Stereoselective reactivity of diastereotopic carbon-carbon triple bonds induced by chiral orthosubstituted arene tricarbonyl chromium complexes. Diastereoselective Co2(CO)8 complexation and LiAlH4 reduction

Article abstract of DOI:10.1016/S0022-328X(99)00187-4

The diastereoselective Co₂(CO)₈ complexation and LiAlH₄ reduction of diastereotopic carbon-carbon triple bond, induced by chiral ortho substituted arene tricarbonylchromium complexes is described. The relative configuratio

Full text of DOI:10.1016/S0022-328X(99)00187-4

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 585 (1999) 43–52
Stereoselective reactivity of diastereotopic carbon–carbon triple
bonds induced by chiral orthosubstituted arene tricarbonyl
chromium complexes. Diastereoselective Co2(CO)8 complexation
and LiAlH4 reduction
Bertrand Caro *, Marie-Claude Se´ne´chal-Tocquer, Franc¸oise Robin-Le Guen,
Pascal LePoul
Laboratoire de Chimie des organome´talliques et Biologiques, associe´ au CNRS, IUT de Lannion, B.P. 150, F-22302 Lannion Cedex, France
Received 21 December 1998
Abstract
The diastereoselective Co2(CO)8 complexation and LiAlH4 reduction of diastereotopic carbon–carbon triple bond, induced by
chiral ortho substituted arene tricarbonylchromium complexes is described. The relative configuration of the obtained diastereoiso-
1
mers are determined unequivocally by X-ray crystallography, H-NMR and transition state analysis. © 1999 Elsevier Science S.A.
All rights reserved.
Keywords: Arene tricarbonylchromium complex; C–C triple bond; Co2(CO)8 complexation; LiAlH4 reduction
1. Introduction
unexplored approach to diastereoselective and enan-
tioselective synthesis in this series.
1-2 unsymmetrically disubstituted arene tricar-
bonylchromium complexes are chiral molecules. Since
the pioneer work of the groups of Dabard [1] and
Tirouflet [2], several laboratories have reported various
diastereoselective and enantioselective synthesis induced
by the metallocenic chirality [3]. In most known cases,
the stereoselective formation of the new chiral center
was produced from prochiral carbonyls [4], imines [5],
C–C double bonds [6], oxonium ions [7], chromium
stabilized carbocations [8], and arene tricar-
bonylchromium stabilized carbanions [9]. A special case
was the dioxirane oxidation involving diastereotopic
lone pairs of sulfinyl ortho substituted arene tricar-
bonylchromium complex [10].
In this paper, we disclose the diastereoselective reac-
tivity of C–C triple bonds induced by the chirality of
ortho-substituted arene tricarbonylchromium com-
plexes. As first examples we have selected two classic
reactions in acetylenic chemistry: the Co2(CO)8 com-
plexation [11] and the LiAlH4 reduction [12].
2. Results and discussion
2.1. Synthesis of the diacetylenic complexes
The racemic diynes 1, 2, 5, 6 are easily accessible in
good yield (64–90%) from the reaction of methyl,
ortho-methoxy or ortho-methyl-benzoate tricar-
bonylchromium complexes with two equivalents of the
adequate lithium acetylide (Scheme 1).
The monoreactivity of diastereotopic functions in
chiral arene tricarbonylchromium complexes, could be
an other attractive, but to the best of our knowledge,
Adding NaOH to methanolic solution of 2 allowed
the formation of complex 3 (yield: 88%) (Scheme 2).
Silylation of the potassium alcoholate, obtained from
* Corresponding author.
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00187-4

44
B. Caro et al. / Journal of Organometallic Chemistry 585 (1999) 43–52
no product resulting from a decomplexation reaction
could be detected. As expected, the monocomplexation
is stereoselective. The diastereoisomer ratio was deter-
mined by 1H-NMR examination of the mixture ob-
tained after chromatographic purification. For the
ortho-methoxy complexes case, the diastereoselectivity
is dependent on the acetylenic carbon–carbon triple
bond substitution and insensitive apparently to the
substitution of the hydroxy hydrogen by a SiMe3
group. The diastereoisomeric mixture of 7a–7b, 8a–8b,
9a–9b, 10a–10b were separated easily by chromatogra-
phy on silica gel plates (eluent: ether–petroleum ether).
The complexation of 5 and 6 (ortho-methyl com-
plexes case) was less stereoselective and the chromato-
graphic separation of the diastereoisomeric mixture was
unsuccessful.
Scheme 1.
1 by Me3SiCl produced 4 in good yield (73,6%) (Scheme
3).
As expected for the presence of diastereotopic func-
tions, H-NMR spectra show two clean singlets for the
The structure of the major diastereoisomeric hetero-
trinuclear complex 7a was determined unequivocally by
single X-ray structural analysis (Fig. 1).
1
acetylenic hydrogens of 3 and for the methyl protons of
the SiMe3 groups of 2 (3: lꢀC–H 3.20 and 3.22 ppm;
2: lꢀC–SiMe3: 0.19 and 0.16 ppm).
Similar inequivalence is found for the Cb of the
carbon–carbon triple bond (3: Cb: 74.34 and 73.64 ppm;
2: CbSi: 89.37 and 88.20 ppm).
The relative configuration was identified as S*R*. It
seems reasonable for us to extend this stereochemical
assignment to the other ortho-methoxy complexes and
consequently to attribute for the major diastereoiso-
mers 8a and 9a the S*R* configuration. The assessment
of this proposal is reinforced by the following facts: (1)
chromatographic analysis (silica gel plates; eluent:
ether–petroleum ether 1/3) gave a greater Rf value for
the major diastereoisomers 7a, 8a, 9a (ortho-methoxy
series, Table 1). In the same conditions the ortho-
methyl isomers 11a–11b and 12a–12b are inseparable;
(2) for the ortho-methoxy series in the same NMR
solvent (CDCl3 or CD3COCD3) a chemical shift corre-
lation is observed between the hydrogens of the alcohol
function of each class of stereoisomers.
2.2. Diastereoselecti6e cobalt carbonyl complexation
The complexation of a carbon–carbon triple bond by
Co2(CO)8 is a very popular reaction in organometallic
chemistry. The synthetic potentiality of the obtained
acetylenic cobalt–carbonyl complexes, especially in the
propargylic series, has been well demonstrated [11].
To test the stereoselectivity of the complexation,
complexes 1–6 (one equivalent) were reacted with
Co2(CO)8 (one and a half equivalents) in ether solution
at room temperature (r.t.) (Scheme 4). In this condition
The low-field resonance of the hydroxyl hydrogen,
found in CDCl3, for the minor ortho-methoxy-isomers
Scheme 2.
Scheme 3.

B. Caro et al. / Journal of Organometallic Chemistry 585 (1999) 43–52
45
Scheme 4.
unfavourable interaction involving the polar oxygenated
groups appears. To minimize this interaction, the least
sterically demanding linear acetylenic function is moved
towards the chromiumtricarbonyl moiety by rotation
around the CAr–C1 bond (transition state B). When
R2=H the corresponding transition state is less strained
and the percentage of the minor diastereoisomer 9b rises
slightly.
7b and 8b (Table 1) suggests the formation of an
intramolecular hydrogen bond, probably with the oxy-
gen of the methoxy group. The lack of significant
chemical shift differences (lOH minor–lOH major,
Table 1) observed for the ortho-methyl series confirms
this view. On the other hand, the donor capacity of
CD3COCD3 [13] allows the formation of an hydrogen
bond with the hydroxyl hydrogen of the major isomers
7a, 9a (Table 1). As a consequence a low-field resonance
is observed for the hydroxy protons and the chemical
shift difference (lOH minor–lOH major) is inverse.
Finally for 10a, the configuration reported in Scheme
4 was validated as follows: 10a was reacted with NBu4F
at −40°C in CH2Cl2 to lead the hetero-trinuclear
complex 7a of known configuration together with the
tricarbonylchromium complex 1 as the result of a de-
complexation process by the fluoride anions [14].
Another important feature of the crystal structure
data of 7a is the location of the metal carbonyl frag-
ments and of the oxygenated groups. In the crystal, to
avoid severe steric interaction, the acetylenic cobalt
carbonyl fragment lies far away from the tricar-
bonylchromium moiety. As a consequence the oxy-
genated groups (OR3–OCH3) are in
a
quasi
anti-conformation.
Having in mind this information, the formation of the
major diastereoisomer, for the ortho-methoxy com-
plexes cases, is at best rationalized by the less strained
transition state A in which the acetylenic cobalt car-
bonyl fragment lies on the exo-face of the arene tricar-
bonylchromium complex (Scheme 5). In the transition
state similar to A, leading to the minor isomers, an
Fig. 1. Structure of 7a.

46
B. Caro et al. / Journal of Organometallic Chemistry 585 (1999) 43–52
Scheme 5.
Scheme 6.

B. Caro et al. / Journal of Organometallic Chemistry 585 (1999) 43–52
47
Table 2
1H-NMR chemical shifts of the hydroxyl hydrogen
No. alcohol
7a
7b
15a
15b
Solvent
l (OH) (ppm)
CDCl3
3.20
CDCl3
5.20
CDCl3
2.60
CDCl3
5.27
reacted with Co2(CO)8 to afford the diastereoisomeric
hetero–trinuclear complexes 15a–15b (Scheme 6). After
separation by chromatography on silica gel plates, the
1H-NMR of 15a and 15b was recorded (solvent CDCl3).
Assuming that 15a and 15b exist predominantly in the
same favoured conformations than 7a and 7b, the
chemical shift values of the alcohol hydrogen would be
comparable for the two types of isomer. In perfect
agreement with the prevision, similar OH chemical shift
values were found for 15a and 7a and for 15b and 7b
(Table 2).
Scheme 7.
For the ortho-methyl-complex case, in the lack of
significant differences, related to those found for the
ortho-methoxy series, the stereochemical assignment for
11a–12a, 11b–12b seems more difficult. However, as-
suming again an exo location of the acetylenic metal
carbonyl fragment in the transition states, and the
prominence of the unfavourable ortho-methyl–OH steric
interaction over the ortho-methyl–R–CꢀC-one [15] we
suggest the configuration reported in Scheme 4 for
11a–12a and 11b–12b.
Consequently we propose the S*R* configuration for
the major hetero–trinuclear en-yne complex 15a and the
S*S* configuration for the tricarbonylchromium com-
plex 13a.
As noted above, the reduction of propargylic alcohols
by LiAlH4 involves in a first step the formation of an
oxygen aluminium bond, followed by an intramolecular
hydride transfer. On this basis the major formation of the
S*S* isomers 13a and 14a can be rationalized in terms
of a cyclic transition state C (Scheme 7) in which the
–OAlH3− anionic group lies away from the tricar-
bonylchromium fragment, which prevents at best the
unfavourable interactions with the ortho-methoxy group.
In the transition state D which leads to the minor isomer,
two unfavorable interactions occur on the one hand
between the aluminium hydride and the phenyl Cr(CO)3
groups and on the other hand between the partly
negatively charged b carbon of the CꢀC bond and the
ortho-methoxy group.
2.3. Diasteroselecti6e LiAlH4 reduction
We then examined the LiAlH4 reduction.
Lithium aluminium hydride reduction of propargylic
alcohols is a convenient route to allylic alcohols [12]. The
mechanistic aspect of this reaction has received a great
deal of attention. The reduction was known to proceed
via specific hydride transfer from the aluminium bond to
oxygen to the adjacent carbon of the acetylenic linkage
[12].
In order to test the stereoselectivity of the reduction,
complexes 1 and 3 were reacted with LiAlH4 in ether
solution to give after hydrolysis an unseparable mixture
of the diastereoisomeric ene-yne complexes 13a–13b
(yield 42%, 13a/13b 3/1) and 14a/14b (yield 46%, 14a–
14b 3/1) (Scheme 6).
1
For 13a and 13b H-NMR coupling constant values
3. Conclusions
are consistent with a cis addition leading exclusively to
the trans complexes [12].
The relative configuration of the diastereoisomers was
determined as follows. The mixture of 13a–13b was
Two diastereoselective reactions, induced by the chi-
rality of ortho-substituted arene tricarbonylchromium
Table 1
1H-NMR chemical shift of the hydroxyl hydrogen
No alcohol
7a a
7a
7b
7b
8a
8b
9a
9b
11a+11b
12a+12b
Solvent
CDCl3
3.20
0.50
acetone-d6
6.59
CDCl3
5.20
0.34
acetone-d6
5.69
CDCl3
3.00
0.74
CDCl3
5.05
0.50
acetone-d6
6.20
0.44
acetone-d6
5.39
0.34
CDCl3
3.31 3.26
CDCl3
3.11 3.05
l (OH) (ppm)
b
Rf
a For the analogous complex (R1=H) l (OH) CDCl3 3.26 ppm (M.-C. Se´ne´chal unpublished result).
b Silica gel 60; 0.25 mm plates; solvent 1:3 ether–petroleum ether.

48
B. Caro et al. / Journal of Organometallic Chemistry 585 (1999) 43–52
Table 4
complexes, involving diastereotopic acetylenic func-
tions, have been reported. Good diastereoselectivity is
obtained in the methoxy-ortho series for the cobalt
carbonyl complexation and the LiAlH4 reduction. The
relative configuration of the diastereoisomeric prod-
ucts have been determined by the aid of X-ray struc-
Bond angles (°) for C33H18O11Co2Cr
C(11)–Cr(1)–C(12) 87.0(2)
C(12)–Cr(1)–C(13) 89.7(2)
C(12)–Cr(1)–C(21) 95.6(1)
C(11)–Cr(1)–C(22) 86.8(1)
C(13)–Cr(1)–C(22) 144.2(1)
C(12)–Cr(1)–C(23) 162.2(1)
C(11)–Cr(1)–C(24) 125.7(2)
C(13)–Cr(1)–C(24) 87.6(2)
C(12)–Cr(1)–C(25) 110.9(1)
C(11)–Cr(1)–C(26) 143.5(1)
C(13)–Cr(1)–C(26) 126.2(1)
Co(2)–Co(1)–C(2) 51.47(7)
C(11)–Cr(1)–C(13)
90.1(2)
107.0(1)
162.3(1)
125.7(1)
94.8(1)
108.0(1)
147.1(2)
161.1(1)
95.7(1)
C(11)–Cr(1)–C(21)
C(13)–Cr(1)–C(21)
C(12)–Cr(1)–C(22)
C(11)–Cr(1)–C(23)
C(13)–Cr(1)–C(23)
C(12)–Cr(1)–C(24)
C(11)–Cr(1)–C(25)
C(13)–Cr(1)–C(25)
C(12)–Cr(1)–C(26)
1
tural analysis and H-NMR.
As the diacetylenic tricarbonylchromium complexes
could be obtained easily in optical active form, from
the corresponding optically pure ester [16], the devel-
opment of enantioselective synthesis based on this
methodology is conceivable.
89.4(1)
Co(2)–Co(1)–C(3)
Co(2)–Co(1)–C(14) 150.9(1)
52.58(7)
C(2)–Co(1)–C(3)
40.4(1)
C(2)–Co(1)–C(14) 104.1(1)
Co(2)–Co(1)–C(15) 100.6(1)
C(3)–Co(1)–C(15) 140.7(1)
Co(2)–Co(1)–C(16) 99.1(1)
C(3)–Co(1)–C(16) 108.0(1)
C(15)–Co(1)–C(16) 104.1(2)
Co(1)–Co(2)–C(3) 50.59(8)
Co(1)–Co(2)–C(17) 97.8(1)
C(3)–Co(2)–C(17) 140.6(1)
C(2)–Co(2)–C(18) 140.7(1)
C(17)–Co(2)–C(18) 102.9(1)
C(2)–Co(2)–C(19) 100.8(1)
C(17)–Co(2)–C(19) 102.5(2)
C(3)–Co(1)–C(14)
C(2)–Co(1)–C(15)
C(14)–Co(1)–C(15)
C(2)–Co(1)–C(16)
C(14)–Co(1)–C(16)
Co(1)–Co(2)–C(2)
C(2)–Co(2)–C(3)
C(2)–Co(2)–C(17)
Co(1)–Co(2)–C(18)
C(3)–Co(2)–C(18)
99.0(1)
101.2(1)
99.8(2)
144.4(1)
95.8(2)
50.79(6)
39.6(1)
104.1(1)
97.6(1)
4. Experimental
All preparations were carried out under an atmo-
sphere of dry nitrogen. Solvents were dried and dis-
tilled according to standard procedures. 1H-NMR
spectra were recorded in CDCl3 or in acetone-d6 on a
Brucker A.M. 300 MHz spectrometer. Infrared spec-
tra were recorded on a Perkin–Elmer Spectrum 1000
FTIR spectrophotometer using KBr plates. Mass
spectra were recorded using a MS/MS Micromass
Zab Sep TOF spectrometer.
104.1(1)
Co(1)–Co(2)–C(19) 148.8(1)
C(3)–Co(2)–C(19) 100.1(1)
C(18)–Co(2)–C(19) 100.6(2)
C(22)–O(2)–C(27) 119.1(3)
O(1)–C(1)–C(2)
C(2)–C(1)–C(4)
C(2)–C(1)–C(21)
Co(1)–C(2)–Co(2)
Co(2)–C(2)–C(1)
Co(2)–C(2)–C(3)
Co(1)–C(3)–Co(2)
Co(2)–C(3)–C(2)
Co(2)–C(3)–C(31)
C(1)–C(4)–C(5)
Cr(1)–C(11)–O(11) 178.2(3)
Cr(1)–C(13)–O(13) 178.6(4)
Co(1)–C(15)–O(15) 178.5(3)
Co(2)–C(17)–O(17) 178.2(3)
Co(2)–C(19)–O(19) 177.4(4)
110.0(2)
110.4(2)
109.4(2)
77.73(7)
132.2(2)
71.7(1)
76.82(9)
68.7(1)
131.1(2)
174.8(3)
O(1)–C(1)–C(4)
109.1(2)
O(1)–C(1)–C(21) 105.5(2)
C(4)–C(1)–C(21) 112.4(2)
Co(1)–C(2)–C(1) 132.7(2)
Table 3
Co(1)–C(2)–C(3)
C(1)–C(2)–C(3)
Co(1)–C(3)–C(2)
69.8(1)
144.9(2)
69.7(1)
,
Interatomic distances (A) for C33H18O11Co2Cr
Cr(1)–C(11)
Cr(1)–C(13)
Cr(1)–C(22)
Cr(1)–C(24)
Cr(1)–C(26)
Co(1)–C(2)
Co(1)–C(14)
Co(1)–C(16)
Co(2)–C(3)
Co(2)–C(18)
O(1)–C(1)
O(2)–C(27)
O(12)–C(12)
O(14)–C(14)
O(16)–C(16)
O(18)–C(18)
C(1)–C(2)
C(1)–C(21)
C(3)–C(31)
C(5)–C(51)
C(21)–C(26)
C(23)–C(24)
C(25)–C(26)
C(31)–C(36)
C(33)–C(34)
C(35)–C(36)
C(51)–C(56)
C(53)–C(54)
C(55)–C(56)
1.827(3)
1.839(3)
2.266(3)
2.207(3)
2.213(3)
1.948(2)
1.793(3)
1.818(3)
2.004(2)
1.820(3)
1.420(3)
1.429(4)
1.139(5)
1.132(5)
1.119(4)
1.124(4)
1.515(3)
1.534(3)
1.460(4)
1.431(4)
1.421(3)
1.386(5)
1.394(4)
1.383(4)
1.360(7)
1.398(6)
1.391(5)
1.375(8)
1.392(5)
Cr(1)–C(12)
Cr(1)–C(21)
Cr(1)–C(23)
Cr(1)–C(25)
Co(1)–Co(2)
Co(1)–C(3)
Co(1)–C(15)
Co(2)–C(2)
Co(2)–C(17)
Co(2)–C(19)
O(2)–C(22)
O(11)–C(11)
O(13)–C(13)
O(15)–C(15)
O(17)–C(17)
O(19)–C(19)
C(1)–C(4)
1.846(3)
2.230
Co(1)–C(3)–C(31) 135.9(2)
C(2)–C(3)–C(31) 145.2(2)
C(4)–C(5)–C(51) 178.3(3)
Cr(1)–C(12)–O(12) 177.2(4)
Co(1)–C(14)–O(14) 176.5(4)
Co(1)–C(16)–O(16) 178.8(4)
Co(2)–C(18)–O(18) 179.0(4)
C(1)–C(21)–C(22) 120.9(2)
C(22)–C(21)–C(26) 119.2(2)
O(2)–C(22)–C(23) 124.0(2)
C(22)–C(23)–C(24) 120.0(3)
C(24)–C(25)–C(26) 119.3(3)
C(3)–C(31)–C(32) 120.2(3)
C(32)–C(31)–C(36) 118.9(3)
C(32)–C(33)–C(34) 120.1(4)
C(34)–C(35)–C(36) 120.5(4)
C(5)–C(51)–C(52) 120.4(3)
C(52)–C(51)–C(56) 119.4(3)
C(52)–C(53)–C(54) 120.4(4)
C(54)–C(55)–C(56) 121.0(4)
2.225(3)
2.230(3)
2.4566(5)
1.949(3)
1.830(4)
1.967(2)
1.826(3)
1.780(3)
1.334(3)
1.139(4)
1.151(4)
1.122(5)
1.125(4)
1.128(5)
1.473(3)
1.347(3)
1.199(4)
1.415(3)
1.427(4)
1.412(5)
1.382(5)
1.400(4)
1.374(8)
1.389(5)
1.390(5)
1.358(8)
C(1)–C(21)–C(26)
O(2)–C(22)–C(21)
C(21)–C(22)–C(23) 119.4(12)
C(23)–C(24)–C(25) 121.1(3)
C(21)–C(26)–C(25) 121.0(3)
119.9(2)
116.6(2)
C(3)–C(31)–C(36)
120.9(3)
C(31)–C(32)–C(33) 120.6(4)
C(33)–C(34)–C(35) 119.9(3)
C(31)–C(36)–C(35) 120.0(4)
C(5)–C(51)–C(56)
120.1(3)
C(2)–C(3)
C(4)–C(5)
C(51)–C(52)–C(53) 119.8(4)
C(53)–C(54)–C(55) 120.0(3)
C(51)–C(56)–C(55) 119.4(4)
C(21)–C(22)
C(22)–C(23)
C(24)–C(25)
C(31)–C(32)
C(32)–C(33)
C(34)–C(35)
C(51)–C(52)
C(52)–C(53)
C(54)–C(55)
4.1. Preparation of the diacetylenic
tricarbonylchromium complexes
4.1.1. General procedure for the preparation of the diynes
1, 2, 5, 6
A solution of the ester (5 mmol in 20 ml of THF)

B. Caro et al. / Journal of Organometallic Chemistry 585 (1999) 43–52
49
was added at −40°C to a solution of the adequate
lithium acetylide (12.5 mmol in 20 ml of THF). The
reaction was warmed to room temperature (r.t.). The
stirring was continued for 2 h. The reaction mixture
was poured onto water. After extraction with ether,
drying over MgSO4 and evaporation of the solvent,
chromatography was then performed on the residue
using silica gel plates (eluent ether–petroleum ether).
t-BuOK (0.224 g, 2 mmol) was added, and the solution
was stirred at r.t. for 15 min. Me3SiCl (0.326 g, 3 mmol)
was then added. Progress of the reaction was monitored
by silica gel TLC plates. The reaction mixture was
poured onto water and the complex extracted with
ether. The organic layer was dried over MgSO4. After
evaporation of the solvent chromatography was per-
formed on the residue using silica gel plates (eluent
ether–petroleum ether) to give 4 (0.402 g, 0.74 mmol).
4.1.2. Preparation of the diyne 3
Aqueous 1 M NaOH was added to a degassed
methanolic solution of 2 (2.44 g, 5.4 mmol). Progress of
the reaction was monitored by silica gel TLC plates.
The reaction mixture was poured onto water and the
organometallic complex extracted with ether. The or-
ganic layer was dried over MgSO4. After evaporation of
the solvent, chromatography was performed on the
crude using silica gel plates (eluent ether–petroleum
ether) to give the diyne 3 (1.44 g, 4.5 mmol).
4.1.4. General procedure for the Co2(CO)6 complexation
of the diynes 1, 3, 4, 5, 6, 13a, 13b
A total of 4 mmol of Co2(CO)8 was added to a
degased solution of diynes (2 mmol in 20 ml of ether) at
r.t. After stirring for 2 h, the solvent was evaporated.
Chromatography was performed on the residue using
silica gel plates (eluent ether–petroleum ether) to give
the expected cobalt carbonyl complexes.
4.1.3. Preparation of the diyne 4
The diyne 1 (0.474 g, 1 mmol) was dissolved in THF.
4.1.5. LiAlH4 reduction of diynes 1 and 3
The appropriate diyne alcohol and an excess of Li Al
H4 was stirred in ether at r.t. for 4 h. Hydrolysis was
carried out by careful dropwise addition of H2O. Then
the organometallic complexes were extracted with ether.
The ether solution was washed with water and dried
over MgSO4. After chromatography (silica gel plates,
eluent ether–petroleum ether) the en-yne complexes
were isolated as a yellow mixture of diastereoisomers.
0.474 g of complex 1 (1 mmol) gave 0.200 g of 13a and
13b. A total of 0.483 g of complex 3 (1.5 mmol) gave
0.223 g of 14a and 14b.
Table 5
Crystal data for C33H18O11Co2Cr
Fw
760.4
10.726(2)
13.572(2)
11.851(1)
90.
109.85(1)
90.
1622.6(4)
,
a (A)
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
3
,
V (A )
Z
2
Crystal system
Monoclinic
Space group
P21
13.87
1.56
4.1.6. Desilylation of the complex 10a
Linear absorption coefficient v (cm−1
)
Complex 10a (0.240 g, 0.29 mmol) was dissolved in
anhydrous CH2Cl2, and the resulting solution cooled to
−40°C. A total of 76 mg (0.29 mmol) of solid TBAF
[NBu4F] was added. The solution was allowed to stir
for 15 min. The reaction mixture was poured onto
water, extracted with ether, and dried over MgSO4.
After evaporation of the solvent, chromatography was
performed on the crude using silica gel plates (eluent
ether–petroleum ether) to give the complex 7a (70 mg,
32% Yield), the complex 1 (40 mg, 29% Yield) and a
small portion of the unreacted complex 10a (40 mg,
17% Yield).
Density z (g cm−3
Diffractometer
Radiation
Scan type
Scan range (°)
q Limits (°)
Temperature of measurement
Octants collected
Nb of data collected
Nb of unique data collected
Nb of unique data used for refinement
R (int)
R=ꢀꢁꢁFoꢁ−ꢁFcꢁꢁ/ꢀꢁFoꢁ
Rw=[ꢀw(ꢁFoꢁ−ꢁFcꢁ)2/ꢀwFo2]1/2 a
Absorption correction
Extinction parameter
Goodness-of-fit
)
CAD4 0Enraf–Nonius
Mo–Ka (u=0.71069 A)
ꢀ/2q
0.8+0.345 tgu
1–35
r.t.
,
0,17; 0,21;−19,17
7665
7347
5477 (Fo)2\3| (Fo)2
0.024
0.0379
0.0391
No
903
0.998
426
4.2. X-ray crystallography (structure resol6ed by J.
Vaisserman, Laboratoire de Chimie de Me´taux de
Transition, Uni6ersite´ Pierre et Marie Curie, Paris,
France)
Nb of variables
−3
,
Dz min (e A
)
)
−0.60
0.40
−3
,
Dz max (e A
a w=w%[1−((ꢁꢁFoꢁ−ꢁFcꢁꢁ)/6| (Fo))2]2 with w%=1/ꢀr ArTr(X) with
three coefficients, 9.02, −2.41 and 6.85 for a Chebychev Serie, for
which X is Fo/Fo(max).
Complex 7a was crystallized from ether with
petroleum ether as co-solvent. The crystal was set up on
an automatic four circle diffractometer. The structures

50
B. Caro et al. / Journal of Organometallic Chemistry 585 (1999) 43–52
were solved by using the Patterson method with the aid
of the program CRYSTALS [17]. The bond distances and
bond angles are collected in Tables 3 and 4. The
crystallographic data collection parameters appear in
Table 5 and atomic positional parameters in Table 6.
(s, 6H, Ph); 6.45 (d, 1H, Bct); 5.64 (s, 1H, Bct); 5.08 (d,
1H, Bct); 4.85 (t, 1H, Bct); 4.01 (s, 1H, OH); 3.94 (s, 3H,
OCH3). IR (KBr) w (cm−1): w (OH) 3524; w (CꢀO) 1963,
1881. MS m/z 474 M+, 457 (M–OH-)+, 390 (M-3
CO)+, 321 (M–OH–Cr(CO)3)+. Calc.: 474.0559.
Found: 474.0585.
1
2 H-NMR (acetone-d6) l (ppm): 6.45 (d, 1H, Bct);
4.3. Spectroscopic data for the new complexes
5.87 (m, 2H, Bct+OH); 5.48 (d, 1H, Bct); 5.05 (t, 1H,
Bct); 3.91 (s, 3H, OCH3). 13C NMR (acetone-d6) l (ppm):
234.01 (COBct); 143.72 (COCH3); 105.15 (CꢀCSi);
102.40 (CBct); 96.97 (CHBct); 89.37 (CꢀCSi); 88.20
(CHBct); 84.33 (CHBct); 75.49 (CHBct); 63.30 (COH);
56.48 (OCH3); −0.18 (SiMe3); −0.23 (SiMe3). IR (KBr)
w (cm−1): w (OH) 3530; w (CꢀO) 1971, 1886, 1874. MS
m/z 466 M+, 382 (M-3 CO)+, 321 (M–OH–Cr(CO)3)+.
Calc.: 466.0724. Found: 466.0726.
4.3.1. NMR, IR and analytical data for the new
compounds
1
1 H-NMR (CDCl3) l (ppm): 7.56 (m, 4H, Ph); 7.35
Table 6
Fractional atomic coordinates for C33H18O11Co2Cr
Atom
x/a
y/b
z/c
Ueq
1
3 H-NMR (acetone-d6) l (ppm): 6.47 (d, 1H, Bct);
Cr(1)
Co(1)
Co(2)
O(1)
0.44886(4)
0.99650(3)
0.99933(3)
0.7160(2)
0.6463(2)
0.2931(3)
0.3519(4)
0.2161(3)
0.8922(3)
0.9908(4)
1.2721(3)
1.0289(3)
1.2722(3)
0.8790(4)
0.7099(2)
0.8478(2)
0.9176(2)
0.6231(2)
0.5530(3)
0.3515(3)
0.3897(3)
0.3049(3)
0.9328(3)
0.9944(4)
1.1673(3)
1.0164(3)
1.1681(3)
0.9262(3)
0.6553(2)
0.6244(2)
0.5738(3)
0.5622(4)
0.5988(4)
0.6429(3)
0.6111(5)
0.9099(3)
0.8113(4)
0.8028(5)
0.8927(6)
0.9917(6)
1.0010(4)
0.4678(3)
0.3316(4)
0.2495(4)
0.3023(6)
0.4356(6)
0.5205(4)
1.03522(4)
0.95495(4)
0.77928(4)
0.8667(2)
0.9390(2)
0.9102(3)
0.9006(3)
1.1675(3)
1.1161(3)
1.0441(3)
0.9752(3)
0.8048(3)
0.7373(3)
0.5858(2)
0.8734 (2)
0.8639(2)
0.8462(2)
0.7947(2)
0.7273(2)
0.9594(3)
0.9537(3)
1.1159(3)
1.0557(3)
1.0109(3)
0.9682(3)
0.7937(3)
0.7526(3)
0.6604(2)
0.9765(2)
1.0054(2)
1.1020(2)
1.1683(2)
1.1419(2)
1.0464(2)
0.9623(4)
0.8168(2)
0.7534(3)
0.7251(3)
0.7594(3)
0.8221(4)
0.8510(3)
0.6469(2)
0.6605(3)
0.5807(4)
0.4884(3)
0.4749(3)
0.5532(3)
0.12717(4)
0.0351
0.0356
0.0340
0.0390
0.0430
0.0724
0.0819
0.0696
0.0739
0.0790
0.0772
0.0653
0.0679
0.0777
0.0305
0.0302
0.0347
0.0361
0.0408
0.0468
0.0520
0.0512
0.0506
0.0529
0.0526
0.0452
0.0478
0.0511
0.0325
0.0370
0.0456
0.0513
0.0483
0.0396
0.0625
0.0390
0.0497
0.0594
0.0625
0.0698
0.0574
0.0417
0.0571
0.0641
0.0622
0.0667
0.0562
6.02 (s, 1H, OH); 5.93 (t, 1H, Bct); 5.50 (d, 1H, Bct); 5.06
(t, 1H, Bct); 3.90 (s, 3H, OCH3); 3.29 (s, 1H, acetylenic
H); 3.23 (s, 1H, acetylenic H). 13C-NMR (acetone-d6) l
(ppm): 233.93 (COBct); 143.60 (COCH3); 102.08 (CBct);
97.24 (CHBct); 96.77 (CHBct); 84.19 (CHBct); 83.71
(CꢀCH); 75.34 (CHBct); 74.34 (CꢀCH); 73.64 (CꢀCH);
62.28 (COH); 56.66 (OCH3). IR (KBr) w (cm−1): w (OH)
3506, 3282; w (CꢀO) 1956, 1869. MS m/z 322 M+, 305
(M–OH−)+, 266 (M−2CO)+, 238 (M−3CO)+.
Calc.: 321.9933. Found: 321.9925.
0.33338(3)
0.28434(3)
0.0673(2)
0.3829(2)
0.2360(3)
−0.0838(3)
0.0175(4)
0.4390(4)
0.1045(3)
0.4944(3)
0.0474(2)
0.4419(3)
0.2713(4)
0.1849 (2)
0.2768(2)
0.3929(2)
0.2016(2)
0.2070(3)
0.1940(3)
−0.0051(3)
0.0604(3)
0.3953(4)
0.1923(3)
0.4322(3)
0.1371(3)
0.3812(3)
0.2740(3)
0.1932(2)
0.2954(2)
0.3001(3)
0.2082(4)
0.1085(3)
0.1007(2)
0.4858(3)
0.5089(2)
0.5144(3)
0.6252(4)
0.7289(3)
0.7248(3)
0.6148(3)
0.2097(3)
0.1741(4)
0.1719(5)
0.2044(4)
0.2398(4)
0.2428(4)
O(2)
O(11)
O(12)
O(13)
O(14)
O(15)
O(16)
O(17)
O(18)
O(19)
C(1)
1
4 H-NMR (CDCl3) l (ppm): 7.55 (m, 2H, Ph); 7.47
(m, 2H, Ph); 7.33 (m, 6H, Ph); 6.44 (d, 1H, Bct); 5.60 (t,
1H, Bct); 5,04 (d, 1H,Bct); 4.81 (t, 1H, Bct); 3.88 (s, 3H,
OCH3); 0,40 (s, 9H, SiMe3). IR (KBr) w (cm−1): w (OH)
3454; w (CꢀO) 1955, 1904, 1890. MS m/z 546 M+, 462
(M−3CO)+, 373 (M−3CO−OSiMe3)+, 321 (M–
Cr(CO)3–OSiMe3)+. Calc.: 546.0955. Found: 546.0969.
C(2)
C(3)
C(4)
C(5)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(27)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(51)
C(52)
C(53)
C(54)
C(55)
C(56)
1
5 H-NMR (CDCl3) l (ppm): 7.52 (m, 4H, Ph); 7.36
(m, 6H, Ph); 6.43 (d, 1H, Bct); 5.52 (t, 1H, Bct); 5.07 (m,
2H, Bct); 3.13 (s, 1H, OH); 2.67 (s, 3H, CH3). IR (KBr)
w (cm−1): w (OH) 3431; w (CꢀO) 1965, 1947, 1885. MS
m/z 458 M+, 441 (M–OH−)+, 374 (M−3CO)+, 305
(M–OH–Cr(CO)3)+. Calc.: 458.0610. Found: 458.0630.
1
6 H-NMR (acetone-d6) l (ppm): 6.45 (d, 1H, Bct);
6.36 (s, 1H, OH); 5.70 (t, 1H, Bct); 5.31 (d+t, 2H, Bct);
2.61 (s, 3H, CH3); 0.20 (s, 9H, SiMe3); 0.17 (s, 9H,
SiMe3). 13C-NMR (acetone-d6) l (ppm): 234.13 (COBct);
112.29 (CꢀCSi); 111.62 (CMe); 105.20 (CBct); 97.14
(CHBct); 96.02 (CHBct); 94.13 (CHBct); 90.58 (CꢀCSi);
89.81 (CꢀCSi); 88.32 (CHBct); 63.60 (COH); 20.06
(CH3); −0.24 (SiMe3); −0.38 (SiMe3). IR (KBr) w
(cm−1): w (OH) 3413; w (CꢀO) 1958, 1899, 1881. MS m/z
442 M+, 366 (M−3CO)+, 297 (M–OH–Cr(CO)3)+.
Calc.: 450.0775. Found: 450.0781.
7a 1H-NMR (CDCl3) l (ppm): 7.74 (m, 2H, Ph); 7.47
(m, 2H, Ph); 7.33 (m, 3H, Ph); 7.31 (m, 3H, Ph); 6.40 (d,
1H, Bct); 5.60 (t, 1H, Bct); 4.94 (d, 1H,Bct); 4.87 (t, 1H,
Bct); 3.48 (s, 3H, OCH3); 3.21 (s, 1H, OH). 13C-NMR
(CDCl3) l (ppm): 232.84 (COBct); 199.02 (COCo);
141.55 (COCH3); 138.03 (C Ph); 131.74 (CH Ph); 129.79

B. Caro et al. / Journal of Organometallic Chemistry 585 (1999) 43–52
51
(CH Ph); 128.75 (CH Ph); 128.46 (CH Ph); 128.34 (CH
Ph); 127.61 (CH Ph); 122.25 (C Ph); 103.55 (CBct);
102.24 (CꢀC Ph); 95.00 (CHBct); 94.52 (CHBct); 91.79
(CꢀC Ph); 90.52 (CꢀC Ph); 86.18 (CꢀC Ph); 83.48
(CHBct); 72.85 (CHBct); 70.21 (COH); 54.97 (OCH3). IR
(KBr) w (cm−1): w (OH) 3544; w (CꢀO) (Co) 2093, 2035,
2026 w (CꢀO) (Cr) 1961, 1890, 1848. MS m/z 760 M+,
743 (M–OH−)+, 592 (M–6CO)+, 564 (M–7CO)+, 508
(M–9CO)+, 456 [M–Cr(CO)3–6CO]+. Calc.: 759.8918.
Found: 759.8926.
1H, acetylenic H); 3.23 (s, 1H, acetylenic H). 13C-NMR
(acetone-d6) l (ppm): 234.31 (COBct); 200.72 (COCo);
143.11 (COCH3); 105.47 (Cbct); 104.12 (CꢀCH); 97.11
(CHBct); 96.04 (CHBct); 85.90 (CꢀCH); 84.76 (CHBct);
75.29 (CHBct); 75.08 (CꢀCH); 74.42 (CꢀCH); 69.52
(COH); 56.20 (OCH3). IR (KBr) w (cm−1): w (OH) 3401,
3297; w CꢀO (Co) 2102, 2041, 2017; w (CꢀO) (Cr) 1961,
1894, 1874. MS m/z 608 M+, 591 (M–OH−)+, 468
(M–5CO)+, 440 (M–6CO)+, 384 (M–8CO)+, 356
(M–9CO)+, 304 [M–Cr(CO)3–6CO]+ Calc.: 607.8292.
Found: 607.8249.
7b 1H-NMR (CDCl3) l (ppm): 7.74 (m, 2H, Ph); 7.34
(m, 8H, Ph); 6.35 (d, 1H, Bct); 5.61 (t, 1H, Bct); 5.21 (s,
1H, OH); 4.96 (d, 1H, Bct); 4.88 (t, 1H, Bct); 3.64 (s, 3H,
OCH3). 13C-NMR (CDCl3) l (ppm): 231.97 (COBct);
199.06 (COCo); 140.27 (COMe); 137.96 (C Ph); 132.08
(CH Ph); 129.94 (CH Ph); 128.99 (CH Ph); 128.72 (CH
Ph); 128.24 (CH Ph); 127.86 (CH Ph); 121.63 (C Ph);
101.57 (CBct); 102.48 (CꢀC Ph); 101.57 (CBct); 96.50
(CHBct); 94.94 (CHBct); 93.69 (CꢀC Ph); 88.44 (CꢀC
Ph); 87.61 (CꢀC Ph); 77.03 (COH); 72.14 (CHBct); 55.44
(OCH3). IR (KBr) w (cm−1): w (OH) 3544; w (CꢀO) (Co)
2094, 2057, 2020; w (CꢀO) (Cr) 1957, 1890, 1873. MS m/z
760 M+, 743 (M–OH−)+, 592 (M–6CO)+, 564 (M−
7CO)+, 508 (M−9CO)+, 456 [M–Cr(CO)3–6CO]+
Calc.: 759.8918. Found: 759.8895.
1
9b H-NMR (acetone-d6) l (ppm): 6.52 (s, 2H, Bct+
complexed acetylenic H); 5.93 (t, 1H, Bct); 5.53 (d, 1H,
Bct); 5.39 (s, 1H, OH); 5.16 (t, 1H, Bct); 4.01 (s, 3H,
OCH3) 3.53 (s, 1H, acetylenic H). 13C-NMR (acetone-d6)
l (ppm): 233.89 (COBct); 200.48 (COCo); 142.63
(COCH3); 104.05 (CBct); 102.25 (CꢀCH); 98.18 (CHBct);
96.73 (CHBct); 85.30 (CHBct); 84.43 (CꢀCH); 76.95
(CHBct); 76.25 (CꢀCH); 75.29 (COH); 75.20 (CꢀCH);
56.87 (OCH3). IR (KBr) w (cm−1): w (OH) 3518, 3317;
w (CꢀO) (Co) 2097, 2025, 2017; w (CꢀO) (Cr) 1961, 1907,
1885.
10a 1H-NMR (CDCl3) l (ppm): 7.58 (m, 4H, Ph); 7.38
(m, 3H, Ph); 7.26 (m, 3H, Ph); 6.18 (d, 1H,Bct); 5.51 (t,
1H, Bct); 4.88 (t, 1H, Bct); 4.76 (d, 1H, Bct); 3.31 (s, 3H,
OCH3); 0.39 (s, 9H, OSiMe3). IR (KBr) w (cm−1): w
(CꢀO) (Co) 2092, 2055, 2034; w (CꢀO) (Cr) 1965, 1886,
1859. MS m/z 832 M+, 692 (M–5CO)+, 636 (M–
7CO)+, 580 (M–9CO)+, 528 [M–Cr(CO)3–6CO]+
Calc.: 831.9313. Found: 831.9313.
8a 1H-NMR (CDCl3) l (ppm): 6.23 (d, 1H, Bct); 5.59
(t, 1H, Bct); 5.02 (d, 1H, Bct); 4.87 (t, 1H, Bct); 3.81 (s,
3H, OCH3); 3.00 (s, 1H, OH); 0.30 (s, 9H, SiMe3); 0.18
(s, 9H, SiMe3). 13C NMR (CDCl3) l (ppm): 232.75
(COBct); 199.80 (COCo); 141.28 (COCH3); 115.58
(CꢀCSi); 105.40 (CBct); 104.02 (CꢀCSi); 94.93 (CHBct);
94.37 (CHBct); 90.70 (CꢀCSi); 83.74 (CHBct); 79.57
(CꢀCSi); 72.93 (CHBct); 70.08 (COH); 55.16 (OCH3);
0.76 (SiMe3); −0.54 (SiMe3). IR (KBr) w (cm−1): w (OH)
3582; w (CꢀO) (Co) 2091, 2054, 2026; w (CꢀO) (Cr) 1952,
1881, 1868. MS m/z 752 M+, 735 (M−OH−)+, 584
(M−6CO)+, 556 (M−7CO)+, 528 (M−8CO)+, 500
(M−9CO)+, 448 [M−Cr(CO)3–6CO]+ Calc.:
751.9083. Found: 751.9033.
10b 1H-NMR (CDCl3) l (ppm): 7.58 (m, 4H, Ph); 7.34
(m, 6H, Ph); 6,30 (d, 1H, Bct) 5.60 (t, 1H, Bct); 4.86 (d,
1H, Bct); 4.68 (t, 1H, Bct); 3.66 (s, 3H, OCH3); 0,31 (s,
9H, OSiMe3). IR (KBr) w (cm−1): w (CꢀO) (Co) 2094,
2055, 2033; w (CꢀO) (Cr) 1962, 1890, 1877.
1
11a+11b H-NMR (CDCl3) l (ppm): 7.62 (m, 2H,
Ph); 7.50 (m, 1H, Ph); 7.35 (m, 7H, Ph); 6.30 (d, 1H,Bct);
6.15 (d, 1H, Bct); 5.49 (t, 2H, Bct); 5.17 (m, 2H, Bct);
4.97 (m, 2H, Bct); 3.31 (s, 1H, OH); 3.27 (s, 1H, OH);
2.45 (s, 3H, CH3); 2.38 (s, 3H, CH3). IR (KBr) w (cm−1):
w (OH) 3418; w (CꢀO) (Co) 2093, 2062, 2049; w (CꢀO) (Cr)
1957, 1886. MS m/z 744 M+, 727 (M–OH-)+, 604
(M–5CO)+, 576 (M–6CO)+, 496 [M–Cr(CO)3–
4CO]+, 440 [M–Cr(CO)3–6CO]+ Calc.: 743.8969.
Found: 743.8940.
8b 1H-NMR (CDCl3) l (ppm): 6.22 (d, 1H, Bct); 5.56
(t, 1H, Bct); 5.05 (s, 1H, OH); 4.92 (t, 1H, Bct); 4.89 (d,
1H, Bct); 3.72 (s, 3H, OCH3); 0.33 (s, 9H, SiMe3); 0.20
(s, 9H, SiMe3). 13C-NMR (CDCl3) l (ppm): 231.73
(COBct); 199.88 (CO Co); 139.89 (COCH3); 117.03
(CꢀCSi); 104.83 (CBct); 101.82 (CꢀCSi); 95.81 (CHBct);
93.72 (CHBct); 91.88 (CꢀCSi); 83.72 (CHBct); 80.55
(CꢀCSi); 77.02 (COH); 71.93 (CHBct); 55.69 (OCH3);
0.86 (SiMe3); −0.63 (SiMe3). IR (KBr) w (cm−1): w (OH)
3500; w (CꢀO) (Co) 2091, 2053, 2017; w (CꢀO) (Cr) 1969,
1888. MS m/z 752 M+, 735 (M−OH−)+, 584 (M−
6CO)+, 556 (M−7CO)+, 528 (M−8CO)+, 500 (M−
9CO)+, 448 [M−Cr(CO)3–6CO]+ Calc.: 751.9083.
Found: 751.9078.
1
12a+12b H-NMR (CDCl3) l (ppm): 6.14 (d, 1H,
Bct); 5.94 (d, 1H, Bct); 5.48 (t, 1H, Bct); 5.42 (t, 1H, Bct);
5.22 (t, 1H, Bct); 5.15 (t, 1H, Bct); 5.07 (d, 1H, Bct) 5.02
(d, 1H, Bct); 3.11 (s, 1H, OH); 3.05 (s, 1H, OH); 2.67 (s,
3H, CH3); 2.56 (s, 3H, CH3); 0.33 (s, 9H, SiMe3); 0.19
(s, 9H, SiMe3). IR (KBr) w (cm−1): w (OH) 3560; w (CꢀO)
(Co) 2091, 2053, 2025; w (CꢀO) (Cr) 1960, 1894, 1872. MS
m/z 736 M+, 719 (M–OH−)+, 596 (M–5CO)+, 568
(M–6CO)+, 496 [M–Cr(CO)3–4CO]+, 484 (M–
9CO)+, 432 [M–Cr(CO)3–6CO]+ Calc.: 743.8969.
Found: 743.8940.
1
9a H-NMR (acetone-d6) l (ppm): 6.46 (s, 2H, Bct+
acetylenic H); 6.21 (s, 1H, OH); 5.87 (t, 1H,Bct); 5.47 (d,
1H, Bct); 5.09 (t, 1H, Bct); 3.93 (s, 3H, OCH3); 3.23 (s,
1
13a+13b H-NMR (CDCl3) l (ppm): 7.53 (m, 4H,

52
B. Caro et al. / Journal of Organometallic Chemistry 585 (1999) 43–52
[2] J. Besanc¸on, G. Tainturier, J. Tirouflet, Bull. Soc. Chim. Fr. 5
(1971) 180.
Ph); 7.32 (m, 6H, Ph); 7.11 (d, 1H minor, ꢁCH J=16
Hz; 7.01 (d, 1H minor, ꢁCH J=16 Hz); 6.57 (d, 1H
major, ꢁCH J=16 Hz); 6.55 (d, 1H major, ꢁCH J=16
Hz); 6.28 (d, 1H, Bct); 6.26 (d, 1H, Bct); 6.10 (d, 1H,
Bct); 6.09 (d, 1H, Bct); 5.64 (t, 2H, Bct); 5.04 (d, 2H,
Bct); 4.81 (t, 2H, Bct); 3.89 (s, 3H minor, OCH3); 3.86
(s, 3H major, OCH3); 3.80 (s, 1H minor, OH); 3.70 (s,
1Hmajor, OH). IR (KBr) w (cm−1): w (OH) 3475; w
(CꢀO) (Cr) 1960, 1894, 1867. MS m/z 476 M+, 459
(M–OH−)+, 392 (M–3CO)+, 323 [M–Cr(CO)3–
OH]+ Calc.: 476.0716. Found: 476.0712.
[3] A. Solladie´-Cavallo, G. Solladie´, E. Tsama, J. Org. Chem. 44
4189. K. Schlogl, J. Organomet. Chem. 300 (1986) 219. A.
Alexakis, R. Mangeney, I. Marek, F. Rose-Munch, E. Rose,
A. Semra, J. Am. Chem. Soc. 114 (21) (1992) 8288. F. Rose-
Munch, R. Kourzom, J.P. Djukic, A. Perroteug, E. Rose, J.
Organomet. Chem. 467 (1994) 195. Semmelhack in: E.W.
Abel, F.G.A. Stone, G. Wilkinson (Eds.), Comprehensive
Organometallic Chemistry, vol. 12, Pergamon, Oxford, UK,
1995, p. 979.
[4] See for recent examples: S.G. Davies, C.L. Goodfellow, J.
Chem. Soc. Perkin Trans. 1 (1990) 393. A. Solladie´-Cavallo, S.
Quazzotti, S. Colonna, A. Manfredi, J. Fisher, A. Decian,
Tetrahedron Asymmetry 3 (1992) 287. R. Thangarasa, J. R.
Green, T. Nadashi, J. Chem. Soc. Chem. Commun. (1994)
501. S. G. Davies, T. Loveridge, J. M. Clough, Synlett (1997)
66.
[5] P. Bloem, D.M. David, L.A.P. Kane-Maguire, S.G. Pyne,
B.W. Selton, A.H. White, J. Organomet. Chem. 407, (1996)
C19. C. Baldoli, P. Del Buttero, E. Licandro, A. Papagni, T.
Pilati, Tetrahedron 52 (1991) 4849.
[6] V. Gajda, S. Toma, M. Widhalm, Monatsh. Chem. 120 (1989)
147. M. Uemura, H. Oda, T. Minami, T. Shiro, Y. Hayashi,
Organometallics 11 (1992) 3705. C. Baldoli, P. Del Buttero, S.
Maiorana, G. Secchi, M. Moret, Tetrahedron Lett. 34 (1993)
2529.
1
14a+14b H-NMR (CDCl3) l (ppm): 6.18 (dd, 1H
major, ꢁCH J=18 Hz J=10 Hz); 6.17 (d, 1H major,
Bct); 6.14 (dd, 1H minor, ꢁCH J=18 Hz J=10 Hz);
5.96 (t, 1H major, Bct); 5.77 (d, 1H major, ꢁCH2 J=19
Hz); 5.63 (d, 1H minor, ꢁCH2 J=18 Hz); 5.61 (t, 1H
major, Bct); 5.61 (t 1H major, Bct); 5.42 (d, 1H minor,
ꢁCH2 J=10 Hz); 5.32 (d, 1H major, ꢁCH2 J=10 Hz);
5.02 (d, 1H minor, Bct); 5.00 (d, 1H major, Bct); 4.78
(t, 1H major, Bct); 4.77 (t, 1H minor, Bct); 3.86 (s, 3H
minor, OCH3); 3.83 (s, 3H major, OCH3); 3.76 (s, 1H
minor, OH); 3.52 (s, 1H major, OH); 2.83 (s, 1H major,
CꢀH); 2.79 (s, 1H minor, CꢀH)). IR (KBr) w (cm−1): w
(OH) 3513, 3293; w (CꢀO) (Cr) 1959, 1872. MS m/z 324
M+, 307 (M–OH−)+, 240 (M–3CO)+, 171 [M–
Cr(CO)3–OH]+ Calc.: 324.0090. Found: 324.0086.
15a 1H-NMR (CDCl3) l (ppm): 7.37 (m, 11H,
PhꢁCH); 7.00 (d, 1H, ꢁCH J=16 Hz); 6.51 (d, 1H,
Bct); 5.58 (t, 1H, Bct); 4.85 (dd, 2H, Bct); 3.18 (s, 3H,
OCH3); 2.60 (s, 1H, OH). IR (KBr) w (cm−1): w (OH)
3540; w (CꢀO) (Co) 2091, 2055, 2032; w (CꢀO) (Cr)
1965, 1890, 1862. MS m/z 762 M+, 745 (M–OH−)+,
594 (M–6CO)+, 510 (M–9CO)+, 458 (M–9CO–
Cr)+, Calc.: 761.9075. Found: 761.9076.
[7] S.G. Davies, T.J. Donohoe, J.M.J. Williams, Pure Appl.
Chem. 64 (1992) 379. S.G. Davies, L.M.A.P.B. Correia, J.
Chem. Soc. Chem. Commun. 15 (1996) 1803.
[8] S.G. Davies, T.J. Donohoe, Synlett (1993) 323.
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46 (1990) 6011. S.G. Davies, G.L. Goodfellow, K.H. Sutton,
Tetrahedron Asymmetry 3 (1992) 1303. S.G. Davies, O.M.L.R.
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[11] K. Nicholas, Acc. Chem. Res. 20 (1986) 207. N.E. Shore, in:
B.M. Trost (Ed.), Comprehensive Organic Synthesis, vol. 5,
Pergamon, Oxford, 1991, pp. 1037–1064.
[12] J. Gore, R. Baudouy, Tetrahedron Lett. 43 (1974) 3743. B.
Grant, C. Djerassi, J. Org. Chem. 39 (1974) 963.
15b 1H-NMR (CDCl3) l (ppm): 7.36 (m, 11H,
PhꢁCH); 6.60 (d, 1H, ꢁCH J=1.6 Hz); 5.72 (d, 1H,
Bct); 5.34 (t, 1H, Bct); 5.28 (d, 1H, OH J=1.65 Hz);
4.88 (d, 1H, Bct); 4.76 (t, 1H, Bct); 3.39 (s, 3H, OCH3).
IR (KBr) w (cm−1): w (OH) 3508; w (CꢀO) (Co) 2090,
2054, 2022; w (CꢀO) (Cr) 1957, 1881, 1873.
[13] T. Cuvigny, H. Normant, Bull. Soc. Chim. Fr. (1964) 2000. H.
Normant, Angew. Chem. Int. Ed. Engl. 6 (1967) 1046.
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ton, J.E. Mathews, R.S. Huber, J.P. Davidson, J. Org. Chem.
62 (1997) 9379.
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Guide, Chemical Crystallography, University of Oxford, Ox-
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