1290–1309; (c) Hillier, A. C.;
Nolan, S. P. Platinum Met. Rev. 2002, 46, 50–64.
7. (a) Chen, A. C.; Ren, L.; Decken, A.; Crudden, C. M.
Organometallics 2000, 19, 3459–3461; (b) Ko¨cher, C.;
Herrmann, W. A. J. Organomet. Chem. 1997, 532, 261–
265; (c) Herrmann, W. A.; Elison, M.; Fischer, J.;
Ko¨cher, C. US 5663451, 1997.
11. Herrmann, W. A.; Elison, M.; Fischer, J.; Ko¨cher, C. US
5663451, 1997.
12. The decomposition of [Rh(cod)Cl]2 was predominant in
toluene as the solvent and increased with temperature.
The Rh–carbene complex was found to be stable (no
formation of metal particles) up to a temperature of
140°C.
13. Beller, M.; Trauthwein, H.; Eichberger, M.; Breindl, C.;
Herwig, J.; Mu¨ller, T. E.; Thiel, O. R. Chem. Eur. J.
1999, 5, 1306–1319.
8. (a) Jackstell, R.; Gomez, M.; Frisch, A.; Klein, H.;
Selvakumar, K.; Zapf, A.; Spannenberg, A.; Ro¨ttger, D.;