An investigation of carbon-fluorine bond functionalization. Versatile reactivity of tungsten(II) fluoride carbonyl metallacycles with alkynes

Article abstract of DOI:10.1021/om960561s

Metal-assisted functionalization of aromatic fluorocarbons is reported. Sequential carbon - fluorine oxidative addition and migratory insertion with electron-deficient alkynes are employed to construct novel tungsten(II) η²-vinyl complexes in which net replacement of an aromatic carbon-fluorine bond by a carbon-carbon bond has ensued. A competitive reaction involving the formation of four-electron donor alkyne complexes is favored for electron-rich alkynes. Evidence suggests a two-electron donor alkyne complex may serve as a common intermediate in these transformations, which could either participate in the migratory insertion reaction or lose carbon monoxide to generate the four-electron donor alkyne complex. The observed partitioning of products appears to be controlled by the electronic profile of the coordinated alkyne as well as the nucleophilicity of the migrating aryl group. The migratory insertion reaction is regioselective for 1-phenyl-1-propyne with the insertion taking place at the phenyl-substituted alkyne carbon to afford 17. Reaction of the nucleophilic tungsten(II) metallacycle 4 with the electronically unsymmetrical acetylene 18 affords two distinct and isolable η²-vinyl isomers in a 56:44 ratio and suggests that there is not a significant electronic bias for the nucleophilic migration process. The solid state structures of the four-electron donor alkyne complex 9 and the η²-vinyl complexes 16 and 17 have been determined.

Full text of DOI:10.1021/om960561s

5292
Organometallics 1996, 15, 5292-5301
An In vestiga tion of Ca r bon -F lu or in e Bon d
F u n ction a liza tion . Ver sa tile Rea ctivity of Tu n gsten (II)
F lu or id e Ca r bon yl Meta lla cycles w ith Alk yn es
J aqueline L. Kiplinger,† Margaret A. King, Andreas Fechtenko¨tter,‡
Atta M. Arif, and Thomas G. Richmond*
Department of Chemistry, University of Utah, Salt Lake City, Utah 84112
Received J uly 9, 1996X
Metal-assisted functionalization of aromatic fluorocarbons is reported. Sequential carbon-
fluorine oxidative addition and migratory insertion with electron-deficient alkynes are
employed to construct novel tungsten(II) η2-vinyl complexes in which net replacement of an
aromatic carbon-fluorine bond by a carbon-carbon bond has ensued. A competitive reaction
involving the formation of four-electron donor alkyne complexes is favored for electron-rich
alkynes. Evidence suggests a two-electron donor alkyne complex may serve as a common
intermediate in these transformations, which could either participate in the migratory
insertion reaction or lose carbon monoxide to generate the four-electron donor alkyne complex.
The observed partitioning of products appears to be controlled by the electronic profile of
the coordinated alkyne as well as the nucleophilicity of the migrating aryl group. The
migratory insertion reaction is regioselective for 1-phenyl-1-propyne with the insertion taking
place at the phenyl-substituted alkyne carbon to afford 17. Reaction of the nucleophilic
tungsten(II) metallacycle 4 with the electronically unsymmetrical acetylene 18 affords two
distinct and isolable η2-vinyl isomers in a 56:44 ratio and suggests that there is not a
significant electronic bias for the nucleophilic migration process. The solid state structures
of the four-electron donor alkyne complex 9 and the η2-vinyl complexes 16 and 17 have been
determined.
In tr od u ction
an aromatic carbon-fluorine bond takes place at tung-
sten(0) to afford stable tungsten(II) metallacycles with
the cleaved carbon and fluorine atoms both bound to
the metal center as depicted below in eq 1.3
Carbon-fluorine bond activation is an essential step
in the design of useful transition metal reagents for the
functionalization of fluorocarbons.1 Our research group2
has previously demonstrated that oxidative addition of
† Abstracted in part from the Ph.D. thesis of J .L.K., University of
Utah, 1996.
‡ Fellow of the integrated study abroad program sponsored by the
Deutscher Akademischer Austauschdienst (DAAD) between the Tech-
nische Universita¨t Braunschweig and the University of Utah.
* Author to whom correspondence should be addressed.
X Abstract published in Advance ACS Abstracts, November 1, 1996.
(1) (a) Kiplinger, J . L.; Richmond, T. G.; Osterberg, C. E. Chem. Rev.
1994, 94, 373-431. (b) Harrison, R. G.; Richmond, T. G. J . Am. Chem.
Soc. 1993, 115, 5303-5304. (c) Bennett, B. K.; Harrison, R. G.;
Richmond, T. G. J . Am. Chem. Soc. 1994, 116, 11165-11166. (d)
Kiplinger, J . L.; Richmond, T. G. J . Am. Chem. Soc. 1996, 118, 1805-
1806. (e) Kiplinger, J . L.; Richmond, T. G. Chem. Commun. 1996,
1115-1116.
Although this chelate-assisted oxidative addition chem-
istry has been extended to other metals such as Mo,4
Ni,1a,4 and Pt,5 little is known concerning the reaction
chemistry of the resulting metallacycle systems which
may lead to further elaboration of the C-F linkage.
The chemical modification of fluorocarbons presents
a significant synthetic challenge, and examples describ-
ing the replacement of fluorine for groups other than
hydrogen are rare.2b,6 For the most part, chemistry
(2) (a) Osterberg, C. E.; King, M. A.; Arif, A. M.; Richmond, T. G.
Angew. Chem., Int. Ed. Engl. 1990, 29, 888-890. (b) Richmond, T. G.
Coord. Chem. Rev. 1990, 105, 221-250. (c) Lucht, B. L.; Poss, M. J .;
King, M. A.; Richmond, T. G. J . Chem. Soc., Chem. Commun. 1991,
400-401.
(3) Throughout the remainder of the manuscript, for convenience,
(F4-Pia) will refer to the ligand chelate fragment
(4) Osterberg, C. E.; Richmond, T. G. ACS Symp. Ser. 1994, 555,
392-404.
(5) (a) Anderson, C. M.; Crespo, M.; J ennings, M. C.; Lough, A. J .;
Ferguson, G.; Puddephatt, R. J . Organometallics 1991, 10, 2671-2679.
(b) Anderson, C. M.; Crespo, M.; Ferguson, G.; Lough, A. J .; Pud-
dephatt, R. J . Organometallics 1992, 11, 1177-1181. (c) Crespo, M.;
Martinez, M.; Sales, J . Organometallics 1993, 12, 4297-4304.
(6) (a) Organofluorine Chemistry: Principles and Commercial Ap-
plications; Banks, R. E., Smart, B. E., Tatlow, J . C., Eds.; Plenum:
New York, 1994. (b) Chemistry of Organic Fluorine Compounds II. A
Critical Review; Hudlicky, M., Pavlath, A. E., Eds.; ACS Monograph
187; American Chemical Society: Washington, DC, 1995; and refer-
ences therein.
and (Pia) will refer to the ligand chelate fragment
For the η2-vinyl complexes, cis describes the stereochemistry between
the inserted alkyne and the fluoride ligand.
S0276-7333(96)00561-4 CCC: $12.00 © 1996 American Chemical Society

Carbon-Fluorine Bond Functionalization
Organometallics, Vol. 15, No. 25, 1996 5293
capillary tubes and reported in degrees Celsius. Mass spectra
were obtained by Dr. Elliot Rachlin of the University of Utah
on a Finnigan MAT 95 double-focusing high-resolution mass
spectrometer operating with ionization by SIMS using a 20
keV cesium gun. Elemental analyses were performed by
Atlantic Microlab, Norcross, GA, and Desert Analytics, Tucson,
AZ.
effecting the functionalization of fluorinated compounds
has been limited to attack of highly fluorinated aromatic
compounds by strong nucleophilic reagents; the usual
stereochemistry is para to the unique groups present.7
Transition metals have been shown to alter the site of
attack to the ortho position in suitably designed ligand
systems.8 Recently, Crabtree and co-workers reported
that a combination of NH3 with mercury photosensiti-
zation can effect the functionalization of saturated
fluorocarbons to unsaturated fluorinated amines.9
An alternative strategy for the functionalization of
C-F bonds could involve the insertion of unsaturated
organics into the metal-Caryl bonds formed in eq 1.10
In this work we report that internal acetylenes react
with 2 and 4 to afford η2-vinyl (A), or metallacyclopro-
P r ep a r a tion of cis-(F 4-P ia )W(CO)2(F )[η2-C(C6H5)dC-
(C6H5)] (7). Under a nitrogen atmosphere, a 100 mL glass
bomb sealed with a Teflon valve and equipped with a magnetic
stir bar was charged with 2 (0.50 g, 0.93 mmol) (νCO 2020, 1934,
and 1900 cm-1) and diphenylacetylene (0.20 g, 1.1 mmol).
Freshly distilled toluene (30 mL) was added by syringe, and
the bright orange slurry was degassed, placed under reduced
pressure, and heated to 60 °C for 18 h in an oil bath. Initial
color change to dark red-orange was observed within 1 h;
within 18 h the solution turned dark red-green. IR monitoring
confirmed the reaction was complete (νCO 1966 and 1867 cm-1).
Precipitation was achieved by cooling the reaction mixture to
room temperature over 12 h. Isolation by filtration followed
by two washings with 5 mL of THF gave 0.22 g (0.32 mmol,
34% yield) of 7 as a green powder. X-ray quality crystals were
grown by slow diffusion of pentane into a CH2Cl2 solution of
7: mp 182-184 °C dec; IR νCO (CH2Cl2) 1970, 1873 cm-1. Anal.
Calcd for WC27H21N2O2F5‚1/2 CH2Cl2: C, 45.45; H, 3.05; N, 3.85;
F, 13.07. Found: C, 45.73; H, 2.96; N, 3.78; F, 12.84. Note
that CH2Cl2 of crystallization was observed in the NMR
spectra. 1H NMR (CDCl3) (δ): NdCH 8.68 s, 1H; Ar H 7.69
m, 2H; Ar H 7.33 m, 3H; Ar H 7.11 m, 2H; Ar H 6.87 m, 1H;
Ar H 6.49 m, 2H; CdN-CH2 4.65 m, 1H; CdN-CH2 3.78 m,
1H; N-CH3 3.19 s, 3H; N-CH3 2.94 d (4J HF ) 3 Hz), 3H;
N-CH2 2.89 m, 1H; N-CH2 2.68 m, 1H. 13C{1H} NMR
(CDCl3) (δ): WdCR 230.1 s; W-CO 224.4 d (2J CF ) 5 Hz);
W-CO 222.2 d (2J CF ) 56 Hz); NdCH 156.1 d (3J CF ) 6 Hz);
CR-Cquat 146.8 d (3J CF ) 3 Hz); Câ-Cquat 144.2 s; Ar CH 129.4
s; Ar CH 129.4 s; Ar CH 128.4 s; Ar CH 127.9 s, 2C; Ar CH
127.6 s, 2C; Ar CH 127.3 s, 2C; Ar CH 123.6 s; CdN-CH2
penyl (B), complexes by insertion into the W-Caryl bond
or to yield four-electron donor coordination compounds
(C) depending on the nature of the acetylene. The key
feature of this work is that net replacement of an
aromatic carbon-fluorine bond by a carbon-carbon
linkage occurs under mild conditions via sequential C-F
oxidative addition and alkyne insertion at a tungsten
carbonyl complex. A portion of this work has been
previously communicated.11
Exp er im en ta l Section
Gen er a l P r oced u r es. All manipulations involving air
sensitive reagents were performed under an atmosphere of
prepurified nitrogen using standard Schlenk techniques or a
Vacuum Atmospheres glove box.12 Solvents were purified as
previously reported13 except that acetonitrile was distilled
under nitrogen from CaH2 prior to use. Tungsten starting
materials were prepared as previously reported.2 All other
chemicals were obtained from commercial sources and were
used without further purification.
62.3 s; N-CH2 60.9 s; N-CH3 55.8 s; N-CH3 50.5 d (3J CF
)
13 Hz); W-Câ 25.7 s. Due to extensive C-F coupling,
fluorinated aryl resonances could not be resolved. 19F NMR
(CDCl3) (δ): Ar F -126.6 m, 1F; Ar F -142.1 m, 1F; Ar F
-142.9 m, 1F; W-F -152.9 s, 1F; Ar F -157.7 m, 1F.
P r epa r a tion of (F4-P ia )W(CO)(F)(CH3CH2CtCCH2CH3)
(9). As for 7, compound 2 (0.32 g, 0.55 mmol), 3-hexyne (0.097
g, 1.2 mmol), and toluene (30 mL) were heated to 70 °C for 51
h in an oil bath. Initial color change to maroon was observed
within 1 h, and within 51 h the solution turned dark blue. IR
monitoring confirmed the reaction was complete (νCO 1912
cm-1). Precipitation was achieved by addition of pentane to
the reaction mixture and cooling the resulting solution to -10
°C. Isolation by filtration, followed by two washings with 10
mL of pentane afforded 0.24 g (1.0 mmol, 77% yield) of 9 as a
purple powder. X-ray quality crystals were grown by slow
diffusion of hexane into a CH2Cl2 solution of 9: mp 169-171
°C; IR νCO (KBr) 1885 cm-1. Anal. Calcd for WC18H21N2O1F5:
C, 38.59; H, 3.78; N, 5.00; F, 16.96. Found: C, 38.87; H, 3.68;
N, 4.81; F, 16.75. 1H NMR (CDCl3) (δ): NdCH 9.24 s, 1H;
CdN-CH2 4.34 m, 1H; CdN-CH2 4.08 m, 1H; CtC-CH2 3.69
m, 2H; N-CH2 3.22 m, 1H; CtC-CH2 3.11 m, 2H; N-CH3
2.99 s, 3H; N-CH2 2.57 m, 1H; N-CH3 1.95 s, 3H; CH2-CH3
1.22 t, 3H; CH2-CH3 0.92 t, 3H. 13C{1H} NMR (CDCl3) (δ):
W-CO 242.1 d (2J CF ) 11 Hz); CtC-Et 219.9 d (2J CF ) 15
Hz); CtC-Et 213.2 d (2J CF ) 31 Hz); NdCH 165.6 s; CdN-
CH2 65.5 s; N-CH2 56.8 s; N-CH3 54.6 d (3J CF ) 7 Hz);
N-CH3 49.7 s; CtC-CH2 30.9 s; CtC-CH2 28.1 s; CH2-CH3
14.1 s; CH2-CH3 13.6 s. Due to extensive C-F coupling,
fluorinated aryl resonances could not be resolved. 19F NMR
(CD2Cl2) (δ): Ar F -104.8 m, 1F; W-F -140.2 s, 1F; Ar F
-141.7 m, 1F; Ar F -149.7 m, 1F; Ar F -161.7 m, 1F. 19F
NMR (CD2Cl2 + D2O) (δ): W-F -143.1 m, 1F.
1H, 13C{1H}, 13C{19F}, and 19F NMR spectra were obtained
on Varian XL-300 spectrometers at 300, 75, 75, and 281 MHz,
respectively. All chemical shifts are reported in δ units with
the following abbreviations: d ) doublet, m ) multiplet, q )
quartet, s ) singlet, t ) triplet, and apr ) apparent. For 19F
and 13C{19F} NMR spectra, CFCl3 was used as the external
reference at δ 0.00. FTIR solution spectra were obtained in
0.1 mm CaF2 cells. Melting points were obtained in open
(7) (a) Hudlicky, M. Chemistry of Organic Fluorine Compounds, 2nd
ed.; Wiley: New York, 1972. (b) Park, S.; Roundhill, D. M. Inorg. Chem.
1989, 28, 2905-2906. (c) Miller, T. M.; Neeman, T. X.; Kwock, E. W.;
Stein, S. M. J . Am. Chem. Soc. 1993, 115, 356-357. (d) Vincente, J .;
Chicote, M. T.; Fernandez-Baeza, J .; Fernandez-Baeza, A.; J ones, P.
G. J . Am. Chem. Soc. 1993, 115, 794-796.
(8) (a) Uso´n, R.; Fornies, J .; Espinet, P.; Garcia, A.; Foces-Foces, C;
Cano, F. J . Organomet. Chem. 1985, 282, C35-C38. (b) Park, S.;
Pontier-J ohnson, M.; Roundhill, D. M. J . Am. Chem. Soc. 1989, 111,
3101-3103.
(9) Burdenuic, J .; Chupka, W.; Crabtree, R. H. J . Am. Chem. Soc.
1995, 117, 10119-10120.
(10) (a) Wu, G.; Rheingold, A. L.; Heck, R. F. Organometallics 1986,
5, 1922-1924. (b) Maassarani, F.; Pfeffer, M.; Le Borgne, G. Organo-
metallics 1987, 6, 2029-2042; and references therein. (c) Grigsby, W.
J .; Main, L.; Nicholson, B. K. Organometallics 1993, 12, 397-407.
(11) Kiplinger, J . L.; King, M. A.; Arif, A. M.; Richmond, T. G.
Organometallics 1993, 12, 3382-3384.
(12) Shriver, D. F.; Drezdon, M. A. Manipulation of Air Sensitive
Compounds, 2nd ed.; Wiley: New York, 1986.
(13) Kiplinger, J . L.; Richmond, T. G.; Arif, A. M.; Du¨cker-Benfer,
C.; van Eldik, R. Organometallics 1996, 15, 1545-1564.

5294 Organometallics, Vol. 15, No. 25, 1996
Kiplinger et al.
P r ep a r a tion of (F 4-P ia )W(CO)F (CH3CtCCH3) (10). As
for 7, complex 2 (0.29 g, 0.55 mmol), 2-butyne (0.15 mL, 1.9
mmol), and 20 mL of toluene were heated in an oil bath at a
temperature of 90 °C for 2 h. Within 20 min the solution color
changed to dark red, and within 40 min the solution was
purple-blue. An IR spectrum of the crude product solution
confirmed the reaction was complete (νCO 1914 cm-1). The
reaction solution was filtered through Celite, and the purple
filtrate was collected. Crystallization was achieved by reduc-
tion of the toluene solvent volume to 10 mL, followed by
addition of 5 mL of pentane and cooling to -10 °C. The solid
was collected by filtration and washed with two 20 mL portions
of pentane. Isolation afforded purple crystalline 10 in 72%
yield (0.21 g, 0.39 mmol): mp 159-161 °C dec; IR νCO (KBr)
1902 cm-1. Anal. Calcd for WC16F5H17N2O‚1/8C7H8: C, 37.28;
H, 3.34; N, 5.15. Found: C, 37.57; H, 3.40; N, 5.14. Note that
toluene of crystallization was observed in the NMR spectra.
1H NMR (-60 °C, CD2Cl2) (δ): NdC-H 9.31 s, 1H; CdN-
CH2 4.33 m, 1H; CdN-CH2 4.15 m, 1H; CtC-CH3 3.09 s,
3H; N-CH2 3.09 m, 1H; N-CH3 2.90 s, 3H; N-CH2 2.55 m,
1H; CtC-CH3 2.81 s, 3H; N-CH2 2.63 m, 1H; N-CH3 1.84 s,
3H. 13C{1H} NMR (-60 °C, CD2Cl2) (δ): W-CO 244.0 d (2J CF
) 10 Hz); CtC-CH3 214.4 d (2J CF ) 15 Hz); CtC-CH3 209.5
d (2J CF ) 32 Hz); NdCH 165.1 s; CdN-CH2 64.7 s; N-CH2
56.2 s; N-CH3 54.1 (under CD2Cl2 reference peak); N-CH3
48.9 s; CtC-CH3 21.7 d (3J CF ) 3 Hz); CtC-CH3 18.0 s. Due
to extensive C-F coupling, fluorinated aryl resonances could
not be resolved. 19F NMR (-60 °C, CD2Cl2) (δ): Ar F -104.9
m, 1F; Ar F -140.4 m, 1F; W-F -145.7 s, 1F; Ar F -149.3 m,
1F; Ar F -160.7 m, 1F.
m, 1F; Ar F -145.1, 1F; Ar F -163.4 m, 1F; Ar F -166.9 m,
1F; W-F -194.2 s, 1F.
P r epar ation of cis-{(P ia)W(CO)2(F)[η2-C(CF3)dC(CF3)]}
(15). Under a nitrogen atmosphere, a 100 mL glass bomb
sealed with a Teflon valve and equipped with a magnetic stir
bar was cooled to -196 °C and charged with perfluoro-2-butyne
(1.3 g, 7.7 mmol). In a separate Schlenk flask, a slurry of 4
(1.0 g, 2.2 mmol) (νCO 2004, 1915, and 1881 cm-1) in freshly
distilled toluene (30 mL) was prepared, degassed and trans-
ferred under nitrogen by syringe to the glass bomb. The
resulting bright orange solution was degassed by three freeze-
pump-thaw cycles and warmed to room temperature. The
reaction mixture was heated to 100 °C for 6 h in an oil bath.
Initial color change to orange-brown was observed within 30
min, and within 6 h the solution turned ruby red. An IR
spectrum of the crude product solution confirmed the reaction
was complete (νCO 2008 and 1908 cm-1). The solvent was
removed in vacuo, and the crude solid was redissolved in a
minimal amount of CH2Cl2 and filtered through a pad of Celite.
The volume of the filtrate was reduced, and the product was
recrystallized by the addition of hexanes (CH2Cl2:hexanes )
1:4) and cooling to -10 °C for 20 h. Isolation by vacuum
filtration followed by three washings with 20 mL of toluene
and drying gave 1.0 g (1.8 mmol, 79% yield) of 15 as an army
green powder: mp 158-160 °C; IR νCO (KBr) 2013, 1914 cm-1
.
Anal. Calcd for WC17H15N2O2F7‚1/3CH2Cl2: C, 33.34; H, 2.53;
N, 4.49; F, 20.29. Found: C, 33.63; H, 2.71; N, 4.42; F, 19.12.
Note that CH2Cl2 of crystallization was observed in the NMR
spectra. 1H NMR (CD2Cl2) (δ): NdC-H 8.50 d (4J HF ) 1.70
Hz), 1H; Ar H 7.81 m, 1H; Ar H 7.69 m, 1H; Ar H 7.54 m, 1H;
Ar H 7.45 m, 1H; CdN-CH2 4.66 m, 1H; CdN-CH2 3.87 m,
1H; N-CH3 3.09 s, 3H; N-CH3 2.92 d (4J HF ) 3.12 Hz), 3H;
N-CH2 2.88 m, 1H; N-CH2 2.54 m, 1H. 13C{1H} NMR (CD2-
Cl2) (δ): NdC-H 166.4 s; W-C 137.2 s; Ar-Cquat 136.3 s; Ar
CH 135.5 s; Ar CH 134.3 s; Ar CH 133.9 s; Ar CH 128.7 s;
CdN-CH2 62.3 s; N-CH2 60.1 d (3J CF ) 3 Hz); N-CH3 55.8
s; N-CH3 50.3 d (3J CF ) 14 Hz). 13C{19F} NMR (CD2Cl2) (δ):
W-CO 223.0 d (2J CF ) 5 Hz); W-CO 222.9 (2J CF ) 56 Hz);
P r ep a r a tion of (F 4-P ia )W(CO)F (C6H5CtCCH3) (11). As
for 7, complex 2 (0.24 g, 0.45 mmol), 1-phenyl-1-propyne (0.17
mL, 1.4 mmol), and 20 mL of toluene were heated in an oil
bath at a temperature of 90 °C for 2 h. Within 20 min a purple
color was evident and within 1 h the solution was dark blue.
An IR spectrum of the crude product solution confirmed the
reaction was complete (νCO 1922 cm-1). The reaction solution
was filtered through Celite, and the orange-brown insoluble
matter was discarded. Crystallization was achieved by reduc-
tion of the toluene solvent volume to 10 mL, followed by
addition of 15 mL of pentane and cooling to -10 °C. The solid
was isolated by filtration and washed with two 20 mL portions
of pentane and two 20 mL portions of hexanes. Isolation gave
green-blue microcrystalline 11 in 81% yield (0.21 g, 0.36
mmol): mp 168-170 °C dec; IR νCO (KBr) 1903 cm-1. Anal.
Calcd for WC21F5H19N2O: C, 42.45; H, 3.22; N, 4.71. Found:
C, 42.36; H, 3.24; N, 4.72. 1H NMR (CD2Cl2) (δ): NdC-H
9.37 s, 1H; Ar H 7.30 m, 5H; CdN-CH2 4.20 m, 1H; CdN-
CH2 4.10 m, 1H; CtC-CH3 3.44 s, 3H; N-CH2 3.13 m, 1H;
N-CH3 2.97 s, 3H; N-CH2 2.55 m, 1H; N-CH3 1.92 s, 3H.
13C{1H} NMR (CD2Cl2) (δ): W-CO 241.1 d (2J CF ) 11 Hz);
WdCR-CF3 203.2 dq (2J CF ) 41 Hz); CR-CF3 131.8 q (1J CF
)
269 Hz); Câ-CF3 128.3 q (1J CF ) 266 Hz); W-Câ-CF3 37.6 dq
(coupling could not be resolved). 19F NMR (CD2Cl2) (δ): Câ-
CF3 -57.7 s, 3F; CR-CF3 -58.9 s, 3F; W-F -137.5 s, 1F. 19F
NMR (CD2Cl2 + D2O) δ W-F -139.7 s, 1F.
P r ep a r a t ion of cis-{(P ia )W(CO)2(F )[η2-C(C6H 5)dC-
(C6H5)]} (16). Similar to 15, complex 4 (0.35 g, 0.76 mmol),
diphenylacetylene (0.35 g, 1.9 mmol), and 20 mL of freshly
distilled toluene were heated to 100 °C in an oil bath. Initial
color change to dark red was observed within 5 min, and
within 30 min the solution color changed to dark green. IR
monitoring confirmed the reaction was complete in 1.5 h (νCO
1956 and 1865 cm-1). Crystallization of compound 16 was
achieved by cooling the reaction mixture to room temperature
over a time period of 2 h. Isolation by filtration followed by
three washings with 20 mL of pentane (to remove unreacted
alkyne) gave 0.32 g (0.52 mmol, 68% yield) of dark forest green
microcrystalline 16. X-ray quality crystals were grown by slow
diffusion of pentane into a CH2Cl2 solution of 16: mp 158-
160 °C dec; IR νCO (CH2Cl2) 1957, 1861 cm-1; νCO (KBr) 1948,
1840 cm-1. Anal. Calcd for WC27H25N2O2F: C, 52.96; H, 4.12;
N, 4.57. Found: C, 52.07; H, 4.14; N, 4.55. 1H NMR (CD2-
Cl2) (δ): NdCH 8.43 s, 1H; Ar H 7.78 m, 3H; Ar H 7.57 m,
2H; Ar H 7.38 m, 4H; Ar H 7.02 m, 2H; Ar H 6.81 m, 1H; Ar
H 6.43 m, 2H; CdN-CH2 4.49 m, 1H; CdN-CH2 3.75 m, 1H;
N-CH3 3.16 s, 3H; N-CH3 2.90 d (4J HF ) 3 Hz), 3H; N-CH2
2.83 m, 1H; N-CH2 2.57 m, 1H. 13C{1H} NMR (CD2Cl2) (δ):
WdCR 228.4 d (2J CF ) 2 Hz); W-CO 226.8 d (2J CF ) 6 Hz);
W-CO 222.9 d (2J CF ) 57 Hz); NdCH 165.9 s; CR-Cquat 149.4
d (3J CF ) 4 Hz); Câ-Cquat 144.5 s; Ar-Cquat 143.6 s; Ar-Cquat
137.2 s; Ar CH 135.7 s; Ar CH 135.4 s; Ar CH 134.1 s; Ar CH
131.7 s; Ar CH 130.1 s; Ar CH 128.9 s; Ar CH 128.7 s; Ar CH
128.3 s; Ar CH 127.1 s; Ar CH 122.6 s; CdN-CH2 62.1 s;
N-CH2 60.3 s; N-CH3 55.8 s; N-CH3 50.3 d (3J CF ) 13 Hz);
W-Câ 43.4 s. 19F NMR (CD2Cl2) (δ): W-F -145.3 s.
CtC-Ph 220.0 d (2J CF ) 14 Hz); CtC-CH3 206.7 d (2J CF
)
34 Hz); NdCH 166.3 s; Ar-Cquat 138.8 s; Ar CH 129.2 s, 2C;
Ar CH 128.7 s; Ar CH 128.4 s, 2C; CdN-CH2 65.9 s; CdN-
CH2 57.2 s; N-CH3 54.6 d (3J CF ) 7 Hz); N-CH3 50.1 s; CtC-
CH3 23.4 s. Due to extensive C-F coupling, fluorinated aryl
resonances could not be resolved. 19F NMR (CD2Cl2) (δ): Ar
F -105.5 m, 1F; W-F -132.9 s, 1F; Ar F -141.1, 1F; Ar F
-149.7 m, 1F; Ar F -161.1 m, 1F.
Gen er a tion of (F 4-P ia )W(CO)F (C4H8O) (12). Under a
nitrogen atmosphere, a 50 mL Pyrex Schlenk flask equipped
with a magnetic stir bar was charged with 2 (0.039 g, 0.073
mmol) and 25 mL of freshly distilled tetrahydrofuran. The
flask was sealed with a septum equipped with a needle to
maintain a strong and continuous nitrogen purge, and the
reaction mixture was irradiated with
a Hanovia 450 W
medium-pressure Hg lamp at a distance of ca. 7 cm for 20 min.
The solution changed to a dark cherry red color. An IR
spectrum of the crude product solution confirmed the reaction
was essentially complete (νCO 1957 and 1821 cm-1). The
tetrahydrofuran solvent was removed under reduced pressure,
and the residue was redissolved in deuterated tetrahydrofuran
for spectroscopic analysis 19F NMR (THF-d8) (δ): Ar F -116.6

Carbon-Fluorine Bond Functionalization
Organometallics, Vol. 15, No. 25, 1996 5295
P r epar ation of cis-{(P ia)W(CO)2(F)[η2-C(C6H5)dC(CH3)]}
(17). As for 15, compound 4 (0.55 g, 1.2 mmol), 1-phenyl-1-
propyne (0.30 g, 2.6 mmol), and 20 mL of toluene were heated
to 70 °C in an oil bath. Initial color change to dark red was
observed within 1 h. IR monitoring confirmed the reaction
was complete in 6 h (νCO 1947 and 1851 cm-1). Crystallization
was achieved by the addition of pentane and cooling to -10
°C for 20 h. Isolation by filtration followed by two washings
with 20 mL of pentane gave 0.05 g (9.1 mmol, 16% yield) of
red microcrystalline 17. X-ray quality crystals were grown by
slow diffusion of pentane into a CH2Cl2 solution of 17: mp
181-183 °C; IR νCO (CH2Cl2) 1954, 1854 cm-1, νCO (Nujol) 1947,
1850 cm-1. Anal. Calcd For WC22H23N2O2F: C, 48.02; H, 4.21;
N, 5.09. Found: C, 47.74; H, 4.27; N, 4.98. 1H NMR (CD2-
Cl2) (δ): NdCH 8.39 s, 1H; Ar H 7.66 m, 1H; Ar H 7.53 m,
2H; Ar H 7.41 m, 1H; Ar H 7.03 m, 2H; Ar H 6.77 m, 1H; Ar
H 6.39 m, 2H; CdN-CH2 4.39 m, 1H; CdN-CH2 3.73 m, 1H;
N-CH3 3.11 s, 3H; CR-CH3 3.09 d (4J HF ) 2 Hz), 3H; N-CH2
2.87 m, 1H; N-CH3 2.84 d (3J HF ) 3 Hz), 3H; N-CH2 2.57 m,
1H. 13C{1H} NMR (CD2Cl2) (δ): WdCR 237.2 s; W-CO 223.7
d (2J CF ) 5 Hz); W-CO 217.6 d (2J CF ) 58 Hz); NdCH 165.7
d (3J CF ) 3 Hz); Câ-Cquat 150.3 d (3J CF ) 4 Hz); Ar-Cquat 143.9
s; Ar-Cquat 137.3 s; Ar CH 135.3 s; Ar CH 134.5 s; Ar CH 132.9
s; Ar CH 128.6 s, 2C; Ar CH 127.3 s, 2C; Ar CH 126.9 s; Ar
CH 122.4 s; CdN-CH2 62.1 s; N-CH2 60.1 s; N-CH3 55.7 d
(3J CF ) 6 Hz); N-CH3 50.2 d (3J CF ) 8 Hz); W-Câ 41.9 s; CR-
CH3 29.6 d (3J CF ) 6 Hz). 19F NMR (CD2Cl2) (δ): W-F -160.3
s. 19F NMR (CD2Cl2 + D2O) (δ): W-F -162.8 s.
P r ep a r a tion of P h en yl(4′-(tr iflu or om eth yl)p h en yl)-
a cetylen e (18). A 100 mL flame-dried Schlenk flask was
charged with phenyl(tributyltin)acetylene14 (2.9 g, 7.4 mmol),
4-iodobenzotrifluoride (2.0 g, 7.4 mmol), tetrakis(triphenylphos-
phine)palladium(0) (2.6 g, 30 mol %), copper iodide (0.67 g, 48
mol %), and 50 mL of DMF. The reaction mixture was
degassed, placed under N2, and heated in an oil bath at 85 °C
for 72 h. The reaction mixture was diluted with 100 mL of
Et2O and filtered through a coarse-fritted funnel. The result-
ant mixture was washed with saturated aqueous NH4Cl and
water (2 × 200 mL). The organic layer was separated and
washed with an aqueous 10% KF solution to polymerize the
tin-containing byproducts. The aqueous layer was separated
and extracted with Et2O (2 × 50 mL). The combined organic
extracts were washed with saturated aqueous NH4Cl, dried
(MgSO4), and concentrated. The crude product was diluted
with 200 mL of hot hexane and filtered through a plug of SiO2.
Concentration in vacuo afforded 1.8 g of 18 (7.3 mmol, 97%
yield) as a pale yellow flocculent solid: mp 104-106 °C dec;
IR νCtC (KBr) 2220 cm-1. EI MS (70 eV): m/ z 246 (M+). Anal.
Calcd for C15F3H9: C, 73.17; H, 3.68. Found: C, 73.25; H, 3.92.
1H NMR (CDCl3) (δ): Ar H 7.62 m, 4H; Ar H 7.39 m, 5H. 13C-
{1H} NMR (CDCl3) (δ): Ar CH 131.8 s; Ar CH 131.7 s; CF3-
Cquat 129.8 q (2J CF ) 32 Hz); Ar CH 128.8 s; Ar CH 128.8 s;
Ar-Cquat 127.0 s; Ar CH 125.3 q (3J CF ) 4 Hz); Ar-CF3 123.9
q (1J CF ) 270 Hz); Ar-Cquat 122.5 s; CtC-ArCF3 91.7 s; CtC-
Ar 87.9 s. 19F NMR (CDCl3) (δ): Ar-CF3 -61.4.
7.86 m, 2H; Ar H 7.63 m, 4H; Ar H 7.39 m, 1H; Ar H 7.21 m,
1H; Ar H 7.04 m, 2H; Ar H 6.83 m, 1H; Ar H 6.42 m, 2H;
CdN-CH2 4.53 m, 1H; CdN-CH2 3.78 m, 1H; N-CH3 3.16
s, 3H; N-CH3 2.91 d (4J HF ) 3 Hz), 3H; N-CH2 2.85 m, 1H;
N-CH2 2.56 m, 1H. 13C{1H} NMR (CD2Cl2) (δ): W-CO 226.4
d (2J CF ) 6 Hz); WdCR 225.2 br s; W-CO 223.2 d (2J CF ) 57
Hz); NdCH 166.1 s; CR-Cquat 148.6 d (3J CF ) 4 Hz); Câ-Cquat
146.8 s; Ar-Cquat 144.2 s; Ar CH 135.7 s; Ar CH 134.2 s; Ar
CH 131.5 s; Ar CH 129.6 s; Ar CH 128.8 s; Ar CH 127.3 s; Ar
CH 127.2 s; Ar CCF3 125.9 q (2J CF ) 4 Hz); Ar CH 123.1 s;
CdN-CH2 62.2 s; N-CH2 60.4 s; N-CH3 55.9 s; N-CH3 50.5
d (3J CF ) 13 Hz); W-Câ 44.3 s. The CF3 resonance could not
be detected. 19F NMR (CD2Cl2) (δ): Ar-CF3 -63.8 s, 3F; W-F
-138.8 s, 1F.
2
P r epar ation of cis-{(P ia)W(CO)
2(F)[η -C(4-C6H4CF3)dC-
(C
6H5)]} (20). The green filtrate remaining after the isolation
of 19 was collected, and the toluene solvent was removed under
reduced pressure. The green residue was redissolved in a
minimal amount of methylene chloride (10 mL), was filtered
through a pad of Celite, and was recrystallized by the addition
of 20 mL of hexanes and cooling to -10 °C for 20 h. Isolation
by vacuum filtration followed by three successive washings
with 20 mL of hexanes (to remove any unreacted alkyne) and
drying gave 0.14 g (0.19 mmol, 34% yield) of crystalline green
20: mp 150-152 °C dec; IR ν
CO (CH2Cl2) 1964, 1867 cm-1, νCO
(KBr) 1958, 1859 cm-1
. Anal. Calcd for WC28H24N2O2F4‚
1/2CH2Cl2: C, 47.23; H, 3.75; N, 3.86. Found: C, 46.63; H, 3.81;
N, 3.56. Note that methylene chloride of crystallization was
observed in the NMR spectra.
1H NMR (CD2Cl2) (δ): NdCH
8.44 d (4J HF ) 2 Hz), 1H; Ar H 7.77 m, 3H; Ar H 7.59 m, 2H;
Ar H 7.40 m, 4H; Ar H 6.56 m, 2H; CdN-CH2 4.48 m, 1H;
CdN-CH
2 3.78 m, 1H; N-CH3 3.18 s, 3H; N-CH3 2.89 d (4J HF
) 3 Hz), 3H; N-CH2 2.86 m, 1H; N-CH2 2.60 m, 1H. 13C{1H}
NMR (CD2Cl2) (δ): WdCR 227.5 br s; W-CO 226.5 d (2J CF
)
6 Hz); W-CO 222.4 d (2J CF ) 57 Hz); NdCH 165.9 s; CR-
Cquat
154.8 d (3J CF ) 3 Hz); Câ-Cquat 143.8 s; Ar-Cquat 143.2 s;
Ar-Cquat 137.1 s; Ar CH 135.7 s; Ar CH 134.5 s; Ar CH 131.7
s; Ar CH 130.4 s; Ar CH 129.1 s; Ar CH 128.7 s; Ar CH 128.5
s; Ar CH 127.5 s; Ar CCF3
123.9 q (2J CF ) 4 Hz); CdN-CH2
62.1 s; N-CH2 60.2 s; N-CH3 55.9 s; N-CH3 50.4 d (3J CF
)
13 Hz); W-Câ 42.9 s. The CF3 resonance could not be detected.
19F NMR (CD2Cl2) (δ): Ar-CF3 -62.9 s, 3F; W-F -147.9 s,
1F.
Cr ysta llogr a p h y. Data were collected at ambient tem-
perature on an Enraf-Nonius CAD-4 diffractometer with Cu
KR radiation (for 9 and 16), or Mo KR radiation (for 17), using
the θ-2θ scan technique for a crystal mounted on a glass fiber.
Cell constants were obtained from 25 reflections with 10° <
2θ < 25° and the space groups were determined from system-
atic absences and subsequent least-squares refinement. Stan-
dard reflections showed no decay during data collection.
Lorentz, polarization, and empirical absorption (Ψ scans)
corrections were applied. The structure was solved by the
standard heavy-atom techniques with SPD/VAX package.15
Final refinement included all non-hydrogen atoms as aniso-
tropic contributions and hydrogens as fixed isotropic contribu-
tions. Scattering factors, as well as ∆f′ and ∆f′′ values, were
taken from the literature.16 A summary of the crystallographic
data and structure refinement is collected in Table 1.
P r ep a r a tion of cis-{(P ia )W(CO)2(F )[η2-C(C6H5)dC(4-
C6H4CF 3)]} (19). As for 15, complex 4 (0.25 g, 0.55 mmol),
18 (0.31 g, 1.3 mmol), and 20 mL of toluene were heated to 90
°C in an oil bath. Initial color changed to dark red was
observed within 1 h, and IR monitoring confirmed the reaction
was complete in 4 h (νCO 1960 and 1865 cm-1). Crystallization
of compound 19 was achieved by slow cooling of the reaction
mixture to room temperature over a time period of 12 h.
Isolation by filtration followed by two washings with 20 mL
of hexane (to remove unreacted alkyne) gave 0.11 g (0.15 mmol,
27% yield) of olive green microcrystalline 19: mp 180-182 °C
dec; IR νCO (CH2Cl2) 1964, 1867 cm-1, νCO (KBr) 1962, 1867
cm-1. Anal. Calcd for WC28H24N2O2F4‚1/2C7H8: C, 52.08; H,
3.89; N, 3.86. Found: C, 52.09; H, 3.90; N, 3.92. Note that
toluene of crystallization was observed in the NMR spectra.
1H NMR (CD2Cl2) (δ): NdCH 8.45 d (4J HF ) 1 Hz), 1H; Ar H
Resu lts
Alk yn e In ser tion in to a P er flu or oa r yl-Meta l
Bon d . As depicted in Scheme 1, treatment of 2 with
diphenylacetylene in toluene at 60 °C for 18 h yields a
(15) Frenz, B. A. The Enraf-Nonius CAD 4 SPDsA Real-Time
System for Concurrent X-ray Data Collection and Crystal Structure
Determination. In Computing and Crystallography; Schenk, H., Olthof-
Hazenkamp, R., van Konigsveld, H., Bassi, G. C., Eds.; Delft University
Press: Delft, Holland, 1978; pp 64-71.
(16) Comer, D. T.; Waber, J . T. In International Tables for X-ray
Crystallography; Ibers, J . A., Hamilton, W. C., Eds.; Kynoch: Bir-
mingham, England, 1974; Vol. IV, Tables 2.2B and 2.3.1, pp 72-98,
149-150.
(14) Cetinkaya, B.; Lappert, M. F.; McMeeking, J .; Palmer, D. E. J .
Chem. Soc., Dalton Trans. 1973, 1202-1208.

5296 Organometallics, Vol. 15, No. 25, 1996
Kiplinger et al.
Ta ble 1. Su m m a r y of Cr ysta llogr a p h ic Da ta for Tu n gsten (II) Com p lexes 9, 16, a n d 17
9
16
17
molecular formula
fw, g mol-1
WF5O1N2C18H21
560.223
WF1O2N2C27H25
612.361
WF1Cl2O2N2C23H25
649.229
space group
crystal system
cell constants
P21/c(No. 14)
monoclinic
a ) 11.863(1) Å
b ) 8.298(2) Å
c ) 20.683(2) Å
â ) 103.282(8)°
P21/n(No. 14)
monoclinic
a ) 12.407(1) Å
b ) 12.1689(9) Å
c ) 15.560(2) Å
â ) 92.638(6)°
P1h(No. 2)
triclinic
a ) 10.183(1) Å
b ) 10.64(2) Å
c ) 13.185(2) Å
â ) 113.68(2)°
γ ) 102.61(2)°
1212.72
cell volume, Å3
Z
1981.73
4.0
1.878
2346.83
4.0
1.733
2.0
1.779
calculated density, g cm3
crystal dimensions, mm3
absorption coefficient (µ), cm-1
radiations, Å
0.36 × 0.15 × 0.09
0.22 × 0.19 × 0.12
0.42 × 0.36 × 0.18
114.525
95.072
51.218
λ(Cu ΚR) ) 1.54056
3747
3310
4.00-130.00°
θ/2θ scan
0.9000 + 0.1400 (tan θ)
bisecting, ω ) 0
anisotropic
empirical
78.3160
λ(Cu ΚR) ) 1.54056
4413
3989
4.00-130.00°
θ/2θ scan
0.9000 + 0.1400 (tan θ)
bisecting, ω ) 0
anisotropic
empirical
46.9586
λ(Mo ΚR) ) 0.71073
6154
5844
4.00-56.00°
θ/2θ scan
0.8000 + 0.3400 (tan θ)
bisecting, ω ) 0
none
empirical
77.9552
99.8572
91.9289
0.87
no. of reflections measured
no. of unique reflections
2θ range, deg
scan technique
scan width, deg
data collection position
decay correction
absorption correction
minimum % transmission
maximum % transmission
average % transmission
highest peak in final difference Fourier, e/Å3
maximum ∆F value in Fourier map, e/Å3
ignorance factor, p
98.6302
87.8983
1.08
1666.5
99.9510
75.2681
0.73
1458.7
571.6
0.05
0.05
0.04
no. of observations, I < 3.00 σ(I)
no. of variables
2611
244
3458
301
5087
281
data to parameter ratio
shift to error ratio
10.701
0.013
11.488
0.004
18.103
0.001
error in an observation of unit weight
R
1.3381
0.0426
1.1482
0.0301
0.7173
0.0259
Rw
0.0509
0.0364
0.0297
Sch em e 1
dark green solution composed of two complexes, 7 (νCO
1966, 1867 cm-1) and 8 (νCO 1915 cm-1), in a 3:1 ratio
as quantified by H NMR spectroscopy via integration
chemical shift (δ 230.1), whereas the four-coordinate
carbon, Câ, has a significant upfield chemical shift that
appears at δ 25.7. The fluoride was determined to be
1
of the imine resonance for each compound and 19F NMR
spectroscopy by integration of the metal-bound fluoride
resonance for each compound. The product ratios
remained constant throughout the course of the reac-
tion, which suggests that the resulting complexes are
not interconvertible under the reaction condition and
neither compound is an intermediate in the formation
of the other. The minor product was identified as the
unstable four-electron donor complex 8, and the major
product was recognized as the insertion product 7, which
was isolated in 34% yield.
cis to one CO (δ 224.4, J CF ) 5 Hz) and trans to the
2
second CO (δ 222.2, 2J CF ) 56 Hz), leaving the inserted
acetylene cis to the fluoride. The disposition of the
ligands about the tungsten(II) metal center is in agree-
ment with the structurally characterized compound 6.13
The 19F and 1H NMR spectra for compound 7 are
essentially identical to related η2-vinyl complexes con-
taining the fluorinated η3-[C,N,N′] ligand framework.11,13
Thus, the 1H NMR spectrum for 7 displays four different
highly coupled multiplet resonances (δ 4.65, 3.78, 2.89,
and 2.68) for the methylene protons on the backbone;
each resonance integrates to one proton. This non-
equivalence illustrates not only the chirality of the
pseudo six-coordinate tungsten(II) metal center but also
the retained coordination of the ligand in solution.13,18
The identification of 7 as an η2-vinyl, or metallacy-
clopropene, complex was ascertained from diagnostic
resonances in the 13C{1H} NMR spectrum.17 The car-
benoid character of CR is reflected by a large downfield
(17) (a) Nugent, W. A.; Mayer, J . M. Metal-Ligand Multiple Bonds;
Wiley: New York, 1988. (b) Mann, B. E.; Taylor, B. F. 13C NMR Data
for Organometallic Compounds; Academic Press: New York, 1981.
(18) (a) Kiplinger, J . L.; Richmond, T. G. Polyhedron, in press. (b)
Looman, S. D.; Giese, S.; Arif, A. M.; Richmond, T. G. Polyhedron 1996,
15, 2809-2811.

Carbon-Fluorine Bond Functionalization
Organometallics, Vol. 15, No. 25, 1996 5297
Ta ble 2. Releva n t Sp ectr oscop ic P a r a m eter s for Tu n gsten (II) F ou r -Electr on Don or a n d η2-Vin yl
Com p lexes
complex
ν
CO, cm-1 (toluene)
1966, 1867
δ(CR), ppm
230.1
δ(CO), ppm
δ(Câ), ppm
δ(Calkyne), ppm
N/A
δ(W-F), ppm
-152.9
7
224.4 d (2J CF ) 5 Hz)
222.1 d (2J CF ) 56 Hz)
242.1 d (2J CF ) 11 Hz)
25.7
9
10
11
15
16
17
19
20
1912
N/Aa
N/A
N/A
N/A
N/A
37.6
43.4
41.9
44.3
42.9
219.9 d (2J CF ) 15 Hz)
213.2 d (2J CF ) 31 Hz)
214.4 d (2J CF ) 15 Hz)
209.5 d (2J CF ) 32 Hz)
220.0 d (2J CF ) 14 Hz)
206.7 d (2J CF ) 34 Hz)
N/A
-140.2
-145.7
-132.9
-137.5
-145.3
-160.3
-138.8
-147.9
1914
244.0 d (2J CF ) 10 Hz)
241.1 d (2J CF ) 11 Hz)
1922
N/A
2008, 1908
1956, 1865
1947, 1851
1960, 1865
1960, 1865
203.2
223.0 d (2J CF ) 5 Hz)
222.9 d (2J CF ) 56 Hz)
226.8 d (2J CF ) 6 Hz)
222.9 d (2J CF ) 57 Hz)
223.7 d (2J CF ) 5 Hz)
217.6 d (2J CF ) 58 Hz)
226.4 d (2J CF ) 6 Hz)
223.2 d (2J CF ) 57 Hz)
226.5 d (2J CF ) 6 Hz)
222.4 d (2J CF ) 57 Hz)
228.4
N/A
N/A
N/A
N/A
(2J CF ) 2 Hz)
237.2
225.2
227.5
a
N/A ) not applicable.
The 19F NMR spectrum for 7 shows five resonances as
expected with appropriate integrations. The fluoride
ortho to the η2-vinyl moiety is easily identified and
appears as a distinctive broad resonance at δ -126.6,
and the W-F resonance is located as a singlet at δ
-152.9.
F or m a tion of F ou r -Electr on Don or Alk yn e Co-
or d in a tion Com p lexes. The six-coordinate, four-
electron donor alkyne complexes 9-11 were obtained
as air stable microcrystalline solids in 72-81% isolated
yields upon treatment of 2 with the appropriate electron-
rich internal acetylene in toluene under reduced pres-
sure at elevated temperatures (see Scheme 1). Reaction
of terminal acetylenes with 2 under similar conditions
gave only intractable decomposition products. The
formulation of 9-11 as four-electron donor alkyne
complexes was determined from salient spectroscopic
data which are listed in Table 2. The low-field acety-
lenic 13C{1H} chemical shift values exhibited by com-
plexes 9-11 suggest that the alkyne ligand in these
compounds is serving as a four-electron donor.19 The
lone carbonyl ligand resonates at δ 242.1 (2J CF ) 11 Hz)
for 9, at δ 244.0 (2J CF ) 10 Hz) for 10, and at δ 241.1
F igu r e 1. ORTEP representation of the tungsten(II) four-
electron donor alkyne complex 9.
Hz. Coalescence was observed at 68 °C, and a value of
∆Gq ) 68.2 kJ /mol was calculated for the rotation of the
alkyne ligand about the M-alkyne bond.21 Similarly
for complex 10, a value of ∆Gq ) 63.2 kJ /mol was
calculated for alkyne rotation by monitoring the alkyne
methyl resonances which were observed in the 1H NMR
as a pair of singlets separated by 83 Hz at -60 °C and
which coalesced at 40 °C. For complex 11, coalescence
of the W-F resonance (at -20 °C, ∆ν ) 1090 Hz) was
observed at 75 °C to calculate a ∆Gq ) 63.2 kJ /mol.
X-r a y Cr ysta llogr a p h ic An a lysis of 9. The solid
state structure of 9 is shown in Figure 1. Data collection
information, selected bond distances, and bond angles
for 9 are presented in Tables 1 and 3. The geometry
around the tungsten(II) metal center can be viewed as
roughly octahedral if one considers that the alkyne
ligand with a small Calkyne-W-Calkyne (C2-W-C3) bond
angle of 39.9(4)° occupies a single coordination site. The
rigid η3-[C,N,N′] imine ligand lies meridionally disposed
about the tungsten metal center with C4-W-N2 )
149.3(4)° and C1-W-N1 ) 161.8(5)°, leaving the fluo-
ride trans to the alkyne ligand with F1-W-C2 ) 163.6-
(4)° and F1-W-C3 ) 158.4(4)°. Thus, the C2 alkyne
2
(2J CF ) 11 Hz) for 11. The large J CF for the alkyne
contact carbons in these complexes signifies that the
alkyne ligand is trans to the metal fluoride,11 leaving
the carbonyl ligand cis to the fluoride.20
The tungsten-fluoride resonance is quite sensitive to
substitution at tungsten and shifts to much lower field
for the alkyne complexes relative to the parent tungsten
complex 2, which displays a 19F NMR resonance at δ
-223.4 (CDCl3) for W-F.2 Specific fluoride chemical
shifts for W-F are as follows: δ -145.2 for 9, δ -145.7
for 10, and δ -132.4 for 11. This denotes a significant
decrease in the basicity of the fluoride ligand and
indicates that the alkyne ligand functions as a voracious
π acid.
Dynamic NMR studies on the complexes revealed that
a barrier to alkyne rotation exists. At -20 °C, the
1
alkyne methyl resonances in the H NMR spectrum of
9 were observed as a pair of triplets separated by 116
(19) Templeton, J . L.; Ward, B. C. J . Am. Chem. Soc. 1980, 102,
3288-3290.
(20) (a) Blake, A. J .; Cockman, R. W.; Ebsworth, E. A. V.; Holloway,
J . H. J . Chem. Soc., Chem. Commun. 1988, 529-530. (b) Darensbourg,
D. J .; Klausmeyer, K. K.; Reibenspies, J . H. Inorg. Chem. 1995, 34,
4933-4934.
(21) Sandstro¨m, J . Dynamic NMR Spectroscopy; Academic Press:
London, 1982.
(22) For
Templeton, J . L. Adv. Organomet. Chem. 1989, 29, 1-100.
a
comprehensive review on d4 alkyne complexes, see:

5298 Organometallics, Vol. 15, No. 25, 1996
Kiplinger et al.
Ta ble 3. Selected Dista n ces (Å) a n d An gles (d eg)
Since thermal CO loss is rate determining in the
chemistry in Scheme 1, photochemical methods were
employed to observe intermediates in the migration
process. Room temperature photolysis (450 W Hg lamp
filtered through Pyrex) of 2 in the presence of the
appropriate acetylene gives 7 and 9, but again no
intermediates were detected. Photolysis of 2 in THF
affords the solvato complex 12, which could not be
isolated but was characterized by 19F NMR and IR
spectroscopies.
for (F 4-P ia )W(CO)(F )(CH3CH2CtCCH2CH3) 9a
W-F1
W-N1
W-N2
W-C1
2.005(5)
2.164(8)
2.282(8)
1.89(1)
W-C2
W-C3
W-C4
C2-C3
1.99(1)
2.00(1)
2.20(1)
1.30(2)
F1-W-N1
F1-W-N2
F1-W-C1
F1-W-C2
F1-W-C3
F1-W-C4
C2-C3-C17
77.9(3)
76.4(2)
83.9(4)
163.6(4)
158.4(4)
84.4(2)
139.(1)
C3-C2-C15
N2-W-C4
W-C2-C3
C2-W-C3
W-C3-C2
C1-W-C2-C3
138.(1)
149.3(4)
71.3(7)
37.9(4)
70.8(7)
2.9
Two very strong carbonyl stretches at 1957 and 1830
cm-1 in THF solution signal the presence of 12. The
low-energy carbonyl two-band pattern is consistent with
more electron density at the metal center and is
expected upon loss of a strong π-acid carbonyl ligand
and subsequent replacement by a σ-donor THF ligand.
Also consistent with this formulation is the W-F
resonance at δ -194.2, which is significantly downfield
from that for 2 (δ -223.4, CDCl3). Unfortunately, the
labile complex exhibits only limited stability and rapidly
decomposes in the absence of tetrahydrofuran.
a
Numbers in parentheses are estimated standard deviations
in the least significant digit.
unit is cis to the CO and lies parallel to the W-CO axis
(C1-W-C2-C3 ) 2.9°). The short W-Calkyne bond
distances of 1.99(1) and 2.00(1) Å are indicative of W-C
multiple bond character. The lengthened CtC bond
distance of 1.30(2) Å is also consistent with a tightly
bound four-electron donor alkyne.22 Accordingly, the
alkyne-ethyl substituent is bent away from the metal
with C2-C3-C15 ) 138(1)° and C3-C2-C17 ) 139-
(1)° as would be expected for sp2 hybridization of C2 and
C3.
Alk yn e In ser tion ver su s Ca r bon Mon oxid e Su b-
stitu tion : Evid en ce for a Tw o-Electr on Don or
Alk yn e Com p lex In ter m ed ia te. The reactions shown
in Scheme 1 require temperatures of at least 60 °C (the
same temperature required for isotopic incorporation of
13CO into the parent compound 2),13 which suggests that
the rate-limiting step is loss of CO. The four-electron
donor alkyne and η2-vinyl complexes are not intercon-
vertible moieties, even in the presence of carbon mon-
oxide.
Other σ-donor solvents such as CH3CN and benzoni-
trile are competent ligands and displace THF to afford
different adduct complexes with νCO ) 1951 and 1830
cm-1 and νCO ) 1953 and 1836 cm-1, respectively.
These donor complexes were also unstable and resisted
isolation, decomposing upon isolation and removal of
solvent. Alternatively, the σ-bound nitrile adducts could
be produced by photolysis of 2 in acetonitrile or ben-
zonitrile solution.
As illustrated in Scheme 2, exposure of a solution of
12 to CO cleanly regenerates 2. Reaction of 12 with
diphenylacetylene and 3-hexyne at room temperature
affords 7 and 9, respectively. Thus, aryl migration is
Sch em e 2
Sch em e 3

Carbon-Fluorine Bond Functionalization
Organometallics, Vol. 15, No. 25, 1996 5299
F igu r e 3. ORTEP representation of the tungsten(II) η2-
vinyl complex 17.
F igu r e 2. ORTEP representation of the tungsten(II) η2-
vinyl complex 16.
Ta ble 4. Selected Dista n ces (Å) a n d An gles (d eg)
fast at room temperature as is production of the four-
electron donor alkyne complexes.
for th e Tu n gsten (II) η2-Vin yl Com p lexes 16 a n d 17a
16
17
Alk yn e In ser tion in to a Non flu or in a ted Ar yl
Ca r bon -Tu n gsten (II) Bon d . Reaction of internal
electron-deficient alkynes with 4 results in exclusive η2-
vinyl complex formation as illustrated in Scheme 3.
Treatment of a toluene solution of 4 with the acetylenes
5a -c and 18 at elevated temperatures under reduced
pressure affords the η2-vinyl complexes 15-20. As with
their fluorinated congeners, the η2-vinyl complexes 15-
20 all display the essential spectroscopic features
consistent with their assigned η2-vinyl compositions as
shown in Table 2. The 13C{1H} NMR chemical shift of
CR resonates at higher field as the electron demand of
the alkylidene substituent increases in the series CH3
< Ph < CF3. Also consistent with the amount of
electron density removed from the metal center by the
cyclic carbene is a similar progression toward lower field
strength observed in the 19F NMR spectra for the W-F
resonances with δ -137.54 for 15, δ -145.31 for 16, and
W-F
2.002(3)
2.185(5)
2.352(5)
1.957(6)
1.949(6)
1.976(6)
2.214(6)
1.454(8)
W-F
2.044(3)
2.195(4)
2.344(4)
1.960(6)
1.976(6)
1.966(5)
2.206(5)
1.435(7)
W-N1
W-N2
W-C1
W-C2
W-C3
W-C4
C3-C4
W-N1
W-N2
W-C1
W-C2
W-C3
W-C4
C3-C4
W-C4-C3
F-W-C1
61.1(3)
93.4(2)
171.6(2)
111.4(2)
91.2(2)
76.4(2)
162.3(2)
117.0(5)
81.9(2)
119.7(5)
159.9(2)
158.2(2)
116.4(5)
40.1(2)
78.8(3)
149.0(4)
132.0(5)
68.6
W-C4-C3
F-W-C1
61.1(3)
168.0(2)
97.1(2)
116.8(2)
90.1(2)
77.5(2)
167.8(2)
117.5(4)
84.4(2)
118.9(4)
156.9(2)
161.3(2)
114.6(4)
39.7(2)
79.2(3)
148.5(4)
132.3(5)
72.3
F-W-C2
F-W-C2
F-W-C3
F-W-C3
F-W-C4
F-W-C4
N1-W-N2
N1-W-C1
C3-C4-C5
N1-W-C4
C3-C4-C22
N2-W-C3
N2-W-C4
C5-C4-C22
C3-W-C4
W-C3-C4
W-C3-C16
C4-C3-C16
N1-W-N2
N1-W-C2
C3-C4-C5
N1-W-C4
C3-C4-C16
N2-W-C3
N2-W-C4
C5-C4-C16
C3-W-C4
W-C3-C4
W-C3-C22
C4-C3-C22
2
δ -160.31 for 17. The small J CF coupling of 2 Hz in
the complex 16 is consistent with the assigned cis
arrangement between the inserted alkyne and the metal
fluoride ligand.13
Interestingly, electron-rich acetylenes 2-butyne and
3-hexyne display no reactivity with metallacycle 4;
reactions at elevated temperatures result in decomposi-
tion of starting materials with formation of intractable
products. Likewise, terminal alkynes such as phenyl-
acetylene and 3,3,3-trifluoropropyne do not afford any
productive chemistry upon reaction with metallacycle
4.
X-r a y Cr ysta llogr a p h ic An a lyses of 16 a n d 17.
The molecular structures of the η2-vinyl complexes 16
and 17 were confirmed by X-ray crystallography and are
shown in Figures 2 and 3, respectively, where the atomic
numbering scheme for each compound is defined. Data
collection information, selected bond distances, and bond
angles for 16 and 17 are presented in Tables 1 and 4.
Compounds 16 and 17 exhibit several structural
features which are common22 to η2-vinyl complexes: (1)
The orientation of the two Câ substituents are roughly
orthogonal to the MCRCâ plane. (2) There are short
M-CR distances (1.976(6) and 1.966(5) Å for 16 and 17,
respectively) in the metal-carbon double-bond range.
(3) The M-Câ bond distances (2.214(6) and 2.206(5) Å)
are in the metal-carbon single-bond range. (4) CR-Câ
C16-C3-C4-C22
C16-C3-C4-C5
C22-C3-C4-C16
C22-C3-C4-C5
-81.4
-72.9
a
Numbers in parentheses are estimated standard deviations
in the least significant digit.
bond distances are suggestive of double-bond character
(1.454(8) and 1.435(7) Å). For both compounds 16 and
17, comparable crystallographic data were obtained
supporting their formulation as η2-vinyl complexes.
Clearly, the Câ carbons in both compounds are ap-
proximately tetrahedral and are consistent with an η2-
vinyl composition rather than an η1-vinyl structure
where M, CR, Câ, and the two Câ substituents would lie
in a plane.23 It should be noted that, in both compounds
16 and 17, the sum of the angles around CR(C3) add up
to 360° as expected for an sp2 center.
The geometry around the tungsten(II) metal center
in the η2-vinyl compounds can be described as roughly
octahedral if one considers that the η2-vinyl moiety
occupies a single coordination site. Specific η2-vinyl
(23) (a) Allen, S. R.; Baker, P. K.; Barnes, S. G.; Botrill, M.; Green,
M.; Orpen, G. A.; Welch, A. J . J . Chem. Soc., Dalton Trans. 1983, 927-
939. (b) Reger, D. L. Acc. Chem. Res. 1988, 21, 229-235.

5300 Organometallics, Vol. 15, No. 25, 1996
Kiplinger et al.
bond angles are as follows: C3-W-C4 ) 40.1(2)° for
16 and C3-W-C4 ) 39.7(2)° for 17. A common feature
extant in both 16 and 17 is that the rigid tridentate η3-
[C,N,N′] imine ligand adopts a meridional arrangement
about the tungsten metal center. In both complexes,
the inserted alkyne is approximately cis to the fluoride
(C3-W-F ) 111.4(2)° and C4-W-F ) 91.2(2)° for 16;
C3-W-F ) 116.8(2)° and C4-W-F ) 90.1(2)° for 17)
and one carbonyl ligand (C1-W-F ) 93.4(2)° for 16 and
C2-W-F ) 97.1(2)° for 17) and trans to the second
carbonyl ligand (C2-W-F ) 171.6(2)° for 16 and C1-
W-F ) 168.0(2)° for 17).
Regioch em istr y of th e Alk yn e In ser tion . As
illustrated in Scheme 3, the migratory insertion reaction
is regioselective for the unsymmetrical acetylene, 1-phen-
yl-1-propyne, with the insertion taking place at the
electron-deficient, phenyl-substituted alkyne carbon
(versus the electron-rich, methyl-substituted alkyne
carbon).24 To probe the regioselectivity where only
electronic factors are different, the acetylene 18 was
synthesized via standard Pd(0) coupling protocol in 97%
yield (eq 2).25 Elemental analysis, mass spectrometry,
1 to 6 and 7 and from compound 3 to 15-20 is indeed
unusual and exploits a rare migration reaction of a
fluorinated ligand to afford robust η2-vinyl complexes
in which net replacement of a carbon-fluorine bond
with a carbon-carbon bond has taken place. This
transformation utilizes known oxidative addition chem-
istry in conjunction with migratory insertion of unsat-
urated organic compounds to sequentially activate and
chemically modify carbon-fluorine bonds under mild
conditions.
η2-Vin yl Com p lex ver su s F ou r -Electr on Don or
Alk yn e Com p lex F or m a tion . Reactions of tungsten-
(II) fluoride carbonyl metallacycles with internal acety-
lenes afford a mixture of η2-vinyl and four-electron donor
alkyne complexes. Compatible with other η2-vinyl
systems, all of the η2-vinyl complexes reported in this
work exhibit a large downfield 13C{1H} NMR chemical
shift for the alkylidene carbon as well as a significant
upfield shift for the four-coordinated carbon in the
metallacyclopropenyl moiety (Table 2).22 Similarly, the
four-electron donor alkyne complexes show large down-
field 13C{1H} NMR chemical shifts below δ 200 that
serve as a fingerprint for an alkyne donating four
electrons to a metal center (Table 2).19 Not only does
this description abide by the 18-electron formalism, but
these chemical shifts clearly contrast three- and two-
electron donor alkyne ligands which have 13C{1H} NMR
resonances in the δ 140-190 and δ 90-120 ranges,
respectively.
Consistent with low symmetry of the molecules, the
η2-vinyl complexes show two carbonyl resonances in the
carbon spectrum. The carbonyl ligand trans to the
fluoride ligand possesses a large J CF (∼56 Hz) and the
and 1H, 19F, and 13C{1H} NMR data support the
proposed structure.
2
other carbonyl, which is cis to the fluoride, has a small
2J CF (∼5 Hz).11,13,20 Furthermore, these η2-vinyl com-
plexes do not manifest any dynamic behavior on the
NMR time scale. This contrasts with the several η2-
vinyl systems reported by Green,26 Templeton,27 and
Davidson28 that undergo a variety of fluxional processes,
which are attributed to a windshield-wiper motion (less
than 90° rotation) of the η2-vinyl fragment. Presumably,
the steric constraint imposed by the rigid tridentate η3-
[C,N,N′] chelate ligand prevents this classical windshield-
wiper motion from occurring (rotation of the η2-vinyl
ligand). Any dynamic process would require a discon-
nection/reconnection of the Câ and the aromatic carbon,
which is highly unlikely.
Reaction of 18 with the metallacycle 4 in toluene
solution at 90 °C for 4 h under reduced pressure affords
a mixture of the isomeric η2-vinyl complexes 19 and 20
in 56 and 44% yields, respectively, as determined using
19F NMR spectroscopy from integration of the trifluo-
romethyl and W-F resonances (Scheme 3).
The η2-vinyl isomers 19 and 20 possess different
solubility properties and are easily separated by crystal-
lization. As reported in Table 2, both complexes display
1H, 19F, and 13C{1H} NMR spectra essentially identical
to those of complexes 15-17 as well as contain the vital
spectroscopic features diagnostic for their formulation
as η2-vinyl complexes.22 Noting the trends presented
above for the η2-vinyl complexes 15-17, the NMR data
for compounds 19 and 20 are consistent with the
indicated regiochemistry for the alkyne insertion (Scheme
3). Compound 19 evinces an alkylidene resonance in
the 13C{1H} NMR at δ 225.2 and a W-F resonance in
the 19F NMR at δ -138.7, whereas the alkylidene carbon
in compound 20 resonates further downfield at δ 227.5
and the W-F resonates further upfield at δ -147.9, both
consistent with a greater electron density on CR (and
less electron density at the metal center) containing the
p-CF3C6H4 fragment.
Although the η3-[C,N,N′] chelate is rigid, the alkyne
ligand in complexes 9-11 is dynamic and barriers to
rotation of 15-17 kcal/mol were measured which are
similar to other d4 W(II) cis-L4M(CO)(RCtCR) com-
plexes.22 As reported for all octahedral d4 L4M(CO)-
(RCtCR) complexes characterized to date, the four-
electron donor alkyne complexes possess a cis-M(CO)-
(RCtCR) fragment in which the CO and alkyne ligands
adopt a parallel arrangement. Alignment of the alkyne
parallel to the W-CO axis uniquely positions π to
overlap the lone vacant metal dπ orbital in the octahe-
dral geometry.
Discu ssion
Meta l-Assisted F u n ction a liza tion of F lu or oca r -
bon s. The use of transition metal complexes to mediate
ligand-based transformations on fluorinated substrates
is not well developed due to the great strength of the
carbon-fluorine bond.1 The progression from compound
(26) Allen, S. R.; Beevor, R. G.; Green, M.; Norman, N. C.; Orpen,
A. G.; Williams, I. D. J . Chem. Soc., Dalton Trans. 1985, 435-450.
(27) Gamble, A. S.; White, P. S.; Templeton, J . L. Organometallics
1991, 10, 693-702.
(28) (a) Davidson, J . L.; Wilson, W. F.; Manjlovic-Muir, L.; Muir, K.
W. J . Organomet. Chem. 1983, 254, C6-C10. (b) Carlton, L.; Davidson,
J . L.; Miller, J . C.; Muir, K. W. J . Chem. Soc., Chem. Commun. 1984,
11-13. (c) Carlton, L.; Davidson, J . L. J . Chem. Soc., Dalton Trans.
1987, 895-905. (d) Agh-Atabay, N. M.; Canoira, L. J .; Carlton, L.;
Davidson, J . L. J . Chem. Soc., Dalton Trans. 1991, 1175-1182.
(24) March, J . Advanced Organic Chemistry, 2nd ed.; Wiley: New
York, 1985; Chapter 9.
(25) Stille, J . K. Angew. Chem., Int. Ed. Engl. 1986, 25, 508-524.

Carbon-Fluorine Bond Functionalization
Organometallics, Vol. 15, No. 25, 1996 5301
The η2-vinyl complexes and the four-electron donor
complexes may share a common two-electron donor
alkyne complex intermediate. The THF adduct 12
enables the formation of the η2-vinyl complexes and the
four-electron donor complexes presented in this work
in minutes at room temperature, which supports the
notion that these complexes arise from a common
intermediate. Importantly, since the η2-vinyl complexes
and the four-electron donor complexes do not intercon-
vert under the conditions used for their synthesis,
neither of them is an intermediate in the formation of
the other.
Organometallic η2-vinyl complexes are of interest
because a variety of catalytic chemical transformations
postulate the crucial participation of vinyl intermediates
stabilized by a metal center.29 Thus, aryl migration at
a tungsten(II) two-electron donor alkyne complex is
significant because it provides a new avenue to access
η2-vinyl complexes. Previous synthetic approaches to
η2-vinyl complexes have involved the external attack of
nucleophiles (hydrides,26,30 thiols and thiolates,28bc,31
isonitriles,32 nitrogen,33 and phosphorus28ad,30d,32,34 re-
agents) on coordinated four-electron donor alkyne ligands.
Alk yn e In ser tion w ith a High ly F lu or in a ted
Migr a tin g Gr ou p . Although metal-mediated cou-
plings of perfluoroalkenes and perfluoroalkynes are well
precedented, migratory insertion reactions are quite
rare presumably due to the increased strength and
reduced nucleophilicity of the metal-carbon bond com-
pared to those of hydrocarbon analogues.1a,13,35 The
diverse reactivity of the metallacycles 2 and 4 presented
in this work further underscores this trend. Whereas
the highly fluorinated metallacycle 2 forms the η2-vinyl
complex 7 in low yields accompanied with the genera-
tion of the four-electron donor complex 8, the nucleo-
philic metallacycle 4 affords only the η2-vinyl complex
16 in high yield. In the case of 1-phenyl-propyne,
complex 2 affords only the four-electron donor alkyne
complex 11, whereas complex 4 affords only the η2-vinyl
complex 17. The sluggish migratory aptitude of the
pentafluorophenyl group has been exploited by Espinet
and co-workers to isolate a rare palladium complex with
mutually cis olefin and C6F5 groups and then to study
the kinetics of the subsequent migratory insertion of the
olefin into the C6F5-Pd bond.36 Thus, it is noteworthy
that the migration of the highly fluorinated metallacycle
in 2 is facile at ambient temperature. Terminal acety-
lenes exhibit disappointing reactivity with 2 and 4. This
may be a consequence of reaction of the basic fluoride
with the alkyne proton or polymerization of the alkyne.
Both problems were noted in the low-yield synthesis of
the four-electron donor cyanoacetylene adduct of 2.37
The η2-vinyl complexes are chemically robust toward
multiple alkyne insertions into the W-Caryl bond. This
contrasts with the alkyne reactivity of related 16-
electron later transition metal complexes which readily
undergo multiple insertion reactions to form large
metallacycle complexes as well as novel heterocyclic ring
systems upon metal extrusion.10ab,38
Only one regioisomer was isolated from the insertion
reaction of 4 with 1-phenyl-1-propyne, albeit in low
yield. Since both steric and electronic factors are
different for this acetylene, we prepared the electroni-
cally unsymmetrical acetylene 18 to determine any
electronic bias to the insertion process. Isomeric com-
plexes 19 and 20 were in obtained in high yield with a
56:44 ratio favoring insertion into the more electron-
rich phenyl side rather than the CF3-phenyl site of the
alkyne. The difference is small and suggests that there
is not a great electronic bias for the nucleophilic
migration process.
Con clu sion
We have demonstrated that under mild conditions
oxidative addition of strong aromatic carbon-fluorine
bonds in conjunction with migratory insertion of unsat-
urated organic compounds at a tungsten(II) metal center
can be employed for the elaboration of carbon-fluorine
bonds. A competitive reaction involving formation of
four-electron donor alkyne complexes is favored for
electron-rich alkynes. A two-electron donor alkyne
complex may be a common intermediate in these
transformations which could either participate in the
migratory insertion reaction or lose carbon monoxide
to afford the four-electron donor alkyne complex. Al-
though these ligand-based systems are limited with
respect to catalytic chemistry, they do serve as model
compounds for the systematic studies of structure and
reactivity directed toward catalytic activation and func-
tionalization of carbon-fluorine bonds.
Ack n ow led gm en t. We gratefully acknowledge sup-
port in the form of an AAUW American Fellowship to
J .L.K. (1995-1996) as well as partial support from the
National Science Foundation (Grant CHE-895845) and
the Alfred P. Sloan Foundation in the form of a Research
Fellowship awarded to T.G.R. (1991-1995). The mass
spectrometer was purchased with funds from the NSF
(Grant CHE-9002690) and the University of Utah
Institutional Funds Committee.
(29) (a) Gates, B. C.; Katzer, J . R.; Schuit, G. C. A. Chemistry of
Catalytic Processes; McGraw-Hill: New York, 1979. (b) Carlton, L.;
Davidson, J . L.; Ewing, P.; Manjlovic-Muir, L.; Muir, K. W. J . Chem.
Soc., Chem. Commun. 1985, 1474-1476. (c) Parshall, G. W.; Ittel, S.
D. Homogeneous Catalysis, 2nd ed.; Wiley-Interscience: New York,
1992.
(30) (a) Green, M.; Norman, N. C.; Orpen, A. G. J . Am. Chem. Soc.
1981, 103, 1267-1269. (b) Allen, S. R.; Green, M.; Orpen, A. G.;
William, I. D. J . Chem. Soc., Chem. Commun. 1982, 826-828. (c)
Beevor, R. G.; Green, M.; Orpen, A. G.; Williams, I. D. J . Chem. Soc.,
Chem. Commun. 1983, 673-675. (d) Feng, S. G.; Templeton, J . L.
Organometallics 1992, 11, 2168-2175. (e) Feng, S. G.; White, P. S.;
Templeton, J . L. J . Am. Chem. Soc. 1992, 114, 2951-2960.
(31) Davidson, J . L. J . Organomet. Chem. 1985, 186, C19-C22.
(32) Davidson, J . L.; Vasapollo, G.; Manjlovic-Muir, L.; Muir, K. W.
J . Chem. Soc., Chem. Commun. 1982, 1025-1027.
(33) (a) Davidson, J . L.; Murray, I. E. P.; Preston, P. N.; Russo, M.
V. J . Chem. Soc., Chem. Commun. 1981, 1059-1061. (b) Davidson, J .
L.; Murray, I. E. P.; Preston, P. N.; Russo, M. V. J . Chem. Soc., Dalton
Trans. 1983, 1783-1787.
(34) Morrow, J . R.; Tonker, T. L.; Templeton, J . L. J . Am. Chem.
Soc. 1985, 107, 6956-6963.
(35) (a) Gipson, S. L.; Kneten, K. Inorg. Chim. Acta 1989, 157, 143-
145. (b) Albe´niz, A. C.; Foces-Foces, C.; Cano, F. H. Organometallics
1990, 9, 1079-1085. (c) Albe´niz, A. C.; Espinet, P. Organometallics
1991, 10, 2987-2988.
(36) Albe´niz, A. C.; Espinet, P.; J eannin, Y.; Philoche-Levisalles, M.;
Mann, B. E. J . Am. Chem. Soc. 1990, 112, 6594-6600.
Su p p or tin g In for m a tion Ava ila ble: Tables giving full
crystallographic data for 9, 16, and 17, including bond
distances, bond angles, torsional angles, final positional and
general displacement parameters, and least-squares planes (57
pages). See any current masthead page for ordering infor-
mation.
OM960561S
(37) Kiplinger, J . L.; Arif, A. M.; Richmond, T. G. Inorg. Chem. 1995,
34, 399-401.
(38) (a) Bahsoun, A.; Dehand, J .; Pfeffer, M.; Zinsius, M.; Bouaoud,
S. E.; Le Borgne, G. J . Chem. Soc., Dalton Trans. 1979, 547-556. (b)
Arlen, C.; Pfeffer, M.; Fischer, J .; Mitschler, A. J . Chem. Soc., Chem.
Commun. 1983, 928-929.