Direct reaction of aroyl cyanides with azazirconacyclopentadienes: Synthesis and structural characterization of stabilized azazirconacyclopentenes

Article abstract of DOI:10.1021/om0506264

The direct reaction of aroyl cyanide with azazirconacyclopentadiene takes place at room temperature in THF. The X-ray crystal structure analysis of the product 2e shows a novel azazirconacycle with a bidentate O-C-N unit. Hydrolysis of the newly formed zirconacycle affords the N-substituted benzamide derivative in good yield.

Full text of DOI:10.1021/om0506264

544
Organometallics 2006, 25, 544-547
Direct Reaction of Aroyl Cyanides with
Azazirconacyclopentadienes: Synthesis and Structural
Characterization of Stabilized Azazirconacyclopentenes
Yuanhong Liu* and Bin Yan
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry,
Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, People’s Republic of China
ReceiVed July 25, 2005
Summary: The direct reaction of aroyl cyanide with azazir-
conacyclopentadiene takes place at room temperature in THF.
The X-ray crystal structure analysis of the product 2e shows a
noVel azazirconacycle with a bidentate O-C-N unit. Hydrolysis
of the newly formed zirconacycle affords the N-substituted
benzamide deriVatiVe in good yield.
pentadienes.5 We now report the selective reaction of aroyl
cyanides with azazirconacyclopentadienes and the unique X-ray
crystal structure of the zirconium-containing complex. It is
noteworthy that there has been much less investigation of the
reactivity of nitrogen-containing metallacycles,6 and there has
been no report for the direct reaction of carbon electrophiles
with azazirconacyclopentadienes, to the best of our knowledge.
Alkynes undergo selective intermolecular coupling with
nitriles using a zirconocene-ethylene complex.7 Hydrolysis of
the thus formed azazirconacyclopentadiene 1 with aqueous HCl
solution affords R,â-unsaturated ketones in good to excellent
yields. Initially, aldehydes or acyl chlorides were chosen for
the reaction with zirconacycle 1. However, only complicated
reaction mixtures were observed. Acyl cyanides are known to
be more reactive acylating reagents than acid chlorides, since
the adjacent cyano group enhances the reactivity of the carbonyl
group. As we expected, acyl cyanides reacted smoothly with
zirconacycle 1 to afford the zirconium complex 2 in reasonable
yields (eq 1). The reaction of ArCOCN with 1 was significantly
faster; thus, with use of a 1:1 molar ratio of Zr to ArCOCN,
the azametallacyclopentene 2 was formed within 30 min under
ambient conditions. When a large excess of acyl cyanide was
used, only one ArCOCN molecule was incorporated into the
product, while the Zr-C(sp2) bond of the azazirconacyclopen-
tadiene remained intact. Interestingly, the CN group was found
to be located at the quaternary carbon neighboring the nitrogen
Zirconacycles are attractive intermediates in an impressive
array of synthetic methodology and have received much
attention in recent years.1 In comparison with other metalla-
cycles, zirconacycles have several advantages. (i) They are easily
prepared by reductive coupling of unsaturated compounds such
as alkynes, alkenes, nitriles, or ketones on a zirconocene
equivalent. (ii) They are relatively stable under normal condi-
tions. (iii) They have been proven to be efficient precursors for
a wide range of selective transformation reactions. They are
generally not reactive toward carbon electrophiles, possibly due
to the steric hindrance caused by the bulky cyclopentadienyl
ligands.2 Most of the chemistry of five-membered zirconacycles
has therefore focused on indirect reaction pathways, i.e., through
transmetalation of Zr-R bonds with metal salts such as Cu,
Zn, Li, Bi, and Ni to increase the reactivity.3 There have only
been limited reports of the direct reaction of zirconacycles with
carbon electrophiles. Examples include reactions with CO,4a,b
aldehydes,4c-e and isocyanides,4f carbenoid insertion,4g 1,1-
cycloaddition to propynoates,4h Michael addition to activated
alkenes,4i and insertion of lithiated aryl alkynes.4j Recently, we
reported the direct insertion of aroyl cyanides into zirconacy-
clopentenes and -pentanes, which afforded a controllable
synthesis of homoallyl ketones and multiply substituted cyclo-
(4) (a) Takahashi, T.; Xi, Z.; Nishihara, Y.; Huo, S.; Kasai, K.; Aoyagi,
K.; Denisov, V.; Negishi, E. Tetrahedron 1997, 53, 9123. (b) Agnel, G.;
Negishi, E. J. Am. Chem. Soc. 1991, 113, 7424. (c) Cope´ret, C.; Negishi,
E.; Xi, Z.; Takahashi, T. Tetrahedron Lett. 1994, 35, 695. (d) Zhao, C.;
Yu, T.; Xi, Z. Chem. Commun. 2002, 142. (e) Zhao, C.; Yan, J.; Xi, Z. J.
Org. Chem. 2003, 68, 4355. (f) Negishi, E.; Swanson, D. R.; Miller, S. R.
Tetrahedron Lett. 1988, 29, 1631. (g) Gordon, G. J.; Luker, T.; Tuckett,
M. W.; Whitby, R. J. Tetrahedron 2000, 56, 2113 and references therein.
(h) Takahashi, T.; Sun, W.; Xi, C.; Kotora, M. Chem. Commun. 1997, 2069.
(i) Liu, Y.; Shen, B.; Kotora, M.; Nakajima, K.; Takahashi, T. J. Org. Chem.
2002, 67, 7019. (j) Dumond, Y.; Negishi, E. J. Am. Chem. Soc. 1999, 121,
11223.
(5) Zhou, S. L.; Yan, B.; Liu, Y. H. J. Org. Chem. 2005, 70, 4006.
(6) (a) Hanna, T. A.; Baranger, A. M.; Bergman, R. G. J. Org. Chem.
1996, 61, 4532. (b) Carney, M. J.; Walsh, P. J.; Hollander F. J.; Bergman,
R. G. J. Am. Chem. Soc. 1989, 111, 8751. (c) Ruck, R. T.; Bergman, R. G.
Organometallics 2004, 23, 2231. (d) Hanna, T. A.; Baranger, A. M.; Walsh,
P. J.; Bergman, R. G. J. Am. Chem. Soc. 1995, 117, 3292. For nickel-
promoted reactions, see: (e) Takahashi, T.; Tsai, F.; Li, Y. Z.; Wang, H.;
Kondo, Y.; Yamanaka, M.; Nakajima, K.; Kotora, M. J. Am. Chem. Soc.
2002, 124, 5059. For copper-promoted reactions, see: (f) Zhou, S. L.; Liu,
D. Y.; Liu, Y. H. Organometallics 2004, 23, 5900.
* To whom correspondence should be addressed. E-mail: yhliu@
mail.sioc.ac.cn.
(1) For reviews, see: (a) Takahashi, T.; Xi, Z.; Hara, R. Trends
Organomet. Chem. 1997, 2, 117. (b) Buchwald, S. L. Science 1993, 261.
(c) Kotora, M.; Xi, Z.; Takahashi, T. J. Synth. Org. Chem. Jpn. 1997, 55,
958. (d) Negishi, E.; Takahashi, T. Bull. Chem. Soc. Jpn. 1998, 71, 755.
(e) Takahashi, T.; Xi, Z.; Kotora, M. Pure Appl. Chem. 1998, 2, 515. (f)
Takahashi, T.; Kotora, M.; Hara, R.; Xi, Z. Bull. Chem. Soc. Jpn. 1999,
72, 2591.
(2) (a) Wipf, P.; Jahn, H. Tetrahedron 1996, 52, 12853. (b) Negishi, E.;
Takahashi, T. Aldrichim. Acta 1985, 18, 31.
(3) For Cu, see: (a) Liu, Y.; Xi, C.; Hara, R.; Nakajima, K.; Yamazaki,
A.; Kotora, M.; Takahashi, T. J. Org. Chem. 2000, 65, 6951. (b) Lipshutz,
B. M.; Wood, M. R. J. Am. Chem. Soc. 1993, 115, 12625. (c) Liu, Y.;
Shen, B.; Kotora, M.; Takahashi, T. Angew. Chem., Int. Ed. 1999, 38, 949.
(d) Lipshutz, B. H.; Wood, M. R.; Tirado, R. J. Am. Chem. Soc. 1995, 117,
6126. For Zn, see: (e) Lipshutz, B. H.; Wood, M. R. J. Am. Chem. Soc.
1994, 116, 11689. (f) Duan, Z.; Nakajima, K.; Takahashi, T. Chem.
Commun. 2001, 1672. For Ni, see: (g) Hauske, J. R.; Dorff, P.; Julin, S.;
Martinelli, G.; Bussolari, J. Tetrahedron Lett. 1992, 33, 3715. (h) Takahashi,
T.; Tsai, F.; Li, Y.; Wang, H.; Kondo, Y.; Yamanaka, M.; Nakajima, K.;
Kotora, M. J. Am. Chem. Soc. 2002, 124, 5059. For Li, see: (i) Seki, T.;
Noguchi, Y.; Duan, Z.; Sun, W.; Takahashi, T. Tetrahedron Lett. 2004,
45, 9041. (j) Takahashi, T.; Huo, S.; Hara, R.; Noguchi, Y.; Nakajima, K.;
Sun, W. J. Am. Chem. Soc. 1999, 121, 1094.
(7) For the formation of azazirconacyclopentadienes, see: (a) Takahashi,
T.; Xi, C. J.; Xi, Z. F.; Kageyama, M.; Fischer, R.; Nakajima, K.; Negishi,
E. J. Org. Chem. 1998, 63, 6802-6808. (b) Negishi, E.; Holms, S. J.; Tour,
J. M.; Miller, J. A.; Cederbaum, F. E.; Swanson, D. R.; Takahashi, T. J.
Am. Chem. Soc. 1989, 111, 3336-3346. (c) Fagan, P. J.; Nugent, W. A. J.
Am. Chem. Soc. 1988, 110, 2310-2312. (d) Quntar, A. A.; Melman, A.;
Srebnik, M. J. Org. Chem. 2002, 67, 3769-3772.
10.1021/om0506264 CCC: $33.50 © 2006 American Chemical Society
Publication on Web 12/09/2005

Notes
Organometallics, Vol. 25, No. 2, 2006 545
Table 1. Direct Reaction of Acyl Cyanides with
Azazirconacycles
atom in complex 2. Remarkably, complex 2 proved to be stable
to air and water in its solid state, allowing a convenient
separation through column chromatography on silica gel. It is
noteworthy that air-stable, C-Zr σ-bond-containing complexes
are rare.6f,8 Chemoselectivity in this case was different from
those of some three- or four-membered heterozirconacycles.
Bergman et al. investigated the selective insertion of CO, RCHO,
or RCHdNR′ into the Zr-C bonds of azazirconacyclobutenes.6a-d
Norton et al. observed a similar selectivity for the insertion of
isocyanates or carbodiimides into the Zr-C bond rather than
the Zr-N bond of the zirconocene imine complex.9 Hillhouse
et al. found that the reaction of aldehydes with oxametallacy-
clobutene led exclusively to insertion into the Zr-C(sp2) bond.10
Despite the large number of zirconacycles containing Zr-N
bonds, only a few known complexes, including the diphenyl-
hydrazido(2-) complex Cp2Zr(N2Ph2) and an azaoxazircona-
cycle, have undergone Zr-N bond insertion reactions.11
Representative reactions of various azazirconacyclopenta-
dienes with acyl cyanides are given in Table 1. Zirconacycles
1 bearing alkyl or mixed alkyl-aryl substituents all undergo
selective reactions with acyl cyanides. Thus, the reaction of
zirconacycle 1a prepared by coupling of 4-octyne and benzoni-
trile with benzoyl cyanide gave 2a in 62% yield. Functionalized
acyl cyanides bearing a chlorine or a methyl group afforded
the products 2f,i in 48 and 40% yields, respectively. It is
noteworthy that when p-bromobenzonitrile was used to prepare
the zirconacycle, the removal of residual magnesium salts by
adding 1,4-dioxane and filtration was required in order to get a
good yield of 2d.
The 1H NMR spectrum of 2b showed two sets of singlets at
6.07 and 6.11 ppm, and its 13C NMR spectrum revealed two
singlets at 109.8 and 110.2 ppm, which were assigned to
cyclopentadienyl ligands. Additionally, the 13C NMR spectrum
of 2b showed peaks at 68.1, 123.5, 177.0 ,and 192.2 ppm
assignable to the quaternary carbon, CN, NCOPh, and dCZr
units, respectively. These results suggested that an sp2-hybridized
carbon was bonded to zirconium. Therefore, the data are most
consistent with the reaction of benzoyl cyanide with the Zr-N
bond. The X-ray crystal structure studies on the zirconium
complex 2e provided clear evidence for the five-membered
azametallacyclic framework, as illustrated in Figure 1.
a Isolated yields. Unless noted, all the reactions were performed at room
temperature for 1 h. b 50 °C, 1 h.
Figure 1. ORTEP drawing of complex 2e. Selected bond lengths
(Å) and angles (deg): Zr-N(1) ) 2.186(3), Zr-O(1) ) 2.296(3),
Zr-C(14) ) 2.326(4), O(1)-C(11) ) 1.284(4), N(1)-C(11) )
1.305(5), N(1)-C(12) ) 1.453(4), C(12)-C(13) ) 1.538(5),
C(13)-C(14) ) 1.335(5); N(1)-Zr-O(1) ) 57.06(11), N(1)-Zr-
C(14) ) 68.63(13), O(1)-Zr-C(14) ) 125.39(12), O(1)-C(11)-
N(1) ) 111.7(3), C(11)-O(1)-Zr ) 93.2(2), C(12)-N(1)-Zr )
128.4(2).
atoms Zr, N(1), C(12), C(13), C(14) and Zr, O(1), C(11), N(1)
are coplanar, and the torsion angle of C(14)-Zr-O(1)-C(11)
is -3.3(3)°. The N(1)-C(11) distance (1.305(5) Å) is slightly
longer than the accepted value for a N(sp2)dC(sp2) double bond
(1.28 Å),13 and the O(1)-C(11) distance (1.284 (4) Å) is slightly
but significantly shorter than the value observed for O-C(sp2)
single bonds (e.g. 1.357(6) Å for the zirconocene â-ketone
enolate Cp2ZrMe[OC(Et2C(COOMe)dCEt2)]14 and 1.363(7) Å
for the zirconocene ester enolate rac-(EBI)Zr[OC(OiPr)d
CMe2]2.15 These distances fall into the ranges for normal amide
structures,16 suggesting some electronic delocalization over the
The Zr-C(14) distance of 2.326(4) Å is comparable to that
found for ZrIV-C(sp2)-containing metallacycles.12 The sets of
(8) (a) Luker, T.; Whitby, R. J.; Webster, M. J. Organomet. Chem. 1995,
492, 53-57. (b) Mohamadi, F.; Spees, M. M. Organometallics 1992, 11,
1398.
(9) Tunge, J. A.; Czerwinski, C. J.; Gately, D. A.; Norton, J. R.
Organometallics 2001, 20, 254 and references therein.
(10) Vaughan, G. A.; Hillhouse, G. L.; Rheingold, A. L. J. Am. Chem.
Soc. 1990, 112, 7994.
(12) Sun, H.; Burlakov, V. V.; Spannenberg, A.; Baumann, W.; Arndt,
P.; Rosenthal, U. Organometallics 2002, 21, 3360-3366.
(13) March, J. In AdVanced Organic Chemistry; McGraw-Hill: New
York, 1997; Vol. 2, p 24.
(14) Stuhldreier, T.; Keul, H.; Ho¨cker, H. Organometallics 2000, 19,
5231.
(11) (a) Walsh, P. J.; Hollander, F. J.; Bergman, R. G. J. Am. Chem.
Soc. 1990, 112, 894. (b) Carney, M. J.; Walsh, P. J.; Hollander, F. J.;
Bergman, R. G. J. Am. Chem. Soc. 1989, 111, 8751.
(15) Bolig, A. D.; Chen, E. Y.-X. J. Am. Chem. Soc. 2004, 126, 4897.
(16) Robin, M. B.; Bovey, F. A.; Basch, H. In The Chemistry of Amides;
Zabicky, J., Ed.; Wiley-Interscience: London, 1970; pp 1-72.

546 Organometallics, Vol. 25, No. 2, 2006
Notes
O-C-N unit caused by the resonance of the nitrogen lone pair
with the carbonyl π-system. The distance for Zr-N(1) (2.186-
(3) Å) is indicative of a single bond,17 while the Zr-O(1)
distance (2.296(3) Å) suggests a dative interaction between
carbonyl oxygen and the metal; both values are also within the
limits typical for an amido ligand which bonds the metal in a
C,N-bidentate fashion, such as in Cp2Zr(R)[O-C(R)NAr].18 The
values of the N(1)-C(12) and C(12)-C(13) distances cor-
respond well to single bonds. The air and water stability thus
can be explained by the bidentate coordination mode of the
O-C-N moiety, which gives an electronically saturated (18-
electron) zirconium center. According to the above results,
especially the sp2-hybridized character of the N atom in 2e, the
molecular structure of 2 is represented by the resonance
structures of a Lewis formula (A) and a seven-membered
oxazirconacycle (B) with an intramolecularly coordinated Zr-N
bond.
tion of the reaction mechanism and further applications of this
chemistry are in progress.
Experimental Section
All reactions were carried out using standard Schlenk techniques
under nitrogen. THF was distilled from sodium/benzophenone. All
reagents and chemicals, unless otherwise stated, were purchased
from commercial sources. NMR spectra were recorded at room
temperature in CDCl3 (containing 1% TMS) on a Varian XL-300
MHz spectrometer. High-resolution mass spectra were obtained by
using HP5989A and IonSpec 4.7 T FTMS mass spectrometers.
Elemental analyses were performed on an Italian Carlo-Erba 1106
analyzer. Single-crystal X-ray diffraction data were collected on
Bruker SMART APEX diffractiometers with molybdenum anodes.
Typical Procedure for the Preparation of Azazirconacyclo-
pentene Product 2a. To a solution of Cp2ZrCl2 (0.37 g, 1.25 mmol)
in THF (5 mL) was added EtMgBr (1.0 M THF solution, 2.5 mmol)
at -50 °C. After this mixture was stirred for 1 h at the same
temperature, 4-octyne (0.11 g, 1.0 mmol) was added and the reaction
mixture was warmed to 0 °C and stirred for 1 h. Benzonitrile (0.10
mL, 1.0 mmol) was added, and the mixture was heated to 50 °C
for 3 h. Then, benzoyl cyanide (0.14 g, 1.0 mmol) was added to
the reaction solution containing azazirconacyclopentadiene 1a. After
this mixture was stirred at room temperature for 1 h, the solvent
was evaporated in vacuo and the residue was purified by chroma-
tography on silica gel (1/6 ethyl acetate/petroleum ether). A white
solid of 2a (0.35 g, 62%) was obtained. 1H NMR (CDCl3, Me4Si):
δ 0.73 (t, J ) 7.2 Hz, 3H, CH3), 0.85-0.95 (m, 1H, CH2), 1.00 (t,
J ) 7.5 Hz, 3H, CH3), 1.37-1.53 (m, 2H, CH2), 1.58-1.69 (m,
2H, CH2), 1.80-2.00 (m, 2H, CH2), 2.18-2.28 (m, 1H, CH2), 6.15
(s, 5H, Cp), 6.19 (s, 5H, Cp), 6.98 (d, J ) 7.5 Hz, 2H, Ph), 7.15
(t, J ) 7.5 Hz, 2H, Ph), 7.24-7.32 (m, 4H, Ph), 7.37-7.40 (m,
2H, Ph). 13C NMR (CDCl3): δ 14.96, 15.63 (CH3), 22.29, 23.32,
31.80, 39.30 (CH2), 73.24 (CCN), 109.90, 110.14 (Cp), 120.20
(CN), 126.07, 127.20, 127.79, 127.90, 128.37, 130.91, 132.98,
141.43, 145.01 (Ph), 178.08 (COPh), 189.19 (dCZr). IR (KBr,
cm-1): 2222 (w), 1604 (m), 1521 (s), 1483 (s), 802 (s). Mp: 156-
157 °C. HRMS (m/z): calcd for C33H34N2OZr 564.1718, found
565.1791 [M + H]+. Anal. Calcd for C33H34N2OZr: C, 70.04; H,
6.06; N, 4.95. Found: C, 69.98; H, 5.93; N, 4.74.
Data for 2b are as follows. 1H NMR (CDCl3, Me4Si): δ 0.67 (t,
J ) 7.2 Hz, 3H, CH3), 1.00-1.13 (m, 2H, CH2), 1.18 (t, J ) 7.2
Hz, 6H, CH3), 1.57-1.80 (m, 2H, CH2), 1.98-2.10 (m, 2H, CH2),
2.17-2.31 (m, 2H, CH2), 6.07 (s, 5H, Cp), 6.11 (s, 5H, Cp), 7.43-
7.49 (m, 3H, Ph), 7.61-7.64 (m, 2H, Ph). 13C NMR (CDCl3): δ
13.61, 14.08, 14.87 (CH3), 15.57, 21.45, 28.69, 37.09 (CH2), 68.07
(CCN), 109.81, 110.16 (Cp), 123.45 (CN), 126.44, 128.52, 130.80,
134.64, 141.68 (Ph), 177.06 (COPh), 192.17 (dCZr). IR (KBr,
cm-1): 2218 (w), 1604 (m), 1529 (s), 1486 (s), 799 (s). Mp: 146-
148 °C. HRMS (m/z): calcd for C28H32N2OZr 502.1562, found
503.1634 [M + H]+. Anal. Calcd for C28H32N2OZr: C, 66.75; H,
6.40; N, 5.56. Found: C, 66.41; H, 6.39; N, 5.36.
The details of the conversion of 1 to the final azazirconacy-
clopentenes are not yet clear. Possible mechanisms that may
account for this reaction involve selective insertion of acyl
cyanide into the Zr-N bond11 of zirconacycle 1 followed by
â-elimination of a cyano group; subsequent nucleophilic addi-
tion/cyclization affords the product 2. Hydrolysis of 2h gave
the N-(1-cyano-2,3-diphenyl-1-propylallyl)benzamide 3 in 89%
yield (eq 2). â-Elimination of the leaving group (halide or alkoxy
group) from zirconacycles has been reported, which resulted in
the formation of carbozirconation products such as allylzir-
conation, alkynylzirconation, and vinylzirconation.19 We also
reported that the CN group could be eliminated from the
zirconium intermediates.5 The preferred insertion of Zr-N bond
into the Zr-C bond may be due to facile CN group elimination
and subsequent formation of a stabilized zirconium complex.
Alternatively, a mechanism which involves addition of ArCOCN
across the imine function to afford 2 cannot be ruled out.
In conclusion, we have discovered the direct reaction of acyl
cyanide with azazirconacyclopentadienes, which afforded a
novel azazirconacycle with a bidentate O-C-N unit, as
characterized by X-ray crystal analysis. This chemistry was
different from those of some three- or four-membered azazir-
conacycles, in which the reaction with carbon electrophiles
exclusively occurred at the zirconium-carbon bond. Clarifica-
Data for 2c are as follows. 1H NMR (CDCl3, Me4Si): δ 0.67 (t,
J ) 7.2 Hz, 3H, CH3), 0.95 (t, J ) 7.2 Hz, 3H, CH3), 1.00 (t, J )
7.2 Hz, 3H, CH3), 1.06-1.20 (m, 2H, CH2), 1.30-1.51 (m, 6H,
CH2), 1.54-1.80 (m, 4H, CH2), 1.85-2.02 (m, 2H, CH2), 2.11-
2.24 (m, 2H, CH2), 6.04 (s, 5H, Cp), 6.10 (s, 5H, Cp), 7.44-7.46
(m, 3H, Ph), 7.60-7.63 (m, 2H, Ph). 13C NMR (CDCl3): δ 13.58,
13.84, 14.13 (CH3), 15.47, 23.73, 24.24, 28.86, 31.28, 32.32, 36.58,
37.09 (CH2), 68.01 (CCN), 109.81, 110.15 (Cp), 123.33 (CN),
126.40, 128.44, 130.71, 134.60, 140.66 (Ph), 177.00 (COPh), 190.89
(dCZr). IR (KBr, cm-1): 2220 (w), 1559 (m), 1539 (s), 1489 (s),
1416 (s), 801 (s). Mp: 147-149 °C. HRMS (m/z): calcd for
C32H40N2OZr 558.2188, found 558.2182. Anal. Calcd for C32H40N2-
OZr: C, 68.65; H, 7.20; N, 5.00. Found: C, 68.38; H, 7.07; N,
4.71.
(17) (a) Bradley, D. C.; Hursthouse, M. B.; Rendall, I. F. Chem. Commun.
1970, 368. (b) Pauling, L. The Nature of the Chemical Bond, 3rd ed.; Cornell
University Press: Ithaca, NY, 1960. (c) Spannenberg, A.; Arndt, P.;
Baumann, W.; Burlakov, V. V.; Rosenthal, U.; Becke, S.; Weiss, T.
Organometallics 2004, 23, 3819. (d) Reference 6a. (e) Walsh, P. J.; Carney,
M. J.; Bergman, R. G. J. Am. Chem. Soc. 1991, 113, 6343.
(18) Gambarotta, S.; Strologo, S.; Floriani, C.; Chiesi-Villa, A.; Guastini,
C. Inorg. Chem. 1985, 24, 654.
(19) (a) Suzuki, N.; Kondakov, D. Y.; Kageyama, M.; Kotora, M.; Hara,
R.; Takahashi, T. Tetrahedron 1995, 51, 4519. (b) Liu, Y.; Zhong, Z.;
Nakajima, K.; Takahashi, T. J. Org. Chem. 2002, 67, 7451. (c) Takahashi,
T.; Kondakov, D. Y.; Xi, Z.; Suzuki, N. J. Am. Chem. Soc. 1995, 117, 587.

Notes
Organometallics, Vol. 25, No. 2, 2006 547
1
Data for 2d are as follows. H NMR (CDCl3, Me4Si): δ 6.13
(s, 5H), 6.29 (s, 5H), 6.51-6.55 (m, 2H), 6.80-6.86 (m, 4H), 6.90-
6.93 (m, 2H), 7.01-7.07 (m, 3H), 7.14-7.25 (m, 5H), 7.32-7.36
(m, 3H). 13C NMR (CDCl3): δ 72.98 (CCN), 111.01, 111.76 (Cp),
119.12, 121.99, 123.05, 125.96, 126.76, 127.29, 127.64, 127.83,
128.12, 130.99, 131.48, 131.63, 132.33, 138.24, 139.55, 145.89,
149.93 (Ar), 178.09 (COPh), 192.69 (dCZr). The signal for CN
was not identified. IR (KBr, cm-1): 2228 (w), 1593 (m), 1516 (s),
1481 (s), 797 (s), 70 (s). Mp: 247-249 °C. HRMS (m/z): calcd
for C39H29N2OBrZr 710.0510, found 710.0505. Anal. Calcd for
C39H29N2OBrZr: C, 65.72; H, 4.10; N, 3.93. Found: C, 65.31; H,
4.16; N, 3.58.
Data for 2i are as follows. 1H NMR (CDCl3, Me4Si): δ 0.68 (t,
J ) 7.2 Hz, 3H, CH3), 0.97 (t, J ) 7.2 Hz, 3H, CH3), 1.02 (t, J )
7.2 Hz, 3H, CH3), 1.06-1.18 (m, 2H, CH2), 1.51-1.61 (m, 2H,
CH2), 1.63-1.79 (m, 4H, CH2), 1.83-2.00 (m, 2H, CH2), 2.03-
2.21 (m, 2H, CH2), 2.39 (s, 3H, Me), 6.03 (s, 5H, Cp), 6.08 (s, 5H,
Cp), 7.24 (d, J ) 8.4 Hz, 2H, Ar), 7.53 (d, J ) 8.4 Hz, 2H, Ar).
13C NMR (CDCl3): δ 13.69 (CH3), 15.25 (CH3), 15.50 (CH2), 15.73
(CH3), 21.55 (Me), 22.65, 23.47, 31.59, 37.09, 39.51 (CH2), 68.06
(CCN), 109.81, 110.15 (Cp), 123.42 (CN), 126.63, 129.09, 131.74,
140.92, 141.16 (Ar), 177.20 (COAr), 191.00 (dCZr). IR (KBr,
cm-1): 2219 (w), 1613 (s), 1559 (s), 1497 (s), 801 (s). Mp: 187-
189 °C. HRMS (m/z): calcd for C31H38N2OZr 544.2031, found
544.2026. Anal. Calcd for C31H38N2OZr: C, 68.21; H, 7.02; N,
5.13. Found: C, 67.94; H, 6.85; N, 4.81.
Data for 2j are as follows. 1H NMR (CDCl3, Me4Si): δ 0.96 (t,
J ) 7.2 Hz, 3H, CH3), 1.02 (t, J ) 7.2 Hz, 3H, CH3), 1.31 (s, 3H,
Me), 1.47-1.62 (m, 2H, CH2), 1.69-1.76 (m, 2H, CH2), 2.00-
2.07 (m, 4H, CH2), 6.02 (s, 5H, Cp), 6.10 (s, 5H, Cp), 7.45-7.48
(m, 3H, Ph), 7.70-7.73 (m, 2H, Ph). 13C NMR (CDCl3): δ 15.18,
15.74 (CH3), 22.89, 23.20 (CH2), 24.69 (Me), 31.49, 39.14 (CH2),
65.04 (CCN), 109.84, 110.10 (Cp), 123.27 (CN), 127.29, 128.60,
131.13, 134.19, 143.43 (Ph), 176.65 (COPh), 187.94 (dCZr). IR
(KBr, cm-1): 2221 (w), 1732 (s), 1527 (s), 1451 (s), 801 (s). HRMS
(m/z): calcd for C28H32N2OZr 502.1562, found 502.1556. Anal.
Calcd for C28H32N2OZr: C, 66.75; H, 6.40; N, 5.56. Found: C,
66.83; H, 6.39; N, 5.34.
Data for 2e are as follows. 1H NMR (CDCl3, Me4Si): δ 0.67 (t,
J ) 7.2 Hz, 3H, CH3), 0.97 (t, J ) 7.2 Hz, 3H, CH3), 1.02 (t, J )
7.2 Hz, 3H, CH3), 1.07-1.19 (m, 2H, CH2), 1.47-1.75 (m, 6H,
CH2), 1.78-2.00 (m, 2H, CH2), 2.04-2.22 (m, 2H, CH2), 6.02 (s,
5H, Cp), 6.09 (s, 5H, Cp), 7.43-7.47 (m, 3H, Ph), 7.59-7.62 (m,
2H, Ph). 13C NMR (CDCl3): δ 13.61 (CH3), 15.21 (CH3), 15.46
(CH2), 15.69 (CH3), 22.60, 23.44, 31.53, 37.10, 39.45 (CH2), 68.01
(CCN), 109.83, 110.16 (Cp), 123.34 (CN), 126.39, 128.46, 130.73,
134.59, 140.84 (Ph), 177.04 (COPh), 191.09 (dCZr). IR (KBr,
cm-1): 2219 (w), 1606 (w), 1531 (s), 1426 (s), 803 (s). Mp: 140-
142 °C. Anal. Calcd for C30H36N2OZr: C, 67.75; H, 6.82; N, 5.27.
Found: C, 67.71; H, 6.84; N, 5.06.
Data for 2f are as follows. 1H NMR (CDCl3, Me4Si): δ 0.70 (t,
J ) 7.2 Hz, 3H, CH3), 0.96 (t, J ) 7.2 Hz, 3H, CH3), 1.02 (t, J )
7.2 Hz, 3H, CH3), 1.06-1.26 (m, 2H, CH2), 1.47-1.80 (m, 6H,
CH2), 1.82-1.99 (m, 2H, CH2), 2.04-2.20 (m, 2H, CH2), 6.03 (s,
5H, Cp), 6.08 (s, 5H, Cp), 7.43 (d, J ) 8.4 Hz, 2H, Ar), 7.58 (d,
J ) 8.4 Hz, 2H, Ar). 13C NMR (CDCl3): δ 13.67 (CH3), 15.21
(CH3), 15.49 (CH2), 15.70 (CH3), 22.60, 23.44, 31.56, 37.20, 39.44
(CH2), 67.93 (CCN), 109.88, 110.20 (Cp), 123.32 (CN), 128.11,
128.83, 132.86, 136.99, 140.72 (Ar), 175.55 (COPh), 191.28
(dCZr). IR (KBr, cm-1): 2219 (w), 1600 (m), 1553 (m), 1485 (s),
802 (s). Mp: 170-171 °C. HRMS (m/z): calcd for C30H35ClN2-
OZr 564.1485, found 565.1558 [M + H]+. Anal. Calcd for C30H35-
ClN2OZr: C, 63.63; H, 6.23; N, 4.95. Found: C, 63.47; H, 6.34;
N, 4.69.
Data for 2g are as follows. 1H NMR (CDCl3, Me4Si): δ 3.75 (s,
3H, OMe), 6.13 (s, 5H, Cp), 6.30 (s, 5H, Cp), 6.52-6.54 (m, 2H),
6.73-6.93 (m, 8H), 7.04 (t, J ) 7.5 Hz, 2H), 7.16-7.24 (m, 6H),
7.30-7.32 (m, 1H). 13C NMR (CDCl3): δ 55.22 (OMe), 72.97
(CCN), 110.88, 111.73 (Cp), 119.50 (CN), 122.87, 125.70, 126.09,
126.55, 127.22, 127.80, 127.98, 131.08, 131.40, 132.49, 132.61,
138.65, 146.49, 150.23, 159.09 (Ar), 177.91 (COPh), 191.42
(dCZr). IR (KBr, cm-1): 2228 (w), 1737 (m), 1507 (s), 1475 (s),
801 (s), 705 (s). Mp: 250-251 °C. HRMS (m/z): calcd for
C40H32N2O2Zr 662.1511, found 662.1505. Anal. Calcd for C40H32-
N2O2Zr: C, 72.36; H, 4.86; N, 4.22. Found: C, 72.30; H, 4.97; N,
4.06.
N-(1-Cyano-2,3-diphenyl-1-propylallyl)benzamide (3). Hy-
drogen chloride was prepared by dropping concentrated sulfuric
acid into concentrated hydrochloric acid and dried by passing
through a wash bottle containing concentrated sulfuric acid. The
product 3 was obtained by treatment of 2h (0.11 g, 0.2 mmol) with
dry HCl gas in THF (3 mL) at room temperature for 5 min. The
solvent was evaporated in vacuo, and the crude product was purified
by chromatography on silica gel (1/20 ethyl acetate/petroleum
1
ether). A white solid of 3 (67 mg, 89%) was obtained. H NMR
(CDCl3, Me4Si): δ 1.05 (t, J ) 7.2 Hz, 3H, CH3), 1.76-1.80 (m,
2H, CH2), 1.99-2.08 (m, 2H, CH2), 6.08 (s, 1H, NH), 6.86-6.89
(m, 2H), 7.04-7.11 (m, 3H), 7.12-7.15 (m, 2H), 7.27 (s, 1H,
dCH), 7.32-7.39 (m, 3H), 7.41 (d, J ) 8.4 Hz, 2H), 7.60-7.63
(m, 3H). 13C NMR (CDCl3): δ 13.42 (CH3), 17.73, 39.84 (CH2),
60.38 (CCN), 118.29 (CN), 127.02, 127.38, 127.79, 128.22, 128.47,
128.78, 129.38, 129.97, 131.35, 131.89, 133.21, 135.02, 135.15,
135.92 (Ar), 166.68 (COPh). IR (KBr, cm-1): 3294 (m), 1651 (s),
1521 (s), 1487 (s), 693 (s). Mp: 155-156 °C. HRMS (m/z): calcd
for C26H24N2O 380.1889, found 381.1961 [M + H]+. Anal. Calcd
for C26H24N2O: C, 82.07; H, 6.36; N, 7.36. Found: C, 82.05; H,
6.42; N, 7.23.
Data for 2h are as follows. 1H NMR (CDCl3, Me4Si): δ 0.63 (t,
J ) 7.2 Hz, 3H, CH3), 0.87-1.25 (m, 2H, CH2), 1.46-1.63 (m,
2H, CH2), 6.06 (s, 5H, Cp), 6.20 (s, 5H, Cp), 6.92-7.01 (m, 4H,
Ph), 7.02-7.12 (m, 6H, Ph), 7.44-7.50 (m, 3H, Ph), 7.69-7.72
(m, 2H, Ph). 13C NMR (CDCl3) δ 13.44 (CH3), 15.65, 36.27 (CH2),
68.27 (CCN), 111.09, 111.65 (Cp), 122.51 (CN), 122.85, 126.04,
126.12, 126.49, 127.16, 127.27, 128.61, 130.33, 131.07, 134.45,
139.11, 142.75, 150.57 (Ar), 177.67 (COPh), 195.08 (dCZr). IR
Acknowledgment. We thank the National Natural Science
Foundation of China (Grant No. 20402019), the Chinese
Academy of Science, and the Science and Technology Com-
mission of Shanghai Municipality (Grant No. 04QMX1446) for
financial support.
Supporting Information Available: CIF files giving crystal-
lographic data for complex 2e and figures giving 1H and 13C NMR
spectra of all new compounds. This material is available free of
charge via the Internet at http://pubs.acs.org.
(KBr, cm-1): 2219 (w), 1538 (s), 1415 (s), 1017 (m), 801 (s) cm-1
.
Mp: 225-227 °C. HRMS (m/z): calcd for C36H32N2OZr 598.1561,
found 599.1634 [M + H]+. Anal. Calcd for C36H32N2OZr: C, 72.08;
H, 5.38; N, 4.67. Found: C, 71.86; H, 5.27; N, 4.35.
OM0506264