Unusual pathways for metal-assisted C-C and C-P coupling reactions using allenylidenerhodium complexes as precursors

Article abstract of DOI:10.1021/ja012479g

The rhodium allenylidenes trans-[RhCl{=C=C=C(Ph)R}(P/Pr₃)₂] [R = Ph (1), p-Tol (2)] react with NaC₅H₅ to give the half-sandwich type complexes [(η⁵-C₅H₅)Rh{=C=C=C(Ph)R} (P/Pr₃)] (3, 4). The reaction of 1 with the Grignard reagent CH₂=CHMgBr affords the η³-pentatrienyl compound [Rh(η³- CH₂CHC=C=CPh₂)(P/Pr₃)₂] (6), which in the presence of CO rearranges to the η1-pentatrienyl derivative trans-[Rh{η¹-C(CH=CH₂)=C=CPh₂} (CO)(P/Pr₃)₂] (7). Treatment of 7 with acetic acid generates the vinylallene CH₂=CH-CH=C=CPh₂ (8). Compounds 1 and 2 react with HCl to give the five-coordinate allenylrhodium(III) complexes [RhCl₂{CH=C=C(Ph)R}(P/Pr₃)₂] (10, 11). An unusual [C₃ + C₂ + P] coupling process takes place upon treatment of 1 with terminal alkynes HC=CR′, leading to the formation of the η³-allylic compounds [RhCl{η³-anti-CH(P/Pr₃)C(R′) C=C=CPh₂}(P/Pr₃)] [R′ = Ph (12), p-Tol (13), SiMe₃ (14)]. From 12 and RMgBr the corresponding phenyl and vinyl rhodium(I) derivatives 15 and 16 have been obtained. The previously unknown unsaturated ylide /Pr₃PCHC(Ph)=C=C=CPh₂ (17) was generated from 12 and CO. A [C₃ + P] coupling process occurs on treatment of the rhodium allenylidenes 1, 2, and trans-[RhCl{=C=C=C(p-Anis)₂}(P/Pr₃)₂] (20) with either Cl₂ or PhlCl₂, affording the ylide-rhodium(III) complexes [RhCl₃(C(P/Pr₃)C=C(R)R′}(P/Pr₃)] (21-23). The butatrienerhodium(I) compounds trans-[RhCl{η²-H₂C=C=C=C(R)R′} (P/Pr₃)₂] (28-31) were prepared from 1, 20, and trans-[RhCl{=C=C=C(Ph)R}(P/Pr₃)₂] [R = CF₃ (26), tBu (27)] and diazomethane; with the exception of 30 (R = CF₃, R′ = Ph), they thermally rearrange to the isomers trans-[RhCl{η²-H₂C=C=C=C=(R)R′} (P/Pr₃)₂] (32, 33, and syn/anti-34). The new 1,1-disubstituted butatriene H₂C=C=C=C(tBu)Ph (35) was generated either from 31 or 34 and CO. The iodo derivatives trans-[Rhl(η²-H₂C=C=C=CR₂) (P/Pr₃)₂] [R = Ph (38), p-Anis (39)] were obtained by an unusual route from 1 or 20 and CH₃l in the presence of KI. While the hydrogenation of 1 and 26 leads to the allenerhodium(I) complexes trans-[RhCl{η²-H₂C=C=C=C(Ph)R} (P/Pr₃)₂] (40, 41), the thermolysis of 1 and 20 produces the rhodium(I) hexapentaenes trans-[RhCl(η²-R₂C=C=C=CR₂) (P/Pr₃)₂] (44, 45) via C-C coupling. The molecular structures of 3, 7, 12, 21, and 28 have been determined by X-ray crystallography. (Abbreviations used: p-Tol = p-tolyl, 4-C₆H₄CH₃; p-Anis = p-anisyl, 4-C₆H₄OCH₃.).

Full text of DOI:10.1021/ja012479g

Published on Web 05/25/2002
Unusual Pathways for Metal-Assisted C-C and C-P Coupling
Reactions Using Allenylidenerhodium Complexes as
Precursors
Helmut Werner,* Ralf Wiedemann, Matthias Laubender, Bettina Windmu¨ller,
Paul Steinert, Olaf Gevert, and Justin Wolf
Contribution from the Institut fu¨r Anorganische Chemie der UniVersita¨t Wu¨rzburg, Am Hubland,
D-97074 Wu¨rzburg, Germany
Received November 6, 2001
Abstract: The rhodium allenylidenes trans-[RhCl{dCdCdC(Ph)R}(PiPr3)2] [R ) Ph (1), p-Tol (2)] react
with NaC5H5 to give the half-sandwich type complexes [(η5-C5H5)Rh{dCdCdC(Ph)R}(PiPr3)] (3, 4). The
reaction of 1 with the Grignard reagent CH2dCHMgBr affords the η3-pentatrienyl compound [Rh(η3-
CH2CHCdCdCPh2)(PiPr3)2] (6), which in the presence of CO rearranges to the η1-pentatrienyl derivative
trans-[Rh{η1-C(CHdCH2)dCdCPh2}(CO)(PiPr3)2] (7). Treatment of 7 with acetic acid generates the
vinylallene CH2dCH-CHdCdCPh2 (8). Compounds 1 and 2 react with HCl to give the five-coordinate
allenylrhodium(III) complexes [RhCl2{CHdCdC(Ph)R}(PiPr3)2] (10, 11). An unusual [C3 + C2 + P] coupling
process takes place upon treatment of 1 with terminal alkynes HCtCR′, leading to the formation of the
η3-allylic compounds [RhCl{η3-anti-CH(PiPr3)C(R′)CdCdCPh2}(PiPr3)] [R′ ) Ph (12), p-Tol (13), SiMe3
(14)]. From 12 and RMgBr the corresponding phenyl and vinyl rhodium(I) derivatives 15 and 16 have been
obtained. The previously unknown unsaturated ylide iPr3PCHC(Ph)dCdCdCPh2 (17) was generated from
12 and CO. A [C3 + P] coupling process occurs on treatment of the rhodium allenylidenes 1, 2, and trans-
[RhCl{dCdCdC(p-Anis)2}(PiPr3)2] (20) with either Cl2 or PhICl2, affording the ylide-rhodium(III) complexes
[RhCl3{C(PiPr3)CdC(R)R′}(PiPr3)] (21-23). The butatrienerhodium(I) compounds trans-[RhCl{η2-H2Cd
CdCdC(R)R′}(PiPr3)2] (28-31) were prepared from 1, 20, and trans-[RhCl{dCdCdC(Ph)R}(PiPr3)2] [R
) CF3 (26), tBu (27)] and diazomethane; with the exception of 30 (R ) CF3, R′ ) Ph), they thermally
rearrange to the isomers trans-[RhCl{η2-H2CdCdCdC(R)R′}(PiPr3)2] (32, 33, and syn/anti-34). The new
1,1-disubstituted butatriene H2CdCdCdC(tBu)Ph (35) was generated either from 31 or 34 and CO. The
iodo derivatives trans-[RhI(η2-H2CdCdCdCR2)(PiPr3)2] [R ) Ph (38), p-Anis (39)] were obtained by an
unusual route from 1 or 20 and CH3I in the presence of KI. While the hydrogenation of 1 and 26 leads to
the allenerhodium(I) complexes trans-[RhCl{η2-H2CdCdC(Ph)R}(PiPr3)2] (40, 41), the thermolysis of 1
and 20 produces the rhodium(I) hexapentaenes trans-[RhCl(η2-R2CdCdCdCdCdCR2)(PiPr3)2] (44, 45)
via C-C coupling. The molecular structures of 3, 7, 12, 21, and 28 have been determined by X-ray
crystallography. (Abbreviations used: p-Tol ) p-tolyl, 4-C6H4CH3; p-Anis ) p-anisyl, 4-C6H4OCH3.)
Introduction
reactions could occur with C-donors as well. From work in our
laboratory we already knew that the related rhodium vinylidenes
In the context of our investigations on metallacumulenes of
the general composition trans-[RhCl{d(Cd)nCRR′}(PiPr3)2] (n
) 1-4), we recently described the preparation of the corre-
sponding rhodium allenylidenes trans-[RhCl(dCdCdCRR′)-
(PiPr3)2] using propargylic alcohols or propargylic chlorides as
precursors for the coordinated C3 unit.1 After we found that the
chloride in these complexes cannot only be replaced by other
trans-[RhCl(dCdCHR)(PiPr3)2] react with Grignard reagents
R′MgX to give the substitution products trans-[Rh(R′)(dCd
CHR}(PiPr3)2], which for R′ ) CH3 and CHdCH2 rearrange,
even in the absence of a Lewis base, by intramolecular C-C
coupling to yield η3-allyl and η3-butadienyl rhodium com-
pounds.4
In this paper we report that the reactivity of the rhodium
allenylidenes toward carbanions in some cases is analogous and
in some cases different from that of the vinylidene counterparts.
halides but also by pseudohalides such as OCN-, SCN-, N3
-
and even by hydroxide and related O-donor ligands,2,3 we
became interested to find out whether similar substitution
(3) (a) Laubender, M.; Werner, H. Angew. Chem. 1998, 110, 158-160; Angew.
Chem., Int. Ed. Engl. 1998, 37, 150-152. (b) Laubender, M.; Werner, H.
Chem. Eur. J. 1999, 5, 2937-2946.
(4) (a) Wiedemann, R.; Steinert, P.; Scha¨fer, M.; Werner, H. J. Am. Chem.
Soc. 1993, 115, 9864-9865. (b) Wiedemann, R.; Wolf, J.; Werner, H.
Angew. Chem. 1995, 107, 1359-1361; Angew. Chem., Int. Ed. Engl. 1995,
34, 1244-1246. (c) Werner, H.; Wiedemann, R.; Steinert, P.; Wolf, J.
Chem. Eur. J. 1997, 3, 127-137.
(1) (a) Werner, H.; Rappert, T. Chem. Ber. 1993, 126, 669-678. (b) Werner,
H.; Rappert, T.; Wiedemann, R.; Wolf, J.; Mahr, N. Organometallics 1994,
13, 2721-2727.
(2) (a) Werner, H.; Wiedemann, R.; Laubender, M.; Wolf, J.; Windmu¨ller, B.
Chem. Commun. 1996, 1413-1414. (b) Werner, H.; Wiedemann, R.;
Laubender, M.; Windmu¨ller, B.; Wolf, J. Chem. Eur. J. 2001, 7, 1959-
1967.
9
6966
J. AM. CHEM. SOC. 2002, 124, 6966-6980
10.1021/ja012479g CCC: $22.00 © 2002 American Chemical Society

Pathways for Metal-Assisted C−C and C−P Coupling
A R T I C L E S
Moreover, we illustrate that the allenylidene ligand can be
converted to allenes and, by two different pathways, also to
1,1-disubstituted butatrienes CH2dCdCdCRR′, which because
of their lability are otherwise hardly accessible. The most
surprising result, however, is that the starting materials with a
RhdCdCdCRR′ chain undergo upon treatment with either
1-alkynes or phenyliodoniumdichloride an intramolecular C-P
coupling reaction, thereby generating novel highly unsaturated
phosphorus ylides unknown in the free state. Some results of
these studies have already been communicated.5
Results and Discussion
Half-Sandwich-Type Allenylidenerhodium Complexes. To
test the possibility of replacing the chloro ligand in compounds
of the general composition trans-[RhCl(dCdCdCRR′}(PiPr3)2]
by carbanions, first the reactivity of 1 and 2 toward sodium
cyclopentadienide was investigated. Both starting materials, if
mixed with solid NaC5H5 and treated dropwise with THF, react
at room temperature to give the half-sandwich-type complexes
3 and 4 in good yield (Scheme 1). They were isolated as green
Figure 1. Molecular diagram of compound 3. Selected bond distances (Å)
and angles (deg): Rh-P, 2.2700(15); Rh-C1, 1.880(6); Rh-C16, 2.237-
(6); Rh-C17, 2.253(7); Rh-C18, 2.242(6); Rh-C19, 2.231(7); Rh-C20,
2.198(7); C1-C2, 1.255(7); C2-C3, 1.350(7); C3-C4, 1.466(8); C3-C5,
1.465(7); P-Rh-C1, 89.48(17); Rh-C1-C2, 177.1(5); C1-C2-C3,
176.5(6); C2-C3-C4, 119.3(5); C2-C3-C5, 120.2(5); C4-C3-C5,
120.5(5).
Scheme 1. (L ) PiPr3)
The molecular structure of compound 3 is shown in Figure
1. The molecule possesses the expected two-legged piano-stool
configuration with a Rh-C1 bond length of 1.880(6) Å, which
is slightly longer (ca. 0.03 Å) compared to the square-planar
complex 2.1b It is almost identical to the bond length in the
structurally related cyclopentadienylosmium(II) compound [(η5-
C5H5)OsCl(dCdCdCPh2)(PiPr3)].7 The two carbon-carbon
distances in the RhC3 chain differ by 0.10 Å, which suggests
that besides the usual bond description RhdCdCdC a second
zwitterionic resonance structure has to be taken into consider-
ation.8 The RhdCdCdC moiety is nearly linear, while the bond
angles around the γ-carbon atom C3 are, as expected, about
120°.
Coupling of an Allenylidene and a Vinyl Group. Following
the protocol for the preparation of the vinylidene complexes
trans-[Rh(R′)(dCdCHR)(PiPr3)2] (R′ ) CH3, CHdCH2, CtCPh,
C6H4R),4 the allenylidene compound 1 was treated under the
same conditions with the corresponding Grignard reagent
R′MgBr. However, in all cases, with the exception of R′ )
CHdCH2, a mixture of products was obtained that could not
be separated by fractional crystallization or chromatographic
techniques.
The attempt to prepare the vinylrhodium(I) derivative trans-
[Rh(CHdCH2)(dCdCdCPh2)(PiPr3)2] led to a surprising re-
sult. Treatment of the starting material 1 with CH2dCHMgBr
in toluene/THF at -40 °C resulted not only in the substitution
of chloride by the C-nucleophile but also by coupling of the
vinyl and the allenylidene units to form a η3-pentatrienyl ligand
solids that are only moderately air-sensitive and readily soluble
in most common organic solvents. The 13C NMR spectra of 3
and 4 display three characteristic signals in the low-field region
at about δ 228, 205-210, and 122 that, based on the different
103Rh-13C and 31P-13C coupling constants, are assigned to the
1
R-, â-, and γ-carbon atoms of the allenylidene chain. The H
NMR spectrum of 3 exhibits only one set of resonances for the
protons of the two phenyl groups, indicating that on the NMR
time scale (in solution at room temperature) the rotation around
the Rh-Callenylidene bond is not significantly hindered. It should
be mentioned that the vinylidene analogues of 3 and 4 of the
general composition [(η5-C5H5)Rh(dCdCHR)(PiPr3)] were also
prepared in our laboratory but by a different route.6
(7) Crochet, P.; Esteruelas, M. A.; Lo´pez, A.; Ruiz, N.; Tolosa, J. I.
Organometallics 1998, 17, 3479-3486.
(8) (a) Bruce, M. I. Chem. ReV. 1991, 91, 197-257. (b) Le Bozec, H.; Dixneuf,
P. H. Russ. Chem. Bull. 1995, 44, 801-812. (c) Werner, H. Chem. Commun.
1997, 903-910. (d) Bruce, M. I. Chem. ReV. 1998, 98, 2797-2858. (e)
Cadierno, V.; Gamasa, M. P.; Gimeno, J. Eur. J. Inorg. Chem. 2001, 571-
591.
(5) Wiedemann, R.; Steinert, P.; Gevert, O.; Werner, H. J. Am. Chem. Soc.
1996, 118, 2495-2496.
(6) (a) Wolf, J.; Werner, H.; Serhadli, O.; Ziegler, M. L. Angew. Chem. 1983,
95, 428-429; Angew. Chem., Int. Ed. Engl. 1983, 22, 414-415. (b) Werner,
H.; Wolf, J.; Garcia Alonso, F. J.; Ziegler, M. L.; Serhadli, O. J. Organomet.
Chem. 1987, 336, 397-411.
9
J. AM. CHEM. SOC. VOL. 124, NO. 24, 2002 6967

A R T I C L E S
Werner et al.
1
(see Scheme 1). The H spectrum of 6 displays three well-
separated signals for the protons H1, H2 and H3 of the π-bonded
allylic unit at δ 4.79, 3.01, and 2.45, respectively. In agreement
with previous data,4,9 the resonance for the syn proton H2 reveals
a considerably smaller 31P-1H coupling constant (almost zero)
than that of the anti proton H3 (5.8 Hz). In the 13C NMR spec-
trum of 6, a significant difference in chemical shift for the
signals of carbon atoms C3 and C5 is observed, indicating that
the allylic fragment of the pentatrienyl ligand is unsymmetrically
coordinated to the metal center. With regard to the mechanism
of formation of 6, we assume that initially the anticipated four-
coordinate species 5 is generated that rapidly rearranges by
migratory insertion to give the final product. The reason for
the increased lability of 5 compared with the vinylidene counter-
parts trans-[Rh(CHdCH2)(dCdCHR)(PiPr3)2] (R ) tBu, Ph)4
could be that the allenylidene is a weaker π-acceptor ligand
than the related vinylidene and therefore less suitable to stabilize
the bond between the metal and the trans-disposed vinyl
group.6,10 We note that upon treatment of [(η5-C5Me5)RuCl-
(dCdCdCPh2)(κ1-PiPr2CH2CO2Me)] with CH2dCHMgBr also
a η3-pentatrienyl complex is formed, and again in this case no
M-CHdCH2 intermediate could be detected spectroscopi-
cally.11
see ref 5). The rhodium is coordinated in a slightly distorted
square-planar fashion with the two phosphine ligands in a trans
disposition. The allene-like CdCdC chain is linear (177.5(5)°),
with the two vinylic carbon atoms lying in the same plane. The
plane containing the C3 carbons and the ipso-carbon atoms of
the phenyl groups is nearly perpendicular to the plane containing
the metal and the vinylic carbon atoms, the dihedral angle being
95.5(2)°. The two C-C distances of the linear C3 chain differ
only slightly, which is in agreement with structural data for other
transition-metal compounds containing η1-allenyl ligands.12
The cleavage of the Rh-C σ-bond in 7 by an equimolar
amount of acetic acid in benzene proceeds smoothly and gives,
besides the acetatorhodium(I) complex 9,13 selectively the new
vinylallene 8 (see Scheme 1). A characteristic feature of the
13C NMR spectrum of 8 is the low-field signal at δ 210.2 for
the central CdCdC carbon atom, the position of which is
typical for organic allenes.14
Reactions of Rhodium Allenylidenes with HCl and Ter-
minal Alkynes. In contrast to the iridium(I) compounds trans-
[IrCl{dCdCdC(Ph)R}(PiPr3)2] (R ) tBu, Ph), which react
with HCl by oxidative addition to give the octahedral hydri-
doiridium(III) derivatives trans-[IrHCl2{dCdCdC(Ph)R}-
(PiPr3)2],15 treatment of the rhodium(I) precursors 1 and 2 with
an equimolar amount of HCl in benzene affords the five-
coordinate allenyl complexes 10 and 11 in nearly quantitative
yields (Scheme 2). Typical spectroscopic data of 10 and 11 are
The reaction of 6 with CO in benzene at 10 °C leads instan-
taneously to a change of color from red to light yellow and
finally to the isolation of yellow, moderately air-sensitive crys-
tals of the carbonylrhodium(I) compound 7 in 65% yield (see
Scheme 1). The addition of CO to the metal center is accom-
panied by a π-σ conversion of the C5 unit, possibly via an
18-electron intermediate [Rh(η3-CH2CHCdCdCPh2)(CO)-
(PiPr3)2]. The change in hapticity of the pentatrienyl ligand is
clearly indicated by the 1H NMR spectrum of 7, which exhibits
the resonances for the vinyl protons H1, H2, and H3 at signifi-
cantly lower field (δ 6.84, 5.97, and 5.11) compared to 6. The
13C NMR spectrum of 7 displays five signals for the carbon
atoms C1 to C5 (see Chart 1), of which only that for the metal-
bonded atom C3 shows a 31P-13C and a 103Rh-13C coupling.
Scheme 2. (L ) PiPr3)
Chart 1. Assignment of Protons, Carbon, and Phosphorus Atoms
of Ligands in Compounds 6-8 and 12-16
the CdCdC stretching frequency in the IR spectra at about
1880 cm-1, the doublet-of-triplet resonance for the RhCH proton
1
in the H NMR spectra at δ 7.44 (10) or 7.85 (11), and the
three signals for the R-, â-, and γ-allenyl carbon atoms in the
13C NMR spectra at about δ 69, 114, and 200, respectively.
Although the spectroscopic data of 10 and 11 cannot show
whether the configuration around the metal center corresponds
to a square pyramid or a trigonal bipyramid, we assume, in
The proposed stereochemistry of 7 was substantiated by a
single-crystal X-ray structural analysis (for a molecular diagram
(12) (a) Huang, T.-M.; Hsu, R.-H.; Yang, C.-S.; Chen, J.-T.; Lee, G.-H.; Wang,
Y. Organometallics 1994, 13, 3657-3663. (b) Wouters, J. M. A.; Klein,
R. A.; Elsevier: C. J.; Ha¨ming, L.; Stam, C. H. Organometallics 1994, 13,
4586-4593. (c) Werner, H.; Flu¨gel, R.; Windmu¨ller, B.; Michenfelder,
A.; Wolf, J. Organometallics 1995, 14, 612-618.
(9) (a) Vrieze, K.; Volger, H. C.; van Leeuwen, P. W. N. M. Inorg. Chim.
Acta ReV. 1969, 109-129. (b) Hughes, R. P. in ComprehensiVe Organo-
metallic Chemistry, Wilkinson, G.; Stone, F. G. A.; Abel, E. W., Eds.; 1st
ed., Pergamon: Oxford, 1982; Vol. 5, p 492-540.
(13) (a) Ohgomori, Y.; Yoshida, S.; Watanabe, Y. J. Chem. Soc., Dalton Trans.
1987, 2969-2974. (b) Scha¨fer, M.; Wolf, J.; Werner, H. J. Organomet.
Chem. 1995, 476, 85-91.
(10) (a) Antonova, A. B.; Ioganson, A. A. Russ. Chem. ReV. 1989, 58, 693-
710. (b) Kovacik, I.; Gevert, O.; Werner, H.; Schmittel, M.; So¨llner, R.
Inorg. Chim. Acta 1998, 275-276, 435-439.
(14) Munson, J. W. The Chemistry of Ketenes, Allenes and Related Compounds;
Patai, S., Ed.; Wiley: New York, 1980; Vol. 1, Chapter 5.
(15) Ilg, K.; Werner, H. Chem. Eur. J. 2001, 7, 4633-4639.
(11) Braun, T.; Meuer, P.; Werner, H. Organometallics 1996, 15, 4075-4077.
9
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Pathways for Metal-Assisted C−C and C−P Coupling
A R T I C L E S
analogy to [RhHCl2(PiPr3)2],16 that a square pyramidal geom-
etry is preferred. We note that the H NMR spectrum of 11
Scheme 3. (L ) PiPr3)
1
displays two signals (with a small difference in chemical shift)
for the protons of the diastereotopic methyl groups of the
isopropyl units, which is in agreement with the chirality of the
molecule.
The reaction of the starting material 1 with the weakly acidic
terminal alkynes HCtCR′ (R′ ) Ph, p-Tol, SiMe3) proceeds
by an unusual route. If a solution of 1 and the alkyne in benzene
was stirred for 20 h (R′ ) Ph, p-Tol) or 14 days (R′ ) SiMe3)
at 10 °C, a gradual change of color from red to bright red
occurred and, after removal of the solvent, the rhodium(I)
complexes 12-14 were isolated in good to excellent yields. Both
the elemental analyses as well as the mass spectrum of 12
confirmed that formally 1:1 adducts of 1 and the alkyne were
formed that according to the 31P NMR spectra contained two
distinctly different PiPr3 groups. The two 31P NMR signals at
about δ 48-53 and 38-40, corresponding to the AM part of
an AMX pattern, show 103Rh-31P coupling constants of ca. 180
and 4 Hz, which indicates that only one of the phosphines is
coordinated to the rhodium. The nonequivalence of the PiPr3
units is also reflected in the 1H NMR spectra of 12-14 in which
four different resonances for the PCHCH3 protons are ob-
served.
Like in the rhodium vinylidenes trans-[RhCl(dCdCHR)-
(PiPr3)2], the chloro ligand of 12 can easily be displaced by a
phenyl or a vinyl group. Treatment of 12 with C6H5MgBr or
CH2dCHMgBr in benzene/ether or benzene/THF results in the
formation of the substitution products 15 and 16 (Scheme 4),
Scheme 4. (L ) PiPr3)
The X-ray crystal structure analysis of 12 (for a molecular
diagram see ref 5) confirmed that indeed only one of the
phosphines is coordinated to the metal center while the other is
part of a π-bonded unsaturated ylide. This novel ylide is built
up from the allenylidene, the alkyne, and one PiPr3 group. The
PC5 ligand is coordinated like a π-allyl unit, similarly to the C5
moiety in compound 6. The unsymmetric coordination is
illustrated by the three Rh-C bond lengths, which differ by
ca. 0.15 Å. Since the distance between rhodium and the
C-bonded phosphorus atom is 3.367(1) Å, a direct interaction
between these two atoms can be excluded. The P-C bond of
the PC5 ligand is significantly shorter than a P-C single bond
but quite similar to that of [RhCl{η3-anti-CH(PiPr3)C(Ph) )
O}(PiPr3)] (1.799(4) Å)17 and of metal-substituted ylides.18 Both
the C-C distances and the C-C-C bond angle of the π-allylic
moiety are nearly identical to those of the π-benzyl complex
[Rh(η3-CH2C6H5)(PiPr3)2] that was prepared from the dimer 24
(see Scheme 6) and C6H5CH2MgCl.19
The proposed mechanism for the formation of compounds
12-14 is outlined in Scheme 3. We assume that in the initial
step of the reaction a [2 + 2]-cycloaddition of the alkyne to
the RhdC bond of the RhC3 chain to give intermediate A takes
place, which is followed by a migration of one phosphine ligand
from the metal to the RhCH carbon atom. Although the
postulated intermediate B (like the product) is a 16-electron
rhodium(I) species, the π-allylic isomer seems to be energeti-
cally preferred. We note that, to the best of our knowledge,
there is no precedence for the metal-assisted C-C-P coupling
process leading to the ligand system found in complexes 12-
14.
which are isolated as black solids in 65-70% yield. As far as
the π-bonded allylic ligand anti-CH(PiPr3)C(Ph)dCdCdCPh2
1
is concerned, the H, 13C, and 31P NMR data of 15 and 16 are
quite similar to those of 12 and thus deserve no further comment.
The free ylide 17, the preparation of which as far as we know
has not been reported as yet, can be generated on treatment of
12 with CO in benzene at 10 °C. The rhodium-containing
products are 1820 and the well-known dimer 19.21 Ylide 17 was
isolated upon extraction of the product mixture with pentane
1
as a violet solid and characterized by H, 13C, and 31P NMR
spectroscopic data. The influence of the butatrienyl substituent
on the electronic properties of the ylide carbon is reflected by
the signal of the PdCH proton, which appears at δ 3.05 and is
shifted ca. 4 ppm downfield compared with the PdCH2
resonance of iPr3PCH2.22
Generation of Phosphacumulenes via Oxidatively Induced
C-P Coupling. The reaction of the starting material 1 with
(16) Harlow, R. L.; Thorn, D. L.; Baker, R. T.; Jones, N. L. Inorg. Chem. 1992,
31, 993-997.
(17) Werner, H.; Mahr, N.; Frenking, G.; Jonas, V. Organometallics 1995, 14,
619-625.
(18) Inter alia: (a) Fachin, G.; Bertani, R.; Zanotto, L.; Galligaris, M.; Nardin,
G. J. Organomet. Chem. 1989, 366, 409-420. (b) Werner, H.; Schippel,
O.; Wolf, J.; Schulz, M. J. Organomet. Chem. 1991, 417, 149-162.
(19) Werner, H.; Scha¨fer, M.; Nu¨rnberg, O.; Wolf, J. Chem. Ber. 1994, 127,
27-38.
(20) (a) Busetto, C.; D’Alfonso, A.; Maspero, F.; Perego, G.; Zazzetta, A. J.
Chem. Soc., Dalton Trans. 1977, 1828-1834. (b) Wang, K.; Rosini, G. P.;
Nolan, S. P.; Goldman, A. S. J. Am. Chem. Soc. 1995, 117, 5082-5088.
(21) McCleverty, J. A.; Wilkinson, G. Inorg. Synth. 1968, 8, 211-214.
(22) Ko¨ster, R.; Simic, D.; Grassberger, M. A. Justus Liebigs Ann. Chem. 1970,
739, 211-219.
9
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A R T I C L E S
Werner et al.
chlorine in the molar ratio of 1:1 in THF/hexane under the
exclusion of light proceeds by oxidative addition but does not
give, in contrast to the analogous reactions of the carbonyl
complexes trans-[RhCl(CO)(PR3)2] (PR3 ) PMe3, PEt3, PnBu3,
PEt2Ph, PPh3) with Cl2,23 the expected trichlororhodium(III)
compound [RhCl3(dCdCdCPh2)(PiPr3)2]. The five-coordinate
complex 21 is formed instead, which is equally obtained upon
treatment of 1 with PhICl2 in dichloromethane at -60 °C. By
both routes the yield of 21, being a red air-sensitive solid, is
virtually quantitative (Scheme 5). The preparation of 22 and
Scheme 5. (L ) PiPr3)
Figure 2. Molecular diagram of compound 21. Selected bond distances
(Å) and angles (deg): Rh-C1, 2.089(3); Rh-P1, 2.251(1); Rh-Cl1, 2.425-
(1); Rh-Cl2, 2.321(1); Rh-Cl3, 2.339(1); C1-C2, 1.297(5); C2-C3,
1.328(5); C1-P2, 1.817(3); C1-Rh-P1, 102.73(8); C1-Rh-Cl1, 165.44-
(8); C1-Rh-Cl2, 90.98(8); C1-Rh-Cl3, 86.08(8); P1-Rh-Cl1, 91.74-
(4); P1-Rh-Cl2, 90.65(5); P1-Rh-Cl3, 103.88(4); Cl1-Rh-Cl2, 90.47-
(4); Cl1-Rh-Cl3, 88.90(4); Cl2-Rh-Cl3, 165.47(3); Rh-C1-P2, 114.3(1);
Rh-C1-C2, 130.1(2); P2-C1-C2, 114.7(3); C1-C2-C3, 178.2(3).
23 from 2 and 20 as precursors and PhICl2 as the oxidizing
reagent occurs analogously. The 1H, 13C, and 31P NMR spectra
of 21-23 display two completely different sets of signals for
the hydrogen, carbon, and phosphorus atoms of the PiPr3 groups
and, since only one of the 31P NMR resonances shows a strong
103Rh-31P coupling, indicate that one of the phosphines is not
linked to rhodium. The most typical feature of the 13C NMR
spectra of 21-23 is the resonance at δ 75-76 for the metal-
bonded carbon of the phosphacumulene,24 which is split into a
doublet-of-doublet-of-doublets, due to coupling with rhodium
and two different phosphorus atoms.
The proposed structure of 21 has been confirmed by an X-ray
crystal structure analysis. The molecular diagram (Figure 2)
reveals a square-pyramidal geometry around the metal center
with the coordinated triisopropylphosphine in the apical position.
The rhodium atom is situated somewhat above the basal plane
manifested by the bending of the C1-Rh-Cl1 (165.43(1)°) and
Cl2-Rh-Cl3 (165.47(4)°) axes. The bond length Rh-C1 is
nearly identical to that in trans-[Rh{η1-C(CHdCH2)dCHPh}-
(CO)(PiPr3)2] (2.088(5) Å)4 and trans-[Rh{η1-C(CtCCO2Me)
dCHCO2Me}(CO)(PiPr3)2] (2.099(4) Å)25 but slightly shorter
than in the η1-pentatrienyl complex 7. As expected, the C1-
C2-C3 chain is linear (178.3(4)°), whereas the sum of the bond
angles around C1 is almost exactly 360°. The two planes con-
taining the substituents at C1 (Rh and P2) and C3 (ipso-carbons
of C6H5) are orthogonal to each other (the dihedral angle being
89.7(2)°), in agreement with the allene-type structure of the
molecule. Phosphacumulene ligands related to that found in 21
are known from [(η5-C5H5)Mn{C(PPh3)dCdCPh2}(CO)2] and
[Cr{C(PPh3)dCdCiPr2}(CO)5], but in these cases they have
been generated by attack of free triphenylphosphine on alle-
nylidene complexes.26
The mechanism of formation of 21-23 seems to be straight-
forward. We assume that the initial step of the reaction consists
of the anticipated oxidative addition of chlorine at rhodium to
form the six-coordinate species [RhCl3(dCdCdCPh2)(PiPr3)2].
In this intermediate, the steric crowding around the metal center
caused by the three chlorides and in particular by the two bulky
phosphine ligands leads to a 1,2-shift of one PiPr3 group from
the metal to the R-carbon of the allenylidene, yielding a
molecule in which the two PiPr3 units are farther apart than in
the intermediate. In this context we note that while the rhodium-
(II) compound trans-[RhCl2(PiPr3)2] is known,16,27 our attempts
to prepare a rhodium(III) complex of the composition [RhCl3-
(PiPr3)2] remained unsuccessful.
Rhodium Complexes with 1,1-Disubstituted Butatrienes
as Ligands. After we found that the vinylidene compounds [(η5-
C5H5)Rh(dCdCHR)(PiPr3)] react with diazomethane to form
the allene complexes [(η5-C5H5)Rh(η2-CH2dCdCHR)(PiPr3)]
(R ) H, Me, Ph),28 we became interested to find out whether
a similar C-C coupling process would take place upon treatment
of the allenylidene rhodium derivatives trans-[RhCl(dCdCd
CRR′)(PiPr3)2] with CH2N2. In addition to 1, 20, and 27 (see
Scheme 7), we also prepared the new precursor 26 having, in
contrast to the structurally related starting materials, a strong
electron-withdrawing substituent at the terminal carbon of the
allenylidene unit.
(23) (a) Heck, R. F. J. Am. Chem. Soc. 1964, 86, 2796-2799. (b) Chatt, J.;
Shaw, B. L. J. Chem. Soc. A 1966, 1537-1542. (c) Browning, J.; Goggin,
P. L.; Goodfellow, R. J.; Norton, M. G.; Rattray, A. J. M.; Taylor, B. F.;
Mink, J. J. Chem. Soc., Dalton Trans. 1977, 2061-2067.
(24) For a review on phosphacumulenes: Bestmann, H. J. Angew. Chem. 1977,
89, 361-376; Angew. Chem., Int. Ed. Engl. 1977, 16, 349-367.
(25) Scha¨fer, M.; Mahr, N.; Wolf, J.; Werner, H. Angew. Chem. 1993, 105,
1377-1379; Angew. Chem., Int. Ed. Engl. 1993, 32, 1315-1318.
(26) (a) Kolobova, N. E.; Ivanov, L. L.; Zhvanko, O. S.; Khitrova, O. M.;
Batsanov, A. S.; Struchkov, Y. T. J. Organomet. Chem. 1984, 265, 271-
281. (b) Berke, H.; Ha¨rter, P.; Huttner, G., Zsolnai, L. Z. Naturforsch. B
1981, 36, 929-937.
(27) Rappert, T.; Wolf, J.; Schulz, M.; Werner, H. Chem. Ber. 1992, 125, 839-
841.
(28) Wolf, J.; Zolk, R.; Schubert, U.; Werner, H. J. Organomet. Chem. 1988,
340, 161-178.
9
6970 J. AM. CHEM. SOC. VOL. 124, NO. 24, 2002

Pathways for Metal-Assisted C−C and C−P Coupling
Scheme 6. (L ) PiPr3)
A R T I C L E S
Scheme 7. (L ) PiPr3)
Figure 3. Molecular diagram of compound 28. Selected bond distances
(Å) and angles (deg): Rh-P1, 2.365(1); Rh-P2, 2.355(1); Rh-Cl, 2.349-
(1); Rh-C1, 2.060(2); Rh-C2, 2.063(2); C1-C2, 1.408(3); C2-C3, 1.272-
(3); C3-C4, 1.335(3); P1-Rh-P2, 166.45(2); P1-Rh-Cl, 88.16(3); P1-
Rh-C1, 96.70(7); P1-Rh-C2, 90.56(6); P2-Rh-Cl, 87.42(2); P2-Rh-
C1, 94.35(7); P2-Rh-C2, 92.89(6); Cl-Rh-C1, 144.36(7); Cl-Rh-C2,
175.65(6); C1-Rh-C2, 39.96(9); Rh-C1-C2, 70.1(1); Rh-C2-C1, 69.9-
(1); C1-C2-C3, 144.7(2); C2-C3-C4, 174.8(2).
butatriene ligand. Two of these signals show a relatively large
103Rh-13C coupling and are therefore assigned to the two carbon
atoms of the C4 unit bonded to the metal. The chemical shift of
the CH2 resonance of 28 at δ 13.0 as well as the 1J(CH) coupling
constant of 161.4 Hz indicates the predominant sp3 character
of this C atom, which implies that the bonding between rhodium
and the CdCH2 fragment of the butatriene is related to that of
1
a metallacyclopropane. Since the H NMR spectra of 28 and
The synthetic procedure to obtain 26 is shown in Scheme 6.
Treatment of the dimer 2429 with the alkynol in ether in the
presence of NEt3 led in the first step to the formation of the
vinylidene compound 25, which after column chromatography
(with neutral Al2O3) was isolated as a blue solid in 91% yield.
Although we assume that the π-alkyne complex trans-[RhCl-
{η2-HCtCC(Ph)(CF3)OH}(PiPr3)2] is initially formed,1 this
intermediate is probably very labile and rearranges rapidly to
the vinylidene isomer. The conversion of 25 to the rhodium
allenylidene 26 occurs by passing a solution of the vinylidene
compound in benzene through a column filled with acidic Al2O3.
During this procedure a change of color from blue to yellow-
green takes place and, if chromatography is continued, the
product 26 is eluted in virtually quantitative yield. The IR and
NMR spectroscopic data of 26 are similar to those of 273 and
deserve no further comment.
29 exhibit two signals and the spectrum of 30 four signals for
the PCHCH3 protons, we assume that in contrast to trans-[Rh-
(CtCMe)(η2-CH2dCdCH2)(PiPr3)2]30 the rotation of the bu-
tatriene ligand around the rhodium-olefin bond in 28-30 is
slow on the NMR time scale.
With regard to the formation of the coordinated C4 cumulene
from the rhodium allenylidenes and CH2N2, it is conceivable
that the attack of the nucleophilic diazomethane occurs either
at the metal or the R-carbon atom of the RhC3 chain. In the
course of their studies on the reactivity of carbene tungsten and
rhenium complexes toward RCHN2, both Casey31 and Gladysz32
supposed that the first step in these reactions consists of an attack
of the C-nucleophile at the carbene carbon, generating an olefin.
Although these authors as well as we have no evidence for an
initial C-C interaction, theoretical work seems to be in favor
of this proposal.33
The reactions of 1, 20, 26, and 27 with excess diazomethane
in benzene at room temperature are completed within a few
minutes. After removal of the solvent and recrystallization from
pentane, the coupling products 28-31 were isolated as red or
orange solids, only moderately sensitive to air and water, in
91-96% yield. The proposed structure (see Scheme 7) is
particularly supported by the 13C NMR spectra, which display
four signals between δ 184 and 12 for the carbon nuclei of the
The X-ray crystal structure analysis of 28 (Figure 3)
confirmed a distorted square-planar coordination around the
metal center with the Cl, Rh, and C1-C4 atoms lying in one
plane. Although the CdCH2 unit is bonded unsymmetrically
(30) Scha¨fer, M. Ph.D. Thesis, Universita¨t Wu¨rzburg, 1994.
(31) Casey, C. P.; Bertz, S. H.; Burkardt, T. J. Tetrahedron Lett. 1973, 12, 1421-
1424.
(32) Wang, Y.; Gladysz, J. A. Chem. Ber. 1995, 128, 213-220.
(33) (a) Schilling, B. E. R.; Hoffmann, R.; Lichtenberger, D. L. J. Am. Chem.
Soc. 1979, 101, 585-591. (b) Kostic, N. M.; Fenske, R. F. Organometallics
1982, 1, 974-982. (c) Esteruelas, M. A.; Go´mez, A. V.; Lo´pez, A. M.;
Modrego, J.; Onate, E. Organometallics 1997, 16, 5826-5835.
(29) Werner, H.; Wolf, J.; Ho¨hn, A. J. Organomet. Chem. 1985, 287, 395-
407.
9
J. AM. CHEM. SOC. VOL. 124, NO. 24, 2002 6971

A R T I C L E S
Werner et al.
Scheme 8. (L ) PiPr3)
to rhodium, as is shown by the linearity of the Cl-Rh-C2 axis
(175.65(6)°), the distances Rh-C1 and Rh-C2 are nearly
identical. This is in contrast to the structurally similar compound
trans-[RhCl(η2-CH2dCdCHCO2Et)(PiPr3)2], in which the Rh-
C1 and Rh-C2 bond lengths are 2.120(5) and 1.991(5) Å.34
The P1-Rh-P2 axis is somewhat bent (166.45(2)°) and directed
toward the chloride, which is probably due to the steric
requirements of the isopropyl and phenyl groups.
The butatrienerhodium(I) compounds 28, 29, and 31 are
thermally labile and upon heating in toluene at 80-95 °C
rearrange to the thermodynamically more stable complexes 32-
34 (see Scheme 7). The isomerization can easily be followed
by a change of color from red to yellow. In the case of 34, a
mixture of two isomers is formed that differ in the relative
position of the phenyl and tert-butyl groups to the metal center.
If the rearrangement of 31 is monitored by 31P NMR spectros-
copy, a ratio syn-34:anti-34 of 2:1 is observed initially. After 6
h in toluene at 95 °C, the ratio changes to 10:1. However, even
after stirring for 12 h, a complete conversion of anti-34 to syn-
34 does not occur. Nevertheless, compound syn-34 has been
isolated analytically pure upon fractional crystallization from
acetone and, by comparison of the 1H NMR data with those of
anti-34, identified as the isomer in which the phenyl group at
C4 is directed toward the metal. The assignment of the
resonances for the Hendo and Hexo protons at C1 follows from
the work of Gladysz et al., who assigned the signals of the CH2
protons of the allene complex [(η5-C5H5)Re(η2-CH2dCdCH2)-
(NO)(PPh3)]BF4 on the basis of NOE measurements.35 Owing
to the presence of an unsymmetrical butatriene, the 13C NMR
spectra of 32, 33, and cis-34 display four resonances in the
region between δ 144 and 97 for the carbon atoms of the C4
chain. Two of these signals show a 31P-13C coupling and thus
belong to the butatriene C atoms linked to the metal. We note
that in all of the previously described 1,1,4,4-tetrasubstituted
butatrienerhodium(I) compounds trans-[Rh(η2-R2CdCdCd
CR′2)(PPh3)2], which were prepared from [RhCl(PPh3)3] and
corresponding butatrienes,36 the central CdC bond is coordi-
nated to the metal. The linkage of a terminal R2CdC bond not
to rhodium(I) but to platinum(0) was recently reported by
Stang.37
thereby anticipating that they may react analogously to the
Vaska-type compounds trans-[IrCl(CO)(PR3)2] with methyl
iodide,40 we observed that CH3I can behave as a CH2 source.
While in the absence of a basic substrate the reaction of 1 with
methyl iodide proceeds very slowly and gives a mixture of
products, the butatriene complex 38 is formed as the major
species together with 32 in the presence of Na2CO3. Subsequent
treatment of the reaction mixture with KI yields 38 nearly
quantitatively. The bis(p-anisyl) derivative 20 behaves similarly
and affords 39. Both compounds 38 and 39 are also obtained
by treating the allenylidene(iodo)rhodium(I) complexes 36 and
37 with CH3I and Na2CO3. Regarding the mechanism of
formation of 38 and 39, we assume that in the initial step the
anticipated oxidative addition of methyl iodide at the rhodium
center takes place, which is followed by an insertion of the
allenylidene unit into the Rh-CH3 bond. The so-formed
intermediate with the Rh-C(CH3)dCdCPh2 linkage then reacts
by a â-H shift to give an octahedral butatriene(hydrido)rhodium-
(III) species, which upon reductive elimination of HI or HCl
(the latter being facilitated by Na2CO3) generates the final
product. There is precedence for the first two steps (oxidative
addition and methyl migration) insofar as both we41 and Fryzuk
et al.42 found that the vinylidene compounds trans-[IrCl(dCd
CH2)(PiPr3)2] and [Ir(dCdCH2){κ3-N(SiMe2CH2PPh2)2}] react
with methyl iodide to give the vinyl complexes [IrCl(I)-
{C(CH3)dCH2}(PiPr3)2] and [IrI{C(CH3)dCH2)}{κ3-N(SiMe2-
CH2PPh2)2}], respectively. However, in these cases a subsequent
â-H shift does not occur.
Similarly to the allylic type complex 12, compounds 28-31
and 32-34 also react rapidly with CO in benzene at room
temperature to yield the carbonyl complex 18 by ligand
exchange. Of the butatrienes formed in these processes, those
with C(aryl)2 and C(Ph)CF3 as the terminal unit are rather labile
and undergo secondary reactions. The hitherto unknown cu-
mulene 35 was characterized by GC/MS and by comparison of
the spectroscopic data with those of other butatrienes.38,39
Quite unexpectedly, there is also an alternative route to
convert a metal-bonded allenylidene moiety into a butatriene
ligand (see Scheme 8). During attempts to oxidatively add CH3I
to the metal center of the rhodium(I) complexes 1 and 20,
The assumption that both terminal hydrogen atoms of the
allenylidene ligand in 38 stem from the methyl iodide has been
confirmed by the preparation of 38-d2 from 36 and CD3I. Both
substrates react in acetone/THF in the presence of Na2CO3 to
give 38-d2 as a yellow solid in 73% yield. While the 1H NMR
spectrum of 38-d2 displays no signals in the region around δ
2
4.5-5.5, the H NMR spectrum exhibits two resonances at δ
5.35 and 4.86 assigned to the exo- and endo-D atoms of the
dCD2 group.
(34) Werner, H.; Schneider, D.; Schulz, M. J. Organomet. Chem. 1993, 451,
175-182.
Formation of Allenes and Hexapentaenes from Rhodium
Allenylidenes as Precursors. The allenylidene ligand of both
1 and 26 can be converted not only to a butatriene but also to
(35) Pu, J.; Peng, T.-S.; Arif, A. M.; Gladysz, J. A. Organometallics 1992, 11,
3232-3241.
(36) (a) Hagelee, L.; West, R.; Calabrese, J.; Norman, J. J. Am. Chem. Soc.
1979, 101, 4888-4892. (b) Stang, P. J.; White, M. R.; Maas, G.
Organometallics 1983, 2, 720-725.
(37) White, M. R.; Stang, P. J.; Organometallics 1983, 2, 1654-1658.
(38) Runge, W.; Brady, W. T. The Chemistry of Ketenes, Allenes and Related
Compounds; Patai, S., Ed.; Wiley: New York, 1980; Vol. 1.
(39) Westmijze, H.; Nap, I.; Meijer, J.; Kleijn, H.; Vermeer, P. Recl. TraV. Chim.
Pays-Bas 1983, 102, 154-157, and references therein.
(40) Review: Collman, J. P.; Roper, W. R. AdV. Organomet. Chem. 1968, 7,
54-94.
(41) Ho¨hn, A.; Werner, H. J. Organomet. Chem. 1990, 382, 255-277.
(42) Fryzuk, M. D.; Huang, L.; McManus, N. T.; Paglia, P.; Rettig, S. J.; White,
G. S. Organometallics 1992, 11, 2979-2990.
9
6972 J. AM. CHEM. SOC. VOL. 124, NO. 24, 2002

Pathways for Metal-Assisted C−C and C−P Coupling
A R T I C L E S
Scheme 10. (L ) PiPr3)
an allene. The reaction of 1 with H2 in benzene at room
temperature is rather slow, but after 40 h the four-coordinate
rhodium(I) complex 40 is quantitatively formed (see Scheme
9). In contrast, compound 26 reacts significantly faster with H2
and affords after 30 min (benzene, 25 °C) the corresponding
product 41. Quite remarkably, under the chosen conditions no
hydrogenation of the allene ligand occurs. Only after increasing
the time of the reaction to 10 days and raising the temperature
to 60 °C is the formation of a new rhodium complex observed.
It is, according to the NMR data, the chloro(dihydrido) deriva-
tive [RhH2Cl(PiPr3)2].16,29 Since the 1H NMR spectra of 40 and
41 display only one signal for the CH2 protons, we assume that
the unsubstituted double bond of the allene is coordinated to
the metal center. A slippage of the [RhCl(PiPr3)2] fragment along
the axis of the cumulene, as has been observed for some allene
iron and platinum complexes,43,44 could not be detected.
128.0 and 113.4 show a relatively large 103Rh-13C coupling
and are thus assigned to the carbons linked to rhodium. The
assumption that the Câ-Cγ and not the central Cγ-Cδ bond is
coordinated to the metal center is supported by the X-ray crystal
structure analysis of 44.46 It is worth mentioning that there is
precedence for the linkage of two allenylidene fragments to give
a tetrasubstituted hexapentaene, as on the heating of [(η5-C5H5)-
Mn(dCdCdCtBu2)(CO)2] to give small quantities of tBu2Cd
CdCdCdCdCtBu2.47 A related rhodium-mediated coupling
of two vinylidene ligands to generate a coordinated butatriene
is also known.48
Scheme 9. (L ) PiPr3)
Concluding Remarks
The present investigations have shown that square-planar
rhodium allenylidenes of the general composition trans-[RhCl-
(dCdCdCRR′)(PiPr3)2] offer a multifaceted chemistry indeed.
They react not only with C-nucleophiles by replacement of the
chloride but also undergo reactions with H2, Cl2, HCl, methyl
iodide, and phenylacetylene to give products in which the
allenylidene unit is preserved as part of a newly formed ligand.
The potential of the starting materials trans-[RhCl(dCdCd
CRR′)(PiPr3)2] (1, 2, 20, 26) to generate cumulenes such as
allenes, butatrienes, hexapentaenes, and even unsaturated phos-
phorus ylides is clearly illustrated by the preparation of
compounds 8, 17, 35, and 43, which are hardly accessible on
conventional routes. Taking these results into consideration, it
seems at least conceivable that rhodium allenylidenes, possibly
formed in situ from appropriate propargylic alcohols following
the classical Selegue method,49 can be used as precursors for
presently unknown unsaturated hydrocarbons and ylides. On the
basis of this idea, current work in our laboratory is focused on
reaction conditions that allow the conversion, e.g. of the
butatriene complexes 31, 34, or 39, upon treatment with the
corresponding alkynol HCtCCR(R′)OH to the starting materials
20 and 27 and free butatrienes. Another possibility is that
compounds such as 1, 2, 20, 26, and 27, similarly to their iridium
counterparts trans-[IrCl(dCdCdCRR′)(PiPr3)2],15 may serve
as building blocks for the generation of rhodium carbenes and
carbynes, the catalytic activity of which is still unexplored.
In the same way as for 31 and 34, treatment of 40 and 41
with CO in benzene at 10 °C leads to a replacement of the
olefinic ligand. While 1,1-diphenylallene 42 is known,45 the CF3-
substituted derivative 43 has not been reported as yet; it has
been characterized by NMR spectroscopy. Typical features are
1
the quartet for the CH2 protons in the H NMR at δ 4.75, the
three resonances for the R-, â-, and γ-carbon atoms of the C3
chain in the 13C NMR at δ 83.1, 102.0, and 210.2 (the two
latter showing a 13C-19F coupling), and the singlet at δ -60.7
in the 19F NMR spectrum. The metal-containing product of the
reactions of 40 and 41 with CO is the carbonyl complex 18.
Not only the hydrogenation but also the thermolysis of the
starting materials 1 and 20 leads to the cleavage of the RhdC
bond. After stirring of a solution of 1 or 20 in toluene at 95 °C
for 5 days, besides the generation of free PiPr3, the formation
of the hexapentaene complexes 44 and 45 is observed (Scheme
10). Both are bright red, slightly air-sensitive solids that are
readily soluble in dichloromethane, but less soluble in pentane
and ether. Compound 44 is known and has been recently
prepared in our laboratory by treatment of trans-[Rh(CtCCPh2-
Experimental Section
All reactions were carried out under an atmosphere of argon by
Schlenk techniques. The starting materials 1,1a 2,1b 20,3b 24,29 27,3b 36,
and 372b were prepared as described in the literature. NMR spectra
were recorded at room temperature on Bruker AC 200 and Bruker AMX
400 instruments, IR spectra on a IFS 25 FT-IR infrared spectrometer,
OH)(dCdCHCPh2OH)(PiPr3)2] with acidic alumina.46 The 13
C
NMR spectrum of 45 displays, similarly to that of 44, six
resonances for the C atoms of the C6 unit, of which two at δ
(43) Ben-Shoshan, R.; Pettit, R. J. Am. Chem. Soc. 1967, 89, 2231-2232.
(44) Vrieze, K.; Volger, H. C.; Praat, A. P. J. Organomet. Chem. 1970, 21,
467-475.
(47) Berke, H. Angew. Chem. 1976, 88, 684-685; Angew. Chem., Int. Ed. Engl.
1976, 15, 624-625.
(45) Beltrame, P.; Pitea, D.; Marzo, A.; SimOnetta, M. J. Chem. Soc. B 1967,
71-75.
(48) Rappert, T.; Nu¨rnberg, O.; Werner, H. Organometallics 1993, 12, 1359-
1364.
(46) Werner, H.; Wiedemann, R.; Mahr, N.; Steinert, P.; Wolf, J. Chem. Eur.
J. 1996, 2, 561-569.
(49) Selegue, J. P. Organometallics 1982, 1, 217-218.
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J. AM. CHEM. SOC. VOL. 124, NO. 24, 2002 6973

A R T I C L E S
Werner et al.
and mass spectra on a Finnigan MAT 90 (70 eV) or on a Hewlett-
Packard G 1800 GCD instrument. Coupling constants are given in hertz.
Abbreviations used: s, singlet; d, doublet; t, triplet; m, multiplet; v,
virtual coupling; br, broadened signal; N ) 3J(PH) + 5J(PH) or 1J(PC)
+ 3J(PC). Melting points were measured by differential thermal analysis
(DTA).
C1), 50.3 (m, C5), 28.3 (d, J(PC) ) 9.3 Hz, PCHCH3), 28.0 (d, J(PC)
) 10.0 Hz, PCHCH3), 20.8, 20.7, 20.5, 20.4 (all s, br, PCHCH3). 31P
NMR (C6D6, 162.0 MHz): partly resolved AB pattern of ABX spectrum
with signals at δ 52.4 (A part) and 51.4, 51.3, 51.2, 51.1 (B part).
Anal. Calcd for C35H55P2Rh: C, 65.62; H 8.65. Found: C 65.40; H
8.17. For assignment for protons H1 to H3 and carbon atoms C1 to C5,
see Chart 1.
Preparation of [(η5-C5H5)Rh(dCdCdCPh2)(PiPr3)] (3). A mix-
ture of 1 (140 mg, 0.22 mmol) and NaC5H5 (39 mg, 0.44 mmol) was
treated dropwise with THF (3 mL) under stirring at room temperature.
A rapid change of color from red to dark green occurred. After the
solution was stirred for 5 min, the solvent was removed in vacuo and
the residue extracted with pentane (30 mL). The extract was concen-
trated to ca. 3 mL and then chromatographed on Al2O3 (neutral, activity
grade V, height of column 7 cm). With hexane, a green fraction was
eluted that was concentrated to ca. 2 mL in vacuo. After storing the
solution for 3 d at -78 °C, dark green crystals precipitated that were
separated from the mother liquor, washed three times with 1-mL
portions of pentane (0 °C), and dried in vacuo. Yield: 69 mg (62%).
Mp: 124 °C dec. IR (KBr): ν(CdCdC) 1940 cm-1. 1H NMR (C6D6,
200 MHz): δ 7.98 (m, 4H, ortho-H of C6H5), 7.28 (m, 2H, para-H of
C6H5), 7.03 (m, 4H, meta-H of C6H5), 5.01 (s, 5H, C5H5), 2.09 (m,
3H, PCHCH3), 1.00 (dd, J(PH) ) 13.5, J(HH) ) 6.9 Hz, 18H,
PCHCH3). 13C NMR (C6D6, 50.3 MHz): δ 228.6 (dd, J(RhC) ) 71.2,
J(PC) ) 30.5 Hz, RhdCdCdC), 208.9 (dd, J(RhC) ) 16.5, J(PC) )
7.0 Hz, RhdCdCdC), 148.0 (s, br, ipso-C of C6H5), 128.3, 127.8,
126.0 (all s, C6H5), 121.1 (dd, br, J(RhC) ) 1.9, J(PC) ) 5.7 Hz, Rhd
CdCdC), 83.7 (dd, J(RhC) ) 3.8, J(PC) ) 2.5 Hz, C5H5), 26.8 (dd,
J(RhC) ) 1.9, J(PC) ) 22.9 Hz, PCHCH3), 19.9 (s, PCHCH3). 31P
NMR (C6D6, 81.0 MHz): δ 68.5 (d, J(RhP) ) 200.8 Hz). Anal. Calcd
for C29H36PRh: C, 67.18; H, 7.00. Found: C, 67.49; H, 6.83.
Preparation of trans-[Rh{η1-C(CHdCH2)dCdCPh2}(CO)(PiPr3)2]
(7). A slow stream of CO was passed through a solution of 6 (90 mg,
0.14 mmol) in benzene (3 mL) at 10 °C. A change of color from red
to light yellow occurred. After the solution was stirred for 5 min at
room temperature, the solvent was evaporated in vacuo. The yellow
residue was dissolved in acetone (2 mL) and the solution was stored
for 10 h at -78 °C. Yellow crystals precipitated which were separated
from the mother liquor, washed three times with 2-mL portions of
acetone (0 °C) and dried in vacuo: yield 61 mg (65%); mp 98 °C dec.
1
IR (C6H6): ν(CtO) 1930, ν(CdCdC) 1850 cm-1. H NMR (C6D6,
200 MHz): δ 7.63, 7.00 (both m, 10H, C6H5), 6.84 (dd, J(H1H2) )
17.0, J(H1H3) ) 9.5 Hz, 1H, H1), 5.97 (dd, J(H1H2) ) 17.0, J(H2H3)
) 3.1 Hz, 1H, H2), 5.11 (dd, J(H1H3) ) 9.5, J(H2H3) ) 3.1 Hz, 1H,
H3), 2.01 (m, 6H, PCHCH3), 1.06 (dvt, N ) 13.3, J(HH) ) 6.8 Hz,
36H, PCHCH3). 13C NMR (C6D6, 50.3 MHz): δ 209.9 (t, J(PC) ) 3.2
Hz, C2), 195.1 (dt, J(RhC) ) 55.8, J(PC) ) 22.3 Hz, Rh-CO), 144.5
(s, br, C4), 141.3 (s, ipso-C of C6H5), 129.0, 128.1, 125.3 (all s, C6H5),
118.8 (dt, J(RhC) ) 27.0, J(PC) ) 11.4 Hz, C3), 117.8 (s, C5), 98.4 (s,
C1), 26.1 (vt, N ) 19.7 Hz, PCHCH3), 20.5, 20.0 (both s, PCHCH3).
31P NMR (C6D6, 81.0 MHz): δ 47.3 (d, J(RhP) ) 135.1 Hz). Anal.
Calcd for C36H55OP2Rh: C, 64.66; H, 8.29. Found: C, 64.42; H, 8.39.
For assignment for protons H1 to H3 and carbon atoms C1 to C5 see
Chart 1.
Preparation of [(η5-C5H5)Rh{dCdCdC(o-Tol)Ph}(PiPr3)] (4).
This compound was prepared as described for 3 from 2 (176 mg, 0.27
mmol) and NaC5H5 (48 mg, 0.54 mmol) to give a dark green solid.
Yield: 106 mg (75%). Mp: 146 °C dec. IR (KBr): ν(CdCdC) 1930
Reaction of 7 with CH3CO2H. A solution of 7 (35 mg, 0.05 mmol)
in C6D6 (0.5 mL) was treated at 10 °C with acetic acid (3.1 µL, 0.05
mmol), which led to a gradual change of color from yellow to pale-
yellow. After the solution was stirred for 5 min, the NMR spectra
confirmed the formation of both trans-[Rh(κ1-O2CCH3)(CO)(PiPr3)2]
(9)13 and the vinylallene CH2dCH-CHdCdCPh2 (8) as the organic
product. NMR data for 8: 1H NMR (C6D6, 400 MHz): δ 7.40 (m, 4H;
ortho-H of C6H5), 7.15 (m, 4H, meta-H of C6H5), 7.05 (m, 2H, para-H
of C6H5), 6.22 (m, 2H, H1 and H2), 5.09 (m, 1H, H3), 4.87 (m, 1H,
H4). 13C NMR (C6D6, 100.6 MHz): δ 210.2 (s,dCdCPh2), 136.8 (s,
ipso-C of C6H5), 132.5 (s, CHdCH2), 129.0, 128.8, 127.7 (all s, C6H5),
117.0 (s, CHdCH2), 112.0 (s, dCPh2), 97.9 (s, dCH-CHdCH2). For
assignment for protons H1 to H4 see Chart 1.
1
cm-1. H NMR (CDCl3, 200 MHz): δ 7.79, 7.11 (both m, 9H, C6H4
and C6H5), 5.09 (s, 5H, C5H5), 2.00 (s, 3H, C6H4CH3), 1.98 (m, 3H,
PCHCH3), 0.92 (dd, J(PH) ) 13.6, J(HH) ) 6.9 Hz, 18H, PCHCH3).
13C NMR (CDCl3, 100.6 MHz): δ 227.2 (dd, J(RhC) ) 71.0, J(PC) )
31.0 Hz, RhdCdCdC), 204.5 (dd, J(RhC) ) 16.9, J(PC) ) 6.3 Hz,
RhdCdCdC), 146.2 (d, J(PC) ) 2.5 Hz, ipso-C of C6H5 or C6H4),
146.0 (d, J(PC) ) 3.8 Hz, ipso-C of C6H5 or C6H4), 132.9, 129.9, 129.5,
126.5, 125.8, 125.6, 125.4, 124.8 (all s, C6H5 and C6H4), 122.3 (d, br,
J(PC) ) 5.3 Hz, RhdCdCdC), 83.4 (dd, J(RhC) ) 2.7, J(PC) ) 2.7
Hz, C5H5), 26.4 (d, J(PC) ) 22.9 Hz, PCHCH3), 19.9 (s, C6H4CH3),
19.6 (s, PCHCH3). 31P NMR (CDCl3, 162.0 MHz): δ 66.7 (d, J(RhP)
) 197.3 Hz). Anal. Calcd for C30H38PRh: C, 67.67; H, 7.19. Found:
C, 67.64; H, 7.23.
Preparation of [RhCl2(CHdCdCPh2)(PiPr3)2] (10). A solution
of 1 (97 mg, 0.15 mmol) in toluene (5 mL) was treated at 0 °C first
with acetone (1 mL) and then dropwise with a 0.05 M solution of HCl
in benzene (3 mL, 0.15 mmol). A quick change of color from red to
green occurred. After the solution was stirred for 10 min at room
temperature, the solvent was evaporated in vacuo. The residue was
dissolved in acetone (3 mL) and the solution was stored at -20 °C for
24 h. Green crystals precipitated that were separated from the mother
liquor, washed twice with 1-mL portions of acetone (0 °C), and dried
in vacuo. Yield: 90 mg (88%). Mp: 164 °C dec. IR (C6H6): ν(Cd
CdC) 1875 cm-1. 1H NMR (CDCl3, 200 MHz): δ 7.52 (m, 4H, ortho-H
of C6H5), 7.44 (dt, J(RhH) ) 6.4, J(PH) ) 3.6 Hz, 1H, RhCH), 7.23
(m, 6H, C6H5), 2.93 (m, 6H, PCHCH3), 1.24 (dvt, N ) 13.3, J(HH) )
Preparation of [Rh(η3-CH2CHCdCdCPh2)(PiPr3)2] (6). A solu-
tion of 1 (173 mg, 0.27 mmol) in toluene (4 mL) was treated dropwise
at -40 °C with a 1.00 M solution of CH2dCHMgBr in THF (0.30
mL, 0.30 mmol). After warming to 0 °C, the solution was stirred for
1 h, which led to a gradual change of color from red to dark red. The
solvent was removed in vacuo and the residue extracted with pentane
(25 mL). The extract was brought to dryness in vacuo, the oily residue
was dissolved in acetone (2 mL), and the solution was stored for 24 h
at -78 °C. Red crystals precipitated, which were washed twice with
1-mL portions of acetone (-20 °C) and dried in vacuo. Yield: 104
13
7.1 Hz, 36H, PCHCH3). C NMR (C6D6, 50.3 MHz): δ 199.9 (dt,
1
mg (61%). Mp: 62 °C dec. IR (C6H6): ν(CdCdC) 1970 cm-1. H
J(RhC) ) 1.9, J(PC) ) 3.2 Hz, Rh-CHdC), 141.0 (s, br, ipso-C of
C6H5), 129.6, 127.8, 127.1 (all s, C6H5), 114.2 (s, br, Rh-CHdCdC),
68.5 (dt, J(RhC) ) 36.2, J(PC) ) 8.9 Hz, RhCH), 23.0 (vt, N ) 19.1
Hz, PCHCH3), 19.9 (s, PCHCH3). 31P NMR (C6D6, 81.0 MHz): δ 25.4
(d, J(RhP) ) 97.3 Hz). Anal. Calcd for C33H53Cl2P2Rh: C, 57.82; H,
7.79. Found: C, 57.82; H, 8.42.
NMR (C6D6, 400 MHz): δ 7.84, 7.15 (both m, 10H, C6H5), 4.79 (dd,
J(H1H3) ) 12.1, J(H1H2) ) 6.8 Hz, 1H, H1), 3.01 (d, J(H1H2) ) 6.8
Hz, 1H, H2), 2.45 (dd, J(P2H3) ) 5.8, J(H1H3) ) 12.1 Hz, 1H, H3),
2.33, 2.07 (both m, 6H, PCHCH3), 1.18 (dd, J(PH) ) 12.0, J(HH) )
7.6 Hz, 18H, PCHCH3), 1.11 (m, 18H, PCHCH3).13C NMR (C6D6,
100.6 MHz): δ 183.1 (s, C2), 141.1, 140.4 (both s, ipso-C of C6H5),
130.1, 129.2, 127.5, 125.8, 125.2, 122.9 (all s, C6H5), 113.2 (ddd,
J(RhC) ) 54.0, J(PC) ) 17.1 and 16.7 Hz, C3), 106.9 (m, C4), 79.7 (s,
Preparation of [RhCl2{CHdCdC(o-Tol)Ph}(PiPr3)2] (11). This
compound was prepared as described for 10 from 2 (92 mg, 0.14 mmol)
and a 0.05 M solution of HCl in benzene (2.8 mL, 0.14 mmol) to give
9
6974 J. AM. CHEM. SOC. VOL. 124, NO. 24, 2002

Pathways for Metal-Assisted C−C and C−P Coupling
A R T I C L E S
a green air-stable solid. Yield: 83 mg (86%). Mp: 132 °C dec. IR
precipitated that were separated from the mother liquor, washed twice
1
(C6H6): ν(CdCdC) 1885 cm-1. H NMR (C6D6, 400 MHz): δ 7.85
with 1-mL portions of pentane (-20 °C), and dried in vacuo. Yield:
1
(dt, J(RhH) ) 6.4, J(PH) ) 3.6 Hz, 1H, RhCH), 7.40 (m, 9H, C6H4
and C6H5), 2.93 (m, 6H, PCHCH3), 2.14 (s, 3H, C6H4CH3), 1.20 (dvt,
N ) 13.6, J(HH) ) 7.0 Hz, 18H, PCHCH3), 1.19 (dvt, N ) 13.2, J(HH)
) 6.7 Hz, 18H, PCHCH3). 13C NMR (C6D6, 100.6 MHz): δ 198.9 (s,
Rh-CHdC), 141.8, 139.4 (both s, ipso-C of C6H4R), 133.9, 130.6,
128.6, 128.3, 127.6, 126.7, 125.8 (all s, C6H4 and C6H5), 113.2 (s, Rh-
CHdCdC), 69.3 (dt, J(RhC) ) 36.7, J(PC) ) 8.9 Hz, RhCH), 23.0
(vt, N ) 18.9 Hz, PCHCH3), 20.8 (s, C6H4CH3), 20.0 (s, PCHCH3).
31P NMR (C6D6, 162.0 MHz): δ 25.2 (d, J(RhP) ) 96.9 Hz). Anal.
Calcd for C34H55Cl2P2Rh: C, 58.37; H, 7.92. Found: C, 58.53; H, 7.78.
203 mg (72%). Mp: 63 °C. IR (C6H6): ν(CdCdC) 1915 cm-1. H
NMR (C6D6, 400 MHz): δ 7.56, 7.40, 7.12 (all m, 10H, C6H5), 2.55,
2.21 (both m, 3H each, PCHCH3), 2.06 (dd, J(P2H) ) 14.4, J(P1H) )
5.2 Hz, 1H, CHPiPr3), 1.36 (dd, J(PH) ) 12.4, J(HH) ) 7.2 Hz, 9H,
PCHCH3), 1.35 (dd, J(PH) ) 12.3, J(HH) ) 7.2 Hz, 9H, PCHCH3),
1.22 (dd, J(PH) ) 14.8, J(HH) ) 7.2 Hz, 9H, PCHCH3), 0.75 (dd,
J(PH) ) 15.2, J(HH) ) 7.2 Hz, 9H, PCHCH3), 0.46 (s, 9H, SiMe3).
13C NMR (C6D6, 100.6 MHz): δ 187.7 (s, C4), 142.1, 141.4 (both s,
ipso-C of C6H5), 129.0, 128.5, 128.3, 127.5, 125.8, 125.5 (all s, C6H5),
108.4 (s, C5), 106.7 (ddd, J(RhC) ) 25.2, J(P1C) ) J(P2C) ) 4.5 Hz,
C3), 69.2 (dd, J(P1C) ) J(P2C) ) 5.2 Hz, C2), 25.1 (d, J(PC) ) 17.1
Hz, PCHCH3), 23.4 (ddd, J(RhC) ) 66.1, J(P2C) ) 27.2, J(P1C) )
10.4 Hz, C1), 21.5 (d, J(PC) ) 43.3 Hz, PCHCH3), 20.4, 20.3 (both s,
PCHCH3), 18.3 (d, J(PC) ) 2.8 Hz, PCHCH3), 17.4 (d, J(PC) ) 2.1
Hz, PCHCH3), 0.46 (s, SiMe3). 31P NMR (C6D6, 162.0 MHz): δ 48.0
(dd, J(RhP) ) 180.5, J(PP) ) 15.7 Hz, P1), 40.3 (dd, J(RhP) ) 4.5,
J(PP) ) 15.7 Hz, P2). 29Si NMR (C6D6, 39.8 MHz): δ -1.9 (m). Anal.
Calcd for C38H62ClP2RhSi: C, 61.08; H, 8.36. Found: C, 60.83; H,
8.42. For assignment for carbon atoms C1 to C5 and phosphorus atoms
P1 and P2, see Chart 1.
Preparation of [RhCl{η3-anti-CH(PiPr3)C(Ph)CdCdCPh2}-
(PiPr3)] (12). A solution of 1 (191 mg, 0.29 mmol) in benzene (4 mL)
was treated at 10 °C with phenylacetylene (32 µL, 0.29 mmol) and
then stirred for 20 h at room temperature. The solvent was evaporated
in vacuo, and the remaining red solid was washed twice with 1-mL
portions of pentane (-20 °C) and dried in vacuo. Yield: 203 mg (92%).
Mp: 189 °C. IR (C6H6): ν(CdCdC) 1885 cm-1. 1H NMR (C6D6, 400
MHz): δ 8.00, 7.61, 7.51, 7.09 (all m, 15H, C6H5), 2.52, 2.04 (both
m, 3H each, PCHCH3), 2.36 (dd, J(P2H) ) 9.6, J(P1H) ) 5.6 Hz, 1H,
CHPiPr3), 1.33 (dd, J(PH) ) 13.2, J(HH) ) 7.2 Hz, 9H, PCHCH3),
1.18 (dd, J(PH) ) 15.2, J(HH) ) 7.2 Hz, 9H, PCHCH3), 1.12 (dd,
J(PH) ) 12.8, J(HH) ) 7.2 Hz, 9H, PCHCH3), 0.71 (dd, J(PH) )
14.8, J(HH) ) 7.2 Hz, 9H, PCHCH3). 13C NMR (CDCl3, 100.6 MHz):
δ 187.5 (s, C4), 143.7 (s, ipso-C of C-C6H5), 139.9, 139.2 (both s,
ipso-C of dC(C6H5)2), 128.7, 128.2, 128.1, 128.0, 127.2, 126.6, 126.2,
126.0, 125.2 (all s, C6H5), 108.9 (s, C5), 106.7 (m, C3), 71.8 (d, J(PC)
) 6.8 Hz, C2), 24.2 (d, J(PC) ) 17.7 Hz, PCHCH3), 21.6 (d, J(PC) )
44.8 Hz, PCHCH3), 20.9 (ddd, J(RhC) ) 65.8, J(P2C) ) 25.8, J(P1C)
) 10.6 Hz, C1), 20.0, 19.1 (both s, br, PCHCH3), 18.3 (d, J(PC) ) 2.4
Hz, PCHCH3), 17.0 (d, J(PC) ) 1.8 Hz, PCHCH3). 31P NMR (CDCl3,
162.0 MHz): δ 52.9 (dd, J(RhP) ) 179.6, J(PP) ) 14.3 Hz, P1), 39.3
(dd, J(RhP) ) 4.2, J(PP) ) 14.3 Hz, P2). MS (70 eV): m/z 750 (M+).
Anal. Calcd for C41H58ClP2Rh: C, 65.55; H, 7.78. Found: C, 65.76;
H, 7.72. For assignment for carbon atoms C1 to C5 and phosphorus
atoms P1 and P2, see Chart 1.
Preparation of [Rh(C6H5){η3-anti-CH(PiPr3)C(Ph)CdCdCPh2}-
(PiPr3)] (15). A solution of 12 (105 mg, 0.14 mmol) in benzene (3
mL) was treated at 5 °C with a 1.0 M solution of C6H5MgBr in ether
(0.50 mL, 0.50 mmol) and then stirred for 3 h at 50 °C. After the
solution was cooled to room temperature, the solvent was evaporated
in vacuo and the residue extracted with pentane (25 mL). The extract
was brought to dryness in vacuo, the remaining oily residue was
dissolved in ether (5 mL), and the solution stored for 24 h at -78 °C.
Black crystals precipitated, which were separated from the mother
liquor, washed twice with 1-mL portions of acetone (-20 °C), and
dried in vacuo. Yield: 72 mg (65%). Mp: 160 °C. IR (C6H6): ν(Cd
1
CdC) 1925 cm-1. H NMR (C6D6, 200 MHz): δ 8.09, 7.94, 7.72,
7.58, 7.17 (all m, 20H, C6H5), 2.16, 1.89 (both m, 3H each, PCHCH3),
2.08 (dd, J(P2H) ) 8.3, J(P1H) ) 5.4 Hz, 1H, CHPiPr3), 1.22 (dd,
J(PH) ) 12.9, J(HH) ) 7.1 Hz, 9H, PCHCH3), 1.06 (dd, J(PH) )
13.0, J(HH) ) 7.2 Hz, 9H, PCHCH3), 0.99 (dd, J(PH) ) 15.3, J(HH)
) 7.1 Hz, 9H, PCHCH3), 0.55 (dd, J(PH) ) 14.9, J(HH) ) 7.1 Hz,
9H, PCHCH3). 31P NMR (C6D6, 81.0 MHz): δ 53.7 (dd, J(RhP) )
198.1, J(PP) ) 14.2 Hz, P1), 38.2 (dd, J(RhP) ) 4.6, J(PP) ) 14.2 Hz,
P2). Anal. Calcd for C47H63P2Rh: C, 71.20; H, 8.01. Found: C, 70.90;
H, 8.31. For assignment of phosphorus atoms P1 and P2, see Chart 1.
Preparation of [RhCl{η3-anti-CH(PiPr3)C(p-Tol)CdCdCPh2}-
(PiPr3)] (13). This compound was prepared as described for 12 from
1 (123 mg, 0.19 mmol) and p-tolylacetylene (24 µL, 0.19 mmol) to
give a red solid after a 40 h reaction time. Yield: 127 mg (88%). Mp:
1
190 °C. IR (C6H6): ν(CdCdC) 1925 cm-1. H NMR (CDCl3, 400
MHz): δ 7.52, 7.05 (both m, br, 14H, C6H4 and C6H5), 2.26, 2.24
(both m, 3H each, PCHCH3), 2.22 (m, 1H, CHPiPr3), 2.14 (s, 3H,
C6H4CH3), 1.35 (dd, J(PH) ) 15.2, J(HH) ) 7.2 Hz, 9H, PCHCH3),
1.03 (dd, J(PH) ) 13.2, J(HH) ) 7.2 Hz, 9H, PCHCH3), 0.93 (dd,
J(PH) ) 15.2, J(HH) ) 7.2 Hz, 9H, PCHCH3), 0.81 (dd, J(PH) )
11.2, J(HH) ) 7.2 Hz, 9H, PCHCH3). 13C NMR (CDCl3, 100.6 MHz):
δ 187.3 (s, C4), 140.5 (s, ipso-C of C6H4), 139.8, 139.0 (both s, ipso-C
of dC(C6H5)2), 135.6, 128.7, 128.5, 128.0, 127.8, 126.8, 126.5, 125.9,
125.0 (all s, C6H4 and C6H5), 108.6 (s, C5), 106.7 (ddd, J(RhC) ) 26.2,
J(PC) ) 8.0 and 1.9 Hz, C3), 71.9 (d, J(PC) ) 6.0 Hz, C2), 24.0 (d,
J(PC) ) 17.6 Hz, PCHCH3), 21.4 (d, J(PC) ) 43.3 Hz, PCHCH3),
21.2 (s, C6H4CH3), 20.2 (ddd, J(RhC) ) 65.9, J(P2C) ) 41.2, J(P1C)
) 10.1 Hz, C1), 19.8, 19.0 (both s, br, PCHCH3), 18.1 (d, J(PC) ) 2.2
Hz, PCHCH3), 16.9 (d, J(PC) ) 2.0 Hz, PCHCH3). 31P NMR (CDCl3,
162.0 MHz): δ 52.4 (dd, J(RhP) ) 179.3, J(PP) ) 14.2 Hz, P1), 38.7
(dd, J(RhP) ) 4.0, J(PP) ) 14.2 Hz, P2). Anal. Calcd for C42H60ClP2-
Rh: C, 65.92; H, 7.90. Found: C, 65.76; H, 7.80. For assignment for
carbon atoms C1 to C5 and phosphorus atoms P1 and P2, see Chart 1.
Preparation of [Rh(CHdCH2){η3-anti-CH(PiPr3)C(Ph)CdCd
CPh2}(PiPr3)] (16). A solution of 12 (203 mg, 0.27 mmol) in benzene
(4 mL) was treated at 5 °C with a 1.0 M solution of CH2dCHMgBr in
THF (0.50 mL, 0.50 mmol) and then stirred for 24 h at room
temperature. After the solvent was evaporated in vacuo, the oily residue
was worked up as described for 15. A black solid was obtained. Yield:
1
143 mg (71%). Mp: 141 °C. IR (C6H6): ν(CdCdC) 1930 cm-1. H
NMR (C6D6, 400 MHz): δ 8.64 (m, 1H, RhCHdCH2), 7.93, 7.56-
6.98 (both m, 15H, C6H5), 6.47 (m, 1H, one H of RhCHdCH2), 5.76
(m, 1H, one H of RhCHdCH2), 2.25, 1.98 (both m, 3H each, PCHCH3),
1.28 (dd, J(PH) ) 14.4, J(HH) ) 7.2 Hz, 9H, PCHCH3), 1.15 (dd,
J(PH) ) 13.1, J(HH) ) 7.2 Hz, 9H, PCHCH3), 1.06 (dd, J(PH) )
13.2, J(HH) ) 7.1 Hz, 9H, PCHCH3), 0.62 (dd, J(PH) ) 12.2, J(HH)
) 7.1 Hz, 9H, PCHCH3), signal of CHPiPr3 probably covered by
resonances of PCHCH3. 13C NMR (C6D6, 100.6 MHz): δ 177.4 (s,
C4), 173.4 (dd, J(RhC) ) 42.3, J(PC) ) 16.1, RhCH), 146.2 (s, ipso-C
of C-C6H5), 142.0, 141.1 (both s, ipso-C of dC(C6H5)2), 129.4, 128.5,
128.4, 128.3, 127.3, 126.5, 126.2, 125.3, 124.1 (all s, C6H5), 119.5 (s,
dCH2), 106.5 (dd, J(RhC) ) 12.1, J(PC) ) 6.0 Hz, C3), 101.3 (s, C5),
76.7 (d, J(PC) ) 6.1 Hz, C2), 26.2 (d, J(PC) ) 17.4 Hz, PCHCH3),
21.6 (d, J(PC) ) 43.2, PCHCH3), 20.0 (ddd, J(RhC) ) 65.4, J(P2C) )
36.3, J(P1C) ) 12.1 Hz, C1), 20.4, 19.7, 18.2, 17.1 (all s, br, PCHCH3).
31P NMR (C6D6, 162.0 MHz): δ 55.6 (dd, J(RhP) ) 199.6, J(PP) )
Preparation of [RhCl{η3-anti-CH(PiPr3)C(SiMe3)CdCdCPh2}-
(PiPr3)] (14). A solution of 1 (245 mg, 0.38 mmol) in benzene (10
mL) was treated at 10 °C with trimethylsilylacetylene (150 µL, 1.06
mmol) and then stirred for 14 days at room temperature. The solvent
was evaporated in vacuo, the remaining oily residue dissolved in pentane
(15 mL), and the solution stored for 2 days at -78 °C. Red crystals
9
J. AM. CHEM. SOC. VOL. 124, NO. 24, 2002 6975

A R T I C L E S
Werner et al.
13.0 Hz, P1), 37.5 (dd, J(RhP) ) 3.2, J(PP) ) 13.0 Hz, P2). Anal.
Calcd for C43H61P2Rh: C, 69.53; H, 8.28. Found: C, 67.84; H, 8.52.
For assignment for carbon atoms C1 to C5 and phosphorus atoms P1
and P2, see Chart 1.
(d, J(PC) ) 8.0 Hz, ipso-C of C6H4 or C6H5), 134.5 (d, J(PC) ) 7.0
Hz, ipso-C of C6H4 or C6H5), 131.4, 130.8, 128.6, 128.5, 128.2, 126.7,
126.0 (all s, C6H4 and C6H5), 105.5 (d, J(PC) ) 17.1 Hz, C(o-Tol)Ph),
75.5 (ddd, J(RhC) ) 35.0, J(P1C) ) 20.8, J(P2C) ) 5.7 Hz, CPiPr3),
29.8 (d, J(PC) ) 25.5 Hz, PCHCH3), 24.5 (d, J(PC) ) 40.2 Hz,
PCHCH3), 21.4, 18.1 (both s, PCHCH3), 15.3 (s, C6H4CH3). 31P NMR
(162.0 MHz, CD2Cl2): δ 108.6 (d, J(RhP) ) 144.2 Hz, RhPiPr3), 47.6
(s, CPiPr3). Anal. Calcd for C33H54Cl3P2Rh: C, 55.64; H, 7.42. Found:
C, 55.21; H, 7.25.
Reaction of 12 with CO. A slow stream of CO was passed for 30
s through a solution of 12 (70 mg, 0.10 mmol) in C6D6 (1 mL) at 10
°C. A change of color from red to violet occurred. The IR spectrum of
the solution confirmed the formation of trans-[RhCl(CO)(PiPr3)2] (18)20
and [RhCl(CO)2]2 (19).21 The solution was evaporated in vacuo and
the residue extracted with pentane (15 mL). The extract was concen-
trated to ca. 5 mL and the solution stored for 2 h at -78 °C. A violet
solid (18 mg) precipitated that was separated from the mother liquor,
washed twice with pentane (-20 °C), and dried in vacuo. The IR and
NMR spectra indicated that the violet solid contained, besides the
phosphorus ylide iPr3PCHC(Ph)dCdCdCPh2 (17) as the main product,
small quantities of 18 that could not be completely separated by
fractional crystallization. NMR data for 17. 1H NMR (C6D6, 400
MHz): δ 8.06, 7.77, 7.14 (all m, 15H, C6H5), 3.05 (d, J(PH) ) 15.2
Hz, 1H, CHPiPr3), 2.15 (m, 3H, PCHCH3), 0.85 (dd, J(PH) ) 15.2,
J(HH) ) 7.6 Hz, 18H, PCHCH3). 13C NMR (C6D6, 100.6 MHz): δ
174.2, 171.2 (both s, CdCdCPh2 and CdCdCPh2), 143.8, 140.9,
140.1, 139.1, 129.3, 128.7, 128.6, 128.5, 128.4, 127.9, 127.8, 126.0,
125.9 (all s, CPh2 and C6H5), 93.4 (s, br, CHCPh) 45.9 (d, J(PC) )
100.8 Hz, iPr3PCH), 23.5 (d, J(PC) ) 49.0 Hz, PCHCH3), 17.4 (d,
J(PC) ) 2.7 Hz, PCHCH3). 31P NMR (C6D6, 162.0 MHz): δ 33.57
(s).
Preparation of [RhCl3{C(PiPr3)CdC(p-C6H4OMe)2}(PiPr3)] (23).
This compound was prepared as described for 21 (route b) from 20
(78 mg, 0.11 mmol) and PhICl2 (19 mg, 0.11 mmol) tp give dark red
crystals. Yield: 76 mg (88%). Mp: 108 °C. IR (C6H6): ν(CdCdC)
1871 cm-1. 1H NMR (400 MHz, CD2Cl2): δ 7.49, 6.88 (both d, J(HH)
) 8.8 Hz, 4H each, C6H4), 3.80 (s, 6H, OCH3), 3.30, 2.75 (both m, 3H
each, PCHCH3), 1.43, 1.21 (both dd, J(PH) ) 15.6, J(HH) ) 7.2 Hz,
18H each, PCHCH3). 13C NMR (100.6 MHz, CD2Cl2): δ 210.1 (s,
CdC(p-C6H4OMe)2), 159.4 (s, COMe), 130.6 (d, J(PC) ) 3.0 Hz,
C6H4), 129.0 (d, J(PC) ) 8.0 Hz, ipso-C of C6H4), 114.2 (s, C6H4),
105.5 (d, J(PC) ) 17.1 Hz, dC(p-C6H4OMe)2), 75.2 (ddd, J(RhC) )
35.4, J(P1C) ) 19.8, J(P2C) ) 5.8 Hz, CPiPr3), 55.7 (s, OCH3), 31.0
(d, J(PC) ) 26.0 Hz, PCHCH3), 24.8 (d, J(PC) ) 40.0 Hz, PCHCH3),
20.2 (d, J(PC) ) 2.5 Hz, PCHCH3), 19.2 (d, J(PC) ) 2.3 Hz, PCHCH3).
31P NMR (162.0 MHz, CD2Cl2): δ 108.9 (d, J(RhP) ) 145.8 Hz,
RhPiPr3), 47.3 (d, J(RhP) ) 5.2 Hz, CPiPr3). Anal. Calcd for C35H56-
Cl3O2P2Rh: C, 53.89; H, 7.24. Found: C, 53.67; H, 7.46.
Preparation of [RhCl3{C(PiPr3)CdCPh2}(PiPr3)] (21). Method
a. A solution of 1 (91 mg, 0.14 mmol) in THF (3 mL) was treated
dropwise at room temperature under the exclusion of light with a freshly
prepared solution of Cl2 in hexane. The addition was stopped when
the 31P NMR spectrum of the solution confirmed the complete
conversion of 1 to the product. A pink-red precipitate was formed that
was separated from the mother liquor, washed three times with 2-mL
portions of acetone (-20 °C), and dried. The solid was dissolved in
CH2Cl2 (2 mL), and the solution was carefully layered with pentane
(10 mL) and then stored for 24 h at 8 °C. Dark red crystals precipitated
that were washed twice with 1-mL portions of pentane (-10 °C) and
dried in vacuo. Yield: 92 mg (91%).
Preparation of trans-[RhCl{dCdCHC(Ph)(CF3)OH}(PiPr3)2]
(25). A solution of 24 (86 mg, 0.13 mmol) in ether (5 mL) was treated
dropwise with a solution of HCtCC(Ph)(CF3)OH (47 mg, 0.26 mmol)
in ether (2 mL) at room temperature. A change of color from red to
yellow occurred. After NEt3 (3 mL) was added, the reaction mixture
was stirred for 10 h at 20 °C, which led again to a change of color
from yellow to blue. The solvent was evaporated in vacuo, the residue
was dissolved in benzene (2 mL), and the solution was chromatographed
on Al2O3 (activity grade V, neutral, height of column 10 cm). With
benzene a blue fraction was eluted, which was brought to dryness in
vacuo. A blue, moderately air-sensitive solid was obtained that was
washed twice with 2-mL portions of acetone (0 °C) and dried. Yield:
153 mg (91%). Mp: 140 °C dec. IR (C6H6): ν(OH) 3580, ν(CdC)
1650 cm-1. 1H NMR (CDCl3, 200 MHz): δ 7.36 (m, 5H, C6H5), 2.76
(s, 1H, OH), 2.64 (m, 6H, PCHCH3), 1.27 (dvt, N ) 25.2, J(HH) )
11.7 Hz, 18H, PCHCH3), 1.19 (dvt, N ) 13.5, J(HH) ) 6.6 Hz, 18H,
PCHCH3), 0.69 (t, J(PH) ) 3.3 Hz, 1H, RhdCdCHR). 13C NMR
(C6D6, 100.6 MHz): δ 281.0 (dt, J(RhC) ) 62.4, J(PC) ) 15.1 Hz,
RhdCdCHR), 138.7 (s, ipso-C of C6H5), 128.4, 127.9, 126.0 (all s,
C6H5), 125.5 (q, J(CF) ) 286.8 Hz, CF3), 110.3 (dt, br, J(RhC) )
16.1, J(PC) ) 5.2 Hz, RhdCdCHR), 65.0 (q, J(CF) ) 29.7 Hz, CPh-
(CF3)OH), 23.3 (vt, N ) 20.5 Hz, PCHCH3), 19.8 (s, PCHCH3). 31P
NMR (CDCl3, 81.0 MHz): δ 41.9 (d, J(RhP) ) 130.2 Hz). 19F NMR
(CDCl3, 188.3 MHz): δ -82.3 (s). Anal. Calcd for C28H49ClF3OP2-
Rh: C, 51.03; H, 7.49. Found: C, 50.85; H, 7.58.
Method b. A solution of 1 (78 mg, 0.12 mmol) in CH2Cl2 (3 mL)
was treated at -60 °C with PhICl2 (21 mg, 0.12 mmol). After the
solvent was evaporated in vacuo, the residue was washed twice with
1-mL portions of acetone (-20 °C) and worked up as described for
method a. yield: 79 mg (92%). mp 136 °C dec. IR (CH2Cl2): ν(Cd
CdC) 1865 cm-1. 1H NMR (200 MHz, CDCl3): δ 7.55, 7.31 (both m,
10H, C6H5), 3.34, 2.75 (both m, 3H each, PCHCH3), 1.44 (dd, J(PH)
) 15.5, J(HH) ) 7.1 Hz, 18H, PCHCH3), 1.21 (dd, J(PH) ) 15.7,
J(HH) ) 6.9 Hz, 18H, PCHCH3). 13C NMR (100.6 MHz, CDCl3): δ
209.7 (s, CdCPh2), 136.4, 136.3 (both s, ipso-C of C6H5), 128.9, 128.8,
128.5, 128.4, 127.3, 127.2 (all s, C6H5), 105.3 (d, J(RhC) ) 18.1 Hz,
CPh2), 75.8 (ddd, J(RhC) ) 35.6, J(P1C) ) 19.2, J(P2C) ) 5.5 Hz,
CPiPr3), 30.8 (d, J(PC) ) 25.6 Hz, PCHCH3), 24.5 (d, J(PC) ) 40.3
Hz, PCHCH3), 19.9 (d, J(PC) ) 3.3 Hz, PCHCH3), 18.9 (d, J(PC) )
2.2 Hz, PCHCH3). 31P NMR (81.0 MHz, CDCl3): δ 110.9 (dd, J(RhP)
) 144.9, J(PP) ) 2.9 Hz, RhPiPr3), 48.2 (dd, J(RhP) ) 6.5, J(PP) )
2.9 Hz, CPiPr3). Anal. Calcd for C33H52Cl3P2Rh: C, 55.05; H, 7.28;
Rh 14.29. Found: C, 54.89; H, 7.43; Rh, 13.75.
Preparation of trans-[RhCl{dCdCdC(CF3)Ph}(PiPr3)2] (26). A
solution of 25 (153 mg, 0.23 mmol) in benzene (3 mL) was passed
through a column with Al2O3 (activity grade I, acid, height of column
8 cm). While eluting with benzene, a change of color from blue to
green-yellow was observed. The eluted solution was brought to dryness
in vacuo, the remaining yellow solid was washed three times with 1-mL
portions of pentane and dried. Yield: 139 mg (93%). Mp: 124 °C
Preparation of [RhCl3{C(PiPr3)CdC(o-Tol)Ph}(PiPr3)] (22). This
compound was prepared as described for 21 (route b) from 2 (83 mg,
0.12 mmol) and PhICl2 (21 mg, 0.12 mmol) to give dark red crystals.
Yield: 81 mg (92%). Mp: 104 °C dec. IR (CH2Cl2): ν(CdCdC) 1868
1
dec. IR (C6H6): ν(CdCdC) 1855 cm-1. H NMR (C6D6, 400 MHz):
δ 7.98 (m, 2H, ortho-H of C6H5), 7.43 (m, 1H, para-H of C6H5), 6.63
(m, 2H, meta-H of C6H5), 2.96 (m, 6H, PCHCH3), 1.28 (dvt, N ) 13.6,
J(HH) ) 7.1 Hz, 36H, PCHCH3). 13C NMR (C6D6, 100.6 MHz): δ
277.3 (m, RhdCdCdC), 210.3 (m, RhdCdCdC), 152.5 (s, ipso-C
of C6H5), 134.3 (q, J(CF) ) 276.6 Hz, CF3), 130.2, 127.3, 120.7 (all
s, C6H5), 121.8 (q, J(CF) ) 33.2 Hz, RhdCdCdC), 24.1 (vt, N )
20.4 Hz, PCHCH3), 20.2 (s, PCHCH3). 31P NMR (C6D6, 162.0 MHz):
1
cm-1. H NMR (400 MHz, CD2Cl2): δ 7.72, 7.47, 7.25 (all m, 9H,
C6H4 and C6H5), 3.37, 2.77 (both m, 3H each, PCHCH3), 1.87 (s, 3 H,
C6H4CH3), 1.40, 1.37 (both dd, br, J(PH) ) 15.5, J(HH) ) 7.4 Hz, 9H
each, PCHCH3), 1.30 (dd, J(PH) ) 15.7, J(HH) ) 7.0 Hz, 9H,
PCHCH3), 1.18 (dd, J(PH) ) 15.9, J(HH) ) 7.1 Hz, 9H, PCHCH3).
13C NMR (100.6 MHz, CD2Cl2): δ 210.1 (s, CdC(o-Tol)Ph), 136.9
9
6976 J. AM. CHEM. SOC. VOL. 124, NO. 24, 2002

Pathways for Metal-Assisted C−C and C−P Coupling
A R T I C L E S
δ 36.0 (d, J(RhP) ) 127.0 Hz). 19F NMR (C6D6, 376.5 MHz): δ -66.7
(s). MS (70 eV): m/z 640 (M+), 184 (CdCdC(Ph)CF3+). Anal. Calcd
for C28H47ClF3P2Rh: C, 52.47; H, 7.39. Found: C, 52.11; H, 7.21.
Preparation of trans-[RhCl(η2-H2CdCdCdCPh2)(PiPr3)2] (28).
A solution of 1 (90 mg, 0.14 mmol) in benzene (3 mL) was treated
dropwise with a 0.28 M solution of diazomethane in ether (1.5 mL,
0.42 mmol) at room temperature. An instantaneous evolution of gas
(N2) and a change of color from deep red to pale red occurred. After
the solution was stirred for 5 min, the solvent was evaporated in vacuo.
The residue was dissolved in pentane (10 mL) and the solution was
stored for 12 h at -78 °C. Red crystals precipitated that were separated
from the mother liquor, washed twice with 1-mL portions of pentane
(-20 °C), and dried. Yield: 87 mg (95%). Mp: 113 °C dec. IR
mg, 0.14 mmol) and a 0.28 M solution of diazomethane in ether (1.5
mL, 0.42 mmol). After recrystallization from pentane at -78 °C, orange
crystals were obtained. Yield: 80 mg (92%). Mp: 105 °C. IR (C6H6):
1
ν(CdCdCdC) 1945 cm-1. H NMR (400 MHz, C6D6): δ 7.22, 7.02
(both m, 5H, C6H5), 2.65-2.57 (m, 5H, dCH2 and PCHCH3), 2.44
(m, 3H, PCHCH3), 1.42 (m; d in 1H{31P}, J(HH) ) 7.2 Hz, 9H,
1
PCHCH3), 1.26 (m; d in H{31P}, J(HH) ) 7.2 Hz, 9H, PCHCH3),
1.25 (s, 9H, C(CH3)3), 1.08 (m, 18H, PCHCH3). 13C NMR (100.6 MHz,
CDCl3): δ 179.3 (s, CdC(tBu)Ph), 141.6 (s, ipso-C of C6H5), 128.8,
127.4, 125.8 (all s, C6H5), 100.2 (s, dC(tBu)Ph), 109.4 (dt, J(RhC) )
23.1, J(PC) ) 5.0 Hz, CdCH2), 36.3 (s, C(CH3)3), 30.0 (s, C(CH3)3),
22.3 (vt, N ) 24.2 Hz, PCHCH3), 22.3 (vt, N ) 24.0 Hz, PCHCH3),
21.0, 20.6, 20.1, 19.8 (all s, PCHCH3), 12.5 (d, J(RhC) ) 13.4 Hz,
dCH2). 31P NMR (162.0 MHz, C6D6): AB part of a degenerated ABX
spectrum with four signals at δ 36.3, 36.1, 35.6, and 35.4. Anal. Calcd
for C32H58ClP2Rh: C, 59.76; H, 9.09. Found: C, 59.64; H, 8.90.
1
(C6H6): ν(CdCdCdC) 1950 cm-1. H NMR (400 MHz, C6D6): δ
7.48 (m, 4H, ortho-H of C6H5), 7.12 (m, 6H, meta- and para-H of C6H5),
2.61 (dt, J(PH) ) 5.4, J(RhH) ) 1.6 Hz, 2H, dCH2), 2.48 (m, 6H,
PCHCH3), 1.23 (dvt, N ) 14.0, J(HH) ) 7.2 Hz, 18H, PCHCH3), 1.21
(dvt, N ) 14.4, J(HH) ) 7.2 Hz, 18H, PCHCH3). 13C NMR (100.6
MHz, C6D6): δ 181.5 (s, CdCPh2), 141.4 (s, ipso-C of C6H5), 128.8,
128.5, 126.5 (all s, C6H5), 111.4 (s, dCPh2), 108.5 (dt, J(RhC) ) 22.1,
J(PC) ) 5.0 Hz, CdCH2), 23.0 (vt, N ) 18.1 Hz, PCHCH3), 20.8,
20.2 (both s, PCHCH3), 13.0 (d, J(RhC) ) 13.6 Hz, dCH2). 31P NMR
(162.0 MHz, C6D6): δ 35.5 (d, J(RhP) ) 115.7 Hz). Anal. Calcd for
C34H54ClP2Rh: C, 61.58; H, 8.21; Rh, 15.52. Found: C, 61.30; H, 8.37;
Rh, 14.79.
Preparation of trans-[RhCl{η2-H2CdCdCdC(p-C6H4OMe)2}-
(PiPr3)2] (29). This compound was prepared as described for 28 from
20 (83 mg, 0.12 mmol) and a 0.28 M solution of diazomethane in ether
(1.5 mL, 0.42 mmol). After recrystallization from pentane at -78 °C,
orange crystals were obtained. Yield: 81 mg (96%). Mp: 126 °C dec.
IR (C6H6): ν(CdCdCdC) 1939 cm-1. 1H NMR (400 MHz, C6D6): δ
7.47, 6.81 (both d, J(HH) ) 8.8 Hz, 4H each, C6H4), 3.34 (s, 6H,
OCH3), 2.64 (dt, J(PH) ) 5.7, J(RhH) ) 1.6 Hz, 2H, dCH2), 2.50 (m,
6H, PCHCH3), 1.26 (dvt, N ) 14.4, J(HH) ) 7.2 Hz, 18H, PCHCH3),
1.24 (dvt, N ) 14.0, J(HH) ) 7.2 Hz, 18H, PCHCH3). 13C NMR (100.6
MHz, C6D6): δ 179.9 (s, CdC(p-C6H4OMe)2), 159.0 (s, COMe), 134.2
(s, ipso-C of C6H4), 129.9, 114.0 (both s, C6H4), 111.1 (s, dC(p-C6H4-
OMe)2), 108.7 (dt, J(RhC) ) 22.1, J(PC) ) 4.0 Hz, CdCH2), 54.8 (s,
OCH3), 23.1 (vt, N ) 18.1 Hz, PCHCH3), 20.8, 20.3 (both s, PCHCH3),
12.0 (d, J(RhC) ) 13.7 Hz, dCH2). 31P NMR (162.0 MHz, C6D6): δ
35.5 (d, J(RhP) ) 116.8 Hz). Anal. Calcd for C36H58ClO2P2Rh: C,
59.79; H, 8.08. Found: C, 59.64; H, 8.19.
Preparation of trans-[RhCl(η2-H2CdCdCdCPh2)(PiPr3)2] (32).
A solution of 28 (83 mg, 0.13 mmol) in toluene (3 mL) was stirred for
2 h at 80 °C. A smooth change of color from red to yellow occurred.
After the solution was cooled to room temperature, the solvent was
evaporated in vacuo. The remaining yellow microcrystalline residue
was washed twice with 1-mL portions of ether (0 °C) and dried.
Yield: 81 mg (98%). Mp: 162 °C dec. IR (C6H6): ν(CdCdCdC)
1
1930 cm-1. H NMR (400 MHz, CDCl3): δ 9.03, 7.39 (both m, 2H
each, ortho-H of C6H5), 7.34, 7.29 (both m, 2H each, meta-H of C6H5),
7.14 (m, 2 H, para-H of C6H5), 5.46 (s, br, 1H, exo-H of dCH2), 5.00
(s, br, 1H, endo-H of dCH2), 2.46 (m, 6H, PCHCH3), 1.30 (dvt, N )
14.0, J(HH) ) 7.2 Hz, 18H, PCHCH3), 1.14 (dvt, N ) 12.8, J(HH) )
6.8 Hz, 18H, PCHCH3). 13C NMR (100.6 MHz, CDCl3): δ 142.7 (dt,
J(RhC) ) 17.1, J(PC) ) 4.0 Hz, RhC), 141.6, 140.1 (both s, ipso-C of
C6H5), 138.0 (dt, J(RhC) ) 20.1, J(PC) ) 5.0 Hz, RhC), 129.3, 128.8,
128.5, 128.1, 127.0, 126.6 (all s, C6H5), 127.6 (s, br, dCPh2), 98.4 (s,
br, dCH2), 23.5 (vt, N ) 19.4 Hz, PCHCH3), 20.9, 19.8 (both s,
PCHCH3). 31P NMR (162.0 MHz, CDCl3): δ 31.0 (d, J(RhP) ) 116.3
Hz). Anal. Calcd for C34H54ClP2Rh: C, 61.58; H, 8.21; Rh, 15.51.
Found: C, 61.31; H, 8.45; Rh, 15.91.
Preparation of trans-[RhCl{η2-H2CdCdCdC(p-C6H4OMe)2}-
(PiPr3)2] (33). This compound was prepared as described for 32 from
29 (94 mg, 0.13 mmol) to give a yellow microcrystalline solid. Yield:
91 mg (97%). Mp: 167 °C dec. IR (C6H6): ν(CdCdCdC) 2029 cm-1
.
1H NMR (400 MHz, C6D6): δ 9.06, 7.02, 7.35, 6.89 (all d, J(HH) )
8.8 Hz, 2H each, C6H4), 5.47 (s, br, 1H, exo-H of dCH2), 5.00 (s, br,
1H, endo-H of dCH2), 3.38, 3.34 (both s, 3H each, OCH3), 2.49 (m,
6H, PCHCH3), 1.35 (dvt, N ) 14.0, J(HH) ) 7.2 Hz, 18H, PCHCH3),
1.18 (dvt, N ) 12.8, J(HH) ) 6.8 Hz, 18H, PCHCH3). 13C NMR (100.6
MHz, C6D6): δ 159.3, 158.6 (both s, COMe), 142.8 (dt, J(RhC) )
15.1, J(PC) ) 4.0 Hz, RhC), 134.4, 134.0 (both s, ipso-C of C6H4),
133.8 (dt, J(RhC) ) 20.1, J(PC) ) 6.0 Hz, RhC), 130.7, 129.8, 113.9,
113.6 (all s, C6H4), 126.9 (d, br, J(RhC) ) 2.0 Hz, dC(p-C6H4OMe)2),
97.0 (s, br, dCH2), 54.8 (s, OCH3), 23.5 (vt, N ) 19.1 Hz, PCHCH3),
21.0, 19.8 (both s, PCHCH3). 31P NMR (162.0 MHz, C6D6): δ 30.9
(d, J(RhP) ) 116.9 Hz). Anal. Calcd for C36H58ClO2P2Rh: C, 59.79;
H, 8.08; Rh, 14.23. Found: C, 59.78; H, 8.25; Rh, 14.44.
Preparation of trans-[RhCl{η2-H2CdCdCdC(CF3)Ph}(PiPr3)2]
(30). This compound was prepared as described for 28 from 26 (85
mg, 0.13 mmol) and a 0.28 M solution of diazomethane in ether (1.5
mL, 0.42 mmol). After recrystallization from pentane at -78 °C, red
crystals were obtained. Yield: 83 mg (96%). Mp: 118 °C dec. IR
1
(C6H6): ν(CdCdCdC) 2020 cm-1. H NMR (400 MHz, CDCl3): δ
7.27 (m, 5H, C6H5), 2.87, 2.78 (both dddd, J(HH) ) J(P1H) ) J(P2H)
) 5.6, J(RhH) ) 1.6 Hz, 1H each, dCH2), 2.56, 2.33 (both m, 3H
each, PCHCH3), 1.37 (dvt, N ) 14.0, J(HH) ) 7.2 Hz, 9H, PCHCH3),
1.30 (dvt, N ) 12.8, J(HH) ) 6.8 Hz, 9H, PCHCH3), 1.18 (dvt, N )
12.8, J(HH) ) 6.4 Hz, 9H, PCHCH3), 1.04 (dvt, N ) 13.6, J(HH) )
6.8 Hz, 9H, PCHCH3). 13C NMR (100.6 MHz, CDCl3): δ 183.8 (s,
CdC(Ph)CF3), 135.2 (s, ipso-C of C6H5), 128.3, 127.4, 127.1 (all s,
C6H5), 125.0 (q, J(FC) ) 272.2 Hz, CF3), 109.9 (dt, J(RhC) ) 22.1,
J(PC) ) 4.0 Hz, CdCH2), 99.3 (q, J(FC) ) 34.0 Hz, dC(Ph)CF3),
22.2 (vt, N ) 18.9 Hz, PCHCH3), 22.1 (vt, N ) 18.7 Hz, PCHCH3),
20.5, 20.1, 19.8, 19.6 (all s, PCHCH3), 16.1 (d, J(RhC) ) 14.7 Hz,
dCH2). 19F NMR (376.5 MHz, CDCl3): δ -58.6 (s). 31P NMR (162.0
MHz, CDCl3): Partly resolved AB pattern of ABX spectrum with
signals at δ 34.8 and 34.2. MS (70 eV): m/z 654 (M+), 458 ([M - Cl
- PiPr3]+). Anal. Calcd for C29H49ClF3P2Rh: C, 53.18; H, 7.54.
Found: C, 52.98; H, 7.51.
Preparation of trans-[RhCl{η2-H2CdCdCdC(tBu)Ph}(PiPr3)2]
(syn- and anti-34). A solution of 27 (87 mg, 0.14 mmol) in toluene (3
mL) was stirred for 2 h at 95 °C. A change of color from orange to
yellow occurred. After the solution was cooled to room temperature,
the solvent was evaporated in vacuo and the residue washed twice with
1-mL portions of ether (0 °C). The NMR spectra of the yellow solid
indicated that a mixture of syn-34 and anti-34 in the molar ratio of ca.
2:1 was formed. After the yellow solid was dissolved in toluene (3
mL) and the solution stirred again for 6 h at 95 °C, the ratio of syn-34
and anti-34 had changed to 10:1. The solvent was removed in vacuo,
the residue was dissolved in acetone (6 mL), and the solution was stored
for 20 h at -78 °C. Yellow crystals precipitated that were separated
from the mother liquor, washed twice with 1-mL portions of pentane
Preparation of trans-[RhCl{η2-H2CdCdCdC(tBu)Ph}(PiPr3)2]
(31). This compound was prepared as described for 28 from 27 (86
9
J. AM. CHEM. SOC. VOL. 124, NO. 24, 2002 6977

A R T I C L E S
Werner et al.
(0 °C), and dried. The NMR spectra confirmed that a pure sample of
syn-34 was isolated. Yield: 61 mg (67%). Mp: 132 °C dec. IR
CDCl3): δ 28.9 (d, J(RhP) ) 113.5 Hz). Anal. Calcd for C34H54IP2-
Rh: C, 54.12; H, 7.21; Rh, 13.64. Found: C, 53.94; H, 7.49; Rh, 13.41.
Preparation of trans-[RhI(η2-D2CdCdCdCPh2)(PiPr3)2] (38-d2).
This compound was prepared as described for 38 from 36 (112 mg,
0.15 mmol) and CD3I (60 µL, 138 mg, 0.95 mmol). A yellow
microcrystalline solid was obtained. Yield: 83 mg (73%). Mp: 158
1
(C6H6): ν(CdCdCdC) 1950 cm-1. H NMR (400 MHz, CDCl3): δ
8.33, 7.24 (both m, 5H, C6H5), 5.62 (t, J(PH) ) 2.4 Hz, 1H, exo-H of
dCH2), 5.21 (s, br, 1H, endo-H of dCH2), 2.43 (m, 6H, PCHCH3),
1.26 (s, 9H, C(CH3)3), 1.23 (dvt, N ) 14.0, J(HH) ) 7.2 Hz, 18H,
PCHCH3), 1.18 (dvt, N ) 13.2, J(HH) ) 6.8 Hz, 18H, PCHCH3). 13
C
1
°C dec. IR (C6H6): ν(CdCdCdC) 1943 cm-1. H NMR (400 MHz,
NMR (100.6 MHz, CDCl3): δ 143.6 (dt, J(RhC) ) 16.1, J(PC) ) 4.0
Hz, RhC), 142.4 (s, ipso-C of C6H5), 134.3 (d, J(RhC) ) 3.0 Hz, dC-
(tBu)Ph), 132.6 (dt, J(RhC) ) 18.1, J(PC) ) 4.0 Hz, RhC), 130.1,
127.1, 125.9 (all s, C6H5), 100.2 (s, dCH2), 24.3 (vt, N ) 20.0 Hz,
PCHCH3), 20.9, 20.5 (both s, PCHCH3). 31P NMR (162.0 MHz,
CDCl3): δ 28.1 (d, J(RhP) ) 119.2 Hz). Anal. Calcd for C32H58ClP2-
Rh: C, 59.76; H, 9.09. Found: C, 60.06; H, 9.35. NMR data of anti-
CDCl3): δ 8.54, 7.17 (both m, 10H, C6H5), 2.60 (m, 6H, PCHCH3),
1.20 (dvt, N ) 14.0, J(HH) ) 6.4 Hz, 18H, PCHCH3), 1.19 (dvt, N )
2
12.9, J(HH) ) 6.6 Hz, 18H, PCHCH3). H NMR (61.4 MHz, C6H6):
δ 5.35 (s, br, exo-D of dCD2), 4.86 (s, br, endo-D of dCD2). 13C
NMR (100.6 MHz, CDCl3): δ 142.3 (dt, J(RhC) ) 18.1, J(PC) ) 5.0
Hz, RhC), 140.4, 140.1 (both s, ipso-C of C6H5), 136.0 (dt, J(RhC) )
20.1, J(PC) ) 5.0 Hz, RhC), 128.8, 128.3, 128.1, 127.6, 126.5, 126.2
(all s, C6H5), 127.5 (m, dCPh2), 24.3 (vt, N ) 20.1 Hz, PCHCH3),
1
34. H NMR (400 MHz, CDCl3): δ 7.24, 6.92 (both m, 5H, C6H5),
20.9, 20.5 (both s, PCHCH3); signal of dCD2 not exactly located. 31
P
4.65 (s, br, 1H, exo-H of dCH2), 4.19 (s, br, 1H, endo-H of dCH2),
2.55 (m, 6H, PCHCH3), 1.50 (s, 9H, C(CH3)3), 1.38 (dvt, N ) 13.2,
J(HH) ) 6.4 Hz, 18H, PCHCH3), 1.32 (dvt, N ) 12.8, J(HH) ) 6.4
Hz, 18H, PCHCH3). 31P NMR (162.0 MHz, CDCl3): δ 29.0 (d, J(RhP)
) 119.5 Hz).
NMR (162.0 MHz, CDCl3): δ 29.0 (d, J(RhP) ) 113.4 Hz). Anal.
Calcd for C34H52D2IP2Rh: C, 53.98; H, 7.46. Found: C, 54.34; H, 7.82.
Preparation of trans-[RhI{η2-H2CdCdCdC(p-C6H4OMe)2}-
(PiPr3)2] (39). This compound was prepared as described for 38, either
according to method a from 37 (121 mg, 0.15 mmol), Na2CO3 (500
mg, 4.72 mmol), and CH3I (60 µL, 135 mg, 0.95 mmol) or according
to method b from 20 (134 mg, 0.18 mmol), Na2CO3 (550 mg, 5.20
mmol), and CH3I (65 µL, 147 mg, 1.04 mmol) to give a yellow micro-
crystalline solid. Yield: 91 mg (74%) following method a and 122 mg
(79%) following method b. Mp: 156 °C dec. IR (C6H6): ν(CdCd
Generation of H2CdCdCdC(tBu)Ph (35). A slow stream of CO
was passed for 30 s either through a solution of 31 (51 mg, 0.08 mmol)
or of syn-34 (58 mg, 0.09 mmol) in benzene (3 mL) at room
temperature. A gradual change of color from yellow to pale yellow
occurred. After the solvent was evaporated in vacuo, the NMR spectra
of the residue showed that besides 18 the butatriene 35 was formed. It
was identified by comparison with the NMR data of related buta-
trienes.38,39 Data for 35.1H NMR (400 MHz, CDCl3): δ 7.35-7.22 (m,
5H, C6H5), 5.13, 5.05 (both d, 1H each, J(HH) ) 7.6 Hz, dCH2), 1.24
(s, C(CH3)3). 13C NMR (100.6 MHz, CDCl3): δ 168.6, 158.7 (both s,
CdCH2 and CdCPh2), 140.0 (s, ipso-C of C6H5), 135.3 (s, dCPh2),
128.6, 127.8, 127.2 (all s, C6H5), 89.3 (s, dCH2), 37.8 (s, C(CH3)3),
30.1 (s, C(CH3)3).
Preparation of trans-[RhI(η2-H2CdCdCdCPh2)(PiPr3)2] (38).
Method a. A suspension of 36 (97 mg, 0.13 mmol) and Na2CO3 (500
mg, 4.72 mmol) in a 1:1 mixture of acetone and THF (4 mL) was
treated dropwise with CH3I (60 µL, 135 mg, 0.95 mmol) at room
temperature. A change of color from red to yellow occurred. After the
reaction mixture was stirred for 6 h, the solvent was evaporated in
vacuo, and the residue extracted with cooled CH2Cl2 (3 mL, -30 °C).
The extract was brought to dryness in vacuo, and the remaining yellow
solid was washed three times with 2-mL portions of acetone and dried
in vacuo. Yield: 75 mg (76%).
1
CdC) 1790 cm-1. H NMR (400 MHz, CDCl3): δ 8.50, 7.01, 6.80,
6.72 (all d, J(HH) ) 8.8 Hz, 2H each, C6H4), 4.99 (s, br, 1H, exo-H of
dCH2), 4.64 (s, br, 1H, endo-H of dCH2), 3.73, 3.69 (both s, 3H each,
OCH3), 2.59 (m, 6H, PCHCH3), 1.20 (dvt, N ) 13.6, J(HH) ) 6.8 Hz,
18H, PCHCH3), 1.10 (dvt, N ) 12.8, J(HH) ) 6.8 Hz, 18H, PCHCH3).
13C NMR (100.6 MHz, CDCl3): δ 158.4, 157.8 (both s, COMe), 142.6
(dt, J(RhC) ) 17.1, J(PC) ) 4.0 Hz, RhC), 133.3, 132.9 (both s, ipso-C
of C6H4), 132.0 (dt, J(RhC) ) 20.1, J(PC) ) 5.0 Hz, RhC), 130.1,
129.3, 113.3, 112.9 (all s, C6H4), 126.6 (s, br, dC(p-C6H4OMe)2), 96.9
(s, br, dCH2), 55.3, 55.2 (both s, OCH3), 24.2 (vt, N ) 19.8 Hz,
PCHCH3), 20.9, 20.4 (both s, PCHCH3). 31P NMR (162.0 MHz,
CDCl3): δ 28.9 (d, J(RhP) ) 113.9 Hz). Anal. Calcd for C36H58IO2P2-
Rh: C, 53.08; H, 7.18. Found: C, 52.84; H, 7.00.
Preparation of trans-[RhCl(η2-H2CdCdCPh2)(PiPr3)2] (40). A
solution of 1 (160 mg, 0.25 mmol) in benzene (5 mL) was stirred for
40 h under an atmosphere of hydrogen at room temperature. A change
of color from red to yellow occurred. After the solvent was evaporated
in vacuo, the remaining yellow solid was washed twice with 1-mL
portions of pentane and dried. Yield: 152 mg (95%). Mp: 201 °C. IR
(C6H6): ν(CdCdC) 1690 cm-1. 1H NMR (CDCl3, 400 MHz): δ 9.03,
7.47, 7.36, 7.31, 7.13, 7.12 (all m, 10H, C6H5), 2.41 (dt, J(RhH) )
2.1, J(PH) ) 5.1 Hz, 2H, dCH2), 2.33 (m, 6H, PCHCH3), 1.21 (dvt,
N ) 13.5, J(HH) ) 7.0 Hz, 18H, PCHCH3), 1.15 (dvt, N ) 12.8, J(HH)
) 6.7 Hz, 18H, PCHCH3). 13C NMR (CDCl3, 100.6 MHz): δ 173.3
(dt, J(RhC) ) 23.1, J(PC) ) 6.0 Hz, dC ) ), 143.9, 140.6 (both s,
ipso-C of C6H5), 128.7, 128.2, 128.0, 127.4, 125.6, 125.4 (all s, C6H5),
123.1 (s, dCPh2), 22.1 (vt, N ) 18.6 Hz, PCHCH3), 20.6, 19.6 (both
s, PCHCH3), 16.4 (d, J(RhC) ) 13.1 Hz, dCH2). 31P NMR (C6D6,
81.0 MHz): δ 32.7 (d, J(RhP) ) 116.3 Hz). Anal. Calcd for C33H54-
Cl1P2Rh: C, 60.88; H, 8.36. Found: C 60.76; H, 8.38.
Method b. A suspension of 1 (88 mg, 0.14 mmol) and Na2CO3 (500
mg, 4.72 mmol) in a 1:1 mixture of acetone and THF (4 mL) was
treated dropwise with CH3I (60 µL, 135 mg, 0.95 mmol) at room
temperature. A change of color from red to yellow occurred. After the
reaction mixture was stirred for 6 h, the solvent was evaporated in
vacuo and the residue extracted with CH2Cl2 (3 mL, 0 °C). The extract
was brought to dryness in vacuo and the residue dissolved in THF (4
mL). The solution was treated with KI (300 mg, 1.81 mmol) and stirred
for 3 h at room temperature. The solvent was removed and the yellow
residue extracted with benzene (5 mL). After the extract was filtered,
the solvent was evaporated in vacuo, and the remaining yellow solid
was washed three times with 2-mL portions of acetone (0 °C) and dried.
Yield: 83 mg (82%). Mp: 146 °C dec. IR (C6H6): ν(CdCdCdC)
1710 cm-1. 1H NMR (400 MHz, CDCl3): δ 8.62, 7.26 (both m, 10H,
C6H5), 5.13 (s, br, 1H, exo-H of dCH2), 4.78 (s, br, 1H, endo-H of
dCH2), 2.68 (m, 6H, PCHCH3), 1.29 (dvt, N ) 13.8, J(HH) ) 7.0 Hz,
18H, PCHCH3), 1.19 (dvt, N ) 12.9, J(HH) ) 6.6 Hz, 18H, PCHCH3).
13C NMR (100.6 MHz, CDCl3): δ 142.4 (dt, J(RhC) ) 18.1, J(PC) )
3.0 Hz, RhC), 140.4, 140.0 (both s, ipso-C of C6H5), 135.9 (dt, J(RhC)
) 20.1, J(PC) ) 5.0 Hz, RhC), 128.8, 128.3, 128.1, 127.6, 126.5, 126.2
(all s, C6H5), 127.5 (s, br, dCPh2), 98.3 (s, dCH2), 24.3 (vt, N ) 20.0
Hz, PCHCH3), 20.9, 20.5 (both s, PCHCH3). 31P NMR (162.0 MHz,
Preparation of trans-[RhCl{η2-H2CdCdC(CF3)Ph)(PiPr3)2] (41).
This compound was prepared as described for 40 from 26 (107 mg,
0.17 mmol) to give a yellow microcystalline solid. Yield: 103 mg
1
(96%). Mp: 180 °C. IR (C6H6): ν(CdCdC) 1690 cm-1. H NMR
(CDCl3, 400 MHz): δ 8.86, 7.25 (both m, 5H, C6H5), 2.62 (m, 2H,
dCH2), 2.31 (m, 6H, PCHCH3), 1.23 (dvt, N ) 13.5, J(HH) ) 6.9 Hz,
18H, PCHCH3), 1.12 (dvt, N ) 12.8, J(HH) ) 6.2 Hz, 18H, PCHCH3).
13C NMR (CDCl3, 100.6 MHz): δ 179.0 (m, dC ) ), 134.8 (s, ipso-C
of C6H5), 127.8, 127.3, 126.3 (all s, C6H5), 122.5 (q, J(FC) ) 277.4
Hz, CF3), 112.9 (q, J(FC) ) 27.3 Hz, dC(Ph)CF3), 22.3 (vt, N ) 19.4
9
6978 J. AM. CHEM. SOC. VOL. 124, NO. 24, 2002

Pathways for Metal-Assisted C−C and C−P Coupling
Table 1. Crystallographic Data for 3, 21, and 28
A R T I C L E S
3
21
28
formula
fw
C29H36PRh
518.46
C33H51Cl3P2Rh + 1/2CH2Cl2
761.40
C34H54ClP2Rh
663.07
crystal size, mm
crystal syst
0.50 × 0.35 × 0.30
0.20 × 0.23 × 0.40
0.30 × 0.30 × 0.40
orthorhombic
triclinic
monoclinic
space group
cell dimens determn
a, Å
Pcab (No. 61)
23 rflns, 10° < θ < 14°
16.305(3)
P-1 (No. 2)
25 rflns, 8° < θ < 18°
9.463(4)
P21/c (No. 14)
23 rflns, 10° < θ < 14°
18.52(1)
b, Å
17.315(4)
11.369(5)
11.193(3)
c, Å
18.344(4)
17.936(9)
16.523(9)
R, deg
â, deg
γ, deg
V, Å3
Z
90
90
90
92.00(3)
97.90(2)
108.25(2)
1809(1)
90
93.35(3)
90
3520(3)
4
1.29
5178.8(18)
8
1.330
2
d
calcd, g cm-1
1.398
temp, K
µ, mm-1
293(2)
0.735
293(2)
0.872
293(2)
0.680
scan method
ω/θ
ω/θ
ω/θ
2θ(max), deg
52
5620
48
5618
48
5567
total no. of rflns
no. of unique rflns
no. of obsd rflns
no. of rflns used for refinement
no. of params refined
final R indices
5072 (R(int) ) 0.0000)
2500 (I > 2σ(I))
5072
5225 (R(int) ) 0.0188)
5225 (I > 2σ(I))
4411
5351 (R(int) ) 0.0130)
4654 (I > 2σ(I))
4654
286
376
559
R1 ) 0.0523
wR2 ) 0.1170a (I > 2σ(I))
R1 ) 0.1597
wR2 ) 0.1483a
0.999/0.406
R1 ) 0.0317
wR2 ) 0.0791a (I > 2σ(I))
R1 ) 0.0481
wR2 ) 0.0858a
0.707/0.798
R1 ) 0.0214
wR2 ) 0.0568a (I > 2σ(I))
R1 ) 0.0305
wR2 ) 0.0610a
0.296/0.170
R indices (all data)
resid electron density, e Å3
2
a w-1 ) [σ2Fo2 + (0.0681P)2 + 0.0000P] (3), w-1 ) [σ2Fo2 + (0.0422P)2 + 1.8768P] (21), w-1 ) [σ2Fo2 + (0.0456P)2 + 0.0000P] (28), where P ) (Fo
2
+ 2Fc )/3.
Hz, PCHCH3), 20.5, 19.5 (both s, PCHCH3), 18.9 (d, br, J(RhC) )
described for 44 from 20 (190 mg, 0.27 mmol) to give bright red
crystals. Yield: 75 mg (88%). Mp: 155 °C dec. IR (C6H6): ν(CdCd
13.9 Hz, dCH2). 31P NMR (CDCl3, 81.0 MHz): δ 33.5 (d, J(RhP) )
113.4 Hz). 19F NMR (CDCl3, 188.3 MHz): δ -59.44 (s). MS (70
eV): m/z 642 (M+), 458 (RhCl(PiPr3)2+), 184 (H2CdCdC(Ph)CF3+).
Anal. Calcd for C28H49ClF3P2Rh: C, 52.30; H, 7.68; Rh, 16.00.
Found: C, 52.21; H, 7.64; Rh, 15.53.
1
CdC) 1939 cm-1. H NMR (400 MHz, C6D6): δ 8.82, 7.53, 7.28,
7.26 (all d, J(HH) ) 8.8 Hz, 2H each, C6H4), 3.91, 3.88 (both s, 3H
each, OCH3), 3.89 (s, 6H, OCH3), 2.56 (m, 6H, PCHCH3), 1.44 (dvt,
N ) 13.6, J(HH) ) 6.8 Hz, 18H, PCHCH3), 1.27 (dvt, N ) 13.2, J(HH)
) 6.4 Hz, 18H, PCHCH3). 13C NMR (100.6 MHz, CD2Cl2): δ 160.5
(s, dCd), 159.3, 159.1, 158.9, 158.4 (all s, COMe), 134.0 (s, br, dCd),
134.1, 133.5, 132.4, 131.1 (all s, ipso-C of C6H4), 130.9, 130.1, 129.8,
129.6 (all s, C6H4), 128.0 (dt, J(RhC) ) 20.1, J(PC) ) 4.0 Hz, RhC),
127.2 (d, J(RhC) ) 2.0 Hz, dC(p-C6H4OMe)2), 115.3 (s, dC(p-C6H4-
OMe)2), 114.0, 113.9, 113.8, 113.4 (all s, C6H4), 113.4 (dt, J(RhC) )
16.1, J(PC) ) 5.0 Hz, RhC), 55.6, 55.5, 55.4 (all s, OCH3), 23.6 (vt,
N ) 19.2 Hz, PCHCH3), 21.9, 19.7 (both s, PCHCH3). 31P NMR (162.0
MHz, C6D6): δ 32.4 (d, J(RhP) ) 113.9 Hz). Anal. Calcd for C52H70-
ClO4P2Rh: C, 65.10; H, 7.35. Found: C, 64.89; H, 6.94.
Reaction of 40 with CO. A slow stream of CO was passed for 1
min through a solution of 40 (35 mg, 0.05 mmol) in C6D6 (0.5 mL) at
10 °C. A gradual change of color from yellow to pale yellow occurred.
The solution was stored for 5 h at room temperature and then
investigated by NMR spectroscopy. The 1H, 13C, and 31P NMR spectra
indicated that besides 18 the 1,1-disubstituted allene CH2dCdCPh2
(42)45 was formed.
Reaction of 41 with CO. This reaction was carried out analogously
as described for 40 with 41 (40 mg, 0.06 mmol) as starting material.
Besides the formation of 18, only that of CH2dCdC(CF3)Ph (43) was
observed. NMR data for 43. 1H NMR (C6D6, 400 MHz): δ 7.38, 7.06,
6.99 (all m, 5H, C6H5), 4.75 (q, J(FH) ) 3.2 Hz, dCH2). 13C NMR
(C6D6, 100.6 MHz): δ 210.2 (q, J(FC) ) 5.0 Hz, dCd), 138.0 (m,
ipso-C of C6H5), 129.0, 128.4, 127.3 (all s, C6H5), 124.2 (q, J(FC) )
273.7 Hz, CF3), 102.0 (q, J(FC) ) 32.2 Hz, dC(Ph)CF3), 83.1 (s, d
CH2). 19F NMR (C6D6, 188.3 MHz): δ -60.70 (s).
X-ray Structure Determination of Compounds 3, 7, 12, 21, and
28. Single crystals of 3, 7, and 12 were grown by cooling a solution in
acetone at -30 °C, those of 21 by slow diffusion of pentane into a
saturated solution of 21 in CH2Cl2 at room temperature, and those of
28 by cooling a solution in pentane at -10 °C. Crystal data collection
parameters are summarized in Table 1. The data were collected on an
Enraf-Nonius CAD4 diffractometer using monochromated Mo KR
radiation (λ ) 0.71073 Å). Crystal data were corrected by Lorentz and
polarization effects, and empirical absorption corrections were applied
(Ψ-scan method, minimum transmissions 91.97% (3), 95.4% (7),
97.07% (12), and 97.49% (28)). The structures were solved by direct
methods (3, 7, 12, 21) and the Patterson method (28) (SHELXS-86).50
Atomic coordinates and anisotropic thermal parameters of non-hydrogen
atoms were refined by full-matrix least squares on F2 (SHELXL-93).51
Preparation of trans-[RhCl(η2-Ph2CdCdCdCdCdCPh2)(PiPr3)2]
(44). A solution of 1 (180 mg, 0.28 mmol) in toluene (3 mL) was stirred
for 5 days at 95 °C. After the solution was cooled to room temperature,
the residue was washed three times with 2-mL portions of ether and
then twice 1-mL portions of acetone (-20 °C). The remaining solid
was dissolved in acetone (3 mL, 25 °C) and the solution was stored
for 5 days at -78 °C. Bright red crystals precipitated, which were
separated from the mother liquor, washed twice with 1-mL portions of
acetone (-20 °C), and dried. Yield: 75 mg (88%). The IR and NMR
data of the product were identical to those of 44.46
(50) Sheldrick, G. M. Acta Crystallogr. Sect. A 1990, 46, 467.
(51) Sheldrick, G. M. Program for Crystal Structure Refinement; Universita¨t
Go¨ttingen, 1996.
Preparation of trans-[RhCl{η2-(p-C6H4OMe)2CdCdCdCdCd
C(p-C6H4OMe)2}-(PiPr3)2] (45). This compound was prepared as
9
J. AM. CHEM. SOC. VOL. 124, NO. 24, 2002 6979

A R T I C L E S
Werner et al.
Except for H1a and H1b of compound 28, the positions of all hydrogen
atoms were calculated according to ideal geometry and refined using
the riding method. The asymmetric unit of 21 contains one-half of the
solvent molecule CH2Cl2, which was disordered. Near to the center of
symmetry there was one chlorine atom and one-half of the carbon atom,
and the second half was generated by a symmetry operation.
Buchner (NMR measurements), BASF AG for gifts of chemi-
cals, and in particular Mrs. I. Geiter and Mrs. A. Spenkuch for
valuable practical assistance.
Supporting Information Available: Tables of data collection
parameters, bond lengths and angles, positional and thermal
parameters, and least-squares planes for 3, 21, and 28; data for
these compounds are also given in CIF format. (For the cor-
responding data of 7 and 12, see ref 5.) This material is available
free of charge via the Internet at http://pubs.acs.org.
Acknowledgment. We thank the Deutsche Forschungsge-
meinschaft (Grant SFB 347) and the Fonds der Chemischen
Industrie for financial support. Moreover, we gratefully ac-
knowledge support by Mrs. R. Schedl and Mr. C. P. Kneis
(elemental analyses and DTA), Mrs. M.-L. Scha¨fer and Dr. W.
JA012479G
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6980 J. AM. CHEM. SOC. VOL. 124, NO. 24, 2002