Stereochemical control of N,N-disubstitution in alkynylaminocarbene complexes of chromium(O) and tungsten(O)

Article abstract of DOI:10.1021/om960159d

Stereocontrol in the introduction of substituents on the nitrogen of alkynylaminocarbene complexes can be achieved by a proper sequential aminolysis of the starting alkoxy carbene analogs followed by treatment of the resulting (E-alkylamino)carbene complex with Cs₂CO₃ in the presence of the desired electrophile. The use of Cs₂CO₃ as a base affords good yields of N,N-disubstituted alkynylcarbene complexes. The isomerization described for other systems was avoided in this case. The reaction is also applicable to bulky electrophiles like (-)-myrtenyl or (-)-perillyl bromides and also to arylcarbene complexes.

Full text of DOI:10.1021/om960159d

Organometallics 1996, 15, 3611-3615
3611
Ster eoch em ica l Con tr ol of N,N-Disu bstitu tion in
Alk yn yla m in oca r ben e Com p lexes of Ch r om iu m (0) a n d
Tu n gsten (0)
Ramon Sabate´, Ute Schick, J osep M. Moreto´, and Susagna Ricart*
Departament de Qu´ımica Orga`nica Biolo`gica, CID (CSIC), C/ J . Girona 18-26,
E-08034 Barcelona, Spain
Received March 4, 1996X
Stereocontrol in the introduction of substituents on the nitrogen of alkynylaminocarbene
complexes can be achieved by a proper sequential aminolysis of the starting alkoxy carbene
analogs followed by treatment of the resulting (E-alkylamino)carbene complex with Cs2CO3
in the presence of the desired electrophile. The use of Cs2CO3 as a base affords good yields
of N,N-disubstituted alkynylcarbene complexes. The isomerization described for other
systems was avoided in this case. The reaction is also applicable to bulky electrophiles like
(-)-myrtenyl or (-)-perillyl bromides and also to arylcarbene complexes.
Sch em e 1
In tr od u ction
Our interest in the synthesis of N,N-disubstituted
aminoalkynylcarbene complexes 2 lies in the fact that
an intramolecular Pauson-Khand reaction1 is facili-
tated by the lack of rotation around the C-N bond in
(E-allylamino) alkynylcarbene complexes of Cr and W.2
The importance of stereochemical control in the
introduction of both substitutents on the nitrogen atom
arises from the requirement of complexes bearing a
determined functional group specifically in the E or Z
position (with respect to the metal moiety) to further
unequivocally interact with the triple bond or the metal
as is shown in Scheme 1.
Sch em e 2
The procedures reported in the literature for the
synthesis of these complexes consisting of the direct
aminolysis with secondary amines at the carbene cen-
ter3 were not applicable in our case due to the competing
conjugate addition to the triple bond even at very low
temperatures.4
This fact prompted us to look for an alternative
sequential way to obtain N,N-disubstitued amino com-
plexes with two purposes in mind: first, to gain enough
versatility to be applicable to a large variety of N-
substituents and, second, to permit complete control of
the arrangement of the amine on the final complex.
Thus, the general procedure to achieve this is de-
scribed in Scheme 2. After initial aminolysis with a
primary amine, the second substituent would be intro-
duced by base deprotonation and subsequent reaction
with an electrophile, in analogy to the acid-base
chemistry of carboxylic acid amides.
netic control conditions) afforded mostly the correspond-
ing E-allyl isomer. Therefore, the requirement to be
attained was to avoid the isomerization often caused by
the presence of base6 in the introduction of the second
substituent on the nitrogen.
As previously reported,5 the aminolysis of (alkynyl)-
(alkoxy)carbenes with primary amines at -78 °C (ki-
Resu lts a n d Discu ssion
X Abstract published in Advance ACS Abstracts, J uly 1, 1996.
(1) (a) Camps, F.; Moreto´, J . M.; Ricart, S.; Vin˜as, J . M. Angew.
Chem., Int. Ed. Engl. 1991, 30, 1470-1472. (b) J ordi, L.; J ordi, L.;
Moreto´, J . M.; Ricart, S.; Vin˜as, J . M.; Mejias, M.; Molins, E.
Organometallics 1992, 11, 3507-3510.
(2) Connor, J . A.; Fischer, E. O. J . Chem. Soc. A 1969, 578.
(3) (a) Klabunde, U.; Fischer, E. O. J . Am. Chem. Soc. 1967, 89,
7141. (b) Baikie, P. E.; Fischer, E. O.; Mills, O. S. J . Chem. Soc., Chem.
Commun. 1967, 1199.
(4) (a) Duetsch, M.; Stein, F.; Lackmann, R.; Pohl, E.; Herbst-Irmer,
R.; de Meijere, A. Chem. Ber. 1992, 125, 2051-2065. (b) Stein, F.;
Duetsch, M.; Pohl, E.; Herbst-Irmer, R.; de Meijere, A. Organometallics
1993, 12, 2556-2564.
When we applied the described literature procedures
using bases like LDA or NaH7 to our substrates, the
(5) Aumann, R.; Hinterding, P. Chem. Ber. 1993, 126, 421-427.
Also, nonpublished results from our laboratory.
(6) Moser, E.; Fischer, E. O. J . Organomet. Chem. 1968, 15, 147-
155.
(7) (a) Casey, C. P.; Vollendorf, N. W.; Haller, K. J . J . Am. Chem.
Soc. 1984, 106, 3754-3764. (b) Grotjahn, D. B.; Do¨tz, K. H. Synlett
1991, 381. (c) Hegedus, L. S.; Schwindt, M. A.; De Lombaert, S.;
Imwinkelried, R. J . Am. Chem. Soc. 1990, 112, 2264. (d) Rahm, A.;
Wulff, W. D. J . Am. Chem. Soc. 1996, 118, 1807.
S0276-7333(96)00159-8 CCC: $12.00 © 1996 American Chemical Society

3612 Organometallics, Vol. 15, No. 16, 1996
Sabate´ et al.
Ta ble 1
Ta ble 2
product
E/Z
entry
M
base
Cr NaHa
NaH
Cr t-BuOKb
t-BuOK
time (h) solvent (yield (%)) (allyl)
1
2
3
4
5
6
7
3
THF
2a (67)
2b (85)
2a (45)
2b (82)
2a (59)
2a (84)
2b (87)
85/15
100/0
85/15
100/0
75/25
100/0
100/0
W
3
THF
product
2.5
2.5
THF
THF
entry
M
R1X
time (h)
(yield (%))
E/Z
W
1
2
3
4
5
6
7
Cr
W
W
Cr
W
Cr
W
BrCH2CHCH2
BrCH2CHCH2
ClCH2CHCH2
BrCH2Ph
BrCH2Ph
BrCH2CCCH3
BrCH2CCCH3
1.75
1.75
3
1.75
1.75
2
2c (88)
2d (87)
2d (90)a
2e (82)
2f (87)
2g (53)
2h (30)
c
Cr K2CO3
Cr Cs2CO3
W
48
1
1
acetone
acetone
acetone
c
Cs2CO3
100/0
100/0
81/19b
100/0b
a
NaH (2 equiv), dry THF, -78 °C, IMe, -78 °C to room
b
temperature. t-BuOK (2 equiv), dry THF, -78 °C to room
temperature. c K2CO3 or Cs2CO3 (2 equiv), wet acetone,9 room
temperature.
2
Addition of a 10% equiv of KI10 in the reaction mixture.
A
a
b
new compound identified as the corresponding (3-methylalleny-
l)amino complex11 was obtained in both cases and separated form
the mixture by flash chromatography (10% for Cr complexes) (8%
for W complexes).
reaction proceeded fairly well, but some isomerization
was observed and yields, especially for chromium com-
plexes, were erratic and rather low.
In our search for alternative and more efficient bases
to be used in this reaction, we turned our sight to those
used in the related processes with carboxylic amides.8
The results obtained are shown in Table 1.
Ta ble 3
base
product
entry
1
M
R1
(equiv) time (h) (yield (%))
E/Z
Cr
2
3
4
4
2i (24)
2i (89)
100/0
The use of Cs2CO3 (entries 6 and 7, Table 1) instead
of NaH and t-BuOK improved not only the yields but
also the stereoselectivity since only one of the two
possible stereoisomers was obtained. In addition, the
reaction times were reduced and Cs2CO3 was an easier
base to handle than the bases used so far for identical
purposes.
2
Cr
100/0
The extension of this reaction to different electrophiles
was also studied, and the results are reflected in Table
2.
From this table we concluded that Cs2CO3 is an
efficient base for the stereospecific introduction of a
second functionality on the nitrogen of alkynylami-
nocarbene complexes under very mild conditions. The
low yields obtained for chromium compounds using
other bases were also improved (entries, 1, 4, and 6,
Table 2).
3
4
Cr
Cr
2
3
4
6
2j (28)
2j (66)
100/0
100/0
Also remarkable is the successful use of bulky elec-
trophiles such as (-)-myrtenyl or (-)-perillyl bromides
(entries 1 and 3, Table 3) and also secondary allyl
5
6
Cr
Cr
2
3
3
3
2k (traces)
2k (38)
(8) (a) Park, J . D.; Englert, R. D.; Meek, J . S. J . Am. Chem. Soc.
1952, 74, 1010. (b) Luh, T.-L.; Fung, S. H. Synth. Commun. 1979, 9,
757. (c) Slocum, D. W.; Stonermark, F. E. J . Org. Chem. 1973, 38,
1677.
100/0
(9) Addition of 15 µL (approximately 2 drops) of water into the
reaction mixture.
(10) Alami, M.; Ferri, F.; Gaslain, Y. Tetrahedron Lett. 1996, 37,
57-58.
(11) The acidity of the protons of the methylenic group linked to
the nitrogen may account for the rearrangement of the propargilic
group to an allenic one. The structure proposed for these compounds
is as follows:
bromides12 (entry 5, Table 3). In these cases addition
of an additional 1 equiv of Cs2CO3 produced an im-
provement in final yields with complete retention of the
E geometry of the allyl group (entries 2, 4, and 6, Table
3).
(12) Secondary allyl bromide gave only 10% yield of the expected
product 2k when NaH (2 or 3 equiv) was used.

Alkynylaminocarbene Complexes of Cr(0) and W(0)
Organometallics, Vol. 15, No. 16, 1996 3613
Sch em e 3
Sch em e 5
The synthesis of complex 9 illustrates the extension
of this procedure to a carbene complex like 8 (Scheme
5). These complexes do not react with the corresponding
bromides or halides in the presence of NaH or LDA.15
A possible explanation for the stereochemical control
brought about by the Cs2CO3 system may arise from
the reaction conditions. Since base and electrophile are
present in the medium from the very beginning, genera-
tion and quenching of the anionic center on nitrogen
are almost simultaneous, thus reducing the possible
isomerization due to the presence of a base.
Sch em e 4
In conclusion, we present here a versatile, efficient,
and easy way for the preparation of stereodefined
disubstituted alkynylaminocarbene complexes. This
procedure provides an alternative to that previously
described especially for chromium complexes and bulky
substituents.
Exp er im en ta l Section
Unless otherwise stated all common reagents and solvents
were used as obtained from commercial suppliers without
further purification.
NMR spectra were recorded on a Varian Gemini-200 (200
MHz for 1H-NMR and 50 MHz for 13C) or a Varian XL-300
apparatus (300 MHz for 1H-NMR and 75.4 MHz for 13C). All
samples of carbene complexes were filtered through a pad of
Celite and EDTA prior to recording the spectra. IR spectra
were recorded on a Bomem FT-IR M-120 spectrophotometer.
Elemental analyses were performed using a Carlo-Erba 1106
apparatus. MSHR were performed on an AutoSpec-Q mass
spectrometer.
As an example of the stereochemical control displayed
in the present procedure, we were able to stereospecifi-
cally prepare compounds 2e,f,l,m as shown in Scheme
3.
The extension of the Cs2CO3 reaction to other carbene
complexes with a different substituent on the carbenic
carbon atom was also attempted affording good yields
of the corresponding disubstituted amino complexes for
the arene complex 3 (Scheme 4). In contrast, for the
methyl analog 5 considerable E,Z isomerization was
observed.
Despite that, the use of Cs2CO3 allowed us to work
at room temperature avoiding completely the formation
of the complex corresponding to the isomerization of the
double bond via a dipole-stabilized carbanion.13 As
expected from an alkyl-substituted carbene complex,
isomerization around the C-N bond was easier than
for alkynyl or phenyl analogs and also coordination of
the double bond to the metal moiety14 ensued from the
Z isomer (the acidity of the methyl hydrogens did not
significatively interfere with the process).
Flash column chromatography was performed with “flash
grade” silica (SDS 230-400 mesh).
Unless otherwise indicated carbene complexes 1a -d ,5 3,16
5,11b and 81 were prepared by literature procedures and yields
of final products were not optimized.
Syn th esis of P en ta ca r bon yl[(p h en yleth yn yl)(E-a llyl-
Z-m eth yla m in o)ca r ben e]ch r om iu m (0) (2a ). Rea ction of
Na H w ith Com p lex 1a . Meth od A. Complex 1a (0.1 g, 0.28
mmol) was added to a stirred suspension of NaH (0.022 g, 0.56
mmol, 60% in paraffin) in dry THF at -78 °C. The temper-
ature of the suspension was allowed to rise to -40 °C and kept
at this temperature for 2 h. Then the solution was again
cooled to -70 °C and methyl iodide (0.035 mL, 0.56 mmol)
injected. The solution was kept at room temperature for 1 h.
Quenching of the reaction with ice water, extraction with
pentane, and evaporation to dryness afforded a crude mixture,
which after separation by flash chromatography (hexane/CH2-
Cl2, 4/1) gave 0.070 g (0.090 mmol) of the expected carbene
complex 2a as a red oil (67% yield, E/Z ) 85/15).
Rea ction of t-Bu OK w ith 1a . Meth od B. Complex 1a
(0.1 g, 0.28 mmol) was added to a stirred solution of t-BuOK
(0.062 g, 0.56 mmol) in dry THF at -78 °C. The temperature
of the solution was allowed to rise to -40 °C and kept at this
temperature for 2 h. Then the solution was again cooled to
(13) (a) Casey, C. P.; Hornung, N. L.; Vollendorf, N. W. J . Orga-
nomet. Chem. 1986, 303, 375-385. (b) Alvarez, C.; Parlier, A.; Rudler,
H.; Yefsah, R.; Daran, J . C.; Knobler, C.; Organometallics 1989, 8, 2253.
(14) Denise, B.; Goumont, R.; Parlier, A.; Rudler, H.; Daran, J .-C.;
Vaissermann, J .; J . Organomet. Chem. 1989, 377, 89-104.
(15) Unpublished results from our laboratory.
(16) Fischer, E. O. Pure Appl. Chem. 1970, 24, 407-423.

3614 Organometallics, Vol. 15, No. 16, 1996
Sabate´ et al.
-70 °C and methyl iodide (0.035 mL, 0.56 mmol) injected. The
solution was kept at room temperature for 1 h. After quench-
ing, extraction, and separation by flash chromatography, 0.047
g of the carbene complex 2a was obtained (45% yield, E/Z )
85/15).
Syn th esis of P en ta ca r bon yl[(p h en yleth yn yl)(d ia llyl-
a m in o)ca r ben e]tu n gsten (0) (2d ). Compound 2d was ob-
tained in 87% yield as an orange solid using method D.
Da ta for 2d . IR (CHCl3): 2167, 2061, 1947, 1939 cm-1 1H-
.
NMR (CDCl3) (δ): 4.58 (d, J ) 5.7 Hz, 2H, (E)-NCH2), 4.74 (d,
J ) 5.7 Hz, 2H, (Z)-NCH2), 5.25-5.45 (m, 4H, CH2 (E) (Z)),
5.81-5.99 (m, 2H, CH (E) (Z)), 7.40-7.53 (m, 5H, Ph). 13C-
NMR (CDCl3) (δ): 57.8 (t), 63.4 (t), 92.8 (s), 119.8 (t), 120.6
(t), 121.8 (s), 126.6 (s), 128.6 (d), 131.7 (d), 130.3 (d), 130.4 (d),
131.3 (d), 198.2 (s), 203.8 (s), 230.4 (CdW). MS (FAB+): m/e
533 (M+).
Syn th esis of P en ta ca r bon yl[(p h en yleth yn yl)(E-a llyl-
Z-ben zyla m in o)ca r ben e]ch r om iu m (0) (2e). Compound 2e
was obtained in 82% yield as a red solid using method D.
Da ta for 2e. IR (CHCl3): 2167, 2054, 1976, 1936 cm-1 1H-
.
NMR (CDCl3) (δ): 4.50 (d, J ) 5.8 Hz, 2H, E-NCH2), 5.16 (d,
J ) 17 Hz, 1H, CH2), 5.31 (d, J ) 10.2 Hz, 1H, CH2), 5.48 (s,
2H, Z-NCH2), 5.82 (ddt, J ) 17, 10.2, 5.8 Hz, 1H, CH), 7.20-
7.35 (m, 10H, Ph). 13C-NMR (CDCl3) (δ): 58.9 (t), 62.4 (t), 90.9
(s), 119.6 (t), 121.9 (s), 127.6 (d), 128.5 (d), 128.6 (d), 129.1 (d),
130.3 (d), 130.5 (d), 131.5 (d), 134.3 (s), 216.9 (s), 223.9 (s),
251.4 (CdCr). Anal. Calcd for C24H17NO5Cr: C, 63.86; H,
3.77; N, 3.10. Found: C, 64.06; H, 3.88; N, 3.13.
Syn th esis of P en ta ca r bon yl[(p h en yleth yn yl)(E-a llyl-
Z-b en zyla m in o)ca r b en e]t u n gst en (0) (2f). Compound 2f
was obtained in 87% yield as an orange solid using method D.
.
Da ta for 2f. IR (CHCl3): 2167, 2061, 1975, 1934 cm-1 1H-
Rea ction of K2CO3 w ith Com p lex 1a . Meth od C.
Complex 1a (0.1 g, 0.28 mmol) was added to a stirred solution
of K2CO3 (0.077 g, 0.56 mmol) in 10 mL of acetone. After 1 h
at room temperature methyl iodide (0.035 mL, 0.56 mmol) was
added. After 24 h at room temperature control by TLC showed
the existence of some of the starting product and then 1 equiv
of methyl iodide was added. After 48 h the reaction was
stopped by quenching with ice water. Extraction, evaporation
in vacuum, and separation afforded 0.008 g of the starting
compound 1a and 0.061 g of the expected product 2a (59%
yield, E/Z ) 75/25).
Rea ction of Cs2CO3 w ith Com p lex 1a . Meth od D.
Methyl iodide (0.035 mL, 0.56 mmol) was added to a stirred
solution of 1a (0.1 g, 0.28 mmol) and Cs2CO3 (0.181 g, 0.554
mmol) in 10 mL of wet (15 µL of water was added) acetone.
After 1 h at room temperature control by TLC showed the
disappearance of the starting compound. Quenching, extrac-
tion, and separation by flash chromatography afforded 0.087
g of the expected product 2a in 84% yield as an orange solid
(E/Z ) 100/0).
NMR (CDCl3) (δ): 4.45 (d, J ) 6 Hz, 2H, NCH2), 5.15 (d, J )
16.8 Hz, 1H, CH2), 5.30 (d, J ) 10.2 Hz, 1H, CH2), 5.34 (s, 2H,
NCH2), 5.81 (ddt, J ) 16.8, 10.2, 6 Hz, 1H, CH), 7.27-7.53
(m, 10H, Ph). 13C-NMR (CDCl3) (δ): 57.8 (t), 64.3 (t), 92.9 (s),
120.0 (t), 121.8 (s), 126.9 (s), 127.7 (d), 128.6 (d), 128.7 (d),
129.2 (d), 130.4 (d), 130.5 (d), 131.8 (d), 134.1 (s), 198.1 (s),
203.8 (s), 231.0 (CdW). Anal. Calcd for C24H17NO5W: C,
49.40; H, 2.92; N, 2.40. Found: C, 49.53; H, 3.02; N, 2.48.
Syn t h esis of P en t a ca r b on yl[(p h en ylet h yn yl)(a llyl-
p r op a r gyla m in o)ca r ben e]ch r om iu m (0) (E- a n d Z-2g).
Compound 2g was obtained in 70% yield as a dark red oil,
which proved to be a mixture of two isomers not separable by
chromatography (81 (E-allyl)/19 (Z-allyl) determined by NMR),
using method D.
Da ta for 2a . IR (CHCl3): 2169, 2061, 1974, 1932 cm-1 1H-
.
NMR (CDCl3) (δ): 3.84 (s, 3H, CH3), 4.65 (d, J ) 6 Hz, 2H,
CH2N), 5.30 (d, J ) 17.1 Hz, 1H, CH2), 5.38 (d, J ) 10.2 Hz,
1H, CH2), 5.88 (ddt, J ) 17.1, 10.2, 6 Hz, 1H, CH), 7.39-7.53
(m, 5H, Ph). 13C-NMR (CDCl3) (δ): 47.0 (q), 63.2 (t), 90.6 (s),
120.0 (t), 122.2 (s), 128.7 (d), 129.3 (s), 130.3 (d), 130.5 (d),
131.6 (d), 217.4 (s), 224.1 (s), 250.2 (CdCr). Anal. Calcd for
C
18H13NO5Cr: C, 57.60; H, 3.47; N, 3.73. Found: C, 57.53;
H, 3.45; N, 3.80.
Syn th esis of P en ta ca r bon yl[(p h en yleth yn yl)(E-a llyl-
Z-m eth yla m in o)ca r ben e]tu n gsten (0) (2b). Rea ction of
Na H w ith Com p lex 1b. Meth od A. Using the same
procedure described for complex 1a , complex 2b was obtained
in 85% yield (E/Z ) 100/0).
Da ta for 2g (E-Allyl). IR (CHCl3): 2167, 2056, 1978, 1938
cm-1
.
1H-NMR (CDCl3) (δ): 1.90 (t, J ) 2.4 Hz, 3H, CH3),
4.78 (d, J ) 6.3 Hz, 2H, E-CH2N), 4.94 (q, J ) 2.4 Hz, 2H,
Z-CH2N), 5.29 (d, J ) 16.8 Hz, 2H, CH2) 5.36 (d, J ) 10.4 Hz,
1H, CH2), 5.90 (ddt, J ) 16.8, 10.4, 6.3 Hz, 1H, CH), 7.40-
7.52 (m, 5H, Ph). 13C-NMR (CDCl3) (δ): 3.7 (q), 49.1 (t), 59.2
(t), 61.0 (s), 71.9 (s), 90.7 (s), 120.1 (t), 122.0 (s), 128.7 (d), 130.3
(d), 130.5 (d), 131.2 (s), 131.6 (d), 216.7 (s), 224.1 (s), 251.5
(CdCr). Anal. Calcd for C21H15NO5Cr: C, 61.02; H, 3.63; N,
3.37. Found: C, 61.17; H, 3.90; N, 3.35.
Rea ction of t-Bu OK w ith Com p lex 1b. Meth od B.
Using the same procedure described for complex 1a , complex
2b was obtained in 82% yield (E/Z ) 100/0).
Rea ction of Cs2CO3 w ith Com p lex 1b. Meth od D.
Using the same procedure described for complex 1a , complex
2b was obtained in 87% yield as an orange solid (E/Z ) 100/
0).
Da ta for 2g (Z-Allyl). 1H-NMR (CDCl3) (δ): 1.88 (t, J )
2.4 Hz, 3H, CH3), 4.70 (q, J ) 2.4 Hz, 2H, E-CH2N), 4.98 (d, J
) 6.3 Hz, 2H, Z-CH2N), 5.45-5.50 (m, 2H, CH2), 5.90-6.03
(m, 1H, CH), 7.39-7.56 (m, 5H, Ph).
Da ta for 2b. IR (CHCl3): 2169, 2061, 1974, 1932 cm-1 1H-
.
NMR (CDCl3) (δ): 3.73 (s, 3H, CH3), 4.62 (d, J ) 5.7 Hz, 2H,
CH2N), 5.31 (d, J ) 17.1 Hz, 1H, CH2), 5.39 (d, J ) 10 Hz, 1H,
CH2), 5.90 (ddt, J ) 17.1, 10, 5.7 Hz, 1H, CH), 7.39-7.53 (m,
5H, Ph). 13C-NMR (CDCl3) (δ): 49.2 (q), 62.0 (t), 92.4 (s), 120.3
(t), 121.9 (s), 126.0 (s), 128.8 (d), 130.3 (d), 130.4 (d), 131.8 (d),
198.5 (s), 204.2 (s), 229.8 (s).
Syn th esis of P en ta ca r bon yl[(p h en yleth yn yl)(E-a llyl-
Z-p r op a r gyla m in o)ca r ben e]tu n gsten (0) (2h ). Compound
2h was obtained in 30% yield as an orange solid using method
D.
Da ta for 2h . IR (CHCl3): 2169, 2063, 1975, 1934 cm-1 1H-
.
Syn th esis of P en ta ca r bon yl[(p h en yleth yn yl)(d ia llyl-
a m in o)ca r ben e]ch r om iu m (0) (2c). Compound 2c was ob-
tained in 88% yield as an orange-red solid using method D.
NMR (CDCl3) (δ): 1.85 (t, J ) 2.4 Hz, 3H, CH3), 4.74 (d, J )
6.1 Hz, 2H, E-CH2N), 4.83 (q, J ) 2.4 Hz, 2H, Z-CH2N), 5.28-
5.40 (m, 2H, CH2), 5.82-5.96 (m, 1H, CH), 7.38-7.45 (m, 5H,
Ph). Anal. Calcd for C21H15NO5W: C, 46.24; H, 2.57; N, 2.57.
Found: C, 46.21; H, 2.88; N, 2.52.
Da ta for 2c. IR (CHCl3): 2167, 2054, 1978, 1936 cm-1 1H-
.
NMR (CDCl3) (δ): 4.62 (d, J ) 5.2 Hz, 2H, E-NCH2), 4.85 (d,
J ) 5.2 Hz, 3H, Z-CH2), 5.25-5.46 (m, 4H, CH2 (E) (Z)), 5.80-
6.04 (m, 2H, CH (E) (Z)), 7.40-7.54 (m, 5H, Ph). 13C-NMR
(CDCl3) (δ): 58.9 (t), 61.5 (t), 90.9 (s), 119.6 (t), 120.7 (t), 122.1
(s), 128.7 (d), 130.4 (d), 130.0 (s), 130.6 (d), 131.6 (d), 131.7
(d), 217.1 (s), 224.1 (s), 251.0 (CdCr). Anal. Calcd for
Syn th esis of P en ta ca r bon yl[(p h en yleth yn yl)(E-a llyl-
Z-p er illyla m in o)ca r ben e]ch r om iu m (0) (2i). Compound 2i
was obtained in 89% yield as an orange solid using method D
(with 3 equiv of Cs2CO3).
Da ta for 2i. IR (CHCl3): 2171, 2060, 1968, 1916 cm-1 1H-
.
C
20H15NO5Cr: C, 59.85; H, 3.74; N, 3.47. Found: C, 59.90;
NMR (CDCl3) (δ): 1.40-2.30 (m, 6H, CH2), 1.74 (d, J ) 3.4
Hz, CH3), 4.40-4.80 (m, 6H, CH2), 5.20 (d, J ) 16 Hz, 1H,
H, 3.76; N, 3.55.

Alkynylaminocarbene Complexes of Cr(0) and W(0)
Organometallics, Vol. 15, No. 16, 1996 3615
CH2), 5.31 (d, J ) 10.2 Hz, 1H, CH2), 5.68 (bs, 1H, CH), 5.93
(ddt, J ) 17, 10.2, 5.4 Hz, 1H, CH), 7.40-7.60 (m, 5H, Ph).
13C-NMR (CDCl3) (δ): 20.8 (q), 26.9 (t), 27.4 (t), 30.9 (t), 40.6
(d), 59.1 (t), 64.5 (t), 91.2 (s), 109.1 (t), 119.3 (t), 122.2 (s), 125.8
(d), 128.8 (d), 129.6 (s), 130.4 (d), 130.9 (d), 131.4 (s), 131.7
(d), 134.5 (s), 217.3 (s), 224.2 (s), 250.8 (CdCr). MS (EI): m/e
495, 439, 411, 383, 355, 303, 221, 135, 93. Anal. Calcd for
J ) 17 Hz, 1H, CH2), 5.31 (d, J ) 10.2 Hz, 1H, CH2), 5.34 (s,
2H, E-CH2N), 5.81 (ddt, J ) 17, 10, 6 Hz, 1H, CH), 7.28-7.52
(m, 10H, Ph). 13C-NMR (CDCl3) (δ): 58.7 (t), 62.8 (t), 93.3 (s),
121.0 (t), 121.7 (s), 126.2 (s), 127.6 (d), 128.5 (d), 128.7 (d),
129.3 (d), 130.5 (d), 131.3 (d), 131.9 (d), 134.0 (s), 198.2 (s),
203.9 (s), 230.7 (CdW).
Syn th esis of P en ta ca r bon yl[p h en yl(E-a llyl-Z-m eth y-
la m in o)ca r ben e]tu n gsten (0) (4). Compound 4 was obtained
in 88% yield as an orange solid using method D.
.
Da ta for 4. IR (CHCl3): 2061, 1971, 1928 cm-1 1H-NMR
(CDCl3) (δ): 3.86 (s, 3H, CH3), 3.96 (m, 2H, CH2N), 5.15-5.35
(m, 2H, CH2), 5.57-5.70 (m, 1H, CH), 6.76-6.80 (m, 2H, Ph),
7.12-7.18 (m, 1H, Ph), 7.35-7.41 (m, 2H, Ph). 13C-NMR
(CDCl3) (δ): 51.0 (q), 59.3 (t), 119.3 (d), 120.1 (t), 126.3 (d),
128.3 (d), 130.8 (d), 152.7 (s), 198.5 (s), 204.3 (s), 259.1 (CdW).
Anal. Calcd for C16H13NO5W: C, 39.75; H, 2.69; N, 2.90.
Found: C, 39.65; H, 2.64; N, 3.00.
C
27H25NO5Cr: C, 65.45; H, 5.09; N, 2.83. Found: C, 65.36;
H, 5.19; N, 2.84.
Syn th esis of P en ta ca r bon yl[(p h en yleth yn yl)(E-a llyl-
Z-m yr th en ylam in o)car ben e]ch r om iu m (0) (2i). Compound
2j was obtained in 66% yield as an orange solid using method
D (with 3 equiv of Cs2CO3).
Da ta for 2j. IR (CHCl3): 2167, 2053, 1976, 1934 cm-1 1H-
.
NMR (CDCl3) (δ): 0.83 (s, 3H, CH3), 1.31 (s, 3H, CH3), 2.10-
2.50 (m, 6H, CH, CH2), 4.29 (dd, J ) 14.7, 6.3 Hz, 1H, CH2N),
4.50 (d, J ) 15.3 Hz, 1H, CH2N), 4.86 (dd, J ) 14.7, 4.2 Hz,
1H, CH2N), 5.02 (d, J ) 15.3 Hz, 1H, CH2N), 5.20 (d, J ) 16.8
Hz, 1H, CH2), 5.31 (d, J ) 10.2 Hz, 1H, CH2), 5.58 (bs, 1H,
CH), 5.83 (ddt, J ) 16.8, 10.2, 6.3 Hz, 1H, CH), 7.35-7.56 (m,
5H, Ph). 13C-NMR (CDCl3) (δ): 20.8 (q), 25.8 (q), 31.5 (d), 31.7
(s), 38.3 (d), 40.6 (d), 42.9 (t), 58.5 (t), 63.6 (t), 92.0 (s), 119.3
(d), 122.2 (s), 122.8 (t), 126.6 (s), 128.6 (d), 130.2 (d), 130.7 (d),
131.5 (d), 217.1 (s), 224.0 (s), 250.1 (CdCr). HRMS (EI): Calcd
for C27H25O5NCr, m/e 495.115 239; found, m/e 495.113 783.
Syn th esis of P en ta ca r bon yl[(p h en yleth yn yl)(E-a llyl-
Z-cycloh exen yla m in o)ca r ben e]ch r om iu m (0) (2k ). Com-
pound 2k was obtained as an orange solid in 38% yield using
method D (with 3 equiv of Cs2CO3).
Syn th esis of P en ta ca r bon yl[m eth yl(E-a llyl-Z-m eth y-
la m in o)ca r ben e]ch r om iu m (0) (6). Compound 6 was ob-
tained in 41% yield as a yellow solid using method D together
with a 30% yield of compound 7 as a yellow orange solid.
Separation of both products was attained by flash chromatog-
raphy (2:1 hexane/CH2Cl2).
Da ta for 6. 1H-NMR (CDCl3) (δ): 2.72 (s, 3H, CH3), 3.82
(s, 3H, CH3N), 4.27 (ddd, J ) 4.8, 1.8, 1.5 Hz, 2H, CH2N), 5.09
(dt, J ) 17.5, 1.8 Hz, 1H, CH2), 5.33 (dt, J ) 10.5, 1.5 Hz, 1H
CH2), 5.77 (ddt, J ) 17.1, 10.5, 4.8 Hz, 1H, CH). 13C-NMR
(CDCl3) (δ): 39.6 (q), 51.1 (q), 57.3 (t), 118.1 (t), 129.1 (d), 217.9
(s), 223.5 (s), 257.6 (CdCr). Anal. Calcd for C11H11NO5Cr: C,
45.76; H, 3.80; N, 4.84. Found: C, 45.56; H, 3.92; N, 4.82.
Da ta for 7. 1H-NMR (CDCl3) (δ): 2.33 (s, 3H, CH3), 3.07
(s, 3H, CH3N), 2.95-3.10 (m, 2H, CH2), 4.05-4.12 (m, 1H, CH),
4.34-4.46 (m, 2H, CH2N). 13C-NMR (CDCl3) (δ): 33.4 (q), 38.1
(q), 63.6 (t), 64.4 (t), 72.9 (d), 225.5 (s), 225.7 (s), 226.1 (s),
233.1 (s), 281.0 (CdCr). Anal. Calcd for C10H11NO4Cr: C,
45.97; H, 4.21; N, 5.36. Found: C, 46.15; H, 4.48; N, 5.21.
Da ta for 2k . IR (CHCl3): 2167, 2051, 1924 cm-1 1H-NMR
.
(CDCl3) (δ): 1.60-2.40 (m, 6H, CH2), 4.35 (dd, J ) 15.3, 5.1
Hz, 1H, CH2N), 4.76 (bs, 1H, CHN), 5.17 (d, J ) 17.1 Hz, 1H,
CH2), 5.26 (d, J ) 10.5 Hz, 1H, CH2), 5.60-5.90 (m, 2H, CH),
7.30-7.50 (m, 5H, Ph). 13C-NMR (CDCl3) (δ): 20.9 (t), 24.6
(t), 28.5 (t), 55.8 (d), 68.8 (t), 118.2 (t), 122.4 (s), 126.0 (d), 128.7
(d), 130.3 (d), 131.5 (d), 131.6 (d), 133.5 (d), 217.2 (s), 224.4
(s), 249.3 (CdCr). HRMS (EI): Calcd for C23H19O5NCr, m/e
441.067 308; found, m/e 441.066 833.
Syn th esis of Com p ou n d 9. Compound 9 was obtained
in 78% yield as a red solid using method D.
.
Da ta for 9. IR (CHCl3): 2063, 1976, 1938, 1720 cm-1 1H-
Syn th esis of P en ta ca r bon yl[(p h en yleth yn yl)(E-ben -
zyl-Z-a llyla m in o)ca r ben e]ch r om iu m (0) (21). Compound
21 was obtained in 71% yield as a dark red solid using method
D.
NMR (CDCl3) (δ): 2.27 (dd, J ) 18.5, 2.1 Hz, 1H, CH2), 2.67
(dd, J ) 18.5, 6 Hz, 1H, CH2), 3.34-3.44 (m, 2H, CH, CH2),
3.55 (s, 3H, CH3), 3.76-3.87 (m, 1H, CH2), 7.05-7.30 (m, 5H,
Ph). 13C-NMR (CDCl3) (δ): 38.5 (t), 42.7 (q), 45.3 (d), 65.8 (t),
128.3 (d), 129.0 (d), 130.0 (d), 130.2 (s), 141.9 (s), 180.2 (s),
197.3 (s), 202.1 (s), 206.7 (s), 236.2 (CdW). Anal. Calcd for
C19H13NO6W: C, 42.64; H, 2.45; N, 2.62. Found: C, 42.06; H,
2.59; N, 2.57.
Da ta for 2l. IR (CHCl3): 2165, 2054, 1976, 1936 cm-1
.
1H-
NMR (CDCl3) (δ): 4.77 (d, J ) 6 Hz, 2H, Z-CH2N), 5.29 (s,
2H, E-CH2N), 5.38 (d, J ) 17 Hz, 1H, CH2), 5.49 (d, J ) 10.2
Hz, 1H, CH2), 6.00 (ddt, J ) 17, 10.2, 6 Hz, 1H, CH), 7.24-
7.51 (m, 10H, Ph). 13C-NMR (CDCl3) (δ): 59.8 (t), 60.8 (t), 91.3
(s), 120.9 (t), 121.9 (s), 127.5 (d), 128.4 (d), 128.6 (d), 129.2 (d),
129.7 (s), 130.3 (d), 131.6 (d), 131.7 (d), 134.2 (s), 217.0 (s),
224.0 (s), 251.6 (CdCr).
Syn th esis of P en ta ca r bon yl[(p h en yleth yn yl)(E-ben -
zyl-Z-a llyla m in o)ca r ben e]tu n gsten (0) (2m ). Compound
2m was obtained in 68% yield as a red orange solid using
method D.
Ack n ow led gm en t. The authors acknowledge finan-
cial support from the DGICYT (Grant No. PB-94-0084)
and the HCM program (Contract No. CHRX-CT94-0501).
Da ta for 2m . IR (CHCl3): 2167, 2061, 1975, 1934 cm-1
.
1H-NMR (CDCl3) (δ): 4.45 (d, J ) 6 Hz, 2H, Z-CH2N), 5.15 (d,
OM960159D