Thermolysis of Iron N-allylaminocarbene Complexes: Formation of η 3-1-azaallylirontricarbonyl Complexes. Synthetic and Theoretical Study

Article abstract of DOI:10.1021/om0301280

Both chelated and nonchelated N-allyl-N-methylaminocarbene complexes of iron unsubstituted at the 1- and 3-positions of an allyl substituent afforded by thermolysis new η³-iron tricarbonyl complexes of 2,3-dihydropyrrole. The proposed mechanism

Full text of DOI:10.1021/om0301280

Organometallics 2003, 22, 3703-3709
3703
Th er m olysis of Ir on N-Allyla m in oca r ben e Com p lexes:
F or m a tion of η3-1-Aza a llylir on tr ica r bon yl Com p lexes.
Syn th etic a n d Th eor etica l Stu d y
Ludeˇk Meca,† Ivana C´ısarˇova´,‡ and Dalimil Dvorˇa´k*,†
Department of Organic Chemistry, Prague Institute of Chemical Technology, Technicka´ 5,
166 28 Prague 6, Czech Republic, and Department of Inorganic Chemistry, Charles University,
Hlavova 2030, 128 40 Prague 2, Czech Republic
Received February 25, 2003
Both chelated and nonchelated N-allyl-N-methylaminocarbene complexes of iron unsub-
stituted at the 1- and 3-positions of an allyl substituent afforded by thermolysis new η3-iron
tricarbonyl complexes of 2,3-dihydropyrrole. The proposed mechanism of these reactions
involves bicyclo[2.1.1]-2-aza-5-ferrahexane as an intermediate formed by [2+2] cycloaddition.
Formation of this intermediate requires antiparallel arrangement of FedC and CdC double
bonds in the cycloaddition step. This mechanism was supported by reaction of deuterium-
labeled complexes and by the density functional calculations of B3LYP quality. The structure
of tricarbonyl[(η3-N-methyl-2-(biphenyl-4-yl)-4,5-dihydropyrrole]iron(0) (4f) has been deter-
mined by X-ray diffraction.
Sch em e 1
In tr od u ction
N-Allylaminocarbene complexes of group 6 transition
metals and their carba analogues are known to form
stable chelates.1 These compounds were used as models
for the study of coordination of alkene to metal carbene,
the first step in the reaction of Fischer carbene com-
plexes with alkenes. Thermal reaction of group 6 metal
N-allylaminocarbenes with alkynes was reported to
form 3-azabicyclo[4.1.0]heptane derivatives as a result
of metathesis followed by intramolecular cyclopropana-
tion.2 In some cases also a ring expansion with forma-
tion of dihydroazepine derivatives2b or CO insertion with
formation of 2-pyrrolinones3 was observed. To the best
of our knowledge productive thermolysis of N-allyl-
aminocarbene complexes of transition metals has never
been reported. Recently we have observed unexpected
formation of a tetrahydropyridine derivative in the
course of thermolysis of an N-homoallylaminocarbene
complex of iron.4 Because of the different behavior of
iron compared to chromium in the above reaction, the
study of thermolysis of iron N-allyl-N-methylaminocar-
bene complexes was undertaken.
Resu lts a n d Discu ssion
Starting N-allyl-N-methylaminocarbene complexes
were prepared using the Hegedus method5 by reaction
of the corresponding carboxamide with Na2Fe(CO)4 in
the presence of Me3SiCl.6 The reaction produced a
mixture of chelated Z-complexes 2 and nonchelated
E-carbenes 3 (Scheme 1).7
Thermolysis of the mixture of iron N-methyl-N-
allylaminocarbene complexes 2a and 3a in toluene
solution at 100 °C resulted in formation of a new iron
complex. IR revealed the presence of carbonyl ligands.
1
The H NMR spectrum showed, besides aromatic pro-
tons and the signal of the N-methyl group at 2.69 ppm,
five separated one-proton signals, four multiplets at
2.09, 2.49, 2.64-2.71, and 2.92 ppm. These signals can
be attributed to four protons of two CH2 groups, and a
doublet at 3.06 ppm (J ) 4.0 Hz) was assigned to the
proton on the coordinated double bond. 13C NMR
* Corresponding author. E-mail: dvorakd@vscht.cz. Fax: ++ 420-
2-24354288.
† Prague Institute of Chemical Technology.
‡ Charles University.
(1) (a) Parlier, A.; Rudler, H.; Daran, J . C.; Alvarez, C.; Delgado-
Reyes, F. J . Organomet. Chem. 1987, 327, 339. (b) Casey, C. P.;
Shusterman, A. J .; Vollendorf, N. W.; Haller, K. J . J . Am. Chem. Soc.
1982, 104, 2417. (c) Parlier, A.; Rudler, H.; Daran, J . C.; Alvarez, C.
J . Organomet. Chem. 1987, 333, 245. (d) Do¨tz, K. H.; Erben, H. G.;
Harms, K. J . Chem. Soc., Chem. Commun. 1989, 692.
(2) (a) Parlier, A.; Rudler, H.; Yefsah, R.; Alvarez, C. J . Organomet.
Chem. 1987, 328, C 21. (b) Parlier, A.; Rudler, H.; Yefsah, R.; Alvarez,
C. J . Organomet. Chem. 1990, 381, 191. (c) Alvarez, C.; Parlier, A.;
Rudler, H.; Yefsah, R.; Daran, J . C.; Knobler, C. Organometallics 1989,
8, 2253. (d) Parlier, A.; Yefsah, R.; Rudler, M.; Rudler, H.; Daran, J .
C.; Vaissermann, J . J . Organomet. Chem. 1990, 381, 191.
(3) Denise, B.; Goumont, R.; Parlier, A.; Rudler, H.; Daran, J . C.;
Vaissermann, J . J . Organomet. Chem. 1989, 377, 89.
(4) Vyklicky´, L.; Dvorˇa´kova´, H.; Dvorˇa´k, D. Organometallics 2001,
20, 5419.
(5) (a) Imwinkelried, R.; Hegedus, L. S. Organometallics 1988, 7,
702. (b) Schwindt, M. A.; Lejon, T.; Hegedus, L. S. Organometallics
1990, 9, 2814.
(6) Dvorˇa´k, D. Organometallics 1995, 14, 570.
(7) Iron complexes 2 and 3 were obtained as inseparable mixtures.
Since 2 and 3 are not isomers, elemental analysis cannot be used for
their characterization. Also characterization using MS is problematic.
The molecular ion of iron aminocarbene complexes splits6 CO, which
in the case of 2 gives the fragment identical with [M+] of 3. Therefore
carbene complexes 2a -e and 3a ,b,f were characterized only by 1H and
13C NMR and IR spectroscopy.
10.1021/om0301280 CCC: $25.00 © 2003 American Chemical Society
Publication on Web 08/01/2003

3704 Organometallics, Vol. 22, No. 18, 2003
Meca et al.
Sch em e 2
excluded the presence of a carbene ligand with a
characteristic signal around 270 ppm. Instead, a signal
of the carbonyl ligand at 213.7 ppm and the signals of
the carbons of the coordinated double bond, the qua-
ternary carbon at 93.4 ppm and a signal of the CH group
at 46.9 ppm, were observed together with two signals
of CH2 groups (59.3 and 32.6 ppm) and the signal of the
NCH3 group at 43.8 ppm. The connectivities obtained
from COSY, HETCOR, and HMBC experiments were
in agreement with structure 4a . However, all attempts
to liberate free 1-methyl-2-phenyl-4,5-dihydropyrrole
ligand (by oxidation with trimethylamine N-oxide,
Fe(III) or Ce(IV) salts) have failed. Also attempts to
prepare 4a by direct complexation of independently
prepared 1-methyl-2-phenyl-4,5-dihydropyrrole8 with
Fe(CO)5 or Fe2(CO)9 have not been successful.
F igu r e 1. Overall view of 4f. The displacement ellipsoids
are drawn at the 50% probability level.
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 4f
Fe(1)-C(8)
Fe(1)-C(9)
Fe(1)-C(7)
Fe(1)-C(2)
Fe(1)-N(1)
Fe(1)-C(3)
N(1)-C(2)
N(1)-C(5)
C(2)-C(3)
C(3)-C(4)
C(4)-C(5)
1.759(2)
1.788(2)
1.817(2)
1.9263(16)
2.0192(15)
2.0677(18)
1.443(2)
1.493(2)
1.439(2)
1.518(2)
1.524(3)
C(2)-N(1)-C(6)
C(2)-N(1)-C(5)
C(6)-N(1)-C(5)
C(3)-C(2)-N(1)
C(2)-C(3)-C(4)
C(3)-C(4)-C(5)
N(1)-C(5)-C(4)
121.20(14)
109.87(13)
115.01(15)
100.32(13)
110.36(14)
102.68(14)
103.66(14)
The substitution pattern of the allyl group of the
starting carbene complex has substantial influence on
the outcome of the reaction. The mixture of carbene
complexes bearing a methyl group at position 2 of the
allyl substituent, 2b and 3b, afforded the corresponding
dihydropyrrole complex 4b in 62% yield. On the con-
trary, 3-substituted or 3,3-disubstituted derivatives did
not give a dihydropyrrole complex, instead quantitative
formation of chelates 3c-e occurred.
Sch em e 3
Due to low melting point, the complex 4a was not
suitable for X-ray structure analysis. Therefore the
mixture of chelated and nonchelated iron (N-allyl-N-
methylamino)-4-fenylfenylcarbene complexes 2f and 3f
was prepared from the corresponding amide 1f and
thermolyzed, giving crystalline 1-methyl-2-(4-phenylphen-
yl)-4,5-dihydropyrrole iron tricarbonylcomplex4f (Scheme
2). Crystallization from a mixture of diethyl ether and
n-pentane afforded single crystals of 4f suitable for
X-ray analysis.
Sch em e 4
The structure of compound 4f was confirmed by the
single-crystal X-ray diffraction analysis (see Figure 1).
The selected bond distances and angles (Table 1) are
consistent with parameters of the Fe -η3-N-CdC moiety
found in the literature,9,10 witnessing η3-coordination of
metal to the dihydrogen pyrrole as well as delocalization
of the double bond (C2-C3) along the N1-C2-C3
moiety.
The formation of complexes 4 can be explained by
intramolecular generation of bicyclo[2.1.1]-2-aza-5-fer-
rahexane intermediate 7, followed by â-hydrogen elimi-
nation and reductive elimination (Scheme 3). Creation
of intermediate 7 requires antiparallel orientation of
double FedC and CdC bonds. We have already pro-
posed this reaction mode to explain formation of 1-meth-
yl-3,3-dimethyl-6-phenyl-1,2,3,4-tetrahydropyridine (6)
from the pyrolysis of tetracarbonyl[(N-(2,2-dimethyl-3-
butenyl)-N-methylamino)(phenyl)carbene]iron(0) (5)
(Scheme 4).4 Hegedus suggested a similar intermediate
to explain formation of dihydropyranes in the course of
thermolysis of (3-methylbut-3-en-1-yloxy)carbene com-
(8) Lukesˇ, R. Collect. Czech. Chem. Commun. 1937, 2, 531.
(9) de Lange, P. P. M.; Fru¨hauf, H.-W.; van Wijnkoop, M.; K.Vrieze,
K.; Wang, Y.; Heijdenrijk, D.; Stam, C. H. Organometallics 1990, 9,
1691.
(10) de Lange, P. P. M.; van Wijnkoop, M.; Fruhauf, H.-M.; Vrieze,
K.; Goubitz, K. Organometallics 1993, 2, 428.

Iron N-Allylaminocarbene Complexes
Organometallics, Vol. 22, No. 18, 2003 3705
Sch em e 5a
a
(i) CH3OH, HCl, 96%; (ii) 1. LiAlD4, 2. H2O, 66%; (iii) MsCl,
(C2H5)3N; (iv) 1. PhSeNa, 2. NaIO4; (v) sodium naphthalenide;
(vi) (CO)4FedC(OMe)Ph; (vii) toluene, 100 °C.
plexes of chromium.11 In this case the formation of an
“antiparallel intermediate” was explained by steric
interactions between the carbene substituent and the
methyl group of the olefin. Results presented here
together with the above-mentioned formation of tet-
rahydropyridine 6 suggest that iron aminocarbenes form
the “antiparallel intermediate” more often than the
corresponding chromium complexes.
The above mechanism was supported by thermolysis
of a mixture of the carbene complexes d 2-2a and d 2-3a
dideuterated in position 3 of the N-allyl group, prepared
from methyl 3-(N-methyl-N-tosylamino)propanoate as
outlined in Scheme 5. The deuterium label appeared in
positions 3 and 4 of the product d 2-4a , as required by
the mechanism described in Scheme 3.
Another support of this mechanism comes from the
unreactivity of the complexes 2c + 3c and 2d + 3d . This
can be explained by the structure of intermediate 7, in
which, due to the E-configuration on the double CdC
bond, the substituent (Me or Ph) points in the direction
of the metal (Scheme 3), and therefore â-elimination of
hydrogen is not possible. On the contrary, Z-analogues
of the complexes 2c + 3c and 2d + 3d should react.
However, we were not able to prepare Z-isomers of 2c
+ 3c since complete isomerization of the double CdC
bond proceeded in the course of the reaction of (Z)-N-
(but-2-en-1-yl)-N-methylbenzamide with Na2Fe(CO)4
and Me3SiCl.
To further support the mechanism outlined in Scheme
3, density functional calculations of B3LYP quality and
with basis sets 6-31G(d,p) were carried out. The com-
puted reaction path is depicted in Figure 2. It shows
that an energy minimum for the possible intermediate,
bicyclo[2.1.1]-2-aza-5-ferrahexane (7), is of relatively
high energy. In contrast to the proposed mechanism,
the following â-elimination leads to the formation of a
double bond between C(3) and C(4) instead of the
proposed C(2) and C(3). A product of this process, 8, has
a partial zwitterionic character, and the transition state
forms a distorted π-allyl complex. Reinsertion of the
double C(3)dC(4) bond requires relatively high activa-
tion energy (88 kJ /mol) connected with a change of
geometry and leads to the partially zwitterionic σ-alkyl-
iron intermediate 9. Conversion to the final product 4a
goes through transition state 13. The geometry of 13
differs from the local minimum 9 mainly in the Fe-
C(3)-C(4) angle. The highest activation energy in this
process (123 kJ /mol) is in agreement with the temper-
ature required for the reaction to proceed (100 °C).
F igu r e 2. Energy profile for the thermolysis of 3a leading
to 4a (relative energies of stationary points are in kJ /mol).
In conclusion, the obtained results show that unlike
group 6 transition metal Fischer carbenes, η3-allyl-
aminocarbene complexes of iron undergo thermolysis
with formation of η3-1-azaallyliron tricarbonyl com-
plexes. This transformation proceeds very probably via
a bicyclo[2.1.1]-2-aza-5-ferrahexane intermediate.
Exp er im en ta l Section
Melting points were determined on a Kofler block and are
uncorrected. NMR spectra were measured on either a Varian
Gemini 300 (1H, 300.07 MHz; 13C, 75.46 MHz) or Bruker DRX
500 Avance (1H, 500.13 MHz; 13C, 125.77 MHz; 2H, 76.75 MHz)
spectrometer at 298 K. Unambiguous assignment of the NMR
signals is based on 13C{1H}, 13C APT, COSY, and 13C HMBC
spectra. All experiments were carried out under argon. Tet-
rahydrofuran was distilled from benzophenone ketyl under Ar
prior to use. Iron pentacarbonyl, trimethylchlorosilane, 3-chlo-
ropropene, 3-chloro-2-methylpropene, 1-chlorobut-2-ene, cin-
namyl chloride, 1-chloro-3-methylbut-2-ene, and 4-biphenyl-
carbonyl chloride were purchased from Aldrich and were used
without purification. Neutral aluminum oxide (Brockmann
grade) and silica were obtained from Merck.
The density functional calculations of B3LYP quality and
with basis sets 6-31G(d,p) were carried out using the GAUSS-
IAN 9812 package of programs. Transition structure optimiza-
tions have been done using the STQN routine without any
geometry constraints. Second derivative (frequency) calcula-
tions established the nature of stationary points (exactly one
negative eigenvalue). The reaction path was determined by
IRC calculations (6-31G basis sets).
Crystal data for 4f: C20H17FeNO3, M ) 375.2, monoclinic,
P21/ c (No. 14), a ) 7.2350(2) Å, b ) 9.1180(2) Å, c ) 26.9660-
(5) Å, â ) 93.075(1)°, V ) 1776.35(7) Å3, Z ) 4, Dx ) 1.403 Mg
m-3. An orange crystal of dimensions 0.4 × 0.3 × 0.25 mm
was mounted on
a glass capillary with epoxy glue and
measured on a Nonius Kappa CCD diffractometer by mono-
chromatized Mo KR radiation (λ ) 0.71073 Å) at 150(2) K. An
(12) Frisch, M. J .; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J . R.; Zakrzewski, V. G.; Montgomery, J . A.,
J r.; Stratmann, R. E.; Burant, J . C.; Dapprich, S.; Millam, J . M.;
Daniels, A. D.; Kudin, K. N.; Strain, M. C.; Farkas, O.; Tomasi, J .;
Barone, V.; Cossi, M.; Cammi, R.; Mennucci, B.; Pomelli, C.; Adamo,
C.; Clifford, S.; Ochterski, J .; Petersson, G. A.; Ayala, P. Y.; Cui, Q.;
Morokuma, K.; Malick, K.; Rabuck, A. D.; Raghavachari, K.; Foresman,
J . B.; Cioslowski, J .; Ortiz, J . V.; Stefanov, B. B.; Liu, G.; Liashenko,
A.; Piskorz, P.; Komaromi, I.; Gomperts, R.; Martin, R. L.; Fox, D. J .;
Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.; Gonzalez,
C.; Challacombe, M.; Gill, P. M. W.; J ohnson, B.; Chen, W.; Wong, M.
W.; Andres, J . L.; Head-Gordon, M.; Replogle, E. S.; Pople, J . A.
Gaussian 98 (Revision A.6); Gaussian, Inc.: Pittsburgh, PA, 1998.
(11) So¨derberg, B. C.; Hegedus, L. S. Organometallics 1990, 9, 3113.

3706 Organometallics, Vol. 22, No. 18, 2003
Meca et al.
absorption was neglected (µ ) 0.866 mm-1); a total of 16 862
reflections were measured in the range h ) -9 to 9, k ) -11
to 11, l ) -34 to 34 (θmax ) 27.5°), of which 4035 were unique
(Rint ) 0.057), 3651 observed according to the I > 2σ(I)
criterion. Cell parameters were from 23 760 reflections (θ )
1-27.5°). The structure was solved by direct methods
(SIR92)13 and refined by full-matrix least-squares based on F2
(SHELXL97).14 The hydrogen atoms of the dihydropyrrole ring
were refined isotropically; the others were fixed into idealized
positions (riding model) and assigned temperature factors
either Hiso(H) ) 1.2Ueq(pivot atom) or Hiso(H) ) 1.5Ueq(pivot
atom) for the methyl moiety. The refinement converged (∆/
(0.97 mL; 10 mmol) provided 1c (1.12 g; 74%). 1H NMR (CDCl3,
300 MHz), two rotamers in 3:2 ratio, 30% content of Z-isomer
(rotamers in 1:1 ratio): δ 1.50 (d, J ) 6.1 Hz, 3H, -CH3 (Z)),
1.72 (d, J ) 6.1 Hz, 3H, -CH3 (E)), 1.74 (bs, 3H, -CH3 (Z)),
2.86 (bs, 3H, N-CH3 (E, minor + Z)), 3.01 (bs, 3H, N-CH3
(E, major + Z)), 3.75 (bs, 2H, -CH2- (E, major), 3.87 (bs, 2H,
-CH2- (Z)), 4.06 (bs, 2H, -CH2- (E, minor)), 4.21 (bs, 2H,
-CH2- (Z)), 5.30-5.80 (m, 2H, -CHd (E + Z), 7.32-7.50 (m,
5H, Ph-H). 1H NMR (DMSO-d6, 300 MHz, 130 °C), 30%
content of Z-isomer: δ 1.59 (d, J ) 6.1 Hz, 3H, -CH3 (Z)),
1.70 (d, J ) 6.0 Hz, 3H, -CH3 (E)), 2.89 (s, 3H, N-CH3 (E)),
2.91 (s, 3H, N-CH3 (Z)), 3.88 (d, J ) 6.0 Hz, 2H, -CH2- (E)),
4.00 (d, J ) 7.1 Hz, 2H, -CH2- (Z)), 5.42-5.55 (m, 1H, -CHd
(E + Z)), 5.55-5.75 (m, 1H, -CHd (E + Z)), 7.35-7.50 (m,
5H, Ph-H). Anal. Calcd for C12H15NO: C, 76.16; H, 7.99; N,
7.40. Found: C, 76.12; H, 7.83; N, 7.51.
σmax ) 0.000) to R ) 0.0374 for observed reflections and Rw
)
0.104, GOF ) 1.095 for 247 parameters and all 4035 reflec-
tions. The final difference map displayed no peaks of chemical
significance (∆Fmax ) 0.436, ∆Fmin -0.548 e Å-3).
Crystallographic data for structural analysis have been
deposited with the Cambridge Crystallographic Data Centre,
CCDC no. 201179. Copies of this information may be obtained
free of charge from The Director, CCDC, 12 Union Road,
Cambridge CB2 1EY, UK (fax: +44-1223-336033; e-mail:
deposit@ccdc.cam.ac.uk or www: http://www.ccdc.cam.ac.uk).
N-Allyl-N-m eth ylben za m id e (1a ). N-Methylbenzamide
(1.08 g; 8 mmol) and 60% dispersion of sodium hydride (0.38
g; 9.5 mmol) in DMF (15 mL) were stirred at 50 °C for 1 h.
Then 3-chloropropene (0.82 mL; 10 mmol) was added, the
mixture was stirred overnight at room temperature, and the
solvents were removed under reduced pressure. Water (5 mL)
was added, and the product was extracted with dichlo-
romethane (2 × 5 mL). Extracts were dried with Na2SO4,
solvents were evaporated, and the residue was subjected to
column chromatography on silica. Elution with a dichlo-
romethane-methanol mixture (25:1) afforded 1a (0.95 g; 68%).
1H NMR (CDCl3, 300 MHz),15 two rotamers in 3:2 ratio: δ 2.89
(bs, 3H, N-CH3, minor), 3.04 (bs, 3H, N-CH3, major), 3.83
(bs, 2H, -CH2-, major), 4.14 (bs, 2H, -CH2-, minor), 5.15-
5.28 (m, 2H, dCH2), 5.65-5.92 (m, 1H, -CHd), 7.34-7.44 (m,
5H, Ph-H). 13C NMR (CDCl3, 75 MHz): δ 171.9 (CdO), 136.0
(C), 132.8 (dCH, major), 132.5 (dCH, minor), 129.4 (CH-Ph),
128.2 (CH-Ph), 126.8 (o-CH-Ph, minor), 126.4 (o-CH-Ph,
major), 117.5 (dCH2, minor), 117.3 (dCH2, major), 53.7
(-CH2-, major), 49.7 (-CH2-, minor), 36.8 (N-CH3, minor),
32.8 (N-CH3, major). IR15 (CHCl3): ν 2922, 1625, 1604, 1446,
1402, 1265, 1070 cm-1. Anal. Calcd for C11H13NO: C, 75.40;
H, 7.48; N, 7.99. Found: C, 75.22; H, 7.57; N, 7.95.
N-((E)-3-P h en yl-2-p r op en yl)-N-m eth ylben za m id e (1d ).
The same procedure as used for the preparation of 1a starting
from N-methylbenzamide (1.08 g; 8 mmol) and cinnamyl
chloride (1.39 mL; 10 mmol) afforded 1d (1.53 g; 76%). Mp:
84-86 °C. 1H NMR (CDCl3, 300 MHz), two rotamers in 4:3
ratio: δ 2.96 (bs, 3H, N-CH3, minor), 3.12 (bs, 3H, N-CH3,
major), 4.03 (bs, 2H, -CH2-, major), 4.32 (bs, 2H, -CH2-,
minor), 6.04-6.35 (m, 1H, -CHd), 6.43-6.66 (m, 1H, -CHd),
7.25-7.50 (m, 10H, Ph-H). 1H NMR (DMSO-d6, 300 MHz, 130
°C): δ 2.98 (s, 3H, N-CH3), 4.13 (d, J ) 5.5 Hz, 2H, -CH2-),
6.25 (dt, J ) 15.9, 5.5 Hz, 1H, -CH2-CHd), 6.56 (d, J ) 15.9
Hz, 1H, Ph-CHd), 7.20-7.50 (m, 10H, Ph-H). 13C NMR
(CDCl3, 125 MHz): δ 172.0 (CdO), 136.3 (CH-Ph), 133.4 (C-
Ph), 132.6 (C-Ph), 129.6 (CH-Ph), 128.6 (CH-Ph), 128.4
(CH-Ph), 127.9, 127.0, 126.7, 126.4 (CH-Ph), 124.2 (CH-Ph),
53.5 (-CH2-), 49.5 (-CH2-), 36.9 (N-CH3), 33.0 (N-CH3).
IR (CHCl3): ν 3011, 1825, 1578, 1498, 1448, 1402, 1264, 1085,
1071, 967 cm-1. Anal. Calcd for C17H17NO: C, 81.24; H, 6.82;
N, 5.57. Found: C, 81.10; H, 6.96; N, 5.63.
N-(3-Meth yl-2-bu ten yl)-N-m eth ylben za m id e (1e). The
same procedure as used for the preparation of 1a starting from
N-methylbenzamide (1.08 g; 8 mmol) and 1-chloro-3-methyl-
1
but-2-ene (1.13 mL; 10 mmol) gave 1e (1.12 g; 69%). H NMR
(CDCl3, 300 MHz), two rotamers in 3:2 ratio: δ 1.48 (bs, 3H,
-CH3, major), 1.73 (bs, 3H, -CH3), 1.76 (bs, 3H, -CH3, minor),
2.86 (bs, 3H, N-CH3, minor), 3.01 (bs, 3H, N-CH3, major),
3.80 (bd, J ) 5.5 Hz, 2H, -CH2-, major), 4.14 (bd, J ) 6.0
Hz, 2H, -CH2-, minor), 5.10-5.28 (m, 1H, -CHd), 7.34-7.44
(m, 5H, Ph-H). 13C NMR (CDCl3, 125 MHz): δ 171.5 (CdO,
major), 170.9 (CdO, minor), 136.3 (C-Ph), 129.1 (CH-Ph),
128.1 (CH-Ph), 126.7 (CH, minor), 126.6 (CH, major), 119.3
(CH, major), 119.1 (CH, minor), 49.1 (-CH2-, major), 44.6
(-CH2-, minor), 36.5 (N-CH3, minor), 32.2 (N-CH3, major),
25.5 (-CH3), 17.6 (-CH3, minor), 17.5 (-CH3, major). IR
(CHCl3): ν 3007, 2935, 1620, 1578, 1501, 1449, 1403, 1267,
1069 cm-1. Anal. Calcd for C13H17NO: C, 76.81; H, 8.43; N,
6.89. Found: C, 76.63; H, 8.34; N, 6.56.
N-Allyl-N-m eth ylbip h en yl-4-ca r boxa m id e (1f). To a
solution of N-methylallylamine (0.88 mL; 9.2 mmol) and
triethylamine (1.4 mL; 10 mmol) in dichloromethane (30 mL)
was added a solution of 4-biphenylcarbonyl chloride (1.66 g;
7.7 mmol) in dichloromethane (20 mL) via syringe. Stirring
was continued for 3 h, and the mixture was then washed with
diluted HCl (2 × 5 mL) and 5% NaHCO3 (5 mL), dried with
MgSO4, and evaporated. The residue was subjected to column
chromatography on silica (100 g). Elution with a dichlo-
romethane-methanol mixture (100:1) provided 1f (1.45 g; 73%)
as a pale yellow oil. 1H NMR (CDCl3, 500 MHz), two rotamers
in 3:2 ratio: δ 2.98 (bs, 3H, N-CH3, minor), 3.08 (bs, 3H,
N-CH3, major), 3.92 (bs, 2H, -CH2-, major), 4.18 (bs, 2H,
-CH2-, minor), 5.22-5.35 (m, 2H, dCH2), 5.73-5.96 (m, 1H,
-CHd), 7.34-7.41 (m, 1H, Ph), 7.43-7.48 (m, 2H, Ph), 7.50-
7.55 (m, 2H, Ph-H), 7.57-7.66 (m, 4H, Ph-H). 13C NMR
(CDCl3, 125 MHz): δ 142.4 (C-Ph), 140.2 (C-Ph), 135.0 (C-
Ph), 133.0 (-CHd, major), 132.7 (-CHd, minor), 128.8 (CH-
N-(2-Meth yl-2-p r op en yl)-N-m eth ylben za m id e (1b). The
same procedure as used for the preparation of 1a starting from
N-methylbenzamide (1.08 g; 8 mmol) and 3-chloro-2-methyl-
1
propene (0.98 mL; 10 mmol) gave 1b (1.09 g; 72%). H NMR
(CDCl3, 300 MHz), two rotamers in 3:2 ratio: δ 1.58 (bs, 3H,
-CH3, major), 1.76 (bs, 3H, -CH3, minor), 2.85 (bs, 3H,
N-CH3, minor), 3.02 (bs, 3H, N-CH3, major), 3.75 (bs, 2H,
-CH2-, major), 4.11 (bs, 2H, -CH2-, minor), 4.89 (bs, 2H,
dCH2, minor), 4.95 (bs, 2H, dCH2, major), 7.32-7.46 (m, 5H,
Ph-H). 13C NMR (CDCl3, 75 MHz): δ 172.2 (CdO), 140.4 (C),
136.2 (C), 129.4 (CH-Ph), 128.3 (CH-Ph), 126.7 (CH-Ph),
126.5 (CH-Ph), 112.4 (dCH2, minor), 112.1 (dCH2, major),
57.2 (-CH2-, major), 52.7 (-CH2-, minor), 36.8 (N-CH3,
minor), 33.1 (N-CH3, major), 19.8 (-CH3). Anal. Calcd for
C12H15NO: C, 76.16; H, 7.99; N, 7.40. Found: C, 75.92; H, 7.76;
N, 7.38.
N-((E)-2-Bu ten yl)-N-m eth ylben za m id e (1c). The same
procedure as used for the preparation of 1a starting from
N-methylbenzamide (1.08 g; 8 mmol) and 1-chlorobut-2-ene
(13) Altomare, A.; Cascarano, G.; Giacovazzo, C.; Guagliardi, A.;
Burla, M. C.; Polidori, G.; Camalli, M. J . Appl. Crystallogr. 1994, 27,
435.
(14) Sheldrick, G. M. SHELXL97; University of Go¨ttingen: Ger-
many, 1997.
(15) Bocelli, G.; Chiusoli, G. P.; Costa, M.; Michelotti, M. J . Chem.
Soc., Perkin Trans. 1 1994, 1347.

Iron N-Allylaminocarbene Complexes
Organometallics, Vol. 22, No. 18, 2003 3707
Ph), 127.6 (CH-Ph), 127.0 (CH-Ph), 126.9 (CH-Ph), 117.4
(dCH2), 53.9 (-CH2-, major), 49.9 (-CH2-, minor), 36.9 (N-
CH3, minor), 33.0 (N-CH3, major). IR (CHCl3): ν 3011, 1623,
1482, 1450, 1403, 1265, 1071, 1009, 930, 848 cm-1. Anal. Calcd
for C17H17NO: C, 81.24; H, 6.82; N, 5.57. Found: C, 81.06; H,
6.97; N, 5.54.
((E)-2-b u t en yl)-N-m et h yla m in o)(p h en yl)ca r b en e]ir on -
(0) (3c). The same method as was used for the preparation of
2a and 3a starting from N-((E)-2-butenyl)-N-methylbenzamide
(1c) (0.946 g; 5 mmol) provided a mixture of 2c and 3c in the
1
ratio 3:1 (1.30 g; 78%). H NMR (C6D6, 300 MHz): 2c: δ 1.27
(d, J ) 6.0 Hz, 3H, -CH3), 3.13 (d, J ) 5.5 Hz, 2H, N-CH2-),
3.40 (s, 3H, N-CH3), 4.63-4.78 (m, 1H, -CHd), 4.96-5.07
(m, 1H, -CHd), 6.63 (d, J ) 7.1 Hz, 2H, Ph-H), 6.83-7.07
(m, 3H, Ph-H); 3c: δ 1.78 (d, J ) 6.1 Hz, 3H, -CH3), 1.89 (s,
3H, N-CH3), 2.28 (m, 1H, CH3-CHd), 2.90 (d, J ) 9.6 Hz,
1H, N-CHd), 3.44 (s, 2H, N-CH2-), 6.69 (bs, 2H, Ph-H),
6.91-6.97 (m, 1H, Ph-H), 7.01-7.08 (m, 2H, Ph-H). 13
Tet r a ca r b on yl[(N-a llyl-N-m et h yla m in o)(p h en yl)ca r -
ben e]ir on (0) (2a ) a n d cis-Tr ica r bon yl[(η2-N-a llyl-N-m eth -
yla m in o)(p h en yl)ca r ben e]ir on (0) (3a ). To a solution of iron
pentacarbonyl (1.3 mL, 10 mmol) in THF (50 mL) was added
a solution of sodium naphthalenide prepared from sodium (0.6
g; 26 mmol) and naphthalene (3.4 g; 26.5 mmol) in THF (50
mL) at -78 °C via syringe. The reaction mixture was then
allowed to warm to 0 °C, stirred at this temperature for 30
min, and cooled to -78 °C, and N-allyl-N-methylbenzamide
(1a ) (0.88 g; 5 mmol) in THF (5 mL) was added via syringe.
The solution was allowed to warm to 0 °C, stirred for 30 min
at 0 °C, and then cooled to -78 °C, and trimethylchlorosilane
(2.5 mL; 20 mmol) was added via syringe. The solution was
stirred at -78 °C for 30 min, then the cooling bath was
removed, the mixture was stirred for 1 h without cooling, and
neutral alumina (8 g) was added. THF was removed under
reduced pressure, and the residue was dried under high
vacuum to remove all solvents. Light petroleum (20 mL) was
then added, and the suspension formed was transferred on
top of a column filled with neutral alumina (150 g). Naphtha-
lene was eluted with light petroleum, and further elution with
C NMR
(C6D6, 75 MHz): 2c: δ 260.5 (carbene), 216.0 (CO), 153.7 (C-
Ph), 132.3 (CH-Ph), 127.4 (CH-Ph), 124.3 (CH-Ph), 121.2
(-CHd), 121.1 (-CHd), 60.2 (N-CH2-), 47.6 (N-CH3), 18.3
(-CH3); 3c: δ 264.8 (carbene), 217.5 (CO), 147.8 (C-Ph), 129.2
(CH-Ph), 128.2 (CH-Ph), 122.0 br (o-CH-Ph), 66.5 (N-CH2-),
51.0 (-CHd), 50.8 (-CHd), 40.5 (N-CH3), 25.0 (-CH3). IR
(CHCl3): ν 3024, 2041, 2015, 1966, 1938, 1916, 1525, 1440
cm-1
.
Tetr a ca r bon yl[(N-((E)-3-p h en yl-2-p r op en yl)-N-m eth yl-
a m in o)(p h en yl)ca r ben e]ir on (0) (2d ) a n d cis-Tr ica r bon -
yl[(η2-N-((E)-3-ph en yl-2-pr open yl)-N-m eth ylam in o)(ph en -
yl)ca r ben e]ir on (0) (3d ). The same method as was used for
the preparation of 2a and 3a starting from N-((E)-3-phenyl-
2-propenyl)-N-methylbenzamide (1d ) (0.754 g; 3 mmol) gave
a mixture of 2d and 3d in 3:1 ratio (0.85 g; 72%), which
a
light petroleum-dichloromethane mixture (5:1) gave a
1
solidified upon several days in a freezer. H NMR (C6D6, 300
mixture of 2a and 3a in a ratio 1:1 as an orange oil (0.95 g;
60%). 1H NMR (CDCl3, 300 MHz): 2a : δ 3.95 (s, 3H, N-CH3),
4.02 (d, J ) 5.2 Hz, 2H, N-CH2), 5.21 (d, J ) 17 Hz, 1H,
dCH2), 5.33 (d, J ) 10.4 Hz, 1H, dCH2), 5.62 (m, 1H, -CHd),
6.85 (d, J ) 7.7 Hz, 2H, Ph-H), 7.18-7.28 (m, 1H, Ph-H),
7.30-7.40 (m, 2H, Ph-H); 3a : δ 1.53 (d, J ) 10.4 Hz, 1H,
dCH2), 2.04 (d, J ) 8.0 Hz, 1H, dCH2), 2.94 (s, 3H, N-CH3),
3.21 (m, 1H, -CHd), 4.18-4.34 (m, 2H, N-CH2-), 6.85 (d, J
) 7.7 Hz, 2H, Ph-H), 7.18-7.28 (m, 1H, Ph-H), 7.30-7.40
(m, 2H, Ph-H). 13C NMR (CDCl3, 75 MHz): 2a : δ 261.3
(carbene), 214.3 (CO), 152.4 (C-Ph), 130.5 (CH-Ph), 126.6
(CH-Ph), 119.8 (dCH2), 119.6 (-CHd), 60.2 (N-CH2), 47.6
(N-CH3); 3a : δ 265.4 (carbene), 215.8 br (CO), 146.8 (C-Ph),
128.2 (CH-Ph), 127.3 (CH-Ph), 120.8 br (o-CH-Ph), 66.1
(N-CH2-), 42.8 (-CHd), 40.6 (N-CH3), 32.8 (dCH2). IR
MHz): 2d : δ 3.32 (dm, J ) 5.7 Hz, 2H, -CH2-), 3.45 (s, 3H,
N-CH3), 5.33 (dt, J ) 15.7, 5.8 Hz, 1H, -CHd), 6.03 (d, J )
15.7 Hz, 1H, Ph-CHd), 6.67 (m, 2H, Ph-H), 6.83-7.33 (m,
3H, Ph-H); 3d : δ 1.92 (s, 3H, N-CH3), 3.45-3.62 (m, 4H, 2
-CHd + -CH2-), 6.74 (bs, 2H, Ph-H), 6.92-7.01 (m, 2H,
Ph-H), 7.03-7.10 (m, 2H, Ph-H), 7.16-7.23 (m, 2H, Ph-H),
7.28-7.33 (m, 2H, Ph-H). 13C NMR (C6D6, 75 MHz): 2d : δ
262.0 (carbene), 215.8 br (CO), 153.6 (C-Ph), 136.5 (C-Ph),
135.0 (CH-Ph), 129.7 (CH-Ph), 129.2 (CH-Ph), 127.5 (CH-
Ph), 122.0 (-CHd), 121.0 (-CHd), 60.1 (N-CH2-), 48.1 (N-
CH3); 3d : δ 263.9 (carbene), 217.7 br (CO), 147.7 (C-Ph), 147.6
(C-Ph), 129.3 (CH-Ph), 128.4 (CH-Ph), 126.6 (CH-Ph),
125.3 (CH-Ph), 122.1 br (o-CH-Ph), 66.7 (N-CH2-), 55.2
(-CHd), 42.7 (-CHd), 40.6 (N-CH3). IR (CHCl3): ν 3027,
2042, 2022, 1966, 1939, 1917, 1522 cm-1
.
(CHCl3): ν 3020, 2042, 2021, 1939, 1919 cm-1
.
Tetr a ca r bon yl[(N-(3-m eth yl-2-bu ten yl)-N-m eth yla m i-
n o)(p h en yl)ca r ben e]ir on (0) (2e) a n d cis-Tr ica r bon yl[(η2-
N-(3-m eth yl-2-bu ten yl)-N-m eth ylam in o)(ph en yl)car ben e]-
ir on (0) (3e). The same method as was used for the preparation
of 2a and 3a starting from N-(3-methyl-2-butenyl)-N-methyl-
benzamide (1e) (0.816 g; 4 mmol) afforded a mixture of 2e and
3e in 9:1 ratio (1.22 g; 87%), which solidified upon several days
in a freezer. 1H NMR (C6D6, 300 MHz): 2e: δ 0.93 (s, 3H,
-CH3), 1.31 (s, 3H, -CH3), 3.23 (d, J ) 7.1 Hz, 2H, N-CH2-),
3.41 (s, 3H, N-CH3), 4.62 (t, J ) 7.1 Hz, 1H, -CHd), 6.65 (d,
J ) 7.7 Hz, 2H, Ph-H), 6.83-6.89 (m, 1H, Ph-H), 7.02 (t, J
) 7.7 Hz, 2H, Ph-H); 3e: δ 1.49 (s, 3H, -CH3), 1.78 (s, 3H,
-CH3), 1.88 (s, 3H, -CH3), 3.16-3.23 (m, 1H, -CHd), 3.35-
3.57 (m, 2H, N-CH2-), 6.79 (bs, 2H, Ph-H), 6.91 (m, 1H, Ph-
H), 7.04 (m, 2H, Ph-H). 13C NMR (C6D6, 75 MHz): 2e: δ 259.6
(carbene), 216.0 (CO), 153.8 (C-Ph), 139.5 (dC(CH3)2), 129.3
(CH-Ph), 127.2 (CH-Ph), 121.2 (-CHd), 118.2 (CH-Ph), 56.6
(N-CH2-), 47.5 (N-CH3), 26.1 (-CH3), 18.2 (-CH3); 3e: δ
263.4 (carbene), 217.9 (CO), 147.9 (C-Ph), 129.2 (CH-Ph),
128.2 (CH-Ph), 121.9 br (o-CH-Ph), 65.3 (dC(CH3)2), 64.8
(N-CH2-), 55.2 (-CHd), 39.5 (N-CH3), 35.5 (-CH3), 25.6
Tetr acar bon yl[(N-(2-m eth yl-2-pr open yl)-N-m eth ylam i-
n o)(p h en yl)ca r ben e]ir on (0) (2b) a n d cis-Tr ica r bon yl[(η2-
N-(2-m et h yl-2-p r op en yl)-N-m et h yla m in o)(p h en yl)ca r -
ben e]ir on (0) (3b). The same method as was used for the
preparation of 2a and 3a , starting from N-(2-methyl-2-pro-
penyl)-N-methylbenzamide (1b) (0.56 g; 3.75 mmol), iron
pentacarbonyl (0.98 mL, 7.5 mmol), sodium (0.45 g; 19.5
mmol), naphthalene (2.55 g; 19.9 mmol), and Me3SiCl (1.88
mL; 15 mmol) gave a mixture of 2b and 3b in a ratio 5:2 as a
yellow-orange oil (0.7 g; 56%), which solidified upon several
1
days in a freezer. H NMR (CDCl3, 300 MHz): 2b: δ 1.57 (s,
3H, -CH3), 3.93-3.95 (s, 3H, N-CH3 + s, 2H, N-CH2), 4.90
(s, 1H, dCH2), 5.05 (s, 1H, dCH2), 6.85 (d, J ) 7.7 Hz, 2H,
Ph-H), 7.17-7.29 (m, 1H, Ph-H), 7.29-7.41 (m, 2H, Ph-H);
3b: δ 1.68 (s, 1H, dCH2), 1.86 (s, 3H, -CH3), 2.11 (s, 1H, d
CH2), 2.97 (s, 3H, N-CH3), 4.13 (s, 2H, N-CH2-), 6.85 (d, J
) 7.7 Hz, 2H, Ph-H), 7.17-7.29 (m, 1H, Ph-H), 7.29-7.41
(m, 2H, Ph-H). 13C NMR (CDCl3, 75 MHz): δ 263.1 (carbene),
262.0 (carbene), 215.9 br (CO, 3b), 214.5 (CO, 2b), 152.6 (C-
Ph, 2b), 147.0 (C-Ph, 3b), 138.4 (dC(CH3)-, 2b), 128.2 (CH-
Ph, 2b), 127.4 (CH-Ph, 3b), 126.6 (CH-Ph, 2b), 121.0 br (o-
CH-Ph, 3b), 120.1 (dCH2, 2b), 114.4 (CH-Ph, 2b), 69.7 (N-
CH2-, 3b), 63.3 (N-CH2, 2b), 47.5 (N-CH3, 2b), 40.7 (N-
CH3, 3b), 38.3 (dCH2, 3b), 26.2 (-CH3, 3b), 20.0 (-CH3, 2b).
(-CH3). IR (CHCl3): ν 2041, 1966, 1938, 1915, 1525 cm-1
.
cis-Tr ica r bon yl[(η2-N-((E)-2-bu ten yl)-N-m eth yla m in o)-
(p h en yl)ca r ben e]ir on (0) (3c). The same method as was used
for the preparation of 4a starting from the above mixture of
2c and 3c (0.80 g; 2.39 mmol) provided pure 3c (0.68 g; 91%)
IR (CHCl3): ν 2042, 2017, 1967, 1939, 1917, 1522 cm-1
.
Te t r a ca r b on yl[(N -((E )-2-b u t e n yl)-N -m e t h yla m in o)-
(p h en yl)ca r ben e]ir on (0) (2c) a n d cis-Tr ica r bon yl[(η2-N-
as a red-orange oil. IR (CHCl3): ν 2015, 1946, 1916, 1556 cm-1
.

3708 Organometallics, Vol. 22, No. 18, 2003
Meca et al.
Anal. Calcd for C15H15NO3Fe: C, 57.54; H, 4.83; N, 4.47.
Found: C, 57.36; H, 4.96; N, 4.46.
3H, Ph-H). 1H NMR (C6D6, 300 MHz): δ 1.48 (d, J ) 10.7
Hz, 1H, dCH2, minor), 1.86 (s, 3H, N-CH3, minor), 2.19 (d, J
) 7.2 Hz, 1H, dCH2, minor), 3.00-3.09 (m, 1H, -CHd, minor),
3.15 (d, J ) 5.2 Hz, 2H, N-CH2, major), 3.38 (s, 3H, N-CH3,
major), 3.47 (bs, 2H, N-CH2-, minor), 4.63-4.78 (m, 2H, d
CH2, major), 4.82-4.97 (m, 1H, -CHd, major), 6.69 (d, J )
8.3 Hz, 2H, Ph-H, major), 6.74 (bs, 2H, Ph-H, minor), 7.12-
7.24 (m, 2H, Ph-H), 7.30-7.44 (m, 5H, Ph-H). 13C NMR
(CDCl3, 125 MHz): δ 265.7 (carbene, minor), 261.9 (carbene,
major), 216.1 br (CO, minor), 214.6 (CO, major), 151.5 (C-
Ph, major), 145.8 (C-Ph, minor), 140.0 (C-Ph, major), 139.4
(C-Ph, major), 130.7 (CH-Ph), 128.8 (CH-Ph, major), 127.6
(CH-Ph, major), 126.9 (CH-Ph, major), 121.7 br (o-CH-Ph,
minor), 120.5 (dCH2, major), 119.7 (-CHd, major), 66.1 (N-
CH2-, minor), 60.3 (N-CH2, major), 47.6 (N-CH3, major), 42.8
(-CHd, minor), 40.6 (N-CH3, minor), 32.8 (dCH2, minor). IR
(CHCl3): ν 2042, 2021, 1967, 1939, 1917, 1623, 1525, 1484,
cis-Tr icar bon yl[(η2-N-((E)-3-ph en yl-2-pr open yl)-N-m eth -
yla m in o)(p h en yl)ca r ben e]ir on (0) (3d ). The same method
as was used for the preparation of 4a starting from the above
mixture of 2d and 3d (0.55 g; 1.39 mmol) gave pure 3d (0.50
g; 96%) as an orange foam. IR (CHCl3): ν 3029, 2022, 1959,
1925, 1556 cm-1. Anal. Calcd for C20H17NO3Fe: C, 64.02; H,
4.57; N, 3.73. Found: C, 63.71; H, 4.62; N, 3.67.
cis-Tr ica r bon yl[(η2-N-(3-m eth yl-2-bu ten yl)-N-m eth yl-
a m in o)(p h en yl)ca r ben e]ir on (0) (3e). The same method as
was used for the preparation of 4a starting from the above
mixture of 2e and 3e (0.25 g; 0.71 mmol) provided orange
crystals of pure 3e (0.22 g; 95%). IR (CHCl3): ν 3020, 2030,
1940, 1912, 1617, 1556 cm-1. Anal. Calcd for C16H17NO3Fe:
C, 58.74; H, 5.24; N, 4.28. Found: C, 58.55; H, 5.20; N, 4.19.
Tr icar bon yl[(η3-N-m eth yl-2-ph en yl-4,5-dih ydr opyr r ole]-
ir on (0) (4a ). A solution of the above mixture of 2a and 3a
(0.95 g; 3 mmol) in toluene (10 mL) was heated to 100 °C for
8 h under argon. Toluene was removed under reduced pres-
sure, and the residue was subjected to column chromatography
(neutral alumina, 20 g). Elution with a light petroleum-
dichloromethane mixture (10:1) afforded an orange oil of 4a
(0.61 g; 68%), which solidified upon several days in a freezer.
Mp: 18-20 °C. 1H NMR (CDCl3, 500 MHz): δ 2.08 (m, 1H,
dCH-CH2-), 2.48 (m, 1H, dCH-CH2-), 2.64-2.71 (m, 1H,
N-CH2-), 2.69 (s, 3H, N-CH3), 2.91 (m, 1H, N-CH2-), 3.05
(d, J ) 4.0 Hz, 1H, -CHd), 7.37-7.43 (m, 3H, Ph-H), 7.47-
7.51 (m, 2H, Ph-H). 13C NMR (CDCl3, 125 MHz): δ 213.7
(CO), 135.5 (C-Ph), 131.5 (CH-Ph), 128.3 (CH-Ph), 128.2
(CH-Ph), 93.4 (Ph-C(-N)d), 59.3 (N-CH2-), 46.9 (-CHd),
43.8 (N-CH3), 32.6 (-CH2-). IR (CHCl3): ν 2928, 2873, 2024,
1944, 1478, 1453 cm-1. HRMS: calcd 299.02448, found
299.02209.
1403 cm-1
.
Tr ica r b on yl[(η3-N-m et h yl-2-(b ip h en yl-4-yl)-4,5-d ih y-
d r op yr r ole]ir on (0) (4f). The same method as used for the
preparation of 4a starting from the above mixture of 2f and
3f (0.4 g; 1 mmol) afforded after crystallization from
a
pentane-ether mixture pure 4f (0.195 g; 52%) as a yellow-
1
orange plates. Mp: 77-79 °C. H NMR (CDCl3, 500 MHz): δ
2.10 (m, 1H, dCH-CH2-), 2.50 (m, 1H, dCH-CH2-), 2.69
(m, 1H, N-CH2-), 2.75 (s, 3H, N-CH3), 2.93 (dt, J ) 4.1, 9.0
Hz, 1H, N-CH2-), 3.09 (d, J ) 3.8 Hz, 1H, -CHd), 7.37-
7.42 (m, 1H, Ph-H), 7.46-7.51 (m, 2H, Ph-H), 7.54-7.58 (m,
2H, Ph-H), 7.61-7.66 (m, 4H, Ph-H). 13C NMR (CDCl3, 125
MHz): δ 213.7 (CO), 141.1 (C-Ph), 140.4 (C-Ph), 134.7 (C-
Ph), 131.7 (CH-Ph), 128.9 (CH-Ph), 127.6 (CH-Ph), 127.1
(CH-Ph), 127.0 (CH-Ph), 92.9 (Ph-C(-N)d), 59.4 (N-CH2-),
46.8 (-CHd), 43.8 (N-CH3), 32.6 (-CH2-). IR (CHCl3): ν
2874, 2025, 1945, 1489 cm-1. Anal. Calcd for C20H17NO3Fe:
C, 64.02; H, 4.57; N, 3.73. Found: C, 63.76; H, 4.79; N, 3.68.
Tr icar bon yl[(η3-N,4-dim eth yl-2-ph en yl-4,5-dih ydr opyr -
r ole]ir on (0) (4b). The same method as was used for the
preparation of 4a starting from the above mixture of 2b and
3b (0.5 g; 1.5 mmol) afforded 4b (0.29 g; 62%) as a mixture of
two diastereoisomers in 4:1 ratio. The complex was obtained
as an orange oil, which solidified upon several days in a
freezer. 1H NMR (CDCl3, 500 MHz): δ 1.14 (d, J ) 6.5 Hz,
3H, -CH3, minor), 1.24 (d, J ) 6.7 Hz, 3H, -CH3, major), 2.04
(dd, J ) 9.5, 4.0 Hz, 1H, minor), 2.35 (dd, J ) 9.5, 3.8 Hz, 1H,
major), 2.53 (m, 1H, major), 2.59 (s, 3H, N-CH3, minor), 2.61
(s, 3H, N-CH3, major), 2.88 (s, 1H, major), 2.92 (dd, J ) 9.5,
7.4 Hz, 1H, major), 3.00-3.05 (m, 2H, minor), 7.36-7.43 (m,
3H, Ph-H), 7.46-7.49 (m, 2H, Ph-H, minor), 7.52-7.56 (m,
2H, Ph-H, major). 13C NMR (CDCl3, 125 MHz): δ 214.0 (CO,
minor), 213.7 (CO, major), 136.1 (C-Ph, minor), 135.6 (C-
Ph, major), 131.6 (CH-Ph, major), 131.0 (CH-Ph, minor),
128.3 (CH-Ph, major), 128.2 (CH-Ph, major), 128.1 (CH-
Ph, minor), 93.8 (Ph-C(-N)d, major), 92.9 (Ph-C(-N)d,
minor), 68.0 (N-CH2-, major), 67.4 (N-CH2-, minor), 56.2
(-CHd, minor), 54.5 (-CHd, major), 44.0 (N-CH3, minor),
43.8 (N-CH3, major), 41.1 (-CH2-, major), 36.6 (-CH2-,
minor), 23.8 (-CH3, major), 19.3 (-CH3, minor). IR (CHCl3):
ν 2024, 1945 cm-1. Anal. Calcd for C15H15NO3Fe: C, 57.54; H,
4.83; N, 4.47. Found: C, 57.91; H, 5.09; N, 4.34.
Meth yl 3-(N-Meth yl-N-tosyla m in o)p r op a n oa te.16 3-(N-
Methyl-N-tosylamino)propannitrile17 (17.16 g; 72 mmol) in dry
HCl-CH3OH (20%; 90 g) was stirred and heated at reflux for
3 h. The reaction mixture containing precipitated NH4Cl was
evaporated to dryness and the residue neutralized with ice and
K2CO3 solution. The product was extracted with dichlo-
romethane (3 × 30 mL). Combined extracts were dried with
Na2SO4, and evaporation of the solvent gave the title com-
1
pound (18.69 g; 96%) as a colorless oil. H NMR (CDCl3, 300
MHz): δ 2.41 (s, 3H, C-CH3), 2.60 (t, J ) 7.1 Hz, 2H, -CH2-),
2.74 (s, 3H, N-CH3), 3.29 (t, J ) 7.1 Hz, 2H, -CH2-), 3.66 (s,
3H, O-CH3), 7.30 (d, J ) 8.2 Hz, 2H, Ph-H), 7.65 (d, J ) 8.2
Hz, 2H, Ph-H). 13C NMR (CDCl3, 75 MHz): δ 171.7 (CdO),
143.5 (C-Ph), 134.2 (C-Ph), 129.7 (CH-Ph), 127.3 (CH-Ph),
51.8 (O-CH3), 46.0 (-CH2-), 35.6 (N-CH3), 33.5 (-CH2-),
21.4 (C-CH3).
3-(N-Meth yl-N-tosylam in o)pr opan ol-1,1-d2. To the stirred
suspension of lithium aluminum deuteride (1.75 g; 41.7 mmol)
in THF (40 mL) was added dropwise methyl 3-(N-methyl-N-
tosylamino)propanoate (13.6 g; 50 mmol) in THF (60 mL) via
a syringe at 0 °C. The mixture was then refluxed for 6 h, and
after cooling excess deuteride was carefully decomposed with
Na2SO4‚10H2O (10 g). The resulting suspension was stirred
for 3 h and then filtered with suction, and the precipitate was
washed with THF (20 mL). The solvent was then removed
under reduced pressure, the residue was treated with water
(20 mL), and the product was extracted with dichloromethane
(3 × 20 mL). Combined extracts were dried with Na2SO4, and
evaporation of the solvent gave the desired product (9.32 g;
Tet r a ca r b on yl[(N-a llyl-N-m et h yla m in o)(b ip h en yl-4-
yl)ca r ben e]ir on (0) (2f) a n d cis-Tr ica r bon yl[(η2-N-a llyl-
N-m eth yla m in o)(bip h en yl-4-yl)ca r ben e]ir on (0) (3f). The
same method as was used for the preparation of 2a and 3a
starting from N-allyl-N-methylbiphenyl-4-carboxamide (1f)
(0.754 g; 3 mmol) afforded a mixture of 2f and 3f in 3:1 ratio
(0.64 g; 54%) as an oil, which solidified upon several days in
1
76%) as a colorless oil. H NMR (CDCl3, 300 MHz): δ 1.71 (t,
1
a freezer. H NMR (CDCl3, 500 MHz): δ 1.52 (bs, 1H, dCH2,
J ) 6.3 Hz, 2H, -CH2-), 2.42 (s, 3H, C-CH3), 2.42 (bs, 1H,
minor), 2.06 (bs, 1H, dCH2, minor), 2.99 (s, 3H, N-CH3,
minor), 3.22 (m, 1H, -CHd, minor), 3.97 (s, 3H, N-CH3,
major), 4.08 (m, 2H, N-CH2, major), 4.17-4.37 (m, 2H,
N-CH2-, minor), 5.18-5.40 (m, 2H, dCH2, major), 5.60-5.70
(m, 1H, -CHd, major), 6.94 (m, 2H, Ph-H), 7.30-7.70 (m,
(16) The methodology described for the preparation of N-Ts-â,â′-
dicarbomethoxydiethylamine was used: Speckamp, W. N.; Dijkink, J .;
Dekkers, A. W. J . D.; Huisman, H. O. Tetrahedron 1971, 27, 3143.
(17) Shukla, J . S.; Srivastava, R. K. J . Prakt. Chem. 1968, 38, 369.

Iron N-Allylaminocarbene Complexes
Organometallics, Vol. 22, No. 18, 2003 3709
-OH), 2.73 (s, 3H, N-CH3), 3.10 (t, J ) 6.3 Hz, 2H, -CH2-),
7.31 (d, J ) 8.2 Hz, 2H, Ph-H), 7.66 (d, J ) 9.1 Hz, 2H, Ph-
H). 13C NMR (CDCl3, 75 MHz): δ 143.4 (C-Ph), 134.2 (C-
Ph), 129.7 (CH-Ph), 127.2 (CH-Ph), 46.5 (-CH2-), 34.9 (N-
CH3), 29.6 (-CH2-), 21.4 (C-CH3).
via a syringe a solution of sodium naphthalenide prepared by
dissolving sodium (0.6 g; 26 mmol) and naphthalene (3.4 g;
26.5 mmol) in THF (40 mL), until the dark green color
remained. The reaction mixture was then stirred for 15 min
at -78 °C, and water (1 mL) was added. After warming to
room temperature 3 M HCl (10 mL) was added, THF was
evaporated under reduced pressure, and the remaining acidic
water solution was extracted with ether (3 × 10 mL). Then
the water layer was made strongly alkaline with solid NaOH,
and released N-methylallylamine-3,3-d2 was extracted with
ether (4 × 10 mL). Extracts were dried with NaOH and used
without further purification.
1-Mesyloxy-3-(N-m et h yl-N-t osyla m in o)p r op a n e-1,1-
d 2. To a stirred solution of 3-(N-methyl-N-tosylamino)propanol-
1,1-d2 (7.36 g; 30 mmol) and triethylamine (4.9 mL; 35 mmol)
in dichloromethane (60 mL) was added methanesulfonyl
chloride (2.55 mL; 33 mmol) via a syringe. After stirring for 2
h at room temperature water (10 mL) was added, and the
water layer was made acidic with dilute hydrochloric acid. The
solution was then washed with 5% NaHCO3 (5 mL) and dried
with Na2SO4. Evaporation of solvents gave the title compound
To a solution of tetracarbonyl[ethoxy(phenyl)carbene]iron-
(0)18 (1.0 g; 3.3 mmol) and CH3ONa (0.02 g) in THF (2 mL)
was added an ethereal solution of the above amine at room
temperature. The reaction mixture was stirred for 30 min, the
solvent was evaporated, and the residue was chromatographed
on neutral alumina (150 g). Elution with a light petroleum-
dichloromethane mixture (10:1) gave a mixture of d 2-2a and
d 2-3a in 3:2 ratio as an orange oil (0.52 g; 50%). 1H NMR
(CDCl3, 300 MHz): d 2-2a : δ 3.95 (s, 3H, N-CH3), 4.01 (d, J
) 5.5 Hz, 2H, N-CH2-), 5.61 (bs, 1H, -CHd), 6.85 (d, J )
7.1 Hz, 2H, Ph-H), 7.17-7.30 (m, 1H, Ph-H), 7.30-7.42 (m,
2H, Ph-H); d 2-3a : 2.94 (s, 3H, N-CH3), 3.18 (d, J ) 3.9 Hz,
1H, -CHd), 4.18-4.35 (m, 2H, N-CH2-), 6.85 (d, J ) 7.1 Hz,
2H, Ph-H), 7.17-7.30 (m, 1H, Ph-H), 7.30-7.42 (m, 2H, Ph-
H).
1
(9.6 g; 99%) as a yellowish oil. H NMR (CDCl3, 300 MHz): δ
1.98 (t, J ) 6.6 Hz, 2H, -CH2-), 2.43 (s, 3H, C-CH3), 2.72 (s,
3H, N-CH3), 3.07 (s, 3H, S-CH3), 3.10 (t, J ) 6.6 Hz, 2H,
-CH2-), 7.33 (d, J ) 8.2 Hz, 2H, Ph-H), 7.66 (d, J ) 8.2 Hz,
2H, Ph-H). 13C NMR (CDCl3, 75 MHz): δ 143.6 (C-Ph), 133.8
(C-Ph), 129.8 (CH-Ph), 127.4 (CH-Ph), 46.4 (-CH2-), 37.2
(S-CH3), 35.2 (N-CH3), 27.2 (-CH2-), 21.5 (C-CH3).
N-Allyl-3,3-d 2-N-m et h ylt olu en esu lfon a m id e. Sodium
borohydride (1.42 g; 37.5 mmol) was slowly added to a stirred
solution of (PhSe)2 (4.7 g; 15 mmol) in ethanol (60 mL), and
the mixture was cooled to 0 °C. After 20 min a solution of
1-mesyloxy-3-(N-methyl-N-tosylamino)propane-1,1-d2 (9.06 g;
28 mmol) in THF (50 mL) was added via a syringe. The
mixture was stirred overnight at room temperature, ethanol
was evaporated in a vacuum, and the residue was partitioned
between water and dichloromethane. The organic phase was
dried with Na2SO4, solvent was evaporated, and the residue
was dissolved in THF (50 mL). The resulting solution was
added to a stirred solution of NaIO4 (16 g; 75 mmol) in a
mixture of water (125 mL) and THF (100 mL) at 0 °C followed
by NaHCO3 (2.35 g; 28 mmol). The resulting solution was
stirred at 0 °C for 80 min, at room temperature for 1 h, and at
70 °C for 4 h and then allowed to cool to room temperature.
THF was removed under reduced pressure, and the product
was extracted with dichloromethane (3 × 30 mL). Combined
extracts were dried with Na2SO4, solvents were evaporated,
and the product was purified by column chromatography on
silica. Elution with dichloromethane afforded N-allyl-3,3-d2-
N-methyltoluenesulfonamide (5.79 g; 91%) as a yellowish oil.
1H NMR (CDCl3, 300 MHz): δ 2.43 (s, 3H, C-CH3), 2.66 (s,
3H, N-CH3), 3.62 (d, J ) 6.6 Hz, 2H, -CH2-), 5.70 (bs, 1H,
-CHd), 7.32 (d, J ) 7.7 Hz, 2H, Ph-H), 7.67 (d, J ) 8.2 Hz,
2H, Ph-H).
Tr icar bon yl[(η3-N-m eth yl-2-ph en yl-4,5-dih ydr opyr r ole-
3,4-d 2]ir on (0) (d 2-4a ). The same method as was used for the
preparation of 4a starting from (0.32 g; 1 mmol) afforded d 2-
1
4a (0.2 g; 66%). H NMR (CDCl3, 300 MHz): δ 2.05 (m, 1/2H,
dCD-CHD-), 2.44 (m, 1/2H, dCD-CHD-), 2.62-2.69 (m,
1H, N-CH2-), 2.67 (s, 3H, N-CH3), 2.85-2.92 (m, 1H,
N-CH2-), 7.34-7.42 (m, 3H, Ph-H), 7.44-7.50 (m, 2H,
Ph-H).2H NMR(CDCl3,76.75MHz): δ2.07(s,1/2D,dCD-CHD-),
1
2.47 (s, /2D, dCD-CHD-), 3.05 (s, 1D, dCD-). IR (CHCl3):
ν 3020, 2024, 1944, 1445 cm-1. HRMS calcd 301.0371, found
301.0367.
Ack n ow led gm en t. Support of this research under
Grant 203/00/1240 from the Czech Grant Agency is
gratefully acknowledged.
Su p p or tin g In for m a tion Ava ila ble: Complete listings
of structural parameters for 4f. Absolute energies and Carte-
sian coordinates of all stationary points, using 6-31G(d,p) basis
sets. This material is available free of charge via the Internet
at http://pubs.acs.org.
Tet r a ca r b on yl[(N-a llyl-3,3-d 2-N-m et h yla m in o)(p h en -
yl)ca r b en e]ir on (0) (d 2-2a ) a n d cis-Tr ica r b on yl[(η2-N-
a llyl-3,3-d 2-N-m eth yla m in o)(p h en yl)ca r ben e]ir on (0) (d 2-
3a).Toa stirred solution ofN-allyl-3,3-d2-N-methyltoluenesulfon-
amide (3.41 g; 15 mmol) in THF (40 mL) was added at -78 °C
OM0301280
(18) Semmelhack, M. F.; Tamura, R. J . Am. Chem. Soc. 1983, 105,
4099.