Metathesis of electron-rich olefins: Structure and reactivity of electron-rich carbene complexes

Article abstract of DOI:10.1021/om011037a

A study was performed on the metathesis of electron-rich olefins. The structure and reactivity of electron-rich carbene complexes were also investigated. It was found that the complexes coordinated with an N-heterocyclic carbene ligand displayed enhanced activities in olefin metathesis and were thermally more stable than their bis(phosphine) analogues.

Full text of DOI:10.1021/om011037a

Organometallics 2002, 21, 2153-2164
2153
Articles
Meta th esis of Electr on -Rich Olefin s: Str u ctu r e a n d
Rea ctivity of Electr on -Rich Ca r ben e Com p lexes
J anis Louie and Robert H. Grubbs*
Arnold and Mabel Beckman Laboratories of Chemical Synthesis,
Division of Chemistry and Chemical and Chemical Engineering,
California Institute of Technology, Pasadena, California 91125
Received December 5, 2001
The addition of excess H2CdC(H)ER to (PCy3)2Cl2RudC(H)R (1a ,b) afforded a series of
well-defined ruthenium carbene complexes, (PCy3)2Cl2RudC(H)ER (ER ) OEt (5), SEt (6),
SPh (7), N(carbazole) (8), N(pyrrolidinone) (9)) in yields ranging from 66 to 90%. Such
complexes containing an electron-donating group on the carbene carbon are often referred
to as Fischer-type carbenes. Replacement of one phosphine ligand with 1,3-dimesitylimi-
dazolylidene (IMes) afforded the respective mixed-ligand complexes (IMes)(PCy3)Cl2Rud
C(H)ER (11-14) in 48-89% yield. Alternatively, addition of H2CdC(H)OEt to (H2IMes)-
(PCy3)Cl2RudC(H)Ph (3a ; H2IMes ) 1,3-dimesityl-4,5-dihydroimidazolylidene) afforded
(H2IMes)(PCy3)Cl2RudC(H)OEt (15) in 93% yield. The crystal structures of complexes 5,
7-9, and 11 were determined and found to be structurally similar to the parent ruthenium
alkylidene ([Ru]dC(H)R) complexes. In solution, the chemical shift of the [Ru]dC(H)ER
1
resonance in H NMR spectra was found to be inversely related to the electronegativity of
the R-heteratom; however, no trends were evident in the 31P or 13C NMR spectra.
Intramolecular coordination of the pendant amide carbonyl group to the Ru center established
a temperature-dependent equilibrium between complexes 9 and 14 and their cyclometalated
forms. All Ru electron-rich complexes initiated the ring-opening metathesis polymerization
(ROMP) of strained cyclic olefins and the ring-closing metathesis (RCM) of diethyl
diallylmalonate. A general trend in the relative reactivities and thermal stabilities of the
(PCy3)2Cl2RudC(H)ER complexes followed the order C > N > S > O. In addition, complexes
coordinated with an N-heterocyclic carbene ligand (e.g., (IMes)(PCy3)Cl2RudC(H)ER)
displayed enhanced activities in olefin metathesis and were thermally more stable than their
bis(phosphine) analogues. Finally, the thermal decomposition product of (PCy3)2Cl2RudC(H)-
OEt was isolated and determined by X-ray analysis to be (PCy3)2ClRu(H)CO (10).
In tr od u ction
tion, extensive synthetic,2 mechanistic,3 and theoretical4
investigations have continually improved the perfor-
mance of the catalysts and expanded their overall
applicability. For example, early systems such as (PPh3)2-
Cl2RudC(H)C(H)dCPh2 were only effective in the ring-
opening metathesis polymerization (ROMP) of highly
strained olefins (e.g. norbornene) and displayed rather
limited thermal stability.5 The incorporation of more
bulky and electron-donating phosphines (e.g. PCy3)
afforded catalysts, (PCy3)2Cl2RudCHR (1a -c; Figure 1),
that are active in a wide variety of ring-closing metath-
Over the past decade, the development of Ru-based
olefin metathesis catalysts has led to their use in a
variety of organic and polymer synthesis applications.1
The catalysts with the general structure LL′X2RudCHR
have received the bulk of the attention because they are
generally robust and functional group tolerant and
because a variety of synthetic pathways exist. In addi-
(1) (a) Grubbs, R. H.; Chang, S. Tetrahedron 1998, 54, 4413-4450.
(b) Fu¨rstner, A. Angew. Chem., Int. Ed. 2000, 39, 3012-3043. (c)
Schuster, M.; Blechert, S. Angew. Chem., Int. Ed. 1997, 36, 2036-
2056.
(3) (a) Dias, E. L.; Nguyen, S. T.; Grubbs, R. H. J . Am. Chem. Soc.
1997, 119, 3887-3897. (b) Smith, A. B., III; Adams, C. M.; Kozmin, S.
A. J . Am. Chem. Soc. 2001, 123, 990-991. (c) Aldhart, C.; Volland, M.
A. O.; Hofmann, P.; Chen, P. Helv. Chim. Acta 2000, 83, 3306-3311.
(4) (a) Do¨lker, N.; Frenking, G. J . Organomet. Chem. 2001, 617-
618, 225-232. (b) Adlhart, C.; Hinderling, C.; Baumann, H.; Chen, P.
J . Am. Chem. Soc. 2000, 122, 8204-8214. (c) Spivak, G. J .; Coalter, J .
N.; Oliva´n, M.; Eisenstein, O.; Caulton, K. G. Organometallics 1998,
17, 999-1001.
(2) (a) Schwab, P.; France, M. B.; Ziller, R. H.; Grubbs, R. H. Angew.
Chem., Int. Ed. Engl. 1995, 34, 2039-2041. (b) Schwab, P.; Grubbs,
R. H.; Ziller, J . W. J . Am. Chem. Soc. 1996, 118, 100-110. (c) Wilheim,
T. E.; Belderrain, T. R.; Brown, S. N.; Grubbs, R. H. Organometallics
1997, 16, 3867-3869. (d) Belderrain, T. R.; Grubbs, R. H. Organome-
tallics 1997, 16, 4001-4003. (e) Wolf, J .; Stu¨er, W.; Gru¨nwald, C.;
Werner, H.; Schwab, P.; Schulz, M. Angew. Chem., Int. Ed. 1998, 37,
1124-1128. (f) Weskamp, T.; Kohl, F. J .; Herrmann, W. A. J .
Organomet. Chem. 1999, 582, 362-365. (g) J afarpour, L.; Nolan, S. P.
Organometallics 2000, 19, 2055-2057.
(5) Nguyen, S. T.; J ohnson, L. K.; Grubbs, R. H.; Ziller, J . W. J .
Am. Chem. Soc. 1992, 114, 3974-3975.
10.1021/om011037a CCC: $22.00 © 2002 American Chemical Society
Publication on Web 04/25/2002

2154 Organometallics, Vol. 21, No. 11, 2002
Louie and Grubbs
F igu r e 2. Triphenylphosphine-ligated ruthenium alky-
lidenes.
For example, an early report demonstrated that the
ruthenium alkylidenes (PPh3)2(TFA)2RudC(H)R (4a )
reacted with vinyl ethers, amines, and sulfides to afford
the Ru Fischer-type complexes (PPh3)2(TFA)2RudC(H)-
ER (4b-d , ER ) OEt, SPh, N(carbazole); Figure 2),
which were subsequently found to be inert toward
olefins.13 In fact, ethyl vinyl ether is commonly used to
quench Ru-based ring-opening metathesis polymeriza-
tions, affording a methylene-terminated polymer and
the Ru Fischer-type carbene (PCy3)2Cl2RudC(H)OEt.14
However, a number of recent reports have indicated
that [Ru]dC(H)OR type complexes may indeed be active
olefin metathesis catalysts.15 Although a few Ru Fis-
cher-type carbenes have been synthesized and charac-
terized, a detailed study of their fundamental structures
and reactivity is required.13,15b-d,16 In addition to reac-
tivity, the thermal stability of Ru Fischer-type com-
plexes has not been examined, even though they are
believed to be more thermally stable than their alky-
lidene counterparts.15c To address the effect of directly
modifying the electronic nature of the carbene carbon,
we have prepared and characterized a series of well-
defined carbenes (PCy3)2Cl2RudC(H)ER and (L)(PCy3)Cl2-
RudC(H)ER (L ) IMes, H2IMes; ER ) OR, SR, NR).
As will be discussed below, the complexes contain
structural (solution and solid-state) and thermal char-
acteristics similar to those of Ru alkylidenes. More
importantly, these catalysts were found to be active in
a variety of olefin metathesis reactions. These results
define the requirements for the efficient metathesis of
functionalized olefins such as enols, enamines, and vinyl
sulfides.
F igu r e 1. First- and second-generation ruthenium alky-
lidenes.
esis (RCM), cross-metathesis (CM), and ROMP applica-
tions.6 However, they are limited to olefinic substrates
that are not sterically hindered or that do not possess
functionality in the R-position (such as unsaturated
esters and amides). This limitation was recently over-
come through incorporation of large, electron-donating
imidazoylidene ligands.7 The new catalysts (IMes)-
(PCy3)Cl2RudCHR (2a ,b) and (H2IMes)(PCy3)Cl2Rud
CHR (3a ,b) (IMes ) 1,3-dimesitylimidazolylidene; H2-
IMes ) 1,3-dimesityl-4,5-dihydroimidazolylidene) have
enabled the preparation of not only R-functionalized
olefins but also di-, tri-, and tetrasubstitued olefins.8 In
addition, the increased activity of these catalysts has
not resulted in the loss of functional group tolerance and
inertness toward air and moisture.
The recent results with acrylates and related systems
suggested that Ru electron-rich carbene complexes
derived from functionalized olefins such as enols,9
enamines,10 and vinyl sulfides9 were relatively unreac-
tive in metathetical [2 + 2] reactions with olefins.11,12
(6) (a) Nguyen, S. T.; Grubbs, R. H.; Ziller, J . W. J . Am. Chem. Soc.
1993, 115, 9858-9859. (b) Grubbs, R. H.; Miller, S. J .; Fu, G. C. Acc.
Chem. Res. 1995, 28, 446-452. (c) O’Leary, D. J .; Blackwell, H. E.;
Washenfelder, R. A.; Grubbs, R. H. Tetrahedron Lett. 1998, 39, 7427-
7430. (d) O’Leary, D. J .; Blackwell, H. E.; Washenfelder, R. A.; Miura,
K.; Grubbs, R. H. Tetrahedron Lett. 1999, 40, 1091-1094.
(7) (a) Weskamp, T.; Schattenmann, W. C.; Spiegler, M.; Herrmann,
W. A. Angew. Chem., Int. Ed. 1998, 37, 2490-2492. (b) Weskamp, T.;
Kohl, F. J .; Hieringer, W.; Gleich, D.; Herrmann, W. A. Angew. Chem.,
Int. Ed. 1999, 38, 2416-2419. (c) Huang, J .; Stevens, E. D.; Nolan, S.
P.; Petersen, J . L. J . Am. Chem. Soc. 1999, 121, 2674-2678. (d) Scholl,
M.; Deng, S.; Lee, C. W.; Grubbs, R. H. Org. Lett. 1999, 1, 953-956.
(8) (a) Ackermann, L.; Fu¨rstner, A.; Weskamp, T.; Kohl, F. J .;
Herrmann, W. A. Tetrahedron Lett. 1999, 40, 4787-4790. (b) Chat-
terjee, A. K.; Grubbs, R. H. Org. Lett. 1999, 1, 1751-1753. (c)
Chatterjee, A. K.; Morgan, J . P.; Scholl, M.; Grubbs, R. H. J . Am. Chem.
Soc. 2000, 122, 3783-3784. (d) Lee, C. W.; Grubbs, R. H. Org. Lett.
2000, 2, 2145-2147. (e) Fu¨rstner, A.; Thiel, O. R.; Ackerman, L.;
Schanz, H.-J .; Nolan, S. P. J . Org. Chem. 2000, 65, 2204-2207. (f)
Briot, A.; Bujard, M.; Gouverneur, V.; Nolan, S. P.; Mioskowski, C.
Org. Lett. 2000, 2, 1517-1519. (g) Choi, T.-L.; Chatterjee, A. K.;
Grubbs, R. H. Angew. Chem., Int. Ed. 2001, 40, 1277-1279.
(9) Fischer, P. In The Chemistry of Ethers, Crown Ethers, Hydroxyl
Groups and Their Sulpur Analogues; Patai, S., Ed.; Wiley: Chichester,
U.K., 1980; Vol. 1, pp 761-820 and references therein.
Resu lts a n d Discu ssion
Syn th esis a n d Ch a r a cter iza tion of Bis(p h os-
p h in e) Ru Electr on -Rich Ca r ben e Com p lexes. The
reaction between various vinyl ethers and (PCy3)2Cl2-
(13) Wu, Z.; Nguyen, S. T.; Grubbs, R. H.; Ziller, J . W. J . Am. Chem.
Soc. 1995, 117, 5503-5511.
(14) (a) Maynard, H. D.; Grubbs, R. H. Macromolecules 1999, 32,
6917-6924. (b) Weck, M.; Mohr, B.; Maughon, B. R.; Grubbs, R. H.
Macromolecules 1997, 30, 6430-6437. (c) In addition, there has been
one report that involves the use of a derviatized vinyl ether as a means
to add an end cap to a metathesis polymer; see: Gordon, E. J .;
Gestwicki, J . E.; Strong, L. E.; Kiessling, L. L. Chem. Biol. 2000, 7,
9-16.
(15) (a) Katayama, H.; Urushima, H.; Ozawa, F. Chem. Lett. 1999,
269-370. (b) Katayama, H.; Urushima, H.; Ozawa, F. J . Organomet.
Chem. 2000, 606, 16-25. (c) Katayama, H.; Urushima, H.; Nishioka,
T.; Wada, C.; Nagao, M.; Ozawa, F. Angew. Chem., Int. Ed. 2000, 39,
4513-4515. (d) van der Schaaf, P. A.; Kolly, R.; Kirner, H.-J .; Rime,
F.; Mu¨hlebach, A.; Hafner, A. J . Organomet. Chem. 2000, 606, 65-
74.
(16) (a) Coalter, J . N., III; Spivak, G. J .; Ge´rard, H.; Clot, E.;
Davidson, E. R.; Eisenstein, O.; Caulton, K. G. J . Am. Chem. Soc. 1998,
120, 9388-9389. (b) Huang, D.; Bollinger, J . C.; Streib, W. E.; Folting,
K.; Young, V., J r.; Eisenstein, O.; Caulton, K. G. Organometallics 2000,
19, 2281-2290.
(10) (a) Hickmott, P. W. Tetrahedron 1982, 38, 1975-2050. (b) The
Chemistry of Enamines; Rappoport, Z., Ed.; Wiley: Chichester, U.K.,
1994; Vols. 1 and 2.
(11) Coalter, J . N.; Caulton, K. G. New J . Chem. 2001, 25, 679-
684.
(12) For some early-transition-metal Fischer-type carbenes that
undergo metathesis, see: (a) Katz, T. J .; Acton, N. Tetrahedron Lett.
1976, 47, 4251-4254. (b) Katz, T. J .; Lee, S. J .; Shippey, M. A. J . Mol.
Catal. 1980, 8, 219-226.

Electron-Rich Carbene Complexes
Organometallics, Vol. 21, No. 11, 2002 2155
Ta ble 1. Selected 1H, 31P , a n d 13C NMR Da ta a
entry
complex
1H NMR RudC(H)
31P NMR
13C NMR RudC
1
2b
3
4
5
(PCy3)2Cl2RudC(H)Ph (1a )2b
(PCy3)2Cl2RudC(H)Et (1d )2b
(PCy3)2Cl2RudC(H)OEt (5)
20.02
19.12b
14.49
17.67
17.79
17.59
16.64b
19.91
13.81
17.07
16.94
16.12b
19.16
13.63
36.6
36.4b
37.4
32.9
33.3
41.3
38.5b
34.9
35.0
27.8
36.9
34.4b
31.4
32.6
294.72
322.59b
276.86
281.60
280.44
227.99
c
295.26
277.50
281.24
230.02
246.79b
294.24
276.75
(PCy3)2Cl2RudC(H)SEt (6)
(PCy3)2Cl2RudC(H)SPh (7)
6
(PCy3)2Cl2RudC(H)NR (8)d
7
(PCy3)2Cl2RudC(H)NR (9)e
8b
9
(IMes)(PCy3)Cl2RudC(H)Ph (2a )7a
(IMes)(PCy3)Cl2RudC(H)OEt (11)
(IMes)(PCy3)Cl2RudC(H)SEt (12)
(IMes)(PCy3)Cl2RudC(H)NR (13)d
(IMes)(PCy3)Cl2RudC(H)NR (14)e
(H2IMes)(PCy3)Cl2RudC(H)Ph (3a )7b
(H2IMes)(PCy3)Cl2RudC(H)OEt (15)
10
11
12b
13
14
a
b
d
Unless otherwise noted, CD2Cl2 was used as solvent. Solvent C6D6. c Complex was only slightly soluble in C6D6. NR ) carbazole.
e NR ) pyrrolidinone.
RudC(H)Ph (1a ) has been previously shown to afford
complexes with the structure (PCy3)2Cl2RudC(H)OR.15
The reaction between 1a and 10 equiv of ethyl vinyl
ether was monitored in benzene-d6 using a combination
of 1H and 31P NMR spectroscopy. The reaction was
found to be extremely rapid (kobsd ≈ 102 min-1) and
quantitatively afforded (PCy3)2Cl2RudC(H)OEt (5).3a In
addition, no methylidene was observed, which suggested
that the reaction was regiospecific. Similar results were
obtained when other Ru alkylidenes such as (PCy3)2-
Cl2RudC(H)C(H)C(Me)2 (1b) were employed as the
starting material and in other solvents including CD2-
Cl2 and THF-d8. In addition, the reaction appeared
general; other functionalized olefins H2CdC(H)ER (e.g.,
ER ) N(carbazole), N(pyrrolidinone), SEt) gave similar
results. In general, dichloromethane solutions (0.1 M)
of 1a ,b were treated with excess H2CdC(H)ER (ER )
OEt, N(pyrrolidinone), N(carbazole), SEt, SPh), which
produced red to purple powders after removal of solvent
and residual H2CdC(H)ER (eq 1). Recrystallization by
that their solution structures were similar to Ru alky-
lidenes. (As discussed below, the structural similarities
were later confirmed using X-ray crystallography).
Relative to their alkylidene analogues, the respective
1H resonances ([Ru]dC(H)ER) of complexes 5-9 were
strongly shifted upfield (14.5-18 ppm) and appeared to
be inversely proportional to the electronegativity of the
R-heteroatom on the carbene moiety (Table 1). An
additional signal (doublet, J ) 4.0 Hz) was observed in
the 1H NMR spectrum of complex 9, which was the
result of chelation of the carbonyl group (16; vide infra).
Similarly, 13C NMR spectroscopy indicated that the
chemical shifts for the carbene carbons ([Ru]dC(H)R)
(228-282 ppm) were also upfield relative to those of
typical Ru alkylidenes (1a , 294.72 ppm; 1d , 322.59
ppm), although no direct correlation with electronega-
tivity was evident (Table 1). The 31P NMR resonances
of complexes 5-9 were found to be singlets (i.e., no
effective 1H-31P or 31P-31P coupling was observed),
which suggested that the phosphines were disposed in
a trans geometry perpendicular to the carbene ligands.
Relative to Ru alkylidenes 1a (36.6 ppm) and 1d (36.4
ppm), downfield 31P NMR signals were observed for
complexes 5 (E ) O), 8, and 9 (E ) N), whereas upfield
signals were observed for complexes 6 and 7 (E ) S).
Although solution-state NMR characteristics of com-
plexes 5-9 provided some insight as to how the carbene
moiety affects complex geometry and electronics, atten-
tion was shifted toward examining their respective solid-
state structures. In general, crystals suitable for X-ray
analysis were obtained by slowly diffusing pentane into
a saturated solution of complexes 5, 8, and 9 in toluene
at -30 °C. Notably, two slightly different geometries
for complex 5 exist in the unit cell, which differ by only
in a slight twist in the ethyl group. While the high
solubility of complex 6 ([Ru]dC(H)SEt) thwarted efforts
at inducing crystallization, cooling saturated toluene
solutions of complex 7 ([Ru]dC(H)SPh) afforded maroon
crystals that were suitable for X-ray analysis. Data
collection parameters are given in Table 2, and repre-
sentative bond lengths and angles are given in Table 3.
Further details are provided in the Experimental Sec-
tion and Supporting Information. The X-ray crystal
structures of complexes 5 and 7-9 (Figures 3-6) were
similar to those of the parent alkylidene complexes
(PCy3)2Cl2RudC(H)R (1).2a,17 The phosphines were found
to be mutually orientated in a trans disposition perpen-
slow diffusion of pentane into saturated toluene solu-
tions at -30 °C afforded pure (PCy3)2Cl2RudC(H)ER
(5-9) in 66-87% isolated yields.
Ruthenium alkylidenes (PCy3)2Cl2RudC(H)R display
1
characteristic chemical shifts in their H, 13C, and 31P
NMR spectra that provide valuble information for
elucidating solution-state geometries of the complexes.2a
When the phosphines are bulky (e.g., PCy3), effectively
no coupling is observed between the two phosphine
ligands (31P-31P) or between the R-proton on the alky-
lidene moiety and the phosphines (31P-1H). These
observations indicate that the phosphine ligands are
orientated trans to each other and that the alkylidene
moiety bisects the P-Ru-P plane.2a Relevant chemical
shifts in the 1H, 13C, and 31P NMR spectra for complexes
5-9 are shown in Table 1 and qualitatively suggested

2156 Organometallics, Vol. 21, No. 11, 2002
Ta ble 2. Cr ysta llogr a p h ic Da ta for Com p lexes 5, 7, 8, a n d 9
Louie and Grubbs
5
7
8
9
formula
fw
cryst syst
space group
a (Å)
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
C
39H72Cl2RuOP2
C43H72Cl2RuSP2
855.03
triclinic
P1h
9.8211(5)
13.6315(7)
18.7911(1)
83.441(1)
78.732(1)
78.190(1)
2407.7(2)
2
C49H75Cl2RuNP2
912.06
triclinic
P1h
12.6111(1)
14.3083(1)
17.0253(2)
83.518(1)
74.720(1)
77.799(1)
2891.2(4)
2
C41H73Cl2RuNOP2
829.96
nonoclinic
P21/n
9.4246(8)
13.6142(1)
37.570(3)
90
92.123(2)
90
4817.2(7)
4
790.92
nonoclinic
P21/c
10.576(2)
36.738(7)
23.418(4)
90
97.887(4)
90
9013(3)
8
Z
radiation (KR, Å)
0.710 73
98(2)
1.301
0.57
3776
0.710 73
98(2)
1.306
0.58
1008
0.710 73
98(2)
1.048
0.45
968
0.710 73
98(2)
1.306
0.54
2020
T (K)
Dcalcd (mg m-3
)
µcalcd (mm-1
F000
)
R1
0.053
0. 048
0. 064
0. 058
wR2
GOF
0. 082
1.13
0. 089
1.93
0. 232
1.03
0. 089
1.12
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles (d eg) for (P Cy3)2Cl2Ru dC(H)ER Com p lexes
(1d ,2b 5, 7, 8, a n d 9)
1d 2b
5
7
8
9
ER
C6H4-p-Cl
OEt
Bond Distances (Å)
1.812(5)
2.3683(13)
2.3904(13)
2.3886(12)
2.3749(12)
1.275(5)
SPh
N(carb)
N(pyr)
Ru-C(1)
Ru-P(1)
Ru-P(2)
Ru-Cl(1)
Ru-Cl(2)
C(1)-E
1.8393(3)
2.397(1)
2.435(1)
2.401(1)
2.395(1)
1.829(3)
1.863(6)
2.3994(1)
2.4082(1)
2.3742(1)
2.4088(1)
1.366(7)
1.828(4)
2.4041(9)
2.4167(9)
2.3952(7)
2.3968(8)
2.3979(12)
2.4036(12)
2.4041(10)
2.3881(10)
1.365(5)
Bond Angles (deg)
C(1)-Ru-Cl(1)
C(1)-Ru-Cl(2)
C(1)-Ru-P(1)
C(1)-Ru-P(2)
Cl(1)-Ru-Cl(2)
P(1)-Ru-P(2)
Cl(1)-Ru-P(1)
Cl(1)-Ru-P(2)
Cl(2)-Ru-P(1)
Cl(2)-Ru-P(2)
103.7(1)
88.7(1)
101.2(1)
97.5(1)
167.6(1)
161.1(1)
90.8(1)
87.2(1)
86.5(1)
91.5(1)
97.33(16)
89.17(16)
98.07(14)
97.26(14)
173.50(4)
164.67(4)
91.66(5)
88.16(4)
87.58(4)
90.87(4)
92.56(9)
94.61(9)
98.43(9)
95.95(9)
172.81(3)
165.34(3)
87.55(3)
88.96(3)
91.87(3)
89.83(3)
112.95(2)
85.09(2)
99.32(2)
96.04(2)
161.94(6)
164.28(5)
90.05(5)
87.06(5)
87.55(5)
90.43(5)
102.70(13)
89.46(13)
99.17(13)
96.47(13)
167.80(4)
164.27(4)
89.98(4)
88.53(4)
87.77(4)
90.39(4)
F igu r e 4. Molecular structure of (PCy3)2Cl2RudC(H)SPh
(7).
parent alkylidene complex (PCy3)2Cl2RudC(H)CH2R.
Slightly wider Cl-Ru-Cl angles (e6°) and P-Ru-P
angles (e4°) were also observed, which are believed to
stem from alleviation of the increased steric congestion
around the Ru center. Finally, it is important to note
F igu r e 3. Molecular structure of (PCy3)2Cl2RudC(H)OEt
(5).
dicular to the carbene moiety, as expected from NMR
analyses. The average Ru-P, Ru-Cl, and RudC bond
distances of complexes 5 and 7-9 were slightly shorter
(e0.04 Å, e0.02 Å, and e0.03 Å, respectively) than their
(17) (a) Bielawski, C. W.; Louie, J .; Grubbs, R. H. J . Am. Chem. Soc.
2000, 122, 12872-12873. (b) Bielawski, C. W.; Louie, J .; Grubbs, R.
H. Manuscript in preparation.

Electron-Rich Carbene Complexes
Organometallics, Vol. 21, No. 11, 2002 2157
Ta ble 4. Ha lf-Lives for th e Decom p osition of
Com p lexes 5-9
entry
complex
τ1/2
3 h
1
2
3
4
5
6
(PCy3)2Cl2RudC(H)OEt (5)
(PCy3)2Cl2RudC(H)SEt (6)
(PCy3)2Cl2RudC(H)SPh (7)
(PCy3)2Cl2RudC(H)Ph (1a )
(PCy3)2Cl2RudC(H)N(carb) (8)
(PCy3)2Cl2RudC(H)N(pyr) (9)
1 day
3 days
8 daysa
9 days
20 days
a
Data from ref 18.
Ta ble 5. Cr ysta llogr a p h ic Da ta for
(P Cy3)2ClRu (H)(CO) (10)
formula
fw
C37H67ClRuOP2
726.37
cryst syst
space group
a (Å)
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
triclinic
P212121
9.8521(12)
10.2242(12)
10.8316(13)
114.072(2)
108.518(2)
91.270(2)
929.98(19)
1
F igu r e 5. Molecular structure of (PCy3)2Cl2RudC(H)N-
(carbazole) (8).
Z
radiation (KR, Å)
0.710 73
98(2)
1.297
0.61
388
T (K)
Dcalcd (mg m-3
)
µcalcd (mm-1
F000
)
R1
0.026
wR2
0.058
GOF
1.90
solutions of (PCy3)2Cl2RudC(H)OEt (5) resulted in a
distinctive color change from red to bright yellow (eq
2). This was concurrent with the disappearance of the
F igu r e 6. Molecular structure of (PCy3)2Cl2RudC(H)N-
(pyrrolidinone) (9).
carbene resonance (singlet at 14.5 ppm) concomitant
with the appearance of a hydride (triplet at -22 ppm)
that the Ru-C-H plane remained perpendicular to the
P-Ru-C-P plane in complex 9 and the carbonyl oxygen
was not twisted, as might be expected from its solution
behavior (vide infra).
1
resonance in the H NMR spectrum. In addition, a new
signal at 47.1 ppm (singlet) in the 31P NMR spectrum
grew steadily as the signal at 35.6 ppm (resonance of
(PCy3)2Cl2RudC(H)OEt) was attenuated. Thus, the
thermal decomposition process appeared to proceed with
clean conversion to a single product. Analysis of the
product using infrared spectroscopy revealed strong
bands at 1906 and 1444 cm-1, which are characteristic
of Ru-H and Ru-CO complexes, respectively.19 The
decomposition product was isolated in 69% yield, and a
crystal suitable for X-ray analysis was grown by cooling
a saturated benzene solution of 10 from 60 °C to room
temperature over 6 h. Crystal and data collection
parameters are given in Table 5, and representative
bond lengths and angles are given in Table 6. Additional
details of the structure determination can be found in
the Experimental Section and Supporting Information.
Figure 7 shows an ORTEP diagram of (PCy3)2ClRu(CO)-
(H) (10), clearly indicating the loss of the carbene
functionality.20 This complex has been previously re-
Mea su r em en t of th e Th er m a l Sta bility of Ru
F isch er -Typ e Ca r ben e Com p lexes. Benzene-d6 solu-
tions (23 mM) of complexes 5-9 with 1,3,5-trimethoxy-
benzene (12 mM) as an internal standard were heated
1
to 55 °C and monitored by H and 31P NMR spectros-
copy.18 Decomposition rates were determined by mea-
suring the time required for half of the material to
decompose (τ1/2), and the results are summarized in
Table 4. Except for the oxygen-substituted complex 5
(vide infra), multiple decomposition pathways were
evident, as mixtures of products were observed. For
comparison, the τ1/2 value of complex 1a (under identical
conditions) has been included.18 A general trend in the
thermal stability of (PCy3)2Cl2RudC(H)ER complexes
followed the order E ) N > C > S > O. The high
stability of 9 may be a result of the chelation of the
amide carbonyl.
Isola tion of th e Th er m a l Decom p osition P r od -
u ct of (P Cy3)2Cl2Ru dC(H)OEt. Prolonged heating of
(19) Chatt, J .; Hayter, R. G. J . Chem. Soc. 1961, 2605-2611.
(20) This structure has recently been reported; see: Lee, H. M.;
Smith, D. C.; He, Z.; Stevens, E. D.; Yi, C. S.; Nolan, S. P. Organome-
tallics 2001, 20, 794-797.
(18) Ulman, M.; Grubbs, R. H. J . Org. Chem. 1999, 64, 7202-7207.

2158 Organometallics, Vol. 21, No. 11, 2002
Louie and Grubbs
Ta ble 6. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for (P Cy3)2ClRu (H)(CO) (10)
Bond Distances (Å)
Ru-P
Ru-Cl
Ru-C(1)
2.3798(4)
2.4022(18)
1.777(6)
Ru-H
C(1)-O
1.36(4)
1.162(6)
Bond Angles (deg)
P-Ru-P′
180.0
Cl-Ru-H
97.4(18)
82.6(18)
178.4(2)
82.9(18)
97.1(18)
179.1(9)
P-Ru-Cl
88.18(4)
91.82(4)
82.9(19)
97.1(19)
104.3(5)
104.3(5)
Cl′-Ru-H
Cl-Ru-C(1)
C(1)-Ru-H
C(1)′-Ru-H
O-C-Ru
P′-Ru-Cl
P-Ru-H
P′-Ru-H
P(1)-Ru-C(1)
P(2)-Ru-C(1)
F igu r e 8. Molecular structure of (IMes)(PCy3)Cl2Rud
C(H)OEt (11).
Ta ble 7. Cr ysta llogr a p h ic Da ta for
(IMes)(P Cy3)Cl2Ru dC(H)OCH2CH3 (11)
formula
fw
C42H63Cl2RuN2OP
814.93
cryst syst
space group
a (Å)
orthorhombic
P212121
12.1718(1)
17.7113(2)
21.483(2)
4631.4(9)
4
b (Å)
c (Å)
V (Å3)
Z
radiation (KR, Å)
0.710 73
98(2)
1.281
0.52
1888
T (K)
Dcalcd (mg m-3
)
µcalcd (mm-1
F000
)
R1
0.035
wR2
0.047
GOF
1.05
F igu r e 7. Molecular structure of (PCy3)2ClRu(H)(CO) (10).
field shifts of the [Ru]dC(H)ER complexes in relevant
1H (∼0.6 ppm) and 31P (2-5 ppm) NMR spectra (Table
1). Minimal changes were observed in the 13C NMR
spectra (0-2 ppm). Analogous shifts were observed in
Ru alkylidene complexes and were found to reflect the
increased electron-donating ability of the IMes ligand.22
Interestingly, the 1H NMR spectrum of complexes 13
and 14 at room temperature displayed six distinct
methyl groups and four arene protons, in contrast to
the case for other Ru Fischer-type carbene complexes,
which display four methyl groups and two arene pro-
tons. The increased number of observed resonances may
be related to slow rotation about the IMes-Ru bond or
the [Ru]dC bond.23
ported by Yi and co-workers and can be prepared using
other synthetic routes.21 Possible mechanistic pathways
of decomposition that lead to 10 have also been previ-
ously reported.13
Syn th esis a n d Ch a r a cter iza tion of Ru Com -
p lexes P ossessin g a n Im id a zolylid en e Liga n d a n d
a P h osp h in e Liga n d . Treatment of the bis(phosphine)
complexes 5, 6, 8, and 9 with 2 equiv of the free carbene
IMes in benzene afforded (IMes)(PCy3)Cl2RudC(H)ER
(11-14) in 48-89% yield (eq 3). Alternatively, substitu-
To determine whether the IMes ligand induced struc-
tural changes, the X-ray structure of complex 11 was
determined. A single crystal suitable for X-ray analysis
was obtained by slow diffusion of methanol into a
saturated solution of 11 in benzene at -30 °C, and an
ORTEP diagram is shown in Figure 8. Crystal and data
collection parameters are given in Table 7, and repre-
sentative bond lengths and angles are given in Table 8.
Details of the structure determination are provided in
the Experimental Section and as Supporting Informa-
tion. The RudC bond in (IMes)(PCy3)Cl2RudC(H)OEt
tion of one phosphine could be achieved by treatment
with 1.2 equiv of IMes+Cl- and KO-t-Bu in benzene to
generate the free imidazolylidene carbene in situ,
although with lower isolated yields (30-50%). In gen-
eral, substitution of a phosphine ligand with an imida-
zolylidene ligand resulted in approximately equal up-
(22) (a) Huang, J .; Schanz, H.-J .; Stevens, E. D.; Nolan, S. P.
Organometallics 1999, 18, 2370-2375. (b) Huang, J .; Schanz, H.-J .;
Stevens, E. D.; Nolan, S. P. Organometallics 1999, 18, 5375-5380.
(23) Sanford, M. S.; Grubbs, R. H. Unpublished results.
(21) Yi, C. S.; Lee, D. W.; Chen, Y. Organometallics 1999, 18, 2043-
2045.

Electron-Rich Carbene Complexes
Organometallics, Vol. 21, No. 11, 2002 2159
Ta ble 8. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for (TF A)2(P P h 3)2Ru dC(H)SP h (4a ) a n d
(IMes)(P Cy3)Cl2Ru dC(H)OEt (11)
effects are observed in Ru alkylidene complexes (e.g.,
compare 2a to 3a ).7
Syn t h esis a n d Ch a r a ct er iza t ion of Ch ela t ed
Ru th en iu m Ca r ben e Com p lexes. The behavior of 9
in solution is particularly interesting, as another car-
bene resonance was observed as a doublet at 13.99 ppm
(J ) 4.0 Hz) in the 1H NMR spectrum. This doublet
corresponded to the chelate complex 16 formed from
dissociation of one PCy3 ligand and intramolecular
coordination of the amide carbonyl group (to the open
coordination site trans to the ligated PCy3 ligand).25 In
solution, complex 9 existed in a temperature-dependent
equilibrium with the chelate complex 16 and free PCy3
(eq 5).26 The ∆H°, ∆S°, and ∆G° values (298 K) for the
4a 7c
11
Bond Distances (Å)
1.841(11)
Ru-C(22)
Ru-C(1)
Ru-P
Ru-Cl(1)
Ru-Cl(2)
1.790(3)
2.080(2)
2.4166(7)
2.4071(7)
2.3910(8)
2.069(11)
2.419(3)
2.393(3)
2.383(3)
Bond Angles (deg)
99.2(5)
C(22)-Ru-C(1)
C(22)-Ru-Cl(1)
C(22)-Ru-Cl(2)
C(22)-Ru-P
C(1)-Ru-Cl(1)
C(1)-Ru-Cl(2)
C(1)-Ru-P
Cl(1)-Ru-Cl(2)
Cl(1)-Ru-P
Cl(2)-Ru-P
96.26(1)
90.05(1)
96.98(1)
95.92(9)
89.81(7)
89.91(7)
167.79(7)
172.95(3)
89.30(3)
89.49(3)
104.3(5)
87.1(5)
97.1(4)
86.9(3)
163.2(3)
168.62(12)
89.86(9)
(11) (1.79 Å) was shorter than the Ru-C bond of (IMes)-
(PCy3)Cl2RudC(H)Ph (2a ) (1.84 Å),7c as observed in the
respective bis(phosphine) complexes (compare 1d at 1.84
Å vs 5 at 1.81 Å; see above). Interestingly, the RudC
bond was also shorter than in its bis(phosphine) ana-
logue (PCy3)2Cl2RudC(H)OEt (5) (1.81 Å). While all
other lengths (Ru-Cl, Ru-P, Ru-C(1)IMes) were similar
to those of the analagous Ru alkylidene 2a , the Cl-Ru-
Cl and P-Ru-C(1)IMes angles were slightly wider (4 and
5°, respectively), as observed in the bis(phosphine)
complexes. Nevertheless, the effects of the IMes ligand
were minimal and apparently did not exert a significant
structural influence on the structure of the complexes.
Syn th esis a n d Ch a r a cter iza tion of a Ru Com -
p lex P ossessin g a Sa t u r a t ed Im id a zolylid en e
Liga n d a n d a P h osp h in e Liga n d , (H2IMes)(P Cy3)-
Cl2Ru dC(H)OEt (15). The synthetic method used to
prepare complex 11 was unsuccessful for the prepara-
tion of (H2IMes)(PCy3)Cl2RudC(H)OEt (15), and only
decomposition of 5 was observed. However, as shown
in eq 4, 15 could be prepared in 93% yield by adding
equilibrium in benzene-d6 were determined to be 7.6
kcal/mol, 22.5 cal/mol K, and 0.9 kcal/mol, respectively.
Complex 16 was isolated by the addition of 2 equiv of
CuCl to a CH2Cl2 solution of complex 9. After the
reaction mixture was stirred at room temperature for
2 h, precipitated solids (which presumably were PCy3-
CuCl complexes) were filtered away and the resulting
mother liquor was concentrated to afford a dark brown
solid. Unfortunately, efforts to prepare a crystal suitable
for X-ray analysis were thwarted, as 16 was extremely
unstable and rapidly decomposed in the solid state over
time. Nevertheless, NMR analysis demonstrated that
only complex 16 was successfully isolated, as a singlet
1
at 13.99 ppm was observed in the H NMR spectrum
and only a singlet at 57 ppm was observed in the 31P
NMR spectrum.
Similarly complex 14 (doublet at 12.39 ppm) is in
equilibrium with the chelate complex 17 (eq 5). The
∆H°, ∆S°, and ∆G° values (298 K) for this equilibrium
in toluene-d8 were measured to be 14.5 kcal/mol, 35.4
cal/mol K, and 4.0 kcal/mol, respectively. Formation of
the chelated complex 17 from 14 is about 3 kcal/mol
more favored than for formation of complex 16 from 9,
resulting from more favored enthalpic (6.9 kcal/mol) and
entropic (12.9 cal/mol K) contributions. The enhanced
enthalpic contribution was somewhat surprising, con-
sidering the IMes ligand places more electron density
at the Ru center, as supported by NMR and crystal
structure data. Regardless, the result was in agreement
with recent mechanistic analyses, which suggested that
the enhanced activity of second-generation Ru catalysts
(24) (a) Herrmann, W. A.; Ko¨cher, C. Angew. Chem., Int. Ed. Engl.
1997, 36, 2163-2187. (b) Arduengo, A. J ., III Acc. Chem. Res. 1999,
32, 913-921.
(25) (a) Fu¨rstner, A.; Thiel, O. R.; Lehmann, C. W. Organometallics
2002, 21, 331-335. (b) Kingsbury, J . S.; Harrity, J . P. A.; Bonitatebus,
P. J ., J r.; Hoveyda, A. H. J . Am. Chem. Soc. 1999, 121, 791-799. (c)
Garber, S. B.; Kingsbury, J . S.; Gray, B. L.; Hoveyda, A. H. J . Am.
Chem. Soc. 2000, 122, 8168-8179. (d) Coalter, J . N., III; Streib, W.
E.; Caulton, K. G. Inorg. Chem. 2000, 39, 3749-3756.
(26) The equilibrium exhibits an interesting thermochromic behavior
which can be qualitatively assessed by visual inspection. Benzene
solutions of 9 were purple at room temperature and gradually turned
brown upon heating. Cooling the solutions back to room temperature
returned the solution to a purple color, as expected.
excess ethyl vinyl ether to a dichloromethane solution
(0.1 M) of (H2IMes)(PCy3)Cl2RudC(H)Ph (3a ). Monitor-
ing the reaction by 1H NMR revealed that addition was
regiospecific and no methylidene (3c) was observed over
the course of the reaction. In comparison to (IMes)-
(PCy3)Cl2RudC(H)OEt (11), slight upfield shifts were
observed in the 1H, 13C, and 31P NMR spectra. The shifts
stem from the increased electron-donating ability of the
saturated H2IMes ligand as compared to IMes.24 Similar

2160 Organometallics, Vol. 21, No. 11, 2002
Louie and Grubbs
F igu r e 9. ROMP of COD (150 mM) at 60 °C using Ru
Fischer-type carbenes (3 mM).
F igu r e 10. RCM of diethyl diallylmalonate (100 mM) at
60 °C using Ru Fischer-type carbenes 5-9 (3 mM).
such as (IMes)(PCy3)Cl2RudC(H)Ph (2a ) or its satu-
rated imidazolidene analogue (H2IMes)(PCy3)Cl2Rud
C(H)Ph (3a ) may be related to the catalyst’s preference
to bind olefins over phosphines.3a After the isolation and
characterization of Fischer-type complexes (L)(PCy3)Cl2-
RudC(H)ER (L ) PCy3, 5-9; L ) IMes, 11-14; L )
H2IMes, 15), efforts were shifted toward examining their
activities in a variety of olefin metathesis reactions.
Mea su r em en t of th e Activity of Ru F isch er -Typ e
Ca r ben e Com p lexes in Rin g-Op en in g Meta th esis
P olym er iza tion (ROMP ). All Ru Fischer-type carbene
complexes initiated the ROMP of norbornene and nor-
bornene derivatives at room temperature and afforded
quantitative yields of polymer. Although the polymer-
izations were rapid (τ1/2 ≈ minutes), they were signifi-
cantly slower than those initiated with alkylidenes 1-3
(τ1/2 ≈ seconds).2a,5,27 To better define the relative
activities, the polymerizations of monomers with less
ring strain were studied.
A 150 mM benzene solution of 1,5-cyclooctadiene
(COD) was added to 3 mM solutions of Ru Fischer-type
complexes L(PCy3)Cl2RudC(H)ER (5-9, 11-15) with
50 mM 1,3,5-trimethoxybenzene (internal standard),
and the reaction mixtures were heated to 65 °C. The
reactions were monitored by 1H NMR spectroscopy, and
the results are summarized in Figure 9. In contrast to
the polymerization of highly strained cyclic olefins (see
above), a range of reactivity was observed that depended
on the carbene substituent (ER). Complexes 5 (ER )
OEt), 6 (ER ) SEt), and 9 (ER ) pyrrolidinone) were
ineffective for initiating ROMP, even after prolonged
periods at elevated temperature (60 °C, 11 h). However,
minor perturbations of the ER group had a pronounced
influence on activity: complexes 7 (ER ) SPh) and 8
(ER ) carbazole) gave moderate conversions of COD
(26%, 5 h, 60 °C).28 Unfortunately, this range of activi-
ties could not be correlated to NMR or crystal structure
data and thus suggested that there was a complex
relationship between catalyst electronic structure, cata-
lyst activity, and complex stability. As expected from
earlier work, all complexes containing an imida-
zolylidene ligand (11-15) were much more active and
they all effectively initiated the ROMP of COD at 60
°C and afforded high yields of polymer. Complex 13
appeared to have the highest activity, as a quantitative
F igu r e 11. RCM of diethyl diallylmalonate (100 mM) at
60 °C using Ru Fischer-type carbenes 11-15 (3 mM).
yield of PBD was obtained in less than 4 h at room
temperature.29
Mea su r em en t of th e Activity of Ru Electr on
Rich Ca r ben e Com p lexes in Rin g-Closin g Meta th -
esis (RCM). A 100 mM solution of diethyl diallylma-
lonate was added to 3 mM solutions of Ru complexes
5-9 and 11-15 and 50 mM 1,3,5-trimethoxybenzene
(internal standard), and then these mixtures were
heated to 60 °C. Reaction progress was monitored by
1H NMR spectroscopy and summarized in Figure 10
(complexes 5-9) and Figure 11 (complexes 11-15).
Interestingly, all Ru Fischer-type complexes afforded
the ring-closed product. However, the rates of the
reaction were highly dependent on the R-heteroatom.
Collectively, the rates of ROMP and RCM suggest that
relative activities of L(PCy3)Cl2RudC(H)ER complexes
follow the general trend E ) C > N > S > O. As
expected, complexes ligated with IMes or H2IMes dis-
play higher activities than their bis(phosphine) ana-
logues.
Rea ction of Ru -F u n ction a lized Ca r ben e Com -
p lexes w it h F u n ct ion a lized Olefin s. As discussed
above, the activity of Ru Fischer-type carbene complexes
appeared to heavily depend on the R-heteroatom of the
carbene moiety. To help elucidate the source of the
activity difference and possibly establish relative sta-
bilities of the various complexes, the reactivities of the
Ru carbenes described above with various functionalized
olefins (Scheme 1) was examined.
(27) Bielawski, C. W.; Grubbs, R. H. Angew. Chem., Int. Ed. 2000,
39, 2903-2906.
(28) More concentrated conditions, addition of 0.01 M complex 8 to
0.22 M COD, led to 80% conversion at 65 °C in 10 h.
(29) Furthermore, More concentrated conditions, addition of 0.01
M complex 13 to 0.22 M COD, also led to complete conversion at room
temperature in less than 1 h.

Electron-Rich Carbene Complexes
Organometallics, Vol. 21, No. 11, 2002 2161
Sch em e 1
Sch em e 2
Complex 5 ([Ru]dC(H)OEt) reacted with a stoichio-
metric amount of ethyl vinyl sulfide. After 6 h at 60 °C,
a 1:1.2 mixture of 5 and 6 ([Ru]dC(H)SEt) was observed.
Similarly, the addition of an equivalent amount of ethyl
vinyl ether to 6 afforded the identical 1:1.2 mixture of
5 and 6. While no reaction was observed between
complexes 5 and 6 and vinylcarbazole, the addition of a
stoichiometric amount of ethyl vinyl ether to complex 8
([Ru]dC(H)carbazole) quantitatively afforded complex
5 (and vinylcarbazole) after 6 h at 60 °C. A similar
experiment with ethyl vinyl sulfide afforded 6 and vinyl
carbazole over the same time period and temperature.
Finally, complex 5 ([Ru]dC(H)OEt) was allowed to
reacted with a stoichiometric amount of propyl vinyl
ether (eq 6). In this reaction, the resulting metallocy-
of styrene (stoichiometric or excess amounts) to 5 or 6
did not afford any Ru alkylidene species ([Ru]dCH2 and
[Ru]dC(H)Ph). However, the addition of styrene to
complex 8 led to a 16:1 mixture of 8 and 1a after 6 h at
60 °C and the same ratio was observed from the addition
of vinylcarbazole to [Ru]dC(H)Ph (1a ). In addition, the
reactions appeared to be regiospecific, since formation
of methylidene ([Ru]dCH2) was not observed.
Con clu sion s
Ruthenium carbene complexes of the general struc-
ture (PCy3)2Cl2RudC(H)ER were conveniently prepared
in good yields by the addition of excess functionalized
olefin H2CdC(H)ER (ER ) OEt, SEt, SPh, N(carbazole),
N(pyrrolidinone)) to (PCy3)2Cl2RudC(H)R. No meth-
ylidene byproducts ([Ru]dCH2) were observed in any
of these reactions. The respective mixed-ligand com-
plexes (IMes)(PCy3)Cl2RudC(H)ER were also prepared,
either through phosphine replacement with 1,3-dimesi-
tylimidazolylidene (IMes) or 1,3-dimesityl-4,5-dihy-
droimidazolylidene (H2IMes) or by the addition of a
functionalized olefin to (L)(PCy3)Cl2RudC(H)R (L )
IMes, H2IMes). Although X-ray structure analyses sug-
gested that Ru Fischer-type carbene complexes are
structurally similar to typical Ru alkylidenes, the het-
eroatomic carbene moiety (ER) has strong effects on the
chemical shifts of relevant NMR resonances. However,
the effects of the moiety varied among all the complexes,
and the only trend observed was an inverse relationship
between the chemical shift of the R-1H [Ru]dC(H)ER
and the electronegativity of the heteroatom on the
carbene moiety [Ru]dC(H)ER.
At equilibrium, all the Fischer-type complexes were
inherently more stable than the alkylidene analogues.
However, the order of thermal stability of complexes
with the structure (PCy3)2Cl2RudC(H)ER followed the
general trend ER ) NR > CR > SR > OR. In addition,
complexes coordinated with an N-heterocyclic carbene
ligand (e.g., (IMes)(PCy3)Cl2RudC(H)ER) were ther-
mally more robust than their bis(phosphine) analogues.
Although (PCy3)2Cl2RudC(H)OEt was found to cleanly
decompose to (PCy3)2ClRu(H)CO, multiple decomposi-
tion products (and thus pathways) were observed for the
S- and N-substituted complexes.
clobutane intermediate would possess no (significant)
electronic preference to revert to either complex 5 (ER
) OEt) or 5′ (ER ) OPr). Between 20 and 50 °C, complex
5′ was undetectable by 1H NMR spectroscopy. However,
∼10% was generated when the reaction mixture was
warmed to 60 °C. Heating the reaction mixture to 80
°C led to a 1:1 mixture of 5 and 5′, the expected ratio
for a thermoneutral reaction. Collectively, these results
demonstrate that the reaction of Ru-functionalized
carbene complexes with functionalized olefins was an
equilibrium-controlled process and that the oxygen- and
sulfur-substituted complexes 5 and 6 were favored
relative to the nitrogen-substituted complex 8. In ad-
dition, the reaction between electron-rich carbene com-
plexes and electron-rich olefins appeared to proceed with
high regiospecificity, as no Ru methylidene ([Ru]dCH2)
was observed over the course of any of the above
experiments. Likewise, the formation of difunctionalized
olefins (e.g., 1,2-diethoxyethene) was also not observed.
For comparison, stoichiometric amounts of function-
alized olefins were reacted with the Ru alkylidene
complex [Ru]dC(H)Ph (1a ). As shown in Scheme 2, the
reaction of ethyl vinyl ether and ethyl vinyl sulfide led
to complete conversion to complexes 5 and 6, respec-
tively, at room temperature. As expected, the addition

2162 Organometallics, Vol. 21, No. 11, 2002
Louie and Grubbs
Elmer Paragon 1000 FT-IR spectrometer. Elemental analyses
were determined by Midwest Microlab, Inc., Indianapolis, IN.
HR-MS analyses were conducted by the University of Cali-
forniasRiverside Mass-Spectroscopy Facility.
The functionalized Ru carbene complexes ([Ru]dC(H)-
ER) are active in a variety of olefin metathesis reactions,
although with significantly lower rates than the corre-
sponding carbon analogues. All the complexes initiated
the ring-opening metathesis polymerization (ROMP) of
strained cyclic olefins (e.g., norbornene) and the ring-
closing metathesis (RCM) of diethyl diallylmalonate. In
addition, (PCy3)2Cl2RudC(H)SPh and (PCy3)2Cl2Rud
C(H)NR type complexes initiated the ROMP of 1,5-
cyclooctadiene, a monomer with low ring strain. En-
hanced activities were observed when complexes coor-
dinated with an N-heterocyclic carbene ligand (e.g.,
(IMes)(PCy3)Cl2RudC(H)ER) were employed. We also
found that the carbene complexes were reactive toward
a variety of functionalized olefins CH2dC(H)ER and
regiospecifically (i.e., no [Ru]dCH2 is observed) inter-
convert the functionalized Ru carbene complexes. The
reaction appeared to be equilibrium-controlled, with the
relative stability of the various complexes [Ru]dC(H)-
ER being in the order ER ) OR > SR > NR > CR. The
lower reactivity of the Fischer carbene complexes may
be related to their greater ground-state stability, since
the order of metathesis activity (E ) C > N > S > O) is
the reverse of the equilibrium stabilities.
These results define the fundamental features that
must be considered in the metathesis of electron-rich
olefins. Traditionally, ROMP and other metathesis
reactions have been quenched through the addition of
functionalized olefins such as ethyl vinyl ether. As
demonstrated, the resulting complex, [Ru]dC(H)OEt, is
still metathesis active under some conditions. Low
temperatures, rapid workup, and an excess of the vinyl
ether minimizes the formation of byproducts. However,
more importantly, the addition of sulfur- or nitrogen-
functionalized olefins (CH2dC(H)SR and CH2dC(H)NR)
may not be effective quenching agents, as the resulting
Ru complexes exhibit considerable activity. Similarly,
Fischer-type carbene complexes with N-heterocyclic
carbenes require additional care, as they also displayed
relatively high activities.
(P Cy3)2Cl2Ru dC(H)OEt (5). Ethyl vinyl ether (5 mL, 50
mmol) was added to a methylene chloride (10 mL) solution of
Ru alkylidene 1b (1 g, 1.2 mmol). After the reaction mixture
was stirred at room temperature for 2 h, the solution turned
from purple to red. The solvent was evaporated in vacuo,
affording a red powder. Recrystallization by slowly diffusing
pentane into a saturated toluene solution at -30 °C afforded
(PCy3)2Cl2RudC(H)OEt (5) as bright red crystals in 66% yield
(626 mg). 1H NMR (CD2Cl2): δ 14.49 (s, 1H), 4.30 (dd, J 1
)
14.3 Hz, J 2 ) 6.9 Hz, 2H), 2.66-2.58 (m, 6H), 1.94-1.90 (m,
12H), 1.79-1.70 (m, 19H), 1.58-1.47 (m, 13H), 1.34 (t, J )
7.3 Hz, 3H), 1.28-1.23 (m, 16H). 13C NMR (CD2Cl2): δ 276.9,
77.6, 32.3, 30.1, 28.5, 27.2, 15.3. 31P NMR (CD2Cl2): δ 37.4
(s). IR (KBr, cm-1): 2933 (vs), 2847 (s), 1444 (s), 1391 (w), 1368
(w), 1306 (m), 1266 (w), 1194 (s), 1174 (m), 1128 (w), 1104 (m),
1013 (m), 916 (w), 889 (w), 853 (m), 816 (w), 732 (m), 518 (w),
488 (w). Anal. Calcd for C39H72Cl2RuOP2: C, 59.23; H, 9.18.
Found: C, 59.27; H, 9.32. HR-MS calcd: 790.3472; found:
[M+])790.3479.
(P Cy3)2Cl2Ru dC(H)SEt (6). Ethyl vinyl sulfide (5 mL, 49
mmol) was added to a methylene chloride (10 mL) solution of
Ru alkylidene 1b (1.3 g, 1.6 mmol). The reaction was stirred
at room temperature for 5 h during which the solution turned
from purple to red-violet. The solvent was evaportated under
dynamic vacuum and afforded a red-violet powder. Recrystal-
lization by slowly diffusing of pentane into a saturated toluene
solution at -30 °C afforded (PCy3)2Cl2RudC(H)SEt (6) as
1
bright red crystals in 71% yield (917 mg). H NMR (CD2Cl2):
δ 17.67 (s, 1H), 3.17 (dd, J 1 ) 15.0 Hz, J 2 ) 7.7 Hz, 2H), 2.65-
2.56 (m, 6H), 1.94-1.89 (m, 10H), 1.78-1.70 (m, 18H), 1.58-
1.46 (m, 12H), 1.34 (t, J ) 7.7 Hz, 3H), 1.31-1.25 (m, 20H).
13C NMR (CD2Cl2): δ 281.6, 37.5, 32.6 (psuedo t, J ) 8.3 Hz),
30.0, 28.15 (pseudo t, J ) 5.2 Hz), 26.9, 15.0. 31P NMR (CD2-
Cl2): δ 32.9 (s). IR (KBr, cm-1): 2925 (vs), 2848 (s), 1445 (s),
1373 (w), 1343 (w), 1326 (w), 1298 (w), 1264 (m), 1232 (w),
1194 (m), 1172 (m), 1150 (m), 1130 (w), 1112 (w), 1072 (w),
1050 (w), 1004 (s), 970 (w), 914 (w), 895 (w), 846 (s), 816 (w),
731 (s), 516 (m), 506 (m), 488 (w), 472 (w), 461 (w). Anal. Calcd
for C39H72Cl2RuSP2: C, 58.05; H, 8.99. Found: C, 58.32; H,
8.69.
(P Cy3)2Cl2Ru dC(H)SP h (7). Phenyl vinyl sulfide (1 mL,
7.6 mmol) was added to a methylene chloride solution (10 mL)
of Ru alkylidene 1b (1.0 g, 1.3 mmol). The reaction mixture
was stirred at room temperature for 5 h, during which time
the solution turned from purple to red-violet. The solvent was
evaporated under dynamic vacuum, affording a red-violet
powder. Recrystallization by slowly diffusing pentane into a
saturated toluene solution at -30 °C afforded (PCy3)2Cl2Rud
C(H)SPh (7) as dark maroon crystals in 87% yield (967 mg).
1H NMR (CD2Cl2): δ 17.79 (s, 1H), 7.45-7.36 (m, 5H), 2.68-
2.59 (m, 6H), 1.96-1.92 (m, 10H), 1.78-1.71 (m, 18H), 1.57-
1.49 (m, 12H), 1.33-1.24 (m, 20H). 13C NMR (CD2Cl2): δ 280.4
(t, J ) 76.6 Hz), 141.6, 129.8, 129.6, 128.8, 32.9 (psuedo t, J )
9.3 Hz), 30.3, 28.4 (pseudo t, J ) 5.2 Hz), 27.1. 31P NMR (CD2-
Cl2): δ 33.3 (s). IR (KBr, cm-1): 2926 (vs), 2849 (s), 1578 (w),
1478 (w), 1445 (s), 1327 (w), 1298 (w), 1266 (m), 1231 (w), 1197
(m), 1174 (m), 1129 (m), 1081 (w), 1024 (w), 1005 (s), 916 (w),
888 (m), 844 (s), 747 (s), 702 (m), 691 (m), 508 (s).
(P Cy3)2Cl2R u dC(H)N(ca r ba zole) (8). N-Vinylcarbazole
(2.4 g, 12 mmol) was added to a methylene chloride (10 mL)
solution of Ru alkylidene 1b (1 g, 1.2 mmol). The reaction
mixture was stirred at room temperature for 2 h, during which
time the solution turned from purple to deep violet. The solvent
was evaporated under dynamic vacuum, affording a violet
powder. Recrystallization by slowly diffusing pentane into a
saturated toluene solution at -30 °C afforded (PCy3)2Cl2Rud
C(H)N(carbazole) (8) as violet crystals in 77% yield (843 mg).
Although the Ru complexes are reactive in the me-
tathesis of electron-rich olefins, the degenerate nature
of these reactions, i.e., no methylidenes are formed as
intermediates, currently prevents the synthesis of di-
functional olefins by a metathesis mechanism. Circum-
venting this pathway will provide an efficient method
for preparing functionalized, electron-rich olefins, es-
pecially since a wide range of potential substrates, with
O, N, and S atoms at the R-position, is available. It has
recently been demonstrated that the electron-deficient
olefins can take part in productive metathesis reactions
when the catalysts contain the appropriate ligands.8g
Thus, it is anticipated that appropriate ligand arrays
will open reactions of olefins with electron-rich func-
tionalities to metathesis as well.
Exp er im en ta l Section
Gen er a l Con sid er a tion s. All operations were performed
under an inert atmosphere in a nitrogen-filled drybox or by
using standard Schlenk techniques. Unless otherwise specified,
all reagents were purchased from commercial suppliers and
used without further purification. Solvents were dried over
aluminum columns. NMR spectra were obtained on a GE QE
300 Plus (300.1 MHz, 1H; 75.49 MHz, 13C; 121.16 MHz, 31P)
spectrometer. Infrared spectra were recorded on a Perkin-

Electron-Rich Carbene Complexes
Organometallics, Vol. 21, No. 11, 2002 2163
1H NMR (C6D6): δ 17.59 (s, 1H), 8.94 (d, J ) 8.4 Hz, 2H), 7.65
(s, 3H), 6.92 (s, 1H), 2.50 (q, J 1 ) 7.7 Hz, 2H), 2.38 (s, 6H),
2.31 (s, 6H), 2.25 (s, 6H), 1.63-1.57 (m, 16H), 1.19-1.08 (m,
17H), 1.08 (t, J ) 7.7 Hz, 3H). 13C NMR (CD2Cl2): δ 281.2,
188.2 (d, J ) 86.0 Hz), 141.8, 139.6, 138.7, 138.1, 137.8, 137.1,
135.1, 134.7, 130.1, 129.7, 129.1, 125.0, 124.9, 124.3, 37.9, 32.3
(d, J ) 16.6 Hz), 29.8, 28.3 (d, J ) 10.4 Hz), 26.9, 21.5, 21.5,
19.7 (2C), 19.0 (2C), 13.9. 31P NMR (CD2Cl2): δ 27.8 (s). IR
(KBr, cm-1): 2919 (vs), 2843 (s), 1607 (w), 1482 (m), 1446 (s),
1386 (m), 1353 (w), 1311 (s), 1260 (s), 1228 (w), 1208 (w), 1175
(w), 1152 (m), 1124 (w), 1073 (m), 1036 (m), 1005 (m), 923 (w),
891 (w), 854 (vs), 782 (w), 734 (m), 703 (m), 595 (w), 575 (w),
512 (w), 486 (w). Anal. Calcd for C42H63Cl2RuN2SP: C, 60.71;
H, 7.64; N, 3.37. Found: C, 60.54; H, 7.66; N, 3.15.
(dd, J 1 ) 7.7 Hz, J 2 ) 0.7 Hz, 2H), 7.93 (dt, J 1 ) 7.3 Hz, J 2
)
1.1 Hz, 2H), 7.21 (t, J ) 7.3 Hz, 2H), 2.98-2.90 (m, 6H), 2.01-
1.96 (m, 10H), 1.59-1.45 (m, 30H), 1.30-1.07 (m, 20H). 13C
NMR (CD2Cl2): δ 228.0, 140.0, 127.4, 126.539, 124.6, 119.9,
116.4, 33.0 (d, J ) 9.3 Hz), 30.5, 28.5 (d, J ) 5.2 Hz), 27.2. 31
P
NMR (CD2Cl2): δ 41.3 (s). IR (KBr, cm-1): 3060 (m), 2927 (vs),
2849 (s), 2605 (m), 2498 (w), 1482 (m), 1480 (m), 1444 (s), 1363
(m), 1322 (s), 1293 (vs), 1235 (m), 1197 (m), 1164 (s), 1128 (w),
1108 (w), 1089 (m), 1032 (w), 1005 (m), 887 (m), 847 (m), 828
(m), 757 (s), 724 (m), 698 (m), 630 (m), 579 (w), 510 (m), 489
(m). Anal. Calcd for C49H75Cl2RuNP2: C, 64.53; H, 8.29; N,
1.54. Found: C, 64.64; H, 8.10; N, 1.44.
(P Cy3)2Cl2Ru dC(H)N(p yr r olid in on e) (9). 1-Vinyl-2-pyr-
rolidinone (3 mL, 28 mmol) was added to a methylene chloride
(10 mL) solution of Ru alkylidene 1b (1 g, 1.2 mmol). The
reaction mixture was stirred at room temperature for 4 h. The
solvent was evaportated under dynamic vacuum and afforded
a lavender powder. Recrystallization by slowly diffusing pen-
tane into a saturated toluene solution at -30 °C afforded
(PCy3)2Cl2RudC(H)N(pyrrolidinone) (9) as lavender crystals
(IMes)(P Cy3)Cl2Ru dC(H)N(ca r ba zole) (13). Potassium
tert-butoxide (50 mg, 0.45 mmol) and [IMes]+Cl- (150 mg, 0.44
mmol) were added to a solution of complex 8 (200 mg, 0.23
mmol) in 10 mL of benzene. The reaction mixture was stirred
at 65 °C for 3 h, during which time the solution changed color
from purple to a reddish brown. The reaction mixture was then
filtered through Celite and concentrated under dynamic
vacuum to afford a reddish purple powder. Recrystallization
by slowly diffusing pentane into a saturated toluene solution
at -30 °C afforded (IMes)(PCy3)Cl2RudC(H)N(carbazole) (13)
as purple crystals in 48% yield (103 mg). 1H NMR (CD2Cl2):
δ 16.9 (s, 1H), 7.87-7.84 (m, 2H), 7.37-7.32 (m, 4H), 7.07 (d,
J ) 1.8 Hz, 1H), 7.03 (s, 2H), 6.95 (d, J ) 1.8 Hz, 1H), 5.74
(bs, 2H), 2.48 (s, 6H), 2.34 (s, 6H), 2.27-2.21 (m, 3H), 2.20
(bs, 6H), 1.46-1.26 (m, 12H), 0.94-0.86 (m, 18H). 13C NMR
(CD2Cl2): δ 230.0, 190.4 (d, J ) 91.1 Hz), 139.3, 138.4, 138.2,
136.9, 136.0, 135.5, 130.2, 129.7, 129.5, 129.3, 128.8, 126.5,
125.3, 125.3, 124.1, 124.1, 123.7, 119.3, 32.5 (d, J ) 16.6 Hz),
30.0, 28.5 (d, J ) 9.8 Hz), 26.8, 21.5, 20.8, 20.3 (2C), 18.9 (2C).
31P NMR (CD2Cl2): δ 36.9 (s). IR (KBr, cm-1): 3071 (m), 2924
(vs), 2848 (s), 1606 (m), 1594 (w), 1486 (m), 1444 (s), 1395 (m),
1379 (w), 1359 (w), 1319 (s), 1287 (vs), 1259 (m), 1236 (m),
1187 (w), 1163 (m), 1088 (m), 1076 (m), 1032 (w), 1004 (w),
924 (w), 909 (w), 848 (m), 828 (m), 756 (s), 760 (m), 744 (w),
733 (m), 721 (w), 697 (m), 629 (m), 593 (w), 577 (w), 509 (w),
489 (w). Anal. Calcd for C52H66Cl2RuN3P: C, 66.72; H, 7.11;
N, 4.49. Found: C, 67.01; H, 7.02; N, 4.40.
(IMes)(P Cy3)Cl2Ru dC(H)N(p yr r olid in on e) (14). A 25
mL Schlenk flask was charged with IMes (130 mg, 0.427
mmol), complex 9 (215 mg, 0.260 mmol), and 10 mL of toluene.
The red-purple solution was stirred at room temperature for
3 h. Evaporation of the solvent under dynamic vacuum
afforded a maroon powder. Recrystallization from a mixture
of toluene and pentane afforded (IMes)(PCy3)Cl2RudC(H)N-
(pyrrolidinone) (14) as maroon crystals in 89% yield (198 mg).
1H NMR (C6D6): δ 16.12 (s, 1H), 6.91 (s, 1H), 6.84 (s, 1H),
6.80 (s, 1H), 6.52 (s, 1H), 6.20-6.19 (m, 1H), 6.13 (d, J ) 1.8
Hz, 1H), 4.20 (q, J ) 6.6 Hz, 1H), 3.51 (q, J ) 7.3 Hz, 1H),
2.72 (s, 3H), 2.67-2.56 (m, 2H), 2.56 (s, 3H), 2.45 (s, 3H), 2.25
(s, 3H), 2.18 (s, 3H), 2.06 (s, 3H), 1.92-1.82 (m, 5H), 1.70-
1.50 (bm, 12H), 1.44-1.10 (m, 18H). 13C NMR (C6D6): δ 246.8,
193.5 (d, J ) 88.5 Hz), 167.0, 139.3, 138.9, 138.7, 138.2, 138.0,
136.4, 136.3, 131.1, 130.2, 129.9, 128.9, 125.0, 124.9, 123.7,
54.0, 32.7 (d, J ) 16.6 Hz), 31.5, 30.8, 30.3, 29.1 (d, J ) 9.3
Hz), 28.9 (d, J ) 10.4 Hz), 27.3, 21.8, 21.7, 21.0, 20.7, 19.5,
19.4, 17.5. 31P NMR (C6D6): δ 34.4 (s). IR (KBr, cm-1): 2925
(vs), 2851 (s), 1735 (s), 1686 (m), 1560 (w), 1542 (w), 1490 (m),
1448 (m), 1396 (w), 1365 (w), 1290 (s), 1264 (m), 1173 (s), 1076
(w), 1050 (m), 925 (w), 850 (m), 798 (w), 731 (w), 678 (w), 583
(w), 526 (w). Anal. Calcd for C44H64Cl2RuN3OP: C, 61.89; H,
7.55; N, 4.92. Found: C, 61.87; H, 7.27; N, 4.75.
1
in 86% yield (857 mg). H NMR (C6D6): δ 16.64 (s, 1H), 4.20
(t, J ) 7.0 Hz, 2H), 2.93-2.86 (bm, 6H), 2.14-1.90 (m, 10H),
1.91 (t, J ) 8.1 Hz, 2H), 1.74-1.22 (m, 52H). 31P NMR (C6D6):
δ 38.5 (s). IR (KBr, cm-1): 2926 (vs), 2851 (s), 2606 (w), 2498
(w), 1743 (m), 1686 (m), 1446 (m), 1360 (w), 1301 (vs), 1231
(w), 1198 (w), 1160 (s), 1130 (w), 1040 (w), 1005 (m), 934 (w),
917 (w), 888 (w), 874 (w), 848 (m), 798 (m), 732 (m), 638 (w),
526 (m), 492 (w). Anal. Calcd for C41H73Cl2RuNOP2: C, 59.33;
H, 8.87; N, 1.69. Found: C, 59.43; H, 8.87; N, 1.48.
(P Cy3)2Ru (H)(Cl)(CO) (10). A benzene (5 mL) solution of
complex 5 (100 mg, 0.13 mmol) was heated to 65 °C for 12 h,
upon which the solution changed color from red to orange.
Slowly cooling the solution to room temperature afforded
yellow crystals of 10 in 69% yield (65 mg). The spectroscopic
analysis of 10 was identical with that previously reported for
(PCy3)2Ru(H)(Cl)(CO).21 1H NMR (CD2Cl2): δ -27.74 (t, J )
18.3 Hz, 1H, Ru-H). 31P NMR (CD2Cl2): δ 48.5 (d, J ) 6.9
Hz). IR (KBr, cm-1): 1906 (vs, Ru-H), 1444 (s, Ru-CO).
(IMes)(P Cy3)Cl2Ru dC(H)OEt (11). A 25 mL Schlenk flask
was charged with IMes (91 mg, 0.299 mmol), complex 5 (196
mg, 0.250 mmol), and 10 mL of benzene. The red solution was
stirred at room temperature for 12 h. Evaporation of the
solvent under dynamic vacuum afforded a red powder. Re-
crystallization by slowly diffusing methanol into a saturated
benzene solution at -30 °C afforded (IMes)(PCy3)Cl2RudC(H)-
OEt (11) as red-orange crystals in 85% yield (173 mg). 1H NMR
(CD2Cl2): δ 13.81 (d, J ) 0.7 Hz, 1H), 7.00 (s, 2H), 6.98 (s,
2H), 6.95 (dd, J 1 ) 7.7 Hz, J 2 ) 1.8 Hz, 2H), 3.36 (dd, J 1
)
14.3 Hz, J 2 ) 7.3 Hz, 2H), 2.38 (s, 6H), 2.310 (s, 6H), 2.27 (s,
6H), 1.69-1.58 (m, 16H), 1.16 (t, J ) 7.3 Hz, 3H), 1.13-1.04
(m, 17H). 13C NMR (CD2Cl2): δ 277.5, 191.4 (d, J ) 89.1 Hz),
139.4, 138.8, 138.1, 137.6, 137.5, 135.6, 129.6, 129.3, 129.2,
128.5, 125.6, 125.0, 124.9, 124.2, 75.5, 31.8 (d, J ) 17.6 Hz),
29.7, 28.5 (d, J ) 9.3 Hz), 26.9, 21.5, 21.4, 19.8 (2C), 19.0 (2C),
15.1. 31P NMR (CD2Cl2): δ 35.0 (s). IR (KBr, cm-1): 2924 (vs),
2850 (s), 1893 (m), 1673 (w), 1638 (w), 1606 (w), 1542 (w), 1480
(s), 1446 (s), 1396 (m), 1370 (w), 1318 (m), 1306 (m), 1264 (m),
1190 (s), 1131 (w), 1106 (w), 1090 (w), 1076 (w), 1017 (m), 924
(w), 889 (w), 855 (m), 735 (w), 696 (w), 685 (m), 582 (w), 580
(w), 512 (w), 492 (w). HR-MS: calcd, 814.3092; found [M+],
814.3099.
(IMes)(P Cy3)Cl2Ru dC(H)SEt (12). A 25 mL Schlenk flask
was charged with IMes (130 mg, 0.427 mmol), complex 6 (200
mg, 0.250 mmol), and 10 mL of benzene. The resulting red-
purple solution was stirred at room temperature for 3 h.
Evaporation of the solvent under dynamic vacuum afforded a
maroon powder. Recrystallization by slowly diffusing pentane
into a saturated toluene solution at -30 °C afforded (IMes)-
(PCy3)Cl2RudC(H)SEt (12) as maroon crystals in 66% yield
(137 mg). 1H NMR (CD2Cl2): δ 17.07 (s, 1H), 6.99 (s, 2H), 6.94
(H2IMes)(P Cy3)Cl2Ru dC(H)OEt (15). Ethyl vinyl ether
(1 mL, 10 mmol) was added to a methylene chloride (3 mL)
solution of Ru alkylidene 3a (100 mg, 0.12 mmol). The reaction
mixture was then stirred at room temperature for 2 h.
Evaporation of the solvent under dynamic vacuum followed
by washing the residual red powder with cold pentane and
cold methanol afforded (PCy3)(IMesH2)Cl2RudC(H)OEt (15)

2164 Organometallics, Vol. 21, No. 11, 2002
Louie and Grubbs
1
in 93% yield (91 mg). H NMR (CD2Cl2): δ 13.63 (d, J ) 1.1
yield) of (PCy3)Cl2RudC(H)N(pyrrolidinone) (16). 1H NMR
(C6D6): δ 16.64 (s, 1H), 4.20 (t, J ) 7.0 Hz, 2H), 2.93-2.86
(bm, 6H), 2.14-1.90 (m, 10H), 1.91 (t, J ) 8.1 Hz, 2H), 1.74-
1.22 (m, 52H). 31P NMR (C6D6): δ 38.5.
Hz, 1H), 6.96 (s, 2H), 6.94 (s, 2H), 3.89 (m, 4H), 3.24 (dd, J 1
)
14.3 Hz, J 2 ) 7.3 Hz, 2H), 2.59 (s, 6H), 2.48 (s, 6H), 2.26 (s,
6H), 1.61 (bm, 16H), 1.12 (t, J ) 7.3 Hz, 3H), 1.14-1.00 (bm,
17H). 13C NMR (CD2Cl2): δ 276.7, 220.7 (d, J ) 83.9 Hz), 138.9,
138.4, 138.2, 137.7, 137.6, 135.0, 129.8, 129.4, 128.4, 75.0, 52.2,
51.9, 31.4 (d, J ) 15.5 Hz), 29.4, 28.3 (d, J ) 10.4 Hz), 26.7,
21.2, 21.1, 20.0 (2C), 19.0 (2C), 14.8. 31P NMR (CD2Cl2): δ 32.6
(s). IR (KBr, cm-1): 2923 (vs), 2850 (s), 1604 (w), 1479 (s), 1444
(m), 1420 (m), 1370 (w), 1309 (m), 1266 (s), 1188 (vs), 1105
(m), 1019 (s), 888 (w), 855 (m), 814 (w), 734 (w), 688 (s), 627
(w), 579 (w), 511 (w), 490 (w).
Ack n ow led gm en t. We thank Christopher W. Bie-
lawski for helpful discussions. Crystallographers Michael
Day and Lawrence W. Henling are acknowledged for
their help with crystal manipulation and structure
elucidation. J .L. is grateful to the National Institutes
of Health for a postdoctoral fellowship.
(P Cy3)Cl2R u dC(H)N(p yr r olid in on e) (16). A Schlenk
flask equipped with a stirbar was charged with complex 9 (200
mg, 0.24 mmol), CuCl (52 mg, 0.53 mmol), and 12 mL of CH2-
Cl2. The heterogeneous mixture was stirred at room temper-
ature for 3 h. After the residual solids were filtered away, the
mother liquor was concentrated to dryness and afforded a red-
brown solid. Recrystallization by slowly diffusing pentane into
a saturated toluene solution at -30 °C afforded 110 mg (83%
Su p p or tin g In for m a tion Ava ila ble: Tables of experi-
mental data, anisotropic displacement coefficients, atomic
coordinates, interatomic distances and angles, and torsion
angles. This material is available free of charge via the
Internet at http://pubs.acs.org.
OM011037A