C-C-bond formation in reactions of [(η5-C5H4SiMe3)2Ti(C?CR1)2]CuR with acyl chlorides and anhydrides

Article abstract of DOI:10.1016/S0022-328X(00)00793-2

The chemical behaviour of selected {[Ti](C?CR¹)₂}CuR complexes (1a: R¹=SiMe₃, R=CH₃; 1b: R¹=^tBu, R=CH₃; 1c: R¹=^tBu, R=C?CSiMe₃) towards a number of different acyl chlorides and anhydrides is described. The reaction of 1a or 1b with R²C(O)Cl (2a: R²=CH₃, 2b: R²=C₆H₅) produces the ketones R²C(O)R (4a: R=R²=CH₃; 4b: R=CH₃, R²=C₆H₅; 4c: R=C?CSiMe₃, R²=CH₃, 4d: R=C?CSiMe₃, R²=C₆H₅) along with {[Ti](Cnequiv;CR¹)₂}CuCl (3a: R¹=SiMe₃, 3b: R¹=^tBu). However, on treatment of 1b or 1c with [CH₃C(O)]₂O (5a) the ketones 4a or 4c are formed along with the copper(I) acetate complex {[Ti](C?C^tBu)₂}CuOC(O)CH₃ (6), while the reaction of 1b or 1c with CH₃CO₂H (5b) yields methane and 6. In addition, when 1b or 1c are reacted with maleic (7), phthalic (9a) or tetrachlorophthalic anhydride (9b) the copper(I) carboxylates {[Ti](C?C^tBu)₂}CuOC(O)-cis-CH=CH-C(O)R (8a: R=CH₃, 8b: R=C?CSiMe₃) and {[Ti](C?C^tBu)₂}CuOC(O)-C₆H_4-n Cl_n-2-C(O)R (10a: n=0, R=CH₃; 10b: n=0, R=C?CSiMe₃; 10c: n=4, R=C?CSiMe₃) are produced, which upon addition of, e.g. HBr afford via cleavage of the copper-oxygen σ-bond {[Ti](C?C^tBu)₂}CuBr (3c) and the corresponding carboxylic acids cis-HO₂C-CH=CH-C(O)CH₃ (11a) or HO₂C-C₆H₄-2-C(O)CH₃ (11b), respectively.

Full text of DOI:10.1016/S0022-328X(00)00793-2

Journal of Organometallic Chemistry 625 (2001) 140–147
www.elsevier.nl/locate/jorganchem
C–C-bond formation in reactions of
[(h5-C5H4SiMe3)2Ti(CꢀCR1)2]CuR with acyl chlorides and
anhydrides
W. Frosch, S. Back, H. Lang *
Technische Uni6ersita¨t Chemnitz, Institut fu¨r Chemie, Lehrstuhl Anorganische Chemie, Strasse der Nationen 62, D-09111 Chemnitz, Germany
Received 14 July 2000; received in revised form 17 September 2000; accepted 20 September 2000
Abstract
The chemical behaviour of selected {[Ti](CꢀCR1)2}CuR complexes (1a: R1=SiMe3, R=CH3; 1b: R1=tBu, R=CH3; 1c:
R1=tBu, R=CꢀCSiMe3) towards a number of different acyl chlorides and anhydrides is described. The reaction of 1a or 1b with
R2C(O)Cl (2a: R2=CH3, 2b: R2=C6H5) produces the ketones R2C(O)R (4a: R=R2=CH3; 4b: R=CH3, R2=C6H5; 4c:
R=CꢀCSiMe3, R2=CH3, 4d: R=CꢀCSiMe3, R2=C6H5) along with {[Ti](CꢀCR1)2}CuCl (3a: R1=SiMe3, 3b: R1=tBu).
However, on treatment of 1b or 1c with [CH3C(O)]2O (5a) the ketones 4a or 4c are formed along with the copper(I) acetate
complex {[Ti](CꢀCtBu)2}CuOC(O)CH3 (6), while the reaction of 1b or 1c with CH3CO2H (5b) yields methane and 6. In addition,
when 1b or 1c are reacted with maleic (7), phthalic (9a) or tetrachlorophthalic anhydride (9b) the copper(I) carboxylates
{[Ti](CꢀCtBu)2}CuOC(O)-cis-CHꢁCH–C(O)R (8a: R=CH3, 8b: R=CꢀCSiMe3) and {[Ti](CꢀCtBu)2}CuOC(O)–C6H4−nCln-2-
C(O)R (10a: n=0, R=CH3; 10b: n=0, R=CꢀCSiMe3; 10c: n=4, R=CꢀCSiMe3) are produced, which upon addition of, e.g.
HBr afford via cleavage of the copper–oxygen s-bond {[Ti](CꢀCtBu)2}CuBr (3c) and the corresponding carboxylic acids
cis-HO2C–CHꢁCHꢂC(O)CH3 (11a) or HO2C–C6H4-2-C(O)CH3 (11b), respectively. © 2001 Elsevier Science B.V. All rights
reserved.
Keywords: C–C-bond formation; Acyl chlorides; Anhydrides; Copper; Titanium; Organometallic tweezer
est as model complexes for the study of such reactions.
Recently, it has been demonstrated that the chelating
1. Introduction
effect of the organometallic p-tweezer molecule
Organo-copper(I) compounds can be employed as
organometallic reagents to prepare a high variety of
R1CꢀC–[Ti]–CꢀCR1 {e.g. [Ti]=(h5-C5H4SiMe3)2Ti;
t
R1=SiMe3, Bu, C6H5} enables the stabilisation of a
different organic molecules, such as alkanes, alkenes,
high number of different monomeric organo-copper(I)
alkynes or functionalised derivatives thereof [1]. They
entities [4,5]. Complexes of type {[Ti](CꢀCR1)2}CuR
also can be used to synthesise many novel and natural
(R=singly bonded organic ligand), which contain an
compounds [2]. These reactions are characterised by
early (Ti) and a late transition metal (Cu) connected by
high chemo-, regio- and stereoselectivities. As specific
alkynyl groups, are thereby formed in excellent yields.
reagents organo-copper(I) compounds, CuR [1], or
cuprates, [CuR2]− [3], are applied in these reactions [4].
However, there is only little known about the nature
of the reactive species in copper-mediated reactions
[1–3]. Thus, mononuclear and therefore well-defined
organo-copper(I) compounds are of fundamental inter-
In these molecules the copper(I) center possesses a
trigonal-planar environment, involving h2-coordination
of the alkynyl ligands of the bis(alkynyl) titanocene
moiety and h1-bonding of the corresponding organic
groups R. The (h2-alkyne)2CuR building block repre-
sents a 16-valence-electron complex fragment [4,5].
In this respect, we here describe the reaction chem-
istry of selected {[Ti](CꢀCR1)2}CuR species towards
different organic substrates, such as acyl chlorides and
anhydrides.
* Corresponding author. Tel.: +49-371-5311200; fax: +49-371-
5311833.
E-mail address: heinrich.lang@chemie.tu-chemnitz.de (H. Lang).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(00)00793-2

W. Frosch et al. / Journal of Organometallic Chemistry 625 (2001) 140–147
141
2. Results and discussion
Treatment of {[Ti](CꢀCR1)2}CuR {[Ti]=(h5-
C5H4SiMe3)2Ti; 1a: R1=SiMe3, R=CH3; 1b: R1=
tBu, R=CH3; 1c: R1=tBu, R=CꢀCSiMe3) with the
acyl chlorides R2C(O)Cl (2a: R2=CH3, 2b: R2=C6H5)
in tetrahydrofuran or diethyl ether as solvent selectively
produces at −30°C the heterodinuclear Ti(IV)–Cu(I)
complexes {[Ti](CꢀCR1)2}CuCl (3a: R1=SiMe3, 3b:
R1=tBu) along with the ketones R2C(O)R (4a: R=
R2=CH3; 4b: R=CH3, R2=C6H5; 4c: R=
CꢀCSiMe3, R2=CH3; 4d: R=CꢀCSiMe3, R2=C6H5).
The yield of 3 and 4 ranges between 90 and 100%,
depending on the organic groups present (Eq. 1).
Scheme 1. Copper(I)-mediated carbon–carbon bond formation; syn-
thesis of the ketones R2C(O)R (4).
(1)
Scheme 2. Reaction of 1b and 1c with acetic anhydride (5a) or acetic
acid (5b).
[CH3C(O)]2O (5a) in a 1:1 molar ratio. In the tempera-
ture range of −30 to +25°C, the ketones CH3C(O)R
(4a: R=CH3, 4c: R=CꢀCSiMe3) and {[Ti]-
(CꢀCtBu)2}CuOC(O)CH3 (6) are formed in almost
quantitative isolated yield when tetrahydrofuran is used
as the solvent [Scheme 2, pathway (a)].
In contrast, the reaction of 1b or 1c with stoichiomet-
ric amounts of acetic acid (5b) produces under the same
reaction conditions as described for the treatment of 1
with 5a (vide supra) by evolution of R–H (R=CH3,
CꢀCSiMe3) complex 6 in quantitative yields [Scheme 2,
pathway (b)].
The formation of CH3C(O)R (4a: R=CH3, 4c: R=
CꢀCSiMe3) involves the cleavage of one carbon–oxy-
gen-s-bond in the applied anhydride, when 1b or 1c is
reacted with 5a. In contrast, cyclic anhydrides, such as
maleic anhydride (7), phthalic anhydride (9a) or tetra-
chlorophthalic anhydride (9b), produce with 1b or 1c in
a 1:1 molar ratio in polar organic solvents the keto-
The driving force of this Gilman-type reaction [6] is
the formation of the copper(I) chlorides 3a and 3b,
respectively. In the reaction of 1 with 2 tetrahydrofuran
as well as diethyl ether can be used as solvent. How-
ever, for a more convenient work-up diethyl ether is
favourable, since in the latter solvent complexes 3a and
3b precipitate as orange solids. The corresponding ke-
tones R2C(O)R (4) remain in solution and can be
isolated simply by distillation. In contrast, the appro-
priate work-up in tetrahydrofuran is more lavish, since
both reactants, 3 and 4, are well-soluble in this solvent.
As outlined in Scheme 1, the organometallic starting
materials 1a–1c can be recovered by treatment of 3a or
3b, formed by the reaction of 1 with 2, with equimolar
amounts of, e.g. LiR or BrMgR.
A further method to prepare symmetrical or unsym-
metrical ketones is given by reacting, e.g. 1b or 1c with

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W. Frosch et al. / Journal of Organometallic Chemistry 625 (2001) 140–147
functionalised copper(I) carboxylates {[Ti](CꢀCtBu)2}-
CuOC(O)-cis-CHꢁCH–C(O)R (8a: R=CH3, 8b: R=
CꢀCSiMe3, Eq. 2) or {[Ti](CꢀCtBu)2}CuOC(O)–
C6H4−nCln-2-C(O)R (10a: n=0, R=CH3; 10b: n=0,
R=CꢀCSiMe3; 10c: n=4, R=CꢀCSiMe3; Eq. 3) in
high yields. In the course of these reactions, a cleavage
of a carbon-oxygen bond in 7 or 9 takes place, which
means that for example 10 is formed by a formal
insertion of the O2C–C6H4−nCln-2-C(O) moiety into
the copper-R bond in mononuclear 1b or 1c, respec-
tively. Complexes 8 and 10 are produced without any
side-products. They can be isolated in analytically pure
form by simply evaporating the solvent.
Scheme 3. Copper(I)-mediated conversion of cyclic anhydrides to
keto-functionalised carboxylic acids. Exemplary, the reaction of 1b
with 7 is outlined.
(2)
in excellent yields. However, at higher temperature
mixtures of products are obtained from which only 3c
could be isolated and characterised unequivocally.
The copper bromide 3c can be transferred to the
starting material 1b by its treatment with one equiva-
lent of e.g. CH3Li in diethyl ether at −70°C (Scheme
3).
In general, the titanium-copper complexes 1a–1c can
be applied as reagents for organo-copper mediated
carbon-carbon bond formations as presented by their
reaction with diverse acyl chlorides and anhydrides
(vide supra). The resulting symmetrical and unsymmet-
rical ketones or keto-functionalised carboxylates are the
only organic products formed apart from the
monomeric copper(I) chlorides 3a and 3b, when 1 is
reacted with 2.
(3)
Non-coordinated, free organo-copper reagents of
type CuR react in a 1,2- or 1,4-addition with ketones or
a,b-unsaturated ketones [7]. In contrast to this be-
haviour, we found that the CuR moiety in the
The organic bifunctional subunits O2C-cis-CHꢁCH–
C(O)R and O2C–C6H4−nCln-2-C(O)R (n=0, 4) in 8
and 10 can be transferred to the corresponding car-
boxylic acids by treatment of 8 and 10 with stoichio-
metric amounts of e.g. HBr in diethyl ether or
dichloromethane at low temperatures (Scheme 3).
Nevertheless, it should be noted that the selectivity of
the above mentioned reactions is strongly temperature
dependent: In the temperature range of −70 to
−40°C the copper–oxygen-s-bond is upon addition of
HBr selectively cleaved, as it could be demonstrated
organometallic
titanium(IV)–copper(I)
tweezer
molecules 1a–1c does not add to CꢁO or CꢁC double
bond systems at all, which was clearly demonstrated by
the reaction of 1 with 4 or 7–10. Even when an excess
of 1 is applied, no addition reactions at the sp2-hy-
bridised carbon atoms occur. However, at higher tem-
peratures decomposition of the employed reaction
components took place. One explanation is given by the
fact that in these reactions as intermediate a thermally
unstable
mononuclear
copper(I)
alcoholate,
{[Ti](CꢀCR1)2}CuOR3, is generated. The chemical be-
haviour of such an entity is well-known for example
{[Ti](CꢀCSiMe3)2}CuOR3 (R3=e.g. CH3, C2H5, SiMe3,
tBu) [4,8]. Under the conditions applied, these com-
plexes eliminate Me3SiOR3 and the in-situ generated
exemplary
for
8a
and
10a.
Consequently,
{[Ti](CꢀCtBu)2}CuBr (3c) and cis-HO2C–CHꢁCH–
C(O)CH3 (11a) or HO2C–C6H4−nCln-2-C(O)R (12a:
n=0, R=CH3; 12b: n=4, R=CꢀCSiMe3) are formed

W. Frosch et al. / Journal of Organometallic Chemistry 625 (2001) 140–147
143
{[Ti](CꢀCSiMe3)(CꢀCCu) building block affords the ti-
tanium(IV)–copper(I) acetylide {[Ti](CꢀCSiMe3)-
(CꢀCCu)}2 by dimerisation [4,8]. Similar observations
were made when 1 was reacted with carboxylic esters
instead of ketones or a,b-unsaturated ketones.
demonstrates that the carboxylic ligands in 6, 8 and 10
are h1-bonded via one oxygen atom to the copper(I)
ion [15]. Also the wCO vibrations of the keto-functional-
ities in 8 and 10 appear in this region. In contrast, the
CO stretching vibration of ketones 4a–4c is observed
between 1690 and 1710 cm−1 as a very strong band
[14].
Another typical reagent for copper-mediated carbon-
carbon bond formation are cuprates, Li[CuR2] (R=
singly bonded organic ligand, e.g. CH3) [3]. Therefore,
we were interested to apply the bis(alkynyl) titanocene
[Ti](CꢀCtBu)2 (12) as organometallic chelating system
for anionic [CuR2]− entities. In principle, following
procedures can be employed to synthesise compounds
of type {[Ti](CꢀCtBu)2}CuR−2 : (i) reaction of
{[Ti](CꢀCtBu)2}CuSC6H4CH2NMe2-2 (13) [4,5a,c,9]
with two equivalents of LiR; (ii) treatment of
{[Ti](CꢀCtBu)2}CuR with equimolar amounts of LiR;
or (iii) the reaction of [Ti](CꢀCtBu)2 (12) with Li[CuR2].
However, it appeared that in all of these reactions the
only isolated product is [Ti](CH3)2 (14), when the corre-
sponding CH3-functionalised copper(I) species are used
[5a]. Independently, this compound could be synthe-
sised by the reaction of [Ti]Cl2 (15) with two equiva-
lents of CH3Li in diethyl ether at low temperature [10].
Similar observations were made for other organic
groups R, such as alkyls and aryls. In this respect, it
must be noted that {[Ti](CꢀCtBu)2}CuR is formed at
first, which yields by subsequent reaction with R− the
corresponding [Ti]R2 species. A possible reaction mech-
anism was published earlier and includes as initial step
the nucleophilic attack of R− at the titanium(IV) centre
[11].
1
The H-NMR spectra of all compounds consist of
well-resolved resonance signals for the corresponding
organic ligands with the expected resonance patterns
and ratios. Noticeable is the observation that the cy-
clopentadienyl protons, which usually appear as well-
structured AA%XX% patterns, are broadened in 10c
(6.09, 6.19 ppm), while for complexes 8a, 8b, 10a and
10b only a broad resonance signal at 6.03 (6), 6.10 (8a),
6.07 (8b), 6.13 (10a) or 6.12 ppm (10b) is found.
In the 13C{1H}-NMR spectra of complexes 8 and 10,
the region of 114–122 ppm shows a total of three
resonance signals for the cyclopentadienyl carbon
atoms. The resonance signals of the carbon atom of the
corresponding keto groups are observed between 190
and 200 ppm, a region, which is characteristic for these
groupings [16]. Additionally, it is found that the reso-
nance signal of the sp-hybridised carbon atoms of the
CꢀCR1 groups in complexes 6, 8, and 10 (TiCꢀCt
127–134 ppm, TiC
ꢀCtBu: 148–150 ppm) are shifted to
higher field with respect to the starting material 1b
(TiCꢀCt ꢀCtBu: 169.1 ppm) [4,5].
Bu: 138.6 ppm, TiC
6 Bu:
6
6
6
This finding is in agreement with the earlier mentioned
shift of the wCꢀC stretching vibration, where a very
distinct influence is observed by changing from a
stronger to a weaker s-donor ligand or vice versa.
All compounds were characterised by elemental anal-
1
ysis and spectroscopic studies [IR, H-NMR, 13C{1H}-
NMR]. In agreement with the formulation of
compounds 3, 6,
8
and 10 as heterobimetallic
3. Experimental
titanium(IV)–copper(I) tweezer molecules in which the
alkynyl ligands of the [Ti](CꢀCR1)2 building blocks are
likewise h2-coordinated to the copper(I) halide (com-
pound 3) or a copper(I) carboxylate moiety (com-
pounds 6, 8 and 10) is the observation of the distinct
wCꢀC vibration in the IR spectra of these complexes
between 1975 and 1990 cm−1 [4,5]. Compared to the
starting materials 1a–1c [wCꢀC 1867 cm−1 (1a) [12],
1909 cm−1 (1b) [5a], 1939 cm−1 (1c)] [13] the CꢀC
stretching vibrations in 3, 6, 8 and 10 are shifted to
higher wavenumbers. These data verify that a change of
the copper h1-bonded groups CH3 or CꢀCSiMe3, as
given by complexes 1a–1c, from a stronger to a weaker
s-donor ligand (3, 6, 8, 10) leads to a stronger CꢀCR1
triple bond [4,5,14]. Moreover, in the copper(I) car-
boxylates 6, 8 and 10 two distinct wCO vibrations are
found between 1700 and 1720 cm−1 (wsym) and 1540
and 1560 (was), respectively, in a region, which is typical
for h2-alkyne-stabilised copper(I) carboxylates [15].
The difference of the symmetric and asymmetric
stretching vibration Dw is 160 cm−1. This clearly
3.1. General methods
All reactions were carried out in an atmosphere of
purified nitrogen (O2 traces: CuO catalyst, BASF AG,
Ludwigshafen; H2O: molecular sieve 4 A) using stan-
,
dard Schlenk techniques. Solvents were purified by
distillation; n-pentane and dichloromethane: calci-
umhydride; diethyl ether and tetrahydrofuran: sodium/
benzophenone ketyl; toluene: sodium. FT-IR spectra
were recorded on a Perkin–Elmer FT-IR 1000 spec-
trometer as KBr pellets, as film between NaCl plates or
as solution between CaF2 plates. NMR spectra were
recorded on a Bruker Avance 250 spectrometer, operat-
1
ing in the Fourier transform mode; H-NMR spectra:
250.130 MHz (internal standard relative to CDCl3,
l=7.27); 13C{1H}-NMR spectra: 67.890 MHz (stan-
dard intern, relative to CDCl3, l=77.0). Chemical
shifts are reported in d-units (ppm) downfield from
SiMe4 with the solvent signal as reference signal. Melt-
ing points were determined using analytically pure sam-

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W. Frosch et al. / Journal of Organometallic Chemistry 625 (2001) 140–147
ples, sealed off in nitrogen purged capillaries on a
Gallenkamp MFB 595 010 M melting point apparatus.
Microanalyses were performed by the Organic Depart-
ment at the Technical University of Chemnitz.
mmol) in 60 ml of tetrahydrofuran at −20°C. After
stirring for 1 h at this temperature the reaction mixture
was gradually warmed to 25°C and stirred for an
additional 2 h. All volatile materials were removed in
vacuo. By extraction with cold (−20°C) diethyl ether
(3×5 ml) the compounds 4a or 4c were separated from
{[Ti](CꢀCtBu)2}CuOC(O)CH3 (6). The orange residue
consisted of analytically pure 6, which was isolated in
96% yield (205 mg, 0.341 mmol) after drying in vacuo.
Evaporation of the solvent of the diethyl ether solution
afforded 4a or 4c (0.330 mmol, 90–95% yield; 4a: 20
mg; 4c: 45 mg), which could be characterised by com-
parison of the spectroscopic data of authentic samples
[17].
3.2. General remarks
Compounds 1a [12], 1b [5a], 1c [13], 13 [4,5a,c,9], 15
[20], and Li[Cu(CH3)2] [3] were prepared by published
procedures. All other chemicals were purchased by
commercial suppliers and were used as received.
Caution: When repeating the experiments for the
preparation of the methyl copper(I) compounds 1a and
1b [14,15], it must be noted that the uncomplexed
species [CuCH3] is highly explosive when dry [18]. For
this reason care has to be taken with all safety precau-
tions required.
Spectroscopic data of 6 are given in 1, those of 4a in
Ref. [17a] and of 4c in Ref. [17b].
3.5. Synthesis of {[Ti ](CꢀCtBu)2}CuOC(O)-
cis-CHꢁCH–C(O)CH3 (8a)
3.3. Reaction of {[Ti ](CꢀCtBu)2}CuCH3 (1b) or
{[Ti ](CꢀCtBu)2}CuCꢀCSiMe (1c) with CH3COOH
(5b). Synthesis of {[Ti ](CꢀCtBu)2}CuOC(O)CH3 (6)
and CH4 or HCꢀCSiMe3
Maleic anhydride (7) (25 mg, 0.355 mmol) dissolved
in 10 ml of tetrahydrofuran was added dropwise within
5 min to {[Ti](CꢀCtBu)2}CuCH3 (1b) (200 mg, 0.355
mmol) in 60 ml of tetrahydrofuran at −40°C. After
stirring at this temperature for 30 min, the reaction
mixture was gradually warmed to 25 °C within 1 h.
Then, all volatiles were evaporated in vacuo to yield 8a
(255 mg, 0.355 mmol) as orange–red oil in quantitative
yield.
CH3COOH (5b) (10 mg, 0.178 mmol) in 10 ml of
tetrahydrofuran
was
added
dropwise
to
{[Ti](CꢀCtBu)2}CuCH3 (1b) (100 mg, 0.178 mmol) or
{[Ti](CꢀCtBu)2}CuCꢀCSiMe3 (1c) (115 mg, 0.178
mmol) in 40 ml of tetrahydrofuran at −40°C. After
stirring at this temperature for 30 min, the reaction
mixture was gradually warmed to 25°C. Thereby, the
colour changed from red to orange. After stirring for 10
min at 25°C all volatiles were removed in vacuo to
afford {[Ti](CꢀCtBu)2}CuOAc (6) as an orange solid in
quantitative yield (110 mg, 0.178 mmol).
IR (NaCl, w, cm−1) 1983 (CꢀC), 1707 (COsym), 1635
1
(CꢁC), 1550 (COas). H-NMR (CDCl3) 0.26 (s, 18H,
t
SiMe3), 1.26 (s, 18H, Bu), 2.26 (s, 3H, CH3), 6.1 (bs,
8H, C5H4), 6.4 (bs, 2H, ꢁCH). 13C{1H}-NMR (CDCl3)
0.1 (SiMe3), 25.5 (CH3), 30.9 (tBu), 31.0 (tBu, Cq), 114.3
(CH/C5H4), 117.1 (CH/C5H4), 121.5 (iC/C5H4), 127.3
The exclusive formation of HCꢀCSiMe3 was proven
by GC-MS techniques.
(TiCꢀC6 ), 131.8 (ꢁCH), 134.7 (ꢁCH), 148.2 (TiC6 ꢀC),
M.p. 163°C (dec.). IR (NaCl, w, cm−1) 1983 (CꢀC),
169.2 (CO2), 189.7 (CꢁO). Anal. Calc. for
C33H49CuO3Si2Ti (661.35): C, 59.93; H, 7.47. Found: C,
60.34; H, 7.26%.
1
1716 (COsym), 1556 (COas). H-NMR (CDCl3) 0.26 (s,
t
18H, SiMe3), 1.32 (s, 18H, Bu), 2.13 (s, 3H, CH3), 6.0
(bs, 8H, C5H4). 13C{1H}-NMR (CDCl3) 0.1 (SiMe3),
21.5 (CH3), 30.8 (tBu), 31.1 (tBu, Cq), 114.5 (CH/C5H4),
3.6. Synthesis of {[Ti ](CꢀCtBu)2}CuOC-
(O)-cis-CHꢁCH–C(O)CꢀCSiMe3 (8b)
117.4 (CH/C5H4), 121.1 (iC/C5H4), 128.4 (TiCꢀC
6 ),
148.7 (TiCꢀC), 171.4 (CO2). Anal. Calc. for
6
C30H47CuO2Si2Ti (607.32): C, 59.33; H, 7.80. Found: C,
58.87; H, 7.65%.
Maleic anhydride (7) (40 mg, 0.400 mmol) in 10 ml of
tetrahydrofuran was slowly added to {[Ti](CꢀCtBu)2}-
CuCꢀCSiMe3 (1c) (260 mg, 0.400 mmol) in 50 ml of
tetrahydrofuran at −20°C. After stirring for 1 h at this
temperature the reaction mixture was gradually
warmed to 25°C and stirred for another 3 h. All volatile
materials were removed in vacuo and 8b was obtained
as red oil in quantitative yield (300 mg, 0.400 mmol).
3.4. Reaction of {[Ti ](CꢀCtBu)2}CuCH3 (1b) and
{[Ti ](CꢀCtBu)2}CuCꢀCSiMe3 (1c) with acetic
anhydride (5a). Synthesis of CH3C(O)CH3 (4a),
CH3C(O)CꢀCSiMe3 (4c) and
{[Ti ](CꢀCtBu)2}CuOC(O)CH3 (6)
IR (NaCl, w, cm−1
) 2087 (CꢀCSiMe3), 1983
1
Acetic anhydride (5a) (35 mg, 0.355 mmol) in 10 ml
of tetrahydrofuran was added dropwise to
{[Ti](CꢀCtBu)2}CuCH3 (1b) (200 mg, 0.355 mmol) or
{[Ti](CꢀCtBu)2}CuCꢀCSiMe3 (1c) (230 mg, 0.355
(CꢀCtBu), 1716 (COsym), 1632 (CꢁC), 1539 (COas). H-
NMR (CDCl3) 0.06 (s, 9H, SiMe3), 0.26 (s, 18H,
t
SiMe3), 1.26 (s, 18H, Bu), 6.1 (bs, 9H, C5H4, ꢁCH), 6.4
(bs, 1H, ꢁCH). 13C{1H}-NMR (CDCl3) 0.1 (SiMe3),

W. Frosch et al. / Journal of Organometallic Chemistry 625 (2001) 140–147
145
30.7 (tBu), 31.2 (tBu, Cq), 67.6 (CꢀC
(CꢀCSiMe3), 114.1 (CH/C5H4), 117.4 (CH/C5H4),
121.8 (iC/C5H4), 127.7 (TiCꢀC), 131.2 (ꢁCH), 135.2
(ꢁCH), 148.6 (TiCꢀC), 168.7 (CO2), 188.6 (CO). Anal.
Calc. for C37H55CuO3Si3Ti (743.53): C, 59.77; H,
7.46. Found: C, 59.47; H, 7.19%.
6
SiMe3), 68.9
3.9. Synthesis of {[Ti ](CꢀCtBu)2}CuOC(O)–C6Cl4-
2-C(O)CꢀCSiMe3 (10c)
6
6
6
Tetrachlorophthalic anhydride (9b) (60 mg, 0.220
mmol) in 30 ml of tetrahydrofuran was added drop-
wise to {[Ti](CꢀCtBu)2}CuCꢀCSiMe3 (1c) (150 mg,
0.220 mmol) in 50 ml of tetrahydrofuran at −50°C.
Appropriate work-up (see Section 3.7) affords 10c as
red oil in quantitative yield (205 mg, 0.220 mmol).
3.7. Synthesis of {[Ti ](CꢀCtBu)2}CuOC(O)–C6H4–2-
C(O)CH3 (10a)
IR (NaCl, w, cm−1
) 2070 (CꢀCSiMe3), 1990
(CꢀCtBu), 1700 (COsym,), 1682 (CO, C(O)CH3), 1557
(COas). 1H-NMR (CDCl3) 0.08 (s, 9H, SiMe3), 0.26
(s, 18H, SiMe3), 1.28 (s, 18H, tBu), 6.1 (bs, 4H,
C5H4), 6.2 (bs, 4H, C5H4). 13C{1H}-NMR (CDCl3)
0.2 (SiMe3), 1.1 (SiMe3), 31.1 (tBu, Cq), 31.2 (tBu),
Phthalic anhydride (9a) (45 mg, 0.290 mmol) in 30
ml of tetrahydrofuran was added dropwise to
{[Ti](CꢀCtBu)2}CuCH3 (1b) (165 mg, 0.290 mmol) in
50 ml of tetrahydrofuran at −20°C. After 45 min at
−20°C, followed by stirring for 2 h at 25°C, all
volatiles were removed in vacuo. Compound 10a was
obtained as orange–red oil in quantitative yield (205
mg, 0.290 mmol).
67.9 (CꢀC6 SiMe3), 68.5 (C6 ꢀCSiMe3), 114.6 (CH/C5H4),
118.0 (CH/C5H4), 120.3 (iC/C5H4), 130.0 (C6Cl4),
130.1 (C6Cl4), 130.8 (C6Cl4), 130.9 (C6Cl4), 132.0
(C6Cl4), 134.0 (C6Cl4), 134.1 (TiCꢀC6 ), 147.7 (TiC6 ꢀC),
177.6 (CO2), 198.6 (CO). Anal. Calc. for
C41H53CuCl4O3Si3Ti (931.55): C, 52.86; H, 5.73.
Found: C, 53.31; H, 5.93%.
IR (NaCl, w, cm−1) 1983 (CꢀC), 1707 (COsym),
1
1690 (CO, C(O)CH3), 1553 (COas). H-NMR (CDCl3)
t
0.28 (s, 18H, SiMe3), 1.25 (s, 18H, Bu), 2.25 (s, 3H,
CH3), 6.13 (bs, 8H, C5H4), 7.9–8.1 (m, 4H, C6H4).
13C{1H}-NMR (CDCl3) 0.3 (SiMe3), 25.4 (CH3), 30.9
(tBu), 31.1 (tBu, Cq), 114.4 (CH/C5H4), 117.1 (CH/
C5H4), 121.5 (iC/C5H4), 125.6 (CH/C6H4), 131.1 (iC/
3.10. Reaction of {[Ti ](CꢀCtBu)2}CuOC(O)-cis-
CHꢁCH–C(O)CH3 (8a) or {[Ti ](CꢀCtBu)2}-
CuO2C–C6H4-2-C(O)CH3 (10a) with HBr
C6H4), 131.2 (CH/C6H4), 132.2 (TiCꢀC
(CH/C6H4), 133.5 (iC/C6H4), 136.1 (CH/C6H4), 148.0
(TiCꢀC), 162.6 (CO2), 191.3 (CO). Anal. Calc. for
6 ), 133.2
To [Ti](CꢀCtBu)2}CuOC(O)-cis-CHꢁCH–C(O)CH3
(8a) (190 mg, 0.290 mmol) or {[Ti](CꢀCtBu)2}-
CuOC(O)–C6H4-2-C(O)CH3 (10a) (205 mg, 0.290
mmol) in 60 ml of diethyl ether were slowly added
equimolar amounts of HBr in 30 ml diethyl ether at
−70°C. After stirring at this temperature for 20 min,
the corresponding reaction mixture was warmed to
−10°C within 1 h. All volatiles were removed in vacuo
at this temperature. Fractional crystallisation from te-
trahydrofuran yielded first {[Ti](CꢀCtBu)2}CuBr (3c)
(160 mg, 0.252 mmol, 87%) and then HO2C-cis-
CHꢁCH–C(O)CH3 (11a) (30 mg, 0.258 mmol, 89%) or
(11b) HO2C–C6H4-2-C(O)CH3 (45 mg, 0.264 mmol,
91%). Compounds 3c, 11a and 11b were characterised
by comparison with the spectroscopic data of authentic
3c [18], 11a [19] and 11b [17a].
6
C37H51CuO3Si2Ti (711.42): C, 62.47; H, 7.23. Found:
C, 62.13; H, 6.89%.
3.8. Synthesis of {[Ti ](CꢀCtBu)2}CuOC(O)–
C6H4-2-C(O)CꢀCSiMe3 (10b)
Phthalic anhydride (9a) (40 mg, 0.270 mmol) in 20
ml of tetrahydrofuran was added to {[Ti](CꢀCtBu)2}-
CuCꢀCSiMe3 (1c) (185 mg, 0.270 mmol) in 70 ml of
tetrahydrofuran at −30°C. Appropriate work-up (see
Section 3.7) affords 10b as red oil in quantitative
yields (215 mg, 0.270 mmol).
IR (NaCl, w, cm−1
) 2083 (CꢀCSiMe3), 1987
Spectroscopic data of 3c are listed in reference [19],
those of 11a in [19] and of 11b in [17a].
(CꢀCtBu), 1705 (COsym,), 1695 (CO, C(O)CH3), 1552
(COas). 1H-NMR (CDCl3) 0.06 (s, 9H, SiMe3), 0.27
(s, 18H, SiMe3), 1.27 (s, 18H, tBu), 6.1 (bs, 8H,
C5H4), 7.3–7.6 (m, 4H, C6H4). 13C{1H}-NMR
(CDCl3) 0.1 (SiMe3), 0.9 (SiMe3), 30.7 (tBu, Cq), 30.9
3.11. Synthesis of [Ti ](CH3)2 (14) [10]
(tBu), 67.3 (CꢀC
6 SiMe3), 68.1 (C6 ꢀCSiMe3), 113.7 (CH/
C5H4), 115.1 (CH/C5H4), 116.7 (iC/C5H4), 128.7 (CH/
C6H4), 129.1 (CH/C6H4), 129.6 (CH/C6H4), 130.7
(CH/C6H4), 133.1 (iC/C6H4), 134.0 (iC/C6H4), 134.5
3.11.1. Reaction of {[Ti ](CꢀCtBu)2}CuCH3 (1b) with
CH3Li
To [Ti](CꢀCtBu)2}CuCH3 (1b) (180 mg, 0.320
mmol) in 40 ml of diethyl ether were added 0.320
mmol of CH3Li (1.6 M in diethyl ether) at −70°C.
After stirring at this temperature for 20 min the reac-
(TiCꢀC6 ), 150.2 (TiC6 ꢀC), 179.1 (CO2), 195.6 (CO).
Anal. Calc. for C41H57CuO3Si3Ti (793.58): C, 62.05;
H, 7.24. Found: C, 61.64; H, 7.31%.

146
W. Frosch et al. / Journal of Organometallic Chemistry 625 (2001) 140–147
tion mixture was warmed to 25°C within 1 h. All
volatile materials were removed in vacuo. The residue
was redissolved in 10 ml of diethyl ether and filtered
through a pad of Celite (5×3 cm). After evaporation
of all volatiles [Ti](CH3)2 (14) was obtained in 88%
yield (100 mg, 0.282 mmol) [10].
References
[1] For examples see: (a) R.J.K. Taylor, Organocopper Reagents,
A Practical Approach, Oxford University Press, 1994. (b) B.J.
Hathaway, in: G. Wilkinson, R.D. Gillard, J.A. McCleverty
(Eds.) Comprehensive Coord. Chem., 5, 1987, 534. (c) G. van
Koten, S.L. James, J.T.B.H. Jastrzebski, in: E.W. Abel,
F.G.A. Stone, G. Wilkinson (Eds.), Comprehensive
Organomet. Chem. II, 3, 1996, 57, Pergamon Press.
M.p. 143°C (dec.). IR (NaCl, w, cm−1) 2961 (C–H),
1
1248 (C–Si); H-NMR (CDCl3) −0.12 (s, 6H, CH3),
[2] For example see: (a) W. Carruthers, in: E.W. Abel, F.G.A.
Stone, G. Wilkinson (Eds.), Comprehensive Organomet.
Chem., 7, 1982, 685, Pergamon Press. (b) L.S. Hegedus, J.
Organomet. Chem. 477 (1994) 269. (c) E. Nakamura, M. Ya-
manaka, J. Am. Chem. Soc. 121 (1999) 8941.
[3] (a) G.H. Posner, An Introduction to Synthesis Using
Organocopper Reagents, Wiley, New York, 1980. (b) P. Wipf,
Synthesis (1993) 537. (c) B.H. Lipshutz, in: M. Schlosser (Ed.),
Organometallics in Synthesis, Wiley, New York, 1994.
0.17 (s, 18H, SiMe3), 6.19 (pt, JHH=2.1 Hz, 4H,
C5H4Ti), 6.29 (pt, JHH=2.1 Hz, 4H, C5H4Ti); 13C{1H}-
NMR (CDCl3) 0.3 (SiMe3), 31.8 (CH3), 116.3 (C5H4Ti),
120.3 (C5H4Ti), 121.2 (C5H4Ti, Cipso); Anal. Calc. for
C18H32Si2Ti (352.50): C, 61.33; H, 9.15. Found: C,
60.87; H, 9.23.
3.11.2. Reaction of [Ti ](CꢀCtBu)2 (12) with
Li[Cu(CH3)2] [3]
[4] (a) H. Lang, D.S.A. George, G. Rheinwald, Coord. Chem.
Rev. 206-207 (2000) 101. (b) H. Lang, G. Rheinwald, J. Prakt.
To [Ti](CꢀCtBu)2 (12) (210 mg, 0.433 mmol) in 50 ml
of diethyl ether was added one equivalent (0.433 mmol)
of Li[Cu(CH3)2] [3] in 40 ml diethyl ether at −70°C.
After stirring at this temperature for 20 min the reac-
tion mixture was slowly warmed to 25°C. The red
solution was filtered through a pad of Celite (5×3 cm)
to afford [Ti](CH3)2 (14) in 79% yield (120 mg, 0.342
mmol) after evaporation of all volatiles [10].
Chem./Chemiker Zeitung 341 (1999) 1. (c) H. Lang,
W
Frosch, , in: H. Werner, P. Schreier (Eds.), Selective Reactions
of Metal-Activated Molecules, Vieweg-Verlag, 1998, 177. (d)
H. Lang, M. Weinmann, Synlett (1996) 1. (e) H. Lang, K.
Ko¨hler, S. Blau, Coord. Chem. Rev. 143 (1995) 113.
[5] (a) H. Lang, K. Ko¨hler, L. Zsolnai, M Bu¨chner, A. Driess, G
Huttner, J Stra¨hle, Organometallics 18 (1999) 598. (b) M.D.
Janssen, W.J.J. Smeets, A.L. Spek, D.M. Grove, H. Lang, G.
van Koten, J. Organomet. Chem. 505 (1995) 123. (c) M.D.
Janssen, K. Ko¨hler, M. Herres, A. Dedieu, W.J.J. Smeets,
A.L. Spek, M.D. Grove, H. Lang, G. van Koten, J. Am.
Chem. Soc. 118 (1996) 4817. (d) M.D. Janssen, M. Herres, A.
Dedieu, A.L. Spek, M.D. Grove, H. Lang, G. van Koten, J.
Chem. Soc. Chem. Commun. (1995) 925.
3.11.3. Reaction of {[Ti ](CꢀCtBu)2}CuSC6H4-
CH2NMe2-2 (13) [4,5a,c,9] with CH3Li
To
{[Ti](CꢀCtBu)2}CuSC6H4CH2NMe2-2
(13)
[4,5a,c,9] (230 mg, 0.320 mmol) in 40 ml of diethyl ether
were added two equivalents (0.640 mmol) of CH3Li (1.6
M in diethyl ether) at −70°C. After appropriate work-
up (see Section 3.11.1) [Ti](CH3)2 (14) was obtained in
84% yield (95 mg, 0.269 mmol) [10].
[6] H. Gilman, J.M. Straley, Recl. Trav. Chim. Pays-Bas 55
(1936) 821.
[7] J.A. Koslowski, in: B.M. Trost, I. Fleming (Eds.), Comprehen-
sive Org. Synth., 4(1.4.), Pergamon Press, 1991, 169.
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Ko¨hler, H. Pritzkow, H. Lang, J. Organomet. Chem. 553
(1998) 31.
3.11.4. Reaction of [Ti ]Cl2 (15) [20] with CH3Li
To a suspension of [Ti]Cl2 (15) [20] (150 mg, 0.381
mmol) in 70 ml of diethyl ether were added two equiv-
alents (0.562 mmol) of CH3Li (1.6 M in diethyl ether)
at −70°C. After stirring at this temperature for 10 min
the reaction mixture was warmed to 25°C. All volatiles
were removed in vacuo. The residue was dissolved in 10
ml of diethyl ether and filtered through a pad of Celite
(3×3 cm) to afford [Ti](CH3)2 (14) in 94% yield (125
mg, 0.358 mmol) [10].
[9] M.D. Janssen, M. Herres, L. Zsolnai, A.L. Spek, M.D. Grove,
H. Lang, G. van Koten, Inorg. Chem. 35 (1996) 2476.
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Organomet. Chem. 464 (1994) C17 and literature cited therein.
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submitted.
[12] M.D. Janssen, K. Ko¨hler, M. Herres, A. Dedieu, A.L. Spek,
D.M. Grove, H. Lang, G. van Koten, J. Am. Chem. Soc. 118
(1996) 4817.
[13] K. Ko¨hler, M.D. Janssen, M. Herres, L. Zsolnai, A.L. Spek,
G. van Koten, H. Lang, Chem. Eur. J. (2000) submitted.
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and Coordination Compounds, 3rd ed., Wiley Interscience,
New York, 1977. (b) K. Nakamoto, Infrared and Raman
Spectra of Inorganic and Coordination Compounds, 5th ed.,
Vol. 2, Wiley Interscience, New York, 1997. (c) H. Gu¨nzler,
H.M. Heise, IR-Spektroskopie, VCH, Weinheim, 1996. For
influence of s-donor strength in metal-hydrides see: (d) J.
Chatt, L.A. Duncanson, B.L. Shaw, Chem. Ind. (1958) 859. (e)
M.J. Church, M.J. Mays, J. Chem. Soc. A (1968) 2275.
[15] H. Lang, K. Ko¨hler, L. Zsolnai, Chem. Ber. 128 (1995)
525.
Acknowledgements
We are grateful to the Deutsche Forschungsgemein-
schaft, the Fonds der Chemischen Industrie and the
Konrad-Adenauer-Stiftung (W.F.) for financial sup-
port. We thank Mrs. S. Ahrens and Mrs. U. Sto¨ß for
preparing this manuscript.
.

W. Frosch et al. / Journal of Organometallic Chemistry 625 (2001) 140–147
147
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.