NMR, d 7.28–7.15 (m, Ph), 5.36 (t, JHH 10.2 Hz, 1H, Hcentre), 5.29 (s, 5H,
C5H5), 5.05 (d, JHH 10.2 Hz, 1H, Hsyn), 2.81, 2.46 (s, 2H, NCH3), 1.12 (d,
J
spectroscopically. When the reaction was carried out at 260 °C,
an intermediate was indeed observed. Upon addition of
piperidine at 260 °C, the light yellow complex 1 dissolved and
the solution turned deep red, to give a mixture of an unstable
intermediate 4a as well as 3a. In the IR spectrum of the mixture
the intermediate displays two peaks at 1927 and 1828 cm21 as
well as one amido CO stretching absorption at 1577 cm21. The
latter suggested the presence of O-coordinated amido carbonyl.9
Complex 4a† transforms to 2a in 1 h at room temperature but at
lower temperature this process is slowed and the structure of 4a
can be assigned on the basis of the spectroscopic data of the
HH 10.2 Hz, 1H, Hanti). 13C{1H} NMR, d 241.8, 238.3 (CO), 171.8 (CNO),
130.3–126.2 (Ph), 94.2 (Cp), 70.3 (CHcentre), 61.1 (CPh3), 50.8 (CHsyn),
37.1, 36.1 (NCH3). FAB MS: m/z 574 (M+ + 1), 545 (M+ 2 CO), 515 (M+
2 2CO). 4a: 1H NMR (CDCl3): d 7.27–7.08 (m, Ph), 6.55 (s, 1H, NCH),
5.33 (s, 5H, C5H5), 2.74 (d, JHH 22.4 Hz, 1H, CHH), 2.28 (d, JHH 22.4 Hz,
1H, CHH), 3.26–2.66 (m, 4H, CH2NCH2), 1.96 (m, 6H,
CH2NCH2CH2CH2CH2). 13C NMR [(CD3)2CO], d 180 (CON), 162.5 (Mo–
C), 147.5 (NCH–), 47.2 (CH2).
‡ Crystal data for 2b: C34H31O4NMo, M = 613.54, monoclinic, space
group P21/c, a = 13.6809(4), b = 9.8539(3), c = 21.6322(7) Å, b =
104.061(1), V = 2828.9(2) Å3, Z = 4, DC = 1.441 g cm23, m = 5.03 cm21
,
1
mixture obtained at 260 °C. In the H NMR spectrum, two
F(000) = 1264, 20 869 reflections collected on Smart CCD [T = 295(2) K],
6481 independent reflections (Rint = 0.0436) observed with I > 2s(I), 362
parameters, no restraints. The final discrepancy indices R1 and wR2 were
0.0357 and 0.0734 respectively. CCDC 182/980.
doublet resonances at d 2.28 and 2.74 with JHH 22.4 Hz indicate
the presence of a CH2 group while a singlet resonance at d 6.55
is assigned to the NCH– group for 4a. Two-dimensional
HSQC10 data confirms the CH2 13C resonance at d 47.2 and
13CH group at d 147.5. In the HMBC11 spectrum, the cross-peak
between the CH2 (dH 2.28, 2.74) and the CON (dC 180) groups12
indicate C–C bond formation at the terminal CH2 group. These
observations imply that the intermediate could be a vinyl13
complex, (Scheme 1) and the first mechanism is thus ruled out.
Hydrogen migration of 4a may proceed through b-elimination
to give the metal hydride allene followed by coupling of the
hydride at Cb of the allene to give the final product 2a.
1 C.-C. Su, J.-T. Chen, G.-H. Lee and Y. Wang, J. Am. Chem. Soc., 1994,
116, 4999; J.-C. Choi and T. Yamamoto, J. Am. Chem. Soc., 1997, 119,
12390; R.-H. Hsu, J.-T. Chen, G.-H. Lee and Y. Wang, Organome-
tallics, 1997, 16, 1159; K. Okuro and H. Alper, J. Org. Chem., 1997, 62,
1566.
2 K.-W. Liang, G.-H. Lee, S.-M. Peng and R.-S. Liu, Organometallics,
1995, 14, 2353; P. Blenkiron, J. F. Corrigan, N. J. Taylor and A. J. Carty,
Organometallics, 1997, 16, 297; S. Doherty, M. R. J. Elsegood, W.
Clegg, N. H. Rees, T. H. Scanlan and M. Waugh, Organometallics,
1997, 16, 3221; S. Doherty, M. R. J. Elsegood, W. Clegg, M. F. Ward
and M. Waugh, Organometallics, 1997, 16, 4251; M. A. Esteruelas,
F. J. Lahoz, M. Martin, E. Onate and L. A. Oro, Organometallics, 1997,
16, 4572.
Reactions of 1 with other amines such as methylamine,
ethylamine, propylamine, phenylamine, benzylamine, diethyl-
amine, diisopropyl amine, di-sec-butylamine, diisobutyl amine
and hydrazine gave only the b-coupled product. The pKa values
of the three unique amines (8.30 for morpholine, 10.90 for
Me2NH and 11.20 for piperidine) giving the a-coupled product
are in the range of regular amines (4.69 for aniline to 11.1 for
diisopropyl amine) while no striking steric effect is seen for
these three amines. While we cannot explain their different
reactivity, this is the first case where coupling at the a-position
3 M.-C. Chen, R.-S. Keng, Y.-C. Lin, Y. Wang, M.-C. Cheng and G. H.
Lee, J. Chem. Soc., Chem. Commun., 1990, 1138.
4 T.-W. Tseng, I.-Y. Wu, J.-H. Tsai, Y.-C. Lin, D.-J. Chen, G.-H. Lee,
M.-C. Cheng and Y. Wang, Organometallics, 1994, 13, 3963.
5 T.-W. Tseng, I.-W. Wu, Y.-C. Lin, C.-T. Chen, M.-C. Chen, Y.-J. Tsai,
M.-C. Chen and Y. Wang, Organometallics, 1991, 10, 43; I.-Y. Wu,
T.-W. Tseng, Y.-C. Lin, M.-C. Cheng and Y. Wang, Organometallics,
1993, 12, 478.
6 L. Lee, I.-Y. Wu, Y.-C. Lin, G.-H. Lee and Y. Wang, Organometallics,
1994, 13, 2521.
7 H. A. Brune, W. Eberius and H. P. Wolff, J. Organomet. Chem., 1968,
12, 485.
8 K. Hiraki, N. Ochi, Y. Sasada, H. Hayashida, Y. Fuchita and S.
Yamanaka, J. Chem. Soc., Dalton Trans., 1985, 873; E. Hernandez and
H. Hoberg, J. Organomet. Chem., 1986, 315, 245; R. Vac, J. H. Nelson,
E. B. Milosavljevic, L. Solujic and J. Fischer, Inorg. Chem., 1989, 28,
4132.
9 D. Hedden, D. M. Roundhill, W. C. Fultz and A. L. Rheingold,
Organometallics, 1986, 5, 336; R. D. Adams and S. Wang, Organome-
tallics, 1987, 6, 45; M. Shakij, S. P. Varkey and P. S. Hameed,
Polyhedron, 1994, 13, 1355.
10 G. Bodenhausen and D. J. Ruben, Chem. Phys. Lett., 1980, 69, 185.
11 W. Adam, J. Rutterlik, R.-M. Schuhmann and J. Sundermeyer,
Organometallics, 1996, 15, 4586; G. Jia, W.-F. Wu, R. C. Y. Yeung and
H.-P. Xia, J. Organomet. Chem., 1997, 539, 53.
12 A. Bax and M. F. Summers, J. Am. Chem. Soc., 1986, 108, 2093; A. Bax
and D. Marion, J. Magn. Reson., 1988, 78, 186.
2
of a h -allene has been found. A detailed mechanism for this
unusual coupling, the reactivity of compound 1 with other
nucleophiles and the corresponding reaction for the tungsten
system is currently under investigation.
We are grateful for support of this work by the National
Science Council, Taiwan, the Republic of China.
Notes and References
† Selected spectroscopic data: 1H and 13C{1H} NMR were recorded in
CDCl3 relative to SiMe4 and IR in CH2Cl2. 2a: IR, 1954s, 1873s, 1605m
1
cm21. H NMR, d 7.28–7.11 (m, 15H, aromatic H), 5.39 (t, JHH 10.0 Hz,
1H, Hcentre), 5.28 (5H, s, Cp), 5.06 (d, JHH 10.0 Hz, 1H, CHsyn), 3.60, 3.24,
2.83 (m, 4H, H2CNCH2), 1.52 (m, 6H, CH2CNCH2C3H6), 0.99 [1H, d, JHH
10.0 Hz, HCC(O)N]. 13C{1H} NMR, d 241.4, 238.4 (CO), 169.9 (CNO),
130.3, 127.2, 126.1 (Ph), 94.1 (Cp), 70.1 (CHcentre), 68.6 (CHsyn), 61.2
(CPh3), 50.2 (CHanti), 46.3, 43.3 (CH2NC2H), 26.8, 25.7, 24.7
(NC2H4C3H6). FAB MS: m/z 614 (M+ + 1), 585 (M+ 2 CO), 557 (M+
2
2CO). 2b: IR (KBr), 1937s, 1858s, 1623m cm21. 1H NMR, d 7.29–7.15 (m,
Ph), 5.40 (t, JHH 10.2 Hz, 1H, Hcentre), 5.29 (s, 5H, C5H5), 5.07 (d, JHH 10.2
Hz, 1H, Hsyn), 3.57–2.73 (m, 8H, NC4H8O), 0.88 (d, JHH 10.2 Hz, 1H,
13 F. Muller, G. van Koten, K. Vrieze and D. Heijdenrijk, Organome-
tallics, 1989, 8, 33.
H
anti); 13C{1H} NMR, d 241.6, 237.8 (CO), 170.5 (CNO), 130.3–126.1 (Ph),
94.2 (Cp), 69.9 (CHcentre), 68.8 (CHsyn), 66.9 (CH2OCH2), 61.2 (CPh3),
49.0 (CHanti), 45.8, 42.5 (CH2NC2H). FAB MS: m/z 616 (M+ + 1), 587 (M+
2 CO), 559 (M+ 2 2CO). 2c: IR (KBr), 1939s, 1855s, 1611m cm21
.
1H
Received in Cambridge, UK, 21st July 1998; 8/05689G
2028
Chem. Commun., 1998