Base-promoted hydroalkylation reactions of the η5-C5Me5 ligand coordinated to rhodium: Probing a mechanism. New compounds with the η5-C5Me4CF3 ligand

Article abstract of DOI:10.1021/om960213q

Dichloro(pentamethylcyclopentadienyl)rhodiumd(III) dimer, [{(η⁵-C₅Me₅)RhCl₂}₂] (1), reacts with diphenylvinylphosphine to produce [(η⁵-C₅Me₅)Rh{CH₂CHP(C ₆H₅)₂}Cl₂] (2) and [(η⁵-C₅Me₅)Rh{CH₂CHP(C ₆H₅)₂}₂Cl]X (3, X = Cl^- (a), PF₆^-(b)). In acetonitrile, compound 1 undergoes a base-promoted hydroalkylation reaction with potassium tert-butoxide and diphenylvinylphosphine to produce [{η⁵-C₅Me₃-1,3-[CH₂CH ₂CH₂P(C₆H₅)2]₂}RhCl]X (4, X = Cl^- (a), PF₆^- (b), BPh₄^- (c)) and f{η⁵-C₅Me₃-1,2-[CH₂CH ₂CH₂P(C₆H₅)₂] ₂}RhC]X (5, X = Cl^- (a), PF₆^- (b), BPh₄^- (c)). Compounds 4a-c and 5a-c contain chelating 1,3- and 1,2- bis-((diphenylphosphino)propyl)trimethylcyclopentadienide ligands. Compounds 2 and 3 are precursors on the pathway toward formation of 4a and 5a. Compound 1 reacts with allyldiphenylphosphine to produce [(η⁵-C₅,Me₅)Rh{CH₂CHCH ₂P(C₆H₅)₂}Cl₂] (6) and [(η⁵-C₅-Me₅)Rh{CH₂CHCH ₂P(C₆H₅)₂}₂Cl]X (7, X = Cl^- (a), PF₆^- (b)). In acetonitrile, compound 1 reacts with allyldiphenylphosphine in the presence of potassium tert-butoxide to produce a complex mixture of products that may contain hydroalkylation adducts. Dichloro{(trifluoromethyl)tetramethylcyclopentadienyl}rhodium(III) dimer, [{(η⁵-C₅Me₄CF₃)RhCl ₂}₂}₂] (8), reacts with diphenylvinylphosphine to produce [(η⁵-C₅Me₄CF₃)Rh{CH ₂CHP(C₆H₅)₂}Cl₂] (9), however the bis(phosphine) analog cannot be isolated or characterized. In refluxing ethanol, compound 8 reacts with diphenylvinylphosphine in the absence of potassium tertbutoxide to undergo hydroalkylation accompanied by conversion of the CF₃ group into a carboethoxy functionality producing [{η⁵-C₅(CO₂Et)Me₃-2-[CH ₂CH₂CH₂P(C₆H₅) ₂]}RhCl₂] (10). Complexes 3b, 7b, and 10 were characterized by single-crystal X-ray crystallography.

Full text of DOI:10.1021/om960213q

3924
Organometallics 1996, 15, 3924-3934
Ba se-P r om oted Hyd r oa lk yla tion Rea ction s of th e
η5-C5Me5 Liga n d Coor d in a ted to Rh od iu m : P r obin g a
Mech a n ism . New Com p ou n d s w ith th e η5-C5Me4CF 3
Liga n d
Luis P. Barthel-Rosa, Vincent J . Catalano, Kalyani Maitra, and J ohn H. Nelson*
Department of Chemistry/ 216, University of NevadasReno, Reno, Nevada 89557
Received March 21, 1996X
Dichloro(pentamethylcyclopentadienyl)rhodium(III) dimer, [{(η5-C5Me5)RhCl2}2] (1), reacts
with diphenylvinylphosphine to produce [(η5-C5Me5)Rh{CH2CHP(C6H5)2}Cl2] (2) and [(η5-
C5Me5)Rh{CH2CHP(C6H5)2}2Cl]X (3, X ) Cl- (a ), PF6 (b)). In acetonitrile, compound 1
-
undergoes a base-promoted hydroalkylation reaction with potassium tert-butoxide and
diphenylvinylphosphine to produce [{η5-C5Me3-1,3-[CH2CH2CH2P(C6H5)2]2}RhCl]X (4, X )
Cl- (a ), PF6- (b), BPh4- (c)) and [{η5-C5Me3-1,2-[CH2CH2CH2P(C6H5)2]2}RhCl]X (5, X ) Cl-
-
-
(a ), PF6 (b), BPh4 (c)). Compounds 4a -c and 5a -c contain chelating 1,3- and 1,2- bis-
((diphenylphosphino)propyl)trimethylcyclopentadienide ligands. Compounds 2 and 3 are
precursors on the pathway toward formation of 4a and 5a . Compound 1 reacts with
allyldiphenylphosphine to produce [(η5-C5Me5)Rh{CH2CHCH2P(C6H5)2}Cl2] (6) and [(η5-C5-
Me5)Rh{CH2CHCH2P(C6H5)2}2Cl]X (7, X ) Cl- (a ), PF6 (b)). In acetonitrile, compound 1
-
reacts with allyldiphenylphosphine in the presence of potassium tert-butoxide to produce a
complex mixture of products that may contain hydroalkylation adducts. Dichloro-
{(trifluoromethyl)tetramethylcyclopentadienyl}rhodium(III) dimer, [{(η5-C5Me4CF3)RhCl2}2]
(8), reacts with diphenylvinylphosphine to produce [(η5-C5Me4CF3)Rh{CH2CHP(C6H5)2}Cl2]
(9), however the bis(phosphine) analog cannot be isolated or characterized. In refluxing
ethanol, compound 8 reacts with diphenylvinylphosphine in the absence of potassium tert-
butoxide to undergo hydroalkylation accompanied by conversion of the CF3 group into a
carboethoxy functionality producing [{η5-C5(CO2Et)Me3-2-[CH2CH2CH2P(C6H5)2]}RhCl2] (10).
Complexes 3b, 7b, and 10 were characterized by single-crystal X-ray crystallography.
In tr od u ction
lytic systems2,7 or stabilize reactive intermediates.3,4b
η5-C5Me5 ligands may be functionalized before or after
their coordination to a transition metal,1a but the latter
method is sometimes more desirable. Examples of both
methods have been published1-6 that culminate in a
wide variety of pendant R groups including amines
(achiral1a,b,3 and chiral2), alkanes,6 alkenes,1e,g,4a-c
arenes,1d,e,g,j ethers,1a,5 halides,1a-c,f and many others.1a-i
Research dating back to the early seventies established
that methyl groups of a metal-coordinated η5-C5Me5
ligand can be activated thermally8g or by the action of
strong bases.1i Since that time, a great deal of work
demonstrates that a variety of transition metals includ-
ing Rh,1d,h,i Ir,1c,e,g,i,10 Ru,1a,b,f,j Fe,9 Pd,11 Ti,8a,e,f Zr,8b,d
W,12 and other metals8c activate η5-C5Me5 ligands. In
spite of the aforementioned work, there are only a few
Cyclopentadienyl (η5-C5H5) and substituted cyclopen-
tadienyl ligands, especially pentamethylcyclopentadi-
enyl (η5-C5Me5), are ubiquitous in organometallic chem-
istry as stabilizing ligands for transition metals. Recent
synthetic endeavors1-6 have been directed at function-
alizing η5-C5Me5 ligands to make η5-C5Me4R, where the
R groups are pendant arms that may also serve as
donors toward a metal. The impetus is to design
“hybrid” ligands7 that may enhance selectivity in cata-
X Abstract published in Advance ACS Abstracts, August 15, 1996.
(1) (a) Fan, L.; Turner, M. L.; Adams, H.; Bailey, N. A.; Maitlis, P.
M. Organometallics 1995, 14, 676. (b) Fan, L.; Turner, M. L.; Hurst-
house, M. B.; Abdul Malik, K. M.; Gusev, O. V.; Maitlis, P. M. J . Am.
Chem. Soc. 1994, 116, 385. (c) Miguel-Garcia, J . A.; Adams, H.; Bailey,
N. A.; Maitlis, P. M. J . Chem. Soc., Dalton Trans. 1992, 131. (d) Gusev,
O. V.; Rubezhov, A. Z.; Miguel-Garcia, J . A.; Miatlis, P. M. Mendeleev
Commun. 1991, 21. (e) Miguel-Garcia, J . A.; Adams, H.; Bailey, N. A.;
Maitlis, P. M. J . Organomet. Chem. 1991, 413, 427. (f) Wei, C.;
Aigbirhio, F.; Adams, H.; Bailey, N. A.; Hempstead, P. D.; Maitlis, P.
M. J . Chem. Soc., Chem. Commun. 1991, 883. (g) Miguel-Garcia, J .
A.; Maitlis, P. M. J . Chem. Soc., Chem. Commun. 1990, 1472. (h)
Nutton, A.; Maitlis, P. M. J . Chem. Soc., Dalton Trans. 1981, 2335. (i)
Kang, J . W.; Maitlis, P. M. J . Organomet. Chem. 1971, 30, 127. (j)
O’Leary, S. R.; Adams, H.; Bailey, N. A.; Maitlis, P. M. J . Chem. Soc.,
Chem. Commun. 1995, 2019.
(2) Adams, H.; Bailey, N. A.; Colley, M.; Schofield, P. A.; White, C.
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Organometallics 1992, 11, 3935. (b) Okuda, J .; Zimmermann, K. H.
Angew. Chem., Int. Ed. Engl. 1991, 30, 430. (c) Okuda, J .; Zimmer-
mann, K. H. J . Organomet. Chem. 1988, 344, C1.
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L. E.; Brock, C. P.; Marks, T. J . Organometallics 1987, 6, 232. (e)
Pattiasina, J . W.; Hissink, C. E.; de Boer, J . L.; Meetsma, A.; Teuben,
J . H. J . Am. Chem. Soc. 1985, 107, 7758. (f) McDade, C.; Green, J . C.;
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Organometallics 1983, 2, 1369.
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Chem. Soc., Chem. Commun. 1985, 945.
S0276-7333(96)00213-0 CCC: $12.00 © 1996 American Chemical Society

Base-Promoted Hydroalkylation Reactions
Organometallics, Vol. 15, No. 19, 1996 3925
Ch a r t 1. Com p ou n d s 4a -c a n d 5a -c
examples of η5-C5Me4R ligands containing pendant
phosphines1a,1e,9,13,14 and a small number of difunction-
alized (η5-C5Me3R2) ligands.13,14 In this paper we de-
scribe the synthesis and characterization of novel
rhodium complexes containing chelating (phosphino-
propyl)cyclopentadienide ligands of the type η5-C5Me3R2,
which are formed by base-promoted intramolecular
hydroalkyl addition,15 and the intermediates that pre-
cede their formation. Such ligands may be useful in the
same applications described above. A preliminary ac-
count of this work has appeared.13
F igu r e 1. Structural drawing of the cation of [{η5-C5Me3-
1,3-[CH2CH2CH2P(C6H5)2]2}RhCl]PF6 (4b), showing the
atom-numbering scheme (40% probability ellipsoids). Hy-
drogen atoms have been omitted for clarity.13
First, the syntheses of two intermediates that precede
hydroalkylation are described. Next, the conditions that
promote hydroalkylation between diphenylvinylphos-
phine and [{(η5-C5Me5)RhCl2}2] (1) to form the chelating
(phosphinopropyl)cyclopentadienide ligands are de-
scribed. Following that are attempts to produce new
chelating ligands with allyldiphenylphosphine. Finally,
the reactions of the compound [{(η5-C5Me4CF3)RhCl2}2]
(8), (an analog of compound 1) with diphenylvinylphos-
phine were investigated to probe the effects of an
electron-withdrawing group on hydroalkylation.
Resu lts a n d Discu ssion
We recently reported13 that refluxing a mixture of
[{(η5-C5Me5)RhCl2}2] (1) and diphenylvinylphosphine
(DPVP) in benzene in the presence of azobis(isobuty-
ronitrile) (AIBN) led to the formation of two novel rho-
dium complexes, [{η5-C5Me3-1,3-[CH2CH2CH2P(C6H5)2]2}-
F igu r e 2. Structural drawing of the cation of [{η5-C5Me3-
1,2-[CH2CH2CH2P(C6H5)2]2}RhCl]BPh4 (5c), showing the
atom-numbering scheme (40% probability ellipsoids). Hy-
drogen atoms have been omitted for clarity.13
-
-
RhCl]X (4, X ) Cl- (a ), PF6 (b), BPh4 (c)) and [{η5-
C5Me3-1,2-[CH2CH2CH2P(C6H5)2]2}RhCl]X (5, X ) Cl-
(a ), PF6- (b), BPh4- (c)). Schematic representations of
4a -c and 5a -c are shown in Chart 1. The novelty of
this reaction is the unusual reaction between the vinyl
moiety on the coordinated phosphorus atom and the
methyl groups of the η5-C5Me5 ligand. The terminal
vinylic carbon atom forms a new C-C bond to a methyl
group with concomitant C-H bond cleavage and forma-
tion of a new C-H bond on the carbon R to the
phosphorus atom. Formally, the methyl groups of the
η5-C5Me5 have undergone a hydroalkyl addition (or
hydroalkylation) to the vinylphosphine ligands.15 To the
best of our knowledge, this is the only example of such
an addition in these types of systems.
each compound, the analysis revealed a distorted octa-
hedral geometry at rhodium with a coordinated methyl-
substituted cyclopentadienyl ring, two diphenylphos-
phine moieties, and one chloride. Each rhodium-bound
diphenyl phosphine group is connected to the cyclopen-
tadienyl ring via three methylene carbons. A similar
linkage is observed for an analogous phosphine in the
reported17 ruthenium complex [{η5-C5H4CH2CH2PPh2}-
1
Ru(PPh3)Cl]. The H and 13C{1H} NMR spectroscopic
data for 4b and 5c are in accord with both structures
(see Experimental Section).
The structure of a similar molecule, [{η5-C5Me3-
[CH2C6F4P(C6F5)CH2]2-1,3}RhCl]BF4, has been re-
ported14 recently; however in that system the 1,3 methyl
groups formed new C-C bonds with a bis(bis(penta-
flourophenyl)phosphino)ethane (dfppe) ligand (Scheme
1). The authors suggest the mechanism of its formation
involves C-F bond cleavage and elimination of HF to
make a chelating aryldiphosphine. The geometric con-
straints of the dfppe ligand probably prevent the 1,2
isomer from forming in this system.
X-ray crystallographic analyses established the struc-
tures of 4b and 5c.13 Figures 1 and 2 show the structural
drawings of the cations of 4b and 5c, respectively. For
(13) Barthel-Rosa, L. P.; Catalano, V. J .; Nelson, J . H. J . Chem. Soc.,
Chem. Commun. 1995, 1629.
(14) Atherton, M. J .; Fawcett, J .; Holloway, J . H.; Hope, E. G.;
Karac¸ar, A.; Russell, D. R.; Saunders, G. C. J . Chem. Soc., Chem.
Commun. 1995, 191.
(15) March, J . Advanced Organic Chemistry; Wiley: New York,
1992; p 790 ff.
(16) Hoard, D. W.; Sharp, P. R. Inorg. Chem. 1993, 32, 612.
(17) Slawin, A. M. Z.; Williams, D. J .; Crosby, J .; Ramsden, J . A.;
White, C. J . Chem. Soc., Dalton Trans. 1988, 2491.

3926 Organometallics, Vol. 15, No. 19, 1996
Barthel-Rosa et al.
Sch em e 1
F igu r e 3. Structural drawing of the cation of [(η5-C5-
Me5)Rh{CH2CHP(C6H5)2}2Cl]PF6 (3b), showing the atom-
numbering scheme (40% probability ellipsoids). Hydrogen
atoms have been omitted for clarity.
After compounds 4b and 5c were reported, we dis-
covered that these compounds are also formed in the
presence of potassium tert-butoxide (in acetonitrile) and
all subsequent investigations were run under these
conditions. In all investigations regardless of condi-
tions, two compounds were observed (2, 3; vide infra)
in the reaction mixtures before addition of potassium
tert-butoxide. These precursors were independently
synthesized and characterized to better understand the
mechanism leading to the formation of compounds 4 and
5.
function of solvent polarity; less polar solvents favor the
formation of 2, while polar solvents increase the con-
centration of 3a . Following a mixing period of 1 to 2 h,
a halide scavenger is necessary to drive the substitution
to completion (eq 2). For example, a methanolic solution
1.0. Rea ction s of [{(η5-C5Me5)Rh Cl2}2] (1) w ith
Dip h en ylvin ylp h osp h in e (DP VP ). When 1 was re-
fluxed in chloroform with 2 equiv of DPVP, the mono-
substituted rhodium complex [(η5-C5Me5)Rh{CH2CHP-
(C6H5)2}Cl2] (2) formed (eq 1). In chloroform-d, the
of NaPF6 was used to make the salt 3b. In chloroform,
the 31P{1H} NMR spectrum of 3a shows a doublet at δ
) 22.0 (J Rh-P ) 139Hz), while the spectrum of 3b shows
a doublet at δ ) 21.9 (J Rh-P ) 134 Hz). The resonance
for 3b is shifted upfield from that of 2, which is
consistent with 3b having an overall positive charge.
1
The H NMR spectrum for 3b in the olefinic region is
more complicated compared to the spectrum of 2 be-
cause of second-order effects arising from coupling to
both phosphorus nuclei. Three broad resonances are
apparent at δ ) 6.0, 5.7, and 5.3 ppm for the vinyl
protons. The aliphatic region shows a triplet at δ ) 1.4
(J P-H ) 3.5 Hz) for the η5-C5Me5 ligand. The integrated
peak ratio between the vinyl protons and the η5-C5Me5
ligand is 1:2.5. An X-ray diffraction study also con-
firmed the structure of 3b.
Figure 3 shows the structural drawing of the cation
of 3b. Selective bond distances and angles are listed
in Table 1. Crystallographic data and details of struc-
ture determination and refinement are given in Table
4. The analysis revealed a distorted octahedral coor-
dination geometry at rhodium with one η5-C5Me5 ligand,
two DPVP ligands bound through phosphorus, and one
chloride. There are no unusual interionic contacts. The
average Rh-P bond distance in 3b is 2.345(2) Å. The
calculated distance between rhodium and the centroid
of the of η5-C5Me5 ligand is 1.887 Å, which is longer than
the distances of 1.875 Å in 4b, 1.856 Å in 5c,13 and 1.837
Å in the dfppe14 compound. The average P-C(vinyl)
bond distance is 1.808(8) Å, and the average C-C(vinyl)
31P{1H} NMR spectrum for 2 shows a doublet at δ )
27.4 (J Rh-P ) 140.7 Hz) corresponding to the coordinated
DPVP. The 1H NMR spectrum (see Experimental
Section for complete assignments) shows three multip-
lets in the olefinic region consisting of a doublet of
double doublets at δ ) 6.9 (J P-H ) 25, J H-H ) 18.7, J H-H
) 11 Hz), a doublet of doublets at δ ) 5.9 (J P-H ) 39,
J H-H ) 11 Hz), and an apparent triplet at δ ) 5.4 ppm
(J P-H ) J H-H ) 18.7 Hz) for the vinyl protons. The
aliphatic region shows a doublet at δ ) 1.41 (J P-H
)
3.4 Hz) for the η5-C5Me5 ligand. The integrated peak
ratio between the vinyl protons and the η5-C5Me5 ligand
is 1:5. The spectroscopic data confirm two points: (1)
One DPVP had coordinated to rhodium. (2) The vinyl
5
group had not undergone a hydroalkylation with the η -
C5Me5 ligand.
When 1 was stirred at room temperature with 4.5
equiv of DPVP in chloroform, the disubstituted rhodium
complex [(η5-C5Me5)Rh{CH2CHP(C6H5)2}2Cl]Cl (3a )
formed along with compound 2. The ratio of 2 to 3a
typically is 5:1. The ratio of 2 to 3a changes as a

Base-Promoted Hydroalkylation Reactions
Organometallics, Vol. 15, No. 19, 1996 3927
our previous results,13 establish that a base or a radical
initiator is necessary to facilitate hydroalkylation.
Ta ble 1. Selected Bon d Dista n ces (Å) a n d
Bon d An gles (d eg) for
[(η5-C5Me5)Rh {CH2CHP (C6H5)2}2Cl]P F 6 (3b)
Bond Distances
Rh-P(1)
Rh-P(2)
Rh-Cl
2.349(2)
2.340(2)
2.376(2)
1.887
P(1)-C(11)
P(2)-C(25)
C(11)-C(12)
C(25)-C(26)
1.803(8)
1.812(8)
1.304(10)
1.306(10)
Rh-C(1-5)a
Bond Angles
P(1)-Rh-P(2)
Cl-Rh-P(1)
Cl-Rh-P(2)
Rh-P(1)-C(11)
93.96(8)
86.05(8)
90.33(8)
115.7(3)
Rh-P(2)-C(25)
P(1)-C(11)-C(12)
P(2)-C(25)-C(26)
112.0(3)
125.8(8)
128.4(8)
a
C(1-5) denotes the centroid of the cyclopentadienyl ring.
distance is 1.305(10) Å, which is typical for a C-C
double bond distance of 1.3 Å. The crystallographic and
spectroscopic data for 3b confirmed that the vinyl
groups had not undergone hydroalkylation and two
DPVP ligands were coordinated to rhodium.
1.2. Con ver sion of 1 in to 4 a n d 5. The reaction of
1 with DPVP and potassium tert-butoxide was investi-
gated. When 1 was mixed with 4.5 equiv of DPVP in
acetonitrile (before addition of the base), compounds 2
and 3a formed in approximately a 1:1 ratio (by 31P{1H}
NMR spectroscopy). One equiv of potassium tert-
butoxide (per mole of dimer) was added to the mixture,
which was then refluxed for 48 h. The use of excess
base has been avoided since it may promote excessive
decomposition of 3a . The reaction mixture turned from
a clear red to opaque brown upon addition of the base,
and then gradually back to dark red. The workup
included addition of NaPF6, column chromatography
and fractional crystallization to give 4b and 5b. The
results discussed above suggest a stepwise mechanism
for the formation of 4a and 5a (Scheme 2). Compound
1 first reacts with DPVP to form a mixture of 2 and 3a .
Upon addition of the base, compound 3a is converted
1.1. Con ver sion of 3b in to 4b a n d 5b. The reaction
of 3b in the absence of potassium tert-butoxide was
investigated. Compound 3b was refluxed in acetonitrile
for a total time of 18 h. The course of the reaction was
1
monitored at regular intervals using H NMR spectros-
copy. Throughout the duration of the reaction, the vinyl
peaks did not transform into peaks in the aliphatic
region, which would indicate hydroalkylation. After 18
h, the 31P{1H} NMR spectrum of the mixture was meas-
ured. The spectrum showed 3b, a small amount of 2,
diphenylvinylphosphine oxide, unidentified singlets at
δ ) 51.3 and 13.6 ppm, and a broad, featureless hump
around 30 ppm. These results indicate that compound
3b is not converted into 4b and/or 5b in the absence of
potassium tert-butoxide, but some decomposition of 3b
occurs.
The reaction of 3b in the presence of potassium tert-
butoxide was investigated. In acetonitrile, compound
3b was refluxed in the presence of 1 equiv (per mole of
rhodium) of potassium tert-butoxide. After 30 min, the
31P{1H} NMR spectrum of the crude reaction solution
showed doublets at δ ) 17.9 (J Rh-P ) 133 Hz) and δ )
21.9 (J Rh-P ) 132 Hz) and singlets at δ ) 51.3, 23.4,
and 13.5 ppm. In addition, two multiplets which
appeared to be doublets of doublets were present at δ
) 31.8 (J P-P ) 36.3, J Rh-P ) 166.8 Hz) and δ ) -6.7
ppm (J P-P ) 36.3, J Rh-P ) 101.0 Hz). These two
multiplets are not present when the reaction is complete
and may represent an intermediate compound where
one of the two DPVP ligands has undergone hydro-
alkylation (vide infra). Also present in the spectrum
were broad featureless bumps in the baseline around
30 ppm. The doublet at δ ) 17.9 ppm indicates the
presence of compound 5b, the 1,2 hydroalkylation
product. Compound 3b cannot be distinguished from
4b (the 1,3 hydroalkylation product) using 31P{1H} NMR
spectroscopy because their chemical shifts are virtually
identical. Compound 3b shows a doublet at δ ) 21.9
(J Rh-P ) 134 Hz), while that of 4b is a doublet at δ )
22.0 (J Rh-P ) 135 Hz). However, 3b and 4b are easily
Sch em e 2. P r op osed Mech a n ism
1
distinguished by H NMR spectroscopy. The reaction
mixture was refluxed for 48 h. Following workup and
isolation of the products by column chromatography and
fractional crystallization, 1H and 31P{1H} NMR analyses
revealed that compounds 4b and 5b formed in an ap-
proximate 1:1 ratio (eq 3). These results, coupled with

3928 Organometallics, Vol. 15, No. 19, 1996
Barthel-Rosa et al.
Sch em e 3. Sch em a tic Rep r esen ta tion of th e
P r op osed Dia ster eom er ic In ter m ed ia tes (A/A′) for
th e F or m a tion of Com p ou n d s 4 a n d 5 w ith P h en yl
Gr ou p s Om itted for Cla r ity
Sch em e 5. P ossible Rea r r a n gem en t of ADP P
2.0. Rea ction s of [{(η5-C5Me5)Rh Cl2}2] (1) w ith
Allyld ip h en ylp h osp h in e (ADP P ). Another phos-
phine ligand that had the potential to react with 1 by
way of hydroalkylation was allyldiphenylphosphine
(ADPP); therefore the reaction between 1 and ADPP
was investigated. This system is complicated by the
possibility of base-promoted rearrangement of the allyl18
moiety to a propenyl-phosphine moiety, which may then
undergo hydroalkylation (Scheme 5). As a result, a
multitude of potential products may form in this system.
When 1 was refluxed in benzene with 2 equiv of
ADPP, the monosubstituted rhodium complex [(η5-C5-
Me5)Rh{CH2CHCH2P(C6H5)2}Cl2] (6) formed (eq 4). The
into a mixture of 4a and 5a . As compound 3a gets
consumed, compound 2 is converted into 3a .
As mentioned in section 1.1, two resonances were
spectroscopically observed that may have represented
an intermediate species between 3a, 4a, and 5a. Scheme
3 shows a schematic representation of a pair of diaster-
eomeric intermediates (A/A′) that may be immediate
precursors to compounds 4a and 5a . It is unlikely that
both DPVP ligands would simultaneously undergo hy-
droalkylation since that would require a tertiary event.
Therefore, it is reasonable to propose that one DPVP
ligand undergoes hydroalkylation, followed by a second
addition. If this occurs, the first hydroalkylation would
produce structures A and A′. Compounds 4a and 5a
are obtainable from both intermediates. Theoretically,
compounds 4a and 5a should be produced in a statistical
1:1 ratio, which is not altered by the addition of a halide
scavenger. Experimentally, the ratio of 4b,c to 5b,c is
determined after chromatography and fractional crys-
tallization; therefore mechanical losses may influence
the ratios. The intermediates proposed in Scheme 3
have not been isolated but may have been observed in
the 31P{1H} NMR spectrum of the reaction mixture
described in section 1.1.
Besides the conversion of 3a into A/A′, there is
another reasonable pathway for the formation of A/A′
that must be considered. An alternative mechanism
toward the formation of 4a and 5a is shown in Scheme
4. Compound 2 could be hydroalkylated into structure
B, followed by coordination of a second DPVP to give
the intermediates A/A′, which then proceed onto 4a and
5a . It is entirely possible that both mechanisms are
operating simultaneously; however, the observed data
suggest that proceeding through compound 3a is the
more likely pathway. At present, compounds A/A′ and
B have not been isolated; however, the possibility of this
alternative mechanism warrants further investigations.
31P{1H} NMR spectrum for 6 shows a doublet at δ )
31.0 ppm (J Rh-P ) 142.8 Hz) corresponding to the
coordinated ADPP. The 1H NMR spectrum shows three
multiplets at δ ) 5.43, 4.83, and 4.66 ppm for the
olefinic protons and one at δ ) 3.61 ppm for the
methylene protons of the ADPP ligand. The η5-C5Me5
resonance occurs as a doublet at δ ) 1.35 ppm (J P-H
)
3.5 Hz). As with compound 2, the spectroscopic data
for 6 confirms monocoordination without hydroalkyla-
tion.
When 1 was reacted with excess ADPP in refluxing
acetonitrile for 2 h, the disubstituted rhodium complex
[(η5-C5Me5)Rh{CH2CHCH2P(C6H5)2}2Cl]Cl (7a ) formed
along with compound 6. A methanolic solution of NaPF6
was added to drive the reaction to completion and form
the salt 7b (eq 5). The 31P{1H} NMR spectrum of 7a in
Sch em e 4. Alter n a tive Mech a n ism
acetonitrile shows a doublet at δ ) 21.8 ppm (J Rh-P
)
136.4 Hz), while the spectrum of 7b in chloroform-d
(18) Horner, L.; Ertel, I.; Ruprecht, H. D.; Belovsky, O. Chem. Ber.
1970, 103, 1582.
(19) Rigby, W.; McCleverty, J . A.; Maitlis, P. M. J . Chem. Soc.,
Dalton Trans. 1979, 382.

Base-Promoted Hydroalkylation Reactions
Organometallics, Vol. 15, No. 19, 1996 3929
1
investigated. Using 31P{1H} and H NMR spectroscopy,
the experiments showed that 7b decomposed to 6, ADPP
oxide, and other unidentified compounds depending on
the conditions. The other unidentified compounds may
be rearranged ADPP on rhodium or hydroalkylation
products, but the evidence remains inconclusive. The
experiments show that 7b is susceptible to rearrange-
ments and decomposition in both the presence and
absence of base.
The reaction of 1 with ADPP and potassium tert-
butoxide was investigated and monitored by 31P{1H}
NMR spectroscopy. When 1 was mixed with excess
ADPP in acetonitrile, compounds 6 and 7a formed in a
1.7:1 ratio before any base was added. One mole equiv
of potassium tert-butoxide (per mole of dimer) was added
to the mixture, which was then refluxed for 48 h. The
31P{1H} NMR spectrum showed a complex mixture of
compounds exhibited by resonances at δ ) 70.0, 63.9,
43.8, 25.2, 21.3 (d, J Rh-P ) 134Hz), and 16.6 ppm. The
resonances at δ ) 70.0 and 43.8 ppm appear to be
doublets, while those at δ ) 63.9, 25.2, and δ ) 16.6
ppm appear to be doublets of doublets (but may also be
groups of doublets). Also visible were the characteristic
resonances for 6 and ADPP oxide. The doublet at δ )
21.3 ppm may represent the disubstituted hydroalky-
lation product or compound 7a . As stated earlier, the
chemical shift difference between 3b and 4b is ap-
proximately 0.2-0.4 ppm; therefore, it is reasonable to
suggest that the same may be true for 7a and its
hydroalkylated isomer. Identical results were obtained
when tert-butyl alcohol was used as the solvent. Un-
fortunately, chromatography and fractional crystalliza-
tion have failed to produce any pure products from these
mixtures. The reaction of 1 with ADPP in the presence
of base is clearly more complicated than those with the
DPVP ligand, and the results are inconclusive toward
hydroalkylation.
3.0. Rea ction s of [{(η5-C5Me4CF 3)Rh Cl2}2] (8)
w ith DP VP . The recently synthesized20ab (trifluorom-
ethyl)tetramethylcyclopentadienyl ligand (η5-C5Me4CF3)
exhibits electronic properties equivalent to those of η5-
C5H5 but retains the steric equivalence of η5-C5Me5.20b
Derivatives of η5-C5Me4CF3 containing pendant arms
would be interesting analogs of compounds 4 and 5. The
reaction between 8 and DPVP was investigated in order
to probe the effects of the electronic withdrawing
properties on hydroalkylation. The CF3 group has the
potential to increase the selectivity of the “1,3-isomer”
over the “1,2-isomer” because of the increased acidity
of the methyl hydrogens.
F igu r e 4. Structural drawing of the cation of [(η5-C5-
Me5)Rh{CH2CHCH2P(C6H5)2}2Cl]PF6 (7b), showing the
atom-numbering scheme (40% probability ellipsoids). Hy-
drogen atoms have been omitted for clarity.
Ta ble 2. Selected Bon d Dista n ces (Å) a n d
Bon d An gles (d eg) for
[(η5-C5Me5)Rh {CH2CHCH2P (C6H5)2}2Cl]P F 6 (7b)
Bond Distances
Rh-P(1)
Rh-P(2)
Rh-Cl
2.363(2)
2.351(2)
2.402(2)
1.874
P(2)-C(26)
C(11)-C(12)
C(26)-C(27)
C(12)-C(13)
C(27)-C(28)
1.838(7)
1.497(9)
1.516(10)
1.294(10)
1.256(10)
Rh-C(1-5)a
P(1)-C(11)
1.838(7)
Bond Angles
P(1)-Rh-P(2)
Cl-Rh-P(1)
97.60(8)
90.52(7)
86.98(7)
113.5(2)
109.0(2)
P(1)-C(11)-C(12)
P(2)-C(26)-C(27)
C(11)-C(12)-C(13)
C(26)-C(27)-C(28)
117.3(5)
117.8(6)
125.1(8)
125.6(8)
Cl-Rh-P(2)
Rh-P(1)-C(11)
Rh-P(2)-C(26)
a
C(1-5) denotes the centroid of the cyclopentadienyl ring.
shows a doublet at δ ) 20.9 ppm (J Rh-P ) 135.2 Hz).
The upfield shift of the resonance for 7b compared to
that of 6 is consistent with 7b having an overall positive
1
charge. The H NMR spectrum shows significant line
broadening for the allyl protons but the aliphatic region
shows a triplet at δ ) 1.27 ppm (J P-H ) 3.7 Hz) for the
η5-C5Me5 ligand. The integrated peak ratio between the
vinyl and methylene ADPP resonances and the η5-C5-
Me5 methyl resonance is 1:1.5. An X-ray diffraction
study of 7b also confirmed its structure.
Figure 4 shows the structural drawing of the cation
of 7b. Selected bond distances and angles are listed in
Table 2. Crystallographic data and details of structure
determination and refinement are given in Table 4. The
analysis revealed a distorted octahedral coordination at
rhodium with one η5-C5Me5 ligand, two ADPP ligands
bound through phosphorus, and one chloride. There are
no unusual interionic contacts. The average Rh-P bond
distance in 7b, 2.357(2) Å, is not significantly different
from the average Rh-P bond distance of 2.345(2) Å in
3b. The calculated distance of 1.874 Å from rhodium
to the centroid of the η5-C5Me5 ligand is similar to the
distance of 1.887 Å in 3b. The C-C double bonds in
7b, C(12)-C(13) and C(27)-C(28), have distances of
1.294(10) and 1.256(10) Å, respectively, which are
typical for a C-C double-bond distance of about 1.3 Å.
As with 3b, the spectroscopic and crystallographic data
for 7b confirmed disubstitution of ADPP without hy-
droalkylation.
When 8 was stirred with 2 equiv of DPVP in chloro-
form, the monosubstituted rhodium complex [(η5-C5Me4-
CF3)Rh{CH2CHP(C6H5)2}Cl2] (9) formed (eq 6). The
(20) (a) Gassman, P. G.; Mickelson, J . W.; Sowa, J . R., J r. Inorg.
Synth. in press. (b) Gassman, P. G.; Mickelson, J . W.; Sowa, J . R., J r.
J . Am. Chem. Soc. 1992, 114, 6942.
2.1. Rea ction s of 1 a n d 7b. The reaction of 7b in
the presence and absence of potassium tert-butoxide was

3930 Organometallics, Vol. 15, No. 19, 1996
Barthel-Rosa et al.
31P{1H} NMR spectrum in chloroform-d for 9 shows a
doublet at δ ) 28.4 ppm (J Rh-P ) 134.5 Hz) correspond-
1
ing to the coordinated DPVP. The H NMR spectrum
of 9 in the olefinic region shows multiplets at δ ) 6.92,
5.99, and 5.41 ppm corresponding to the vinyl protons.
The aliphatic region shows two doublets at δ ) 1.64
(J P-H ) 3.9 Hz) and δ ) 1.53 ppm (J P-H ) 2.9 Hz)
corresponding to the two sets of methyl groups on the
η5-C5Me4CF3 ligand. The integrated ratio between the
vinyl proton and the η5-C5Me4CF3 methyl resonances
is 1:2:2. The spectroscopic data confirm monocoordina-
tion of DPVP without hydroalkylation.
In an attempt to synthesize a bis(phosphine) complex
with the η5-C5Me4CF3 ligand, compound 8 was reacted
with 4 equiv (or greater) of DPVP under a variety of
conditions. In the 31P{1H} NMR spectra of all mixtures,
small amounts of a compound were observed at δav
)
21 ppm (J Rh-P ) 132 Hz), which may have represented
a bis(phosphine) compound. Unfortunately, this com-
pound remains inseparable from the crude reaction
mixtures. Several different solvents were used includ-
ing methylene chloride, acetone, acetonitrile, and chlo-
roform. A number of different halide scavengers were
also used including AgBF4, NaPF6, NH4PF6, and AgNO3.
Inseparable mixtures of products typically formed after
the addition of a halide scavenger.
F igu r e 5. Structural drawing of [{η5-C5(CO2Et)Me3-2-
[CH2CH2CH2P(C6H5)2]}RhCl2] (10), showing the atom-
numbering scheme (40% probability ellipsoids). Hydrogen
atoms have been omitted for clarity.
Ta ble 3. Selected Bon d Dista n ces (Å) a n d
Bon d An gles (d eg) for
[η5-C5(CO2Et)Me3-2-{CH2CH2CH2P (C6H5)2}Rh Cl2]
(10)
3.1. Rea ction of 8 w ith DP VP in Eth a n ol. In
refluxing ethanol, compound 8 was allowed to react with
2 equiv of DPVP in the absence of potassium tert-
butoxide resulting in the formation of the monosubsti-
tuted hydroalkylated product [{η5-C5(CO2Et)Me3-2-[CH2-
CH2CH2P(C6H5)2]}RhCl2] (10) (eq 7). Presumably, the
Bond Distances
Rh-P(1)
2.284(3)
2.359(3)
2.370(3)
1.824
C(2)-C(7)
C(1)-C(6)
O(1)-C(6)
O(2)-C(6)
O(2)-C(25)
C(25)-C(26)
1.535(12)
1.464(14)
1.199(11)
1.333(12)
1.483(12)
1.454(13)
Rh-Cl(1)
Rh-Cl(2)
Rh-C(1-5)a
P(1)-C(9)
C(8)-C(9)
C(7)-C(8)
1.815(9)
1.526(13)
1.515(14)
Bond Angles
P(1)-Rh-Cl(1)
P(1)-Rh-Cl(2)
Cl(1)-Rh-Cl(2)
C(9)-P(1)-Rh
90.84(10) C(7)-C(8)-C(9)
90.63(10) C(8)-C(7)-C(2)
89.96(11) O(1)-C(6)-O(2)
115.2(10)
117.9(9)
123.8(10)
115.8(8)
109.2(4)
C(6)-O(2)-C(25)
C(8)-C(9)-P(1) 111.6(7)
C(26)-C(25)-O(2) 108.1(10)
a
C(1-5) denotes the centroid of the cyclopentadienyl ring.
enhanced acidity of the methyl hydrogens adjacent to
the CF3 group allows hydroalkylation to occur in the
absence of potassium tert-butoxide. In addition to
hydroalkylation of DPVP, the CF3 group was defluori-
nated and converted to an ethyl ester.21 In chloroform-
d, the 31P{1H} NMR spectrum shows a doublet at δ )
30.3 ppm (J Rh-P ) 135.9 Hz) corresponding to the
hydroalkylated diphenylphosphine moiety. The 19F
crystallographic data are listed in Table 4. The analysis
revealed a distorted octahedral coordination geometry
consisting of the following moieties bound to rhodium:
a substituted cyclopentadienyl ligand containing three
methyl groups and an ethyl ester, one diphenylphos-
phine, and two chloride ions. The remaining position
on the cyclopentadienyl ring is connected via three
methylene carbons to the diphenylphosphine group. The
Rh-P bond distance in 10, 2.284(3) Å, is shorter than
the average Rh-P distances of 2.317(3) Å in 4b and
2.324 Å in 5c13 but longer than the average distance of
2.273 Å in the dfppe compound.14 The calculated
distance between rhodium and the centroid of the
cyclopentadienyl ligand is 1.824 Å for compound 10,
which is shorter than the calculated distances13 of 1.875
Å in 4b, 1.856 Å in 5c, and 1.837 Å in the dfppe14
compound.
1
NMR spectrum is silent. The H NMR spectrum shows
broad resonances in the aliphatic region at δ ) 2.71 and
2.57 ppm corresponding to the methylene linkage. The
methyl groups attached to the cyclopentadienyl ring
occur as doublets at δ ) 2.21 (J P-H ) 3.5 Hz) and 2.01
(J P-H ) 7.5 Hz) and a singlet at 1.61 ppm. The ethyl
ester group contains diastereotopic methylene protons
and shows a second-order, ABX3, multiplet centered at
δ ) 3.96 ppm, while the methyl resonance appears as
an apparent triplet at δ ) 1.18 ppm (J H-H ) 7.0 Hz).
An X-ray diffraction study of 10 also confirmed its
structure.
The defluorination of the CF3 group to the ester was
surprising, but such reactions are known. Kobayashi21
discussed the base-promoted esterification (and other
reactions) of CF3-substituted quinolines, and Olsson22
discovered the defluorination of CF3-substituted cyclo-
Figure 5 shows the structural drawing of 10. Selected
bond distances and angles are listed in Table 3, and
(21) Kobayashi, Y.; Kumadaki, I. Acc. Chem. Res. 1978, 11, 197-
204.
(22) Olsson, T.; Wennerstrom, O. Acta Chem. Scand. 1978, B32, 293.

Base-Promoted Hydroalkylation Reactions
Organometallics, Vol. 15, No. 19, 1996 3931
Ta ble 4. Cr ysta llogr a p h ic Da ta for Com p ou n d s 3b, 7b, a n d 10
3b
7b
10
chem formula
fw
C38H41ClF6P3Rh
842.98
C40H45ClF6P3Rh
871.03
C26H30Cl2O2PRh
579.28
cryst system
space group
a (Å)
b (Å)
c (Å)
monoclinic
P21/c
monoclinic
P21/n
monoclinic
P21/c
10.748(11)
16.838(2)
21.360(3)
98.12(2)
3827.1(8)
4
10.541(1)
14.833(1)
25.362(2)
99.90(1)
3906.4(5)
4
10.586(2)
13.903(2)
17.808(2)
105.914(10)
2520.6(5)
4
â (deg)
V (Å3)
Z
T (K)
298
1.463
293
1.481
298
1.526
Fcalcd (g/cm3)
cryst size (mm)
0.2 × 0.3 × 0.4
0.39 × 0.32 × 0.34
0.18 × 0.19 × 0.38
µ (cm-1
)
6.97
6.86
9.74
transm min/max
2θ range (deg)
F(000)
0.79/0.77
3.5-45
1720
0.45/0.50
3.5-45
1784
0.77/0.83
3.5-45
1184
reflcns collcd
indepdt reflcns
R1(F)a
6449
5013
0.054
0.127
6656
5103
0.056
0.094
4319
3298
0.063
0.132
wR2(F2)b
GOFc
1.017
1.008
1.030
a
b
2
2
R1(F) ) ∑||Fo| - |Fc||/∑|Fo|. wR2(F2) ) [∑[w(Fo - Fc2)2]/∑[w(Fo2)2]0.5
. .
c GOF ) S ) [∑[w(Fo - Fc2)2]/(n - p)]0.5
pentadiene. Sowa, Gassman, and co-workers have
found that a CF3 group is generally quite stable when
attached to five-membered rings that are bound to
transition metals in an η5-fashion.23 Despite this ob-
servation, defluorination is observed24 in the prepara-
tion of [(η5-C5Me4CF3)Fe(CO)2]2 since small amounts of
[(η5-C5Me5)(CO)Fe(µ-CO)2Fe(CO)(η5-C5Me4CF3)] are de-
tectable (see Experimental Section of ref 24). Appar-
ently, the action of refluxing ethanol (without any added
base) was enough to promote the defluorination of 10
(eq 7).
Compound 10 extends the series of chelating (phos-
phinopropyl)cyclopentadienide ligands and increases the
potential derivitization at rhodium compared to 4 and
5 since two chloride ions are available for replacement
at rhodium. In addition, the ester functionality has the
potential to participate in a neighboring group effect and
may enhance the reactivity of a rhodium-coordinated
substrate.
The transformations described in the work may not
be limited to just rhodium and DPVP. The hydroalkyl-
ation of η5-C5Me5 ligands coordinated to ruthenium,
iron, and manganese with substrates such as DPVP,
phenyl vinyl sulfoxide, 2-vinylpyridine, and N,N-di-
methylacrylamide are currently under investigation.
Exp er im en ta l Section
A. Rea gen ts a n d P h ysica l Mea su r em en ts. All chemi-
cals were reagent grade and were used as received from
commercial sources (Aldrich or Fisher Scientific) or synthe-
sized as described below. Solvents were dried by standard
procedures and stored over Linde type 4 Å molecular sieves.
All syntheses were conducted in Schlenk glassware under a
nitrogen atmosphere. C5Me5H,25a HC5Me4CF3,20a [{(η5-C5-
Me5)RhCl2}2],25b and [{(η5-C5Me4CF3)RhCl2}2]20a were synthe-
sized by literature procedures. Elemental analyses were
performed by Galbraith Laboratories, Knoxville, TN. Melting
points were obtained using a Mel-Temp melting point ap-
1
paratus and are uncorrected. 1H, H{31P}, 13C{1H}, and 31P-
{1H} NMR spectra were recorded at 500, 500, 125, and 202.4
MHz, respectively, on a Varian Unity Plus 500 FT-NMR
spectrometer. Proton and carbon chemical shifts are relative
to internal Me4Si, while phosphorus chemical shifts are
relative to external 85% H3PO4(aq) with positive values being
downfield of the respective reference.
Su m m a r y
The hydroalkylation reaction may proceed15 by three
different pathways: thermally via free radical inter-
mediates, under base catalysis via carbanion intermedi-
ates, and/or under acid catalysis via carbocation inter-
mediates. In this contribution, the novel chelating
(phosphinopropyl)cyclopentadienide ligands of com-
pounds 4a and 5a have been shown to form in a
stepwise manner from 1 by a base-promoted reaction.
Compound 1 reacts with DPVP to form 2 and 3a ,
whereupon the base transforms 3a into 4a and 5a . It
is proposed that 4a and 5a are produced from a
diastereomeric pair of intermediates A and A′. Simi-
larly, compound 1 reacts with ADPP to produce 6 and
7a ; however, simple conversion of 7a into hydroalkyla-
tion products remains to be discovered. The ADPP
system is complicated by side reactions and decomposi-
tion. Compound 8 reacts with DPVP in the absence of
base to produce 10, a new compound in the series of
hydroalkylated DPVP groups on rhodium.
B. Syn th eses. Gen er a l Con d ition s. The syntheses of
compounds 4b and 5b are described in detail, but one can
obtain 4c and 5c by using NaBPh4 in place of NaPF6 and by
following the same isolation procedure. Unless otherwise
stated, all chromatography was performed using the following
general procedure: A 60 mL sintered glass fritted funnel was
used as the column and attached to a 1000 mL Erlenmeyer
flask equipped with a side arm. A layer of silica gel (grade
12, 28-300 mesh, Aldrich, 2.5 cm layer) was covered with
Celite (Aldrich, 0.5 cm layer) and firmly packed with a spatula
and suction. The crude reaction product was dissolved in a
minimal amount of a volatile solvent (usually CH2Cl2) and
loaded onto the column, and the solvent was removed with
suction. All subsequent solvents were eluted with suction.
P r ep a r a tion of [(η5-C5Me5)Rh {CH2CHP (C6H5)2}Cl2] (2).
A suspension of [{(η5-C5Me5)RhCl2}2] (0.15 g, 0.24 mmol) in
(23) J ohn R. Sowa, J r. Personal communication.
(24) Gassman, P. G.; Sowa, J . R., J r.; Hill, M. G.; Mann, K. R.
Organometallics 1995, 14, 4879.
(25) (a) Threlkel, R. S.; Bercaw, J . E.; Seidler, P. E.; Stryker, J . M.;
Bergman, R. G. Org. Synth. 1987, 65, 42. (b) White, C.; Yates, A.;
Maitlis, P. M. Inorg. Synth. 1992, 29, 228.

3932 Organometallics, Vol. 15, No. 19, 1996
Barthel-Rosa et al.
25 mL of CHCl3 was purged with nitrogen for 15 min, after
which diphenylvinylphosphine (0.15 mL, 0.51 mmol) was
added via syringe and the mixture was stirred at room
temperature until dissolution of [{(η5-C5Me5)RhCl2}2] was
complete. The clear red solution was refluxed for 6 h, after
which the solvent was removed in vacuo. Excess phosphine
was removed by allowing the oily residue to stand in 200 mL
of hexanes for at least 8 h. The hexanes were decanted
through filter paper and discarded. The product was then
purified by chromatography. The following solvents were
eluted sequentially to collect six fractions: (1) 600 mL of
hexanes, (2) 500 mL of 10% Et2O in hexanes, (3) 750 mL of
40% Et2O in hexanes, (4) 750 mL of Et2O, (5) 450 mL of CH2-
Cl2, and (6) 400 mL of MeOH. The first three fractions
contained diphenylvinylphosphine and its oxide and were
discarded. The fourth and fifth fractions primarily contained
the product, 2, and were evaporated to dryness, combined, and
kept separate from the sixth fraction which contained com-
pounds 3a and diphenylvinylphosphine oxide. The combined
fourth and fifth fractions were rechromatographed on the same
type of column with 750 mL of 30% Et2O in hexanes followed
by 500 mL of CH2Cl2. The CH2Cl2 fraction contained pure 2
and was evaporated to dryness to give 0.12 g (0.23 mmol) in
47% yield based on [{(η5-C5Me5)RhCl2}2]. Complex 2 is air
stable in solution and the solid state. Mp: 212-216 °C. Anal.
Calcd for C24H28Cl2PRh: C, 55.32; H, 5.37; Cl, 13.61. Found:
C, 55.15; H, 5.22; Cl, 13.47.
H, 5.01, Cl, 4.13. 1H NMR (CDCl3): δ 7.86-7.00 (m, 20H, Ph),
5.98 (broad m, 2H, vinyl-CH), 5.68 (broad m, 2H, vinyl-CH),
4
5.32 (broad m, 2H, vinyl-CH), 1.37 (t, J (PH) ) 3.5 Hz, 15H,
CH3). 13C {1H} NMR (CDCl3): δ 134.67 (broad m, Co), 133.51
(broad m, Co), 132.62 (s, Cp), 132.35 (s, Cp), 131.46 (broad m,
Câ), 129.55 (d, 1J (PC) ) 48.8 Hz, Ci), 128.89 (broad m, Cm),
3
1
128.33 (T, | J (PC) + 5J (PC)| ) 10.8 Hz, Cm), 127.60 (d, J (PC)
) 46.6 Hz, CR), 127.42 (d, 1J (PC) ) 49.5 Hz, Ci), 105.48 (dt,
1J (RhC) ) 5.2, J (PC) ) 2.2 Hz, C5Me5), 9.14 (t, J (PC) ) 1.4
2
3
Hz, C5Me5). 31P {1H} NMR (CDCl3): δ 21.9 (d, 1J (RhP) ) 134.1
Hz), -143.6 (septet, J (PF) ) 712.8 Hz, PF6-).
1
P r ep a r a tion of [{η5-C5Me3-1,3-[CH2CH2CH2P (C6H5)2]2}-
Rh Cl]P F 6 (4b) a n d [{η5-C5Me3-1,2-[CH2CH2CH2P (C6H5)2]2}-
Rh Cl]P F 6 (5b). A suspension of [{(η5-C5Me5)RhCl2}2] (0.21
g, 0.34 mmol) in 25 mL CH3CN was purged with nitrogen for
15 min, after which diphenylvinylphosphine (0.30 mL, 1.41
mmol) was added via syringe, and the clear red mixture was
stirred at room temperature for 15 min. To this solution was
added KOC(CH3)3 (0.03 g, 0.31 mmol) with 5 mL of CH3CN.
The clear red reaction solution turned dark brown immediately
after addition of the base. The solution was refluxed for 48 h
and gradually turned back to red. A solution of NaPF6 (0.14g,
0.86 mmol) in 8 mL of MeOH was added to the reaction
mixture, which was then stirred for 15 min at room temper-
ature. All solvents were removed in vacuo, and the crude
product was extracted into CH2Cl2 (150 mL) and filtered to
remove inorganic salts. The product was then purified by
gravity column chromatography using a 2 × 18 cm column
packed with Al2O3. The following fractions were collected: (1)
2500 mL of CH2Cl2; (2) 250 mL of 1% MeOH/CH2Cl2; (3) 250
mL of MeOH. Fractions 1 and 2 contained 4b and 5c and some
impurities and were combined. Compounds 4b and 5b are
then separated from each other by fractional crystallization
by allowing Et2O to slowly diffuse into a saturated CH2Cl2
solution of the combined fractions. Compound 5b precipitates
out of the solution as orange needles. Repeated fractional
crystallizations may be necessary to quantitatively remove 5b
from 4b. If necessary, compound 4b can be chromatographed
using the flash technique described in the general Conditions
Section with Al2O3 and 1000 mL of CH2Cl2 or recrystallized
from CH2Cl2/n-butyl ether solutions as red crystals. Typical
yields for 4b are 0.10 g (35%) and for 5b are 0.12 g (42%) based
on 1. Both 4b and 5b are air stable in solution and the solid
state. Data for 5c are also provided.
1H NMR (CDCl3): δ 7.90-7.38 (m, 10H, Ph), 6.92 (ddd,
2J (PH) ) 24.9 Hz, 3J (HaHc) ) 18.7 Hz, 3J (HaHb) ) 11.7 Hz,
3
3
1H, Ha), 5.94 (dd, J (PH) ) 39.1 Hz, J (HaHb) ) 11.7 Hz, 1H,
3
3
Hb), 5.43 (apparent t, J (PH) ) J (HaHc) ) 18.7 Hz, 1H, Hc),
1.41 (d, J (PH) ) 3.4 Hz, 15H, CH3). 13C{1H} NMR (CDCl3):
4
δ 134.49 (d, 2J (PC) ) 9.4 Hz, Co), 132.47 (d, 1J (PC) ) 49.0 Hz,
CR), 130.77 (s, Câ), 130.75 (s, Cp), 129.61 (d, 1J (PC) ) 44.2 Hz,
Ci), 128.12 (d, 3J (PC) ) 10.1 Hz, Cm), 98.73 (dd, 1J (RhC) )
6.9 Hz, 2J (PC) ) 3.1 Hz, C5Me5), 8.82 (d, 3J (PC) ) 1.5 Hz,
C5Me5). 31P{1H} NMR (CDCl3): δ 27.4 (d, 1J (RhP) ) 140.7
Hz).
P r ep a r a tion of [(η5-C5Me5)Rh {CH2CHP (C6H5)2}2Cl]P F 6
(3b). A suspension of [{(η5-C5Me5)RhCl2}2] (0.20 g, 0.32 mmol)
in 20 mL of CHCl3 was purged with nitrogen for 15 min, after
which diphenylvinylphosphine (0.28 mL, 1.41 mmol) was
added via syringe, and the mixture was stirred at room
temperature for 3 h. A 5 mL volume of MeOH was added to
the reaction solution followed by a methanolic solution of
NaPF6 (0.15g, 0.87 mmol), and the mixture was stirred for 15
min. All solvents were removed in vacuo, and the crude
product was extracted into CH2Cl2 (150 mL) and filtered to
remove inorganic salts. The product was then purified by
chromatography. The following fractions were collected: (1)
500 mL, 4:1 hexanes/Et2O; (2) 500 mL, 1.5:1 hexanes/Et2O;
(3) 500 mL, 1:1.5 hexanes/Et2O; (4) 500 mL, 1:4 hexanes/Et2O;
(5) 750 mL of Et2O; (6) 500 mL of CH2Cl2; (7) 250 mL of CHCl3;
(8) 250 mL of MeOH. Fractions 1-4 were combined and
discarded. Fraction 5 contained product 3b with impurities
and was kept separate. Fractions 6 and 7 contained pure 3b
and were combined. Fraction 8 was discarded. Fraction 5 was
rechromatographed using the same column setup as described
above. The following fractions were collected: (1′) 1750 mL,
1:1 hexanes/Et2O; (2′) 500 mL of CH2Cl2; (3′) 250 mL of CHCl3.
Fractions 2′ and 3′ contained pure 3b and were combined with
fractions 6 and 7 and dried under high vacuum to give 0.50 g
of 3b in 90% yield. Crystals of 3b may be obtained by slow
diffusion of a 1:1 Et2O/hexanes solution into a saturated
CH2Cl2 solution of 3b . Compound 3b is air stable in solu-
tion and the solid state. Mp: 185-189 °C. Anal. Calcd for
Da ta for [{η5-C5Me3-1,3-[CH2CH2CH2P (C6H5)2]2}Rh Cl]-
P F 6 (4b). Mp: 250 °C dec. Anal. Calcd for C38H41ClF6P3-
Rh‚0.5 CH2Cl2: C, 52.24; H, 4.74; Cl, 8.01. Found: C, 51.98;
H, 4.87; Cl, 7.92. 1H NMR (CDCl3): δ 7.36-7.00 (m, 20H, Ph),
5.30 (s, 1H, 0.5 CH2Cl2), 2.46 (broad m, 8H, CH2), 2.20 (broad
4
m, 2H, CH2), 1.86 (T, | J (PH) + 4J (P′H)| ) 6.50 Hz, 6H, CH3),
1.80 (broad m, 2H, CH2), 1.07 (s, 3H, CH3). 13C{1H} NMR
2
(CDCl3): δ 133.97 (T, | J (PC) + 4J (PC)| ) 8.42 Hz, Co), 132.84
2
4
(T, | J (PC) + J (PC)| ) 9.30 Hz, Co), Ci not observed, 131.46
3
(s, Cp), 130.06 (s, Cp), 129.06 (T, | J (PC) + 5J (PC)| ) 9.80 Hz,
3
Cm), 127.87 (T, | J (PC) + 5J (PC)| ) 10.06 Hz, Cm), 98.4 (broad
m, ring-C), 23.76 (complex m, CR), 20.68 (broad s, Cγ), 20.38
2
(T, | J (PC) + 4J (PC)| ) 6.41 Hz, Câ), 11.27 (broad s, CH3), 11.00
3
(T, | J (PC) + 3J (P′C)| ) 2.77 Hz, CH3). 31P{1H} NMR
(CDCl3): δ 22.0 (d, 1J (RhP) ) 134.9 Hz), -143.6 (septet, 1J (PF)
) 712.8 Hz, PF6-).
Da ta for [{η5-C5Me3-1,2-[CH2CH2CH2P (C6H5)2]2}Rh Cl]-
P F 6 (5b). 1H NMR (CDCl3): δ 7.82-6.71 (m, 20H, Ph), 3.16
(broad m, 2H, CH2), 2.90 (broad m, 2H, CH2), 2.57 (broad m,
4H, CH2), 2.16 (broad m, 2H, CH2), 1.86 (s, 3H, CH3), 1.58
4
(broad m, 2H, CH2), 1.45 (T, | J (PH) + 4J (P′H)| ) 10.0 Hz,
6H, CH3). 13C{1H} NMR (CDCl3): δ 133.52 (broad m, Co),
1
3
132.69 (broad m, Co), 131.83 (T, | J (PC) + J (PC)| ) 48.0 Hz,
1
Ci), 131.44 (T, | J (PC) + 3J (PC)| ) 50.8 Hz, Ci), 130.74 (s, Cp),
3
129.65 (s, Cp), 128.47 (T, | J (PC) + 5J (PC)| ) 9.30Hz, Cm),
3
128.40 (T, | J (PC) + 5J (PC)| ) 9.6 Hz, Cm), 121.45 (d, 1J (RhC)
) 3.1 Hz, ring-C), 103.06 (m, ring-C), 94.10 (dT, 1J (RhC) )
2
2
C
38H41ClF6P3Rh: C, 54.16; H, 4.87; Cl, 4.21. Found: C, 54.02;
6.9 Hz, | J (PC) + J (P′C)| ) 2.9 Hz, ring-C), 20.54 (complex

Base-Promoted Hydroalkylation Reactions
Organometallics, Vol. 15, No. 19, 1996 3933
m, CH2), 20.19 (broad s, CH2), 19.41 (broad s, CH2), 11.24 (T,
CH2Cl2; (7) 500 mL, 1:1 CH2Cl2/CHCl3; (8) 250 mL of CH2Cl2;
(9) 250 mL of MeOH. Fractions 1-3 contained phosphine
oxide and were discarded. Fractions 6 and 7 contained 80%
pure (by 31P{1H} NMR) product and were combined. All other
fractions were discarded. All solvents were removed in vacuo,
and the orange solid was dried under high vacuum for 15 h.
The dried product was further purified by washing with 3 ×
75 mL portions of Et2O and decanting through filter paper.
The insoluble residue was dried under high vacuum to give
0.13 g of 7b in 40% yield. The product may be recrystallized
by slow diffusion of Et2O into a saturated CH2Cl2 solution.
Compound 7b is air stable in solution and the solid state. Mp:
142-150 °C. Anal. Calcd for C40H45ClF6P3Rh: C, 55.18; H,
5.17; Cl, 4.07. Found: C, 54.92; H, 5.23; Cl, 3.94. 1H NMR
(CDCl3): δ 7.64-7.27 (m, 20H, Ph), 5.09-4.88 (broad m, 6H,
CHdCH2), 3.19 (broad m, 4H, HR), 1.27 (t, 4J (PH) ) 3.7 Hz,
15H, CH3). 13C{1H} NMR (CDCl3): δ 133.40-133.26 (broad
m, Co), 131.86 (s, Cp), 131.82 (s, Cp), 129.92 (broad m, Ci),
3
3
| J (PC) + 3J (P′C)| ) 4.3 Hz, CH3), 10.07 (T, | J (PC) + 3J (P′C)|
1
) 2.4 Hz, CH3). 31P{1H} NMR (CDCl3): δ 18.2 (d, J (RhP) )
134.0 Hz), -143.5 (septet, J (PF) ) 712.6 Hz, PF6-).
1
Da ta for [{η5-C5Me3-1,2-[CH2CH2CH2P (C6H5)2]2}Rh Cl]-
BP h 4 (5c). Mp: 220 °C dec. Anal. Calcd for C62H61BClP2-
Rh‚0.5 CH2Cl2: C, 70.87; H, 5.85; Cl, 6.69. Found: C, 70.63;
H, 5.91; Cl, 6.47. 1H NMR (CDCl3): δ 7.84-6.68 (m, 40H, Ph),
5.30 (s, 1H, 0.5 CH2Cl2), 2.43 (broad m, 2H, CH2), 2.16 (broad
4
m, 2H, CH2), 1.94 (broad m, 6H, CH2), 1.82 (T, | J (PH) +
4J (P′H)| ) 3.0 Hz, 3H, CH3), 1.46 (broad m, 2H, CH2), 1.34 (T,
4
| J (PH) + 4J (P′H)| ) 10.50 Hz, 6H, CH3). 13C{1H} NMR
(CDCl3): δ 134.71-127.15 (complex m, P-C6H5, B-C6H5),
121.51 (d, 1J (RhC) ) 3.14 Hz, ring-C), 103.09 (complex m, ring-
C), 94.07 (d, 1J (RhC) ) 6.03 Hz, ring-C), 20.67 (complex m,
3
CH2), 20.27 (broad s, CH2), 19.39 (T, | J (PC) + 5J (PC)| ) 3.39
3
3
Hz, CH2), 11.23 (T, | J (PC) + J (P′C)| ) 3.64 Hz, CH3), 10.07
3
(T, | J (PC) + 3J (P′C)| ) 1.89 Hz, CH3). 31P{1H} NMR
1
3
3
129.11 (T, | J (PC) + 5J (PC)| ) 10.06 Hz, Cγ), 128.67 (T, | J (PC)
(CDCl3): δ 18.3 (d, J (RhP) ) 133.8 Hz).
P r ep a r a tion of [(η5-C5Me5)Rh {CH2CHCH2P (C6H5)2}Cl2]
(6). A suspension of [{(η5-C5Me5)RhCl2}2] (0.20 g, 0.33 mmol)
in 25 mL of benzene was purged with nitrogen for 15 min,
after which allyldiphenylphosphine (0.15 mL, 0.695 mmol) was
added via syringe, and the dark red reaction mixture was
refluxed for 24 h. All solvents were removed in vacuo, and
250 mL of hexanes was added to the residue. After standing
for 15 h, the hexane was decanted through a paper filter and
all solvents were removed in vacuo. The hexane extract
contained unreacted phosphine which oxidized. The hexane-
insoluble residue, after drying in vacuo, gave 0.33 g of pure
product 6 in 95% yield based on [{(η5-C5Me5)RhCl2}2]. Mp:
220-223 °C. Anal. Calcd for C25H30Cl2PRh: C, 56.21; H, 5.62;
Cl, 13.27. Found: C, 56.13; H, 5.34; Cl, 13.15.
2
+ 5J (PC)| ) 10.56 Hz, Cm), 120.46 (T, | J (PC) + 4J (PC)| ) 10.18
1
2
Hz, Câ), 105.91 (dt, J (RhC) ) 5.41 Hz, J (PC) ) 1.89 Hz, C5-
Me5), 30.7 (broad m, CR), 9.22 (t, 3J (PC) ) 1.51 Hz, C5Me5).
31P{1H} NMR (CDCl3): δ 20.9 (d, 1J (RhP) ) 134.8 Hz), -143.6
(septet, J (PF) ) 712.8 Hz, PF6-).
1
P r ep a r a tion of [(η5-C5Me4CF 3)Rh {CH2CHP (C6H5)2}Cl2]
(9). A suspension of [{(η5-C5Me4CF3)RhCl2}2] (0.15 g, 0.21
mmol) in 15 mL of CHCl3 was purged with nitrogen for 15
min, after which diphenylvinylphosphine (0.18 mL, 0.91 mmol)
was added via syringe, and the clear red solution was stirred
at room temperature for 2.5 h. All solvents were removed in
vacuo, and the residue was washed with 4 × 100 mL of
hexanes to remove excess phosphine. The hexane-insoluble
portion was chromatographed by eluting with the following:
(1) 1000 mL hexanes; (2) 400 mL, Et2O; (3) 500 mL, CH2Cl2.
The first fraction was discarded, and the second and third were
combined as they contain mostly compound 9 and some
phosphine oxide. The oxide can be removed by washing with
Et2O although this also extracts compound 9. Crystals of 9
can be grown by slow diffusion of 1:1 Et2O/hexanes into a CH2-
Cl2 solution to give 0.22 g of 9 in 89.8% yield. Complex 9 is
air stable in solution and the solid state. Mp: 209-212 °C.
Anal. Calcd for C24H25Cl2F3PRh: C, 50.13; H, 4.35; Cl, 12.33.
Found: C, 49.97; H, 4.19; Cl, 12.21. 1H NMR (CDCl3): δ 7.84-
7.42 (m, 10H, Ph), 6.92 (ddd, 2J (PH) ) 25.5 Hz, 3J (HaHc) )
1H NMR (CDCl3): δ 8.1-7.4 (m, 10H, Ph), 5.43 (ddtd,
3
3
3J (HaHb) ) 10.2 Hz, J (HaHc) ) 17.0 Hz, J (HaHR) ) 8.0 Hz,
3J (PHa) ) 3.9 Hz, 1H, Ha), 4.83 (dddt, 3J (HaHb) ) 10.2 Hz,
2J (HbHc) ) 1.8 Hz, J (HRΗb) ) 1.0 Hz, J (PHb) ) 3.8 Hz, 1H,
Hb), 4.66 (ddtd, 3J (HaHc) ) 17.0 Hz, 2J (HbHc) ) 1.8 Hz,
4J (HRHc) ) 2.0 Hz, 4J (PHc) ) 4.4 Hz, 1H, Hc), 3.61 (dddd,
3J (HaHR) ) 8.0 Hz, 4J (HbHR) ) 1.0 Hz, 4J (HcHR) ) 2.0 Hz,
2J (PHR) ) 9.5 Hz, 2H, HR), 1.35 (d, 4J (PH) ) 3.5 Hz, 15H, CH3).
13C{1H} NMR (CDCl3): δ 134.1 (d, 2J (PC) ) 8.8 Hz, Co), 130.8
(d, 4J (PC) ) 2.6 Hz, Cp), 130.2 (d, 3J (PC) ) 13.2 Hz, Cγ), 128.4
(d, 1J (PC) ) 41.5 Hz, Ci), 127.9 (d, 3J (PC) ) 9.8 Hz, Cm), 119.6
4
4
3
3
18.2 Hz, J (HaHb) ) 12.1 Hz, 1H, Ha), 5.99 (dd, J (PH) ) 40.5
3
3
Hz, J (HaHb) ) 12.1 Hz, 1H, Hb), 5.41 (dd, J (PH) ) 20.3 Hz,
3J (HaHc) ) 18.8 Hz, 1H, Hc), 1.64 (d, 4J (PH) ) 3.9 Hz, 6H,
2,5-CH3), 1.53 (d, 4J (PH) ) 2.9 Hz, 6H, 3,4-CH3). 13C{1H}
NMR (CDCl3): δ 134.6 (d, 2J (PC) ) 9.2 Hz, Co), 131.8 (d, 1J (PC)
) 51.2 Hz, CR), 131.1 (d, 4J (PC) ) 2.6 Hz, Cp), 130.2 (br s, Câ),
128.7 (d, 1J (PC) ) 49.4 Hz, Ci), 128.1 (d, 3J (PC) ) 10.3 Hz,
1
2
1
2
Cm), 124.2 (q, J (CF) ) 273.4 Hz, CF3), 105.3 (s, 2,5-C-CH3),
(d, J (PC) ) 9.4 Hz, Câ), 98.5 (dd, J (RhC) ) 6.9 Hz, J (PC) )
101.6 (s, 3,4-C-CH3), 80.3 (qd, 2J (CF) ) 35 Hz, 1J (RhC) ) 9.0
1
3
2.9 Hz, C5Me5), 33.0 (d, J (PC) ) 26.5 Hz, CR), 8.6 (d, J (PC)
4
3
) 1.4 Hz, C5Me5). 31P{1H} NMR (CDCl3): δ 31.0 (d, J (RhP)
1
Hz, C-CF3), 9.48 (qd, J (CF) ) 2.0 Hz, J (PC) ) 1.8 Hz, 2,5-
CH3), 8.60 (d, 3J (PC) ) 1.6 Hz, 3,4-CH3). 31P {1H} NMR
) 142.8 Hz).
1
P r ep a r a tion of [(η5-C5Me5)Rh {CH2CHCH2P (C6H5)2}2Cl]-
P F 6 (7b). A suspension of [{(η5-C5Me5)RhCl2}2] (0.12 g, 0.19
mmol) in 20 mL of CH3CN was purged with nitrogen for 15
min, after which allyldiphenylphosphine (0.23 mL, 1.1 mmol)
was added via syringe. Upon addition of the phosphine all of
the [{(η5-C5Me5)RhCl2}2] dissolved, resulting in a clear red
solution. The reaction mixture was refluxed for 2 h and then
cooled to room temperature. A methanolic solution of NaPF6
(0.098 g, 0.58 mmol) was added to the reaction mixture, and
it was stirred for 15 min. All solvents were removed in vacuo
resulting in a yellow/red viscous residue. The crude product
was extracted into CH2Cl2 (75 mL) and filtered to remove
NaCl. The CH2Cl2 was removed in vacuo, and the product
was chromatographed. The fractions collected were as fol-
lows: (1) 500 mL, 4:1 hexanes/Et2O; (2) 500 mL, 1.5:1 hexanes/
Et2O; (3) 500 mL, 1:1.5 hexanes/Et2O; (4) 1500 mL, 1:1.5
hexanes/Et2O; (5) 250 mL, 1:4 hexanes/Et2O; (6) 750 mL of
(CDCl3): δ 28.4 (d, J (RhP) ) 134.5 Hz).
P r ep a r a t ion of [{η5-C5(CO2E t )Me3-2-[CH 2CH 2CH 2P -
(C6H 5)2]}R h Cl2] (10). A suspension of [{(η5-C5Me4CF3)-
RhCl2}2] (0.30 g, 0.41 mmol) in 25 mL of EtOH was purged
with nitrogen for 15 min, after which diphenylvinylphosphine
(0.35 mL, 1.8 mmol) was added via syringe, and the clear red
solution was stirred at room temperature for approximately
15 min. The dark red solution was then refluxed for 4 h after
which the solvent was removed in vacuo. The residue was
chromatographed by eluting with the following solvents: (1)
700 mL of 1:1 CH2Cl2/Et2O, (2) 600 mL of MeOH. The MeOH
fraction was discarded. The first fraction was further purified
by recrystallization from acetone at room temperature to give
0.14 g of compound 10 in 29.2% yield. Compound 10 is air
stable in solution and in the solid state. Mp: 123-126 °C.
Anal. Calcd for C26H30Cl2O2PRh: C, 53.93; H, 5.18; Cl, 12.24.
Found: C, 53.78; H, 5.02; Cl, 12.31.

3934 Organometallics, Vol. 15, No. 19, 1996
Barthel-Rosa et al.
were collected in the ω-mode with Mo KR graphite-monochro-
mated radiation (λ ) 0.710 73 Å). Two check reflections
monitored every 100 reflections showed random (<2%) varia-
tion during the data collection. Unit cell parameters were
determined by least-squares refinement of 24 reflections for
3b, 7b, and 10. The data were corrected for Lorentz, polariza-
tion, and absorption (using an empirical model derived from
azimuthal data collections). Scattering factors and corrections
for anomalous dispersion were taken from a standard source.26
Calculations were performed with the Siemens SHELXTL Plus
version 5.0 software package on a personal computer. The
structures were solved by direct methods. Anisotropic thermal
parameters were assigned to all non-hydrogen atoms. Hydro-
gen atoms were refined at calculated positions with a riding
model in which the C-H vector was fixed at 0.96 Å.
1H NMR (CDCl3): δ 7.78-7.27 (m, 10H, Ph), 3.99 (m, A part
2
3
of ABX3, J (HaHb) ) 10.50 Hz, J (HaCH3) ) 7.0 Hz, 1H, Ha),
3.94 (m, B part of ABX3, 2J (HbHa) ) 10.50 Hz, 3J (HbCH3) )
7.0 Hz, 1H, Hb), 2.74-2.53 (broad m, 2H, C7-CH2), 2.23-1.89
4
(broad m, 4H, CH2CH2P), 2.21 (d, J (PH) ) 3.5 Hz, 3H, CH3),
2.01 (d, 4J (PH) ) 7.5 Hz, 3H, CH3), 1.61 (s, 3H, CH3), 1.18
(apparent t, 3J (HaCH3) ) 3J (HbCH3) ) 7.0 Hz, 3H, C26-H3). 13C-
{1H} NMR (CDCl3): δ 166.46 (d, 3J (PC) ) 0.75 Hz, CO2),
134.33 (d, 3J (PC) ) 10.06 Hz, Cm), 132.72 (d, 3J (PC) ) 8.17
Hz, Cm), 132.04 (d, 1J (PC) ) 53.80 Hz, Ci), 131.12 (d, 1J (PC) )
49.28 Hz, Ci), 130.80 (d, 4J (PC) ) 2.64 Hz, Cp), 130.09 (d,
4J (PC) ) 3.14 Hz, Cp), 128.21 (d, 2J (PC) ) 10.56 Hz, Co), 127.64
(d, 2J (PC) ) 10.94 Hz, Co), 118.72 (dd, 1J (RhC) ) 3.96 Hz,
2J (PC) ) 3.33 Hz, ring-C), 106.88 (dd, 1J (RhC) ) 13.58 Hz,
2J (PC) ) 3.52 Hz, ring-C), 105.12 (dd, 1J (RhC) ) 6.66 Hz,
Ack n ow led gm en t. We are grateful to the donors
of the Petroleum Research Fund, administered by the
American Chemical Society, for financial support, to the
National Science Foundation (Grant CHE-9214294) for
funds to purchase the 500 MHz NMR spectrometer, to
J ohnson Mathey Aesar/Alfa for a generous loan of
RhCl3‚3H2O, and to Dr. J ohn R. Sowa, J r., of Seton Hall
University for his very helpful discussions concerning
the chemistry of η5-C5Me4CF3.
1
2J (PC) ) 2.39 Hz, ring-C), 92.75 (d, J (RhC) ) 7.17 Hz, ring-
1
C), 72.53 (broad d, J (RhC) ) 9.68 Hz, ring-C), 61.36 (s, C25),
3
2
21.75 (dd, J (PC) ) 8.8 Hz, J (RhC) ) 1.25 Hz, C7), 21.50 (s,
1
C8), 21.23 (d, J (PC) ) 31.43 Hz, C9), 13.80 (s, CH3), 11.92 (d,
Su p p or tin g In for m a tion Ava ila ble: For the compounds
3b, 7b, and 10, listings of crystal and refinement data, atomic
coordinates and U values, bond lengths and angles, anisotropic
displacement parameters, and H atom coordinates and iso-
tropic displacement parameters (16 pages). Ordering informa-
tion is given on any current masthead page.
3J (PC) ) 2.14 Hz, CH3), 10.44 (s, CH3), 8.84 (d, J (PC) ) 3.90
3
Hz, CH3). 31P {1H} NMR (CDCl3): δ 30.3 (d, J (RhP) ) 135.9
1
Hz).
C. X-r a y Da ta Collection a n d P r ocessin g for 3b, 7b,
a n d 10. Orange crystals of 3b and 7b were grown by slow
diffusion of ether into a saturated CH2Cl2 solution, and deep
red crystals of 10 were grown by slow evaporation of an acetone
solution. Crystal data and details of data collection are given
in Table 4. The crystals were coated with epoxy, mounted on
glass fibers, and placed on a Siemens P4 diffractometer. Data
OM960213Q
(26) International Tables for X-Ray Crystallography; D. Reidel
Publishing Co.: Boston, MA, 1992, Vol. C.