Regio- and stereoselective double addition of anionic C-nucleophiles to cobalt-stabilized acetylenedicarbaldehyde

Article abstract of DOI:10.1002/ejoc.200200593

Though intrinsically unstable, Gorgues' acetylenedicarbaldehyde is an appealing, highly functional C4 synthon, which can be stabilized by η² complexation to a Co₂(CO)₆ unit. In contrast to the homologous dibenzoylacetylene complex, it can be used as a normal, doubly electrophilic, non-conjugated γ-dicarbonyl substrate toward alkyl-, aryl-, and alkynyllithium compounds or magnesium bromides; these anionic C-nucleophiles do not predominantly attack at the metal-carbonyl center. The 1,4-dialkyl- and 1,4-diphenylbut2-yne-1,4-diol products are obtained with significant meso/ dl diastereoselectivity (4-66% de), which can be explained by a simple model based on X-ray diffraction data and MM calculations. The alkyl- and arylmagnesium bromide reactants are more selective than their lithium counterparts. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.

Full text of DOI:10.1002/ejoc.200200593

FULL PAPER
Regio- and Stereoselective Double Addition of Anionic C-Nucleophiles to
Cobalt-Stabilized Acetylenedicarbaldehyde
[a]
[a]
[a]
[a]
`
Christine Sui-Seng, Michele Soleilhavoup, Luc Maurette, Christine Tedeschi,
Bruno Donnadieu,[a] and Remi Chauvin*[a]
Keywords: Alkynes / Cobalt / Diastereoselectivity / Nucleophilic addition
Though intrinsically unstable, Gorgues’ acetylenedicarbal- metal-carbonyl center. The 1,4-dialkyl- and 1,4-diphenylbut-
dehyde is an appealing, highly functional C4 synthon, which
can be stabilized by η2 complexation to a Co2(CO)6 unit. In
contrast to the homologous dibenzoylacetylene complex, it
can be used as a normal, doubly electrophilic, non-conju-
gated γ-dicarbonyl substrate toward alkyl-, aryl-, and alky-
2-yne-1,4-diol products are obtained with significant meso/
dl diastereoselectivity (4−66% de), which can be explained
by a simple model based on X-ray diffraction data and MM
calculations. The alkyl- and arylmagnesium bromide reac-
tants are more selective than their lithium counterparts.
nyllithium compounds or magnesium bromides; these ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
anionic C-nucleophiles do not predominantly attack at the
Germany, 2003)
Introduction
electrophilic center in complexes 4 and 6 gives rise to a
chemical competition between organic carbonyl groups (li-
mit form A) and metal carbonyl groups (limit form B,
Scheme 1). This ambiguity is accompanied by further ques-
tions regarding the mono/bis selectivity, and meso/dl stereo-
selectivity.
Despite its potential strategic interest in retrosynthetic
schemes of symmetrical functional targets, the instability of
acetylene dicarbaldehyde 1, though challenged by Gorgues,
has limited its use in organic synthesis.[1] A stable Co2(CO)6
complex (4) has been prepared by Gorgues and Le Marou-
ille from the Co2(CO)6 complex 3 of the diacetal 2.[2,3] Re-
actions of 4 have been described with amines,[4] phosphorus
ylides,[5] and enol ethers.[6] The numerous applications of
the Co2(CO)6-activated substitution of oxypropyne deriva-
tives (Nicholas reactions of propargylic alcohols, ethers, es-
ters,[7] and acetals[8]) involve formally uncharged nucleo-
philes[9] (except borohydrides[10]) in either monopropargylic
or bispropargylic versions.[6,11] Although Co2(CO)6 com-
plexes of oxopropyne derivatives (alkynyl ketones and alde-
hydes) react with neutral nucleophiles (e.g., oxazaborolid-
ine-BH3 complexes,[12] silylenol ethers[6]), examples of ad-
dition of ligands of anionic C-nucleophiles, such as lithium
enolates[13a] and very recently Grignard reagents,[13b] to ace-
tylenic aldehydes are rare. Here, a parent study was under-
taken with the bispropargylic dialdehyde complex 4 and the
non-enolizable bispropargylic diketone complex 6.
Scheme 1. Formal pairs of electrophilic sites of Co2(CO)6 com-
plexes of diacylacetylenes.
Results
Complex 6 was readily prepared from dibenzoylacetylene
5 and Co2(CO)8.[6] While reaction of 6 with anionic alkyl-
or alkynyllithiums produced intractable material, its reac-
tion with ethylmagnesium bromide led to a mixture of de-
complexation product 5, reduced product 7a,[14] and un-
changed starting material 6. Attempts to improve the selec-
tivity by addition of CeCl3 were unsuccessful.[15a] In the
presence of BF3·OEt2, however, the reaction afforded a mix-
ture of reduction product 7a and acylation product 7b.[16]
The formation of 7a is a consequence of the long-recog-
nized reducing power of Grignard reagents.[15] A plausible
mechanism for the formation of 7b is proposed in Scheme 2.
Actually, this observation is consistent with recent theoreti-
cal results on Nicholas’ propargylic cations, which show
The possibility of 1,2- vs. 1,4-regiochemical competition
in nucleophilic attacks of free diacylacetylenes 1 and 5 is a
priori removed by complexation of the triple bond to
Co2(CO)6. Nevertheless, the introduction of a new kind of
[a]
Laboratoire de Chimie de Coordination du CNRS,
205 Route de Narbonne, 31077 Toulouse cedex 4, France
Fax: (internat.) ϩ 33-(0)5 61 55 30 03
E-mail: chauvin@lcc-toulouse.fr
Supporting information for this article is available on the
WWW under http://www.eurjoc.org or from the author.
Eur. J. Org. Chem. 2003, 1641Ϫ1651
DOI: 10.1002/ejoc.200200593
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1641

R. Chauvin et al.
FULL PAPER
that whereas hard neutral nucleophiles are prone to react at
the carbenium center, softer nucleophiles, such as car-
banions, should react at the carbonylmetal center.[17] In
comparison, free diketone 5 reacted with two equivalents of
EtMgBr in the presence of either BF3·OEt2 or CeCl3 to
afford the expected diethylation product 7c (seemingly as a
single diastereoisomer according to its 13C NMR spec-
trum), along with reduction byproduct 10.
Figure 1. Detailed X-ray crystal structure of complex 4 (triclinic,
˚
PϪ1); selected bond lengths in A and bond angles in degrees:
Co(1)ϪC(1) ϭ 1.924(3); Co(1)ϪC(2) ϭ1.969(3); Co(1)ϪCo(2) ϭ
2.4782(8); Co(2)ϪC(2)
ϭ 1.921(3); Co(2)ϪC(1) ϭ 1.972(3);
O(1)ϪC(3) ϭ 1.198(4); O(2)ϪC(4) ϭ 1.206(4); C(1)ϪC(2) ϭ
1.359(4); C(1)ϪC(3) 1.460(4); C(2)ϪC(4) ϭ1.453(4);
ϭ
C(1)ϪC(2)ϪC(4)
ϭ 142.2(3); C(2)ϪC(1)ϪC(3) ϭ 139.8(3);
Scheme
2.
Synthesis
and
reactivity
of
the
O(1)ϪC(3)ϪC(1) ϭ 124.7(3); O(2)ϪC(4)ϪC(2) ϭ 125.5(3).
Co2(CO)6Ϫdibenzoylacetylene complex with ethyl Grignard re-
agent. A plausible mechanism for the carbonylation/reduction of 6
to 7b is proposed: After nucleophilic attack at a metal carbonyl
and reductive elimination, the negative charge is stabilized in the
β-diketonate fragment; reduction by the primary Grignard re-
agent[15b] brings about the loss of a Co2(CO)5 unit, as suggested in
related processes.[6]
While no selective electrophilicity is observed in complex
6, regioselectivity is restored at the organic carbonyl centers
in complex 4. Indeed, two equivalents of various alkyl-,
aryl- and alkynyllithium reactants added at the aldehyde
functions of 4 to afford bisadducts 9aϪe in moderate yields,
likely via the lithium salts of monoadducts 8aϪe (Scheme 4,
Table 2). Although conversion of 4 to bisadduct 9 is far
from quantitative (the RLi reactant is likely consumed in
residual attack at metal carbonyl centers), monoaddition
product 8 has been detected for alkyl nucleophiles only
(R ϭ Me, Et).
In contrast to the typical electronic and steric deacti-
vation of the ketoyl functions in complex 6, the study of
the strain-free electrophilicity of the formyl functions in
complex 4 deserved separate investigations. According to
Gorgues and Meyer’s reports,[2,3] diacetal 2 was prepared
from acetylene dimagnesium bromide and diethylphenylor-
thoformate. This diacetal behaves as a normal alkyne ligand
of transition metals.[18] In particular, 2 was readily con-
verted into its Co2(CO)6 complex 3. Formolysis of 3 af-
forded the dialdehyde complex 4 in quantitative yield.[2,3]
(Scheme 3).
1
According to the H NMR spectrum of the crude mate-
rial, one of the epimers of 9a was predominantly formed in
12% de. Crystallization from chloroform and analysis by X-
ray diffraction allowed the assignment of a meso configura-
tion to the major epimer of 9a (Figure 2).[19]
The sp3-hybridized carbanion of ethyllithium also reacted
with 4 to give 9b in 23% yield and 4% de. Again, X-ray
diffraction studies (Figure 2) assigned a meso configuration
to the major epimer of 9b. The reaction, however, of tert-
butyllithium with 4 did not yield the expected adduct 9c,
most likely because of steric hindrance.
In contrast, the sp2-hybridized carbanion of phenyllith-
ium reacted with 4 to produce 9d in better isolated yield
(37%) and stereoselectivity (54% de). Again, the meso con-
figuration was assigned to the major epimer by X-ray crys-
Scheme 3. Gorgues’ synthesis of complex 4.
Complex 4 exhibits spectroscopic properties of a classical tallography (Figure 2). For comparison, an authentic
‘‘conjugated’’ aldehyde (νHCϭO ϭ 1671 cmϪ1, δCHO
ϭ
sample of complex 9d was prepared from Co2(CO)8 and
1
10.30 ppm, δCHO ϭ 191.3 ppm, JC,H ϭ 187.1 Hz). Full X- 1,4-diphenylbut-2-yne-1,4-diol 10, which was obtained by
ray diffraction data are consistent with partial data pre- reaction of bis(trimethylsilyl)acetylene with two equivalents
viously reported.[2] As in the case of 6,[6] the crystal struc- of benzaldehyde in the presence of catalytic amounts of KF
ture of 4 displays no hint of a possible [Co···CϩϪOϪ] inter- and [18]crown-6.[20] The overall stereoselectivity of the lat-
action (Figure 1, Table 1).
ter method (dl:meso, 63:37) is reversed with respect to that
1642
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org Eur. J. Org. Chem. 2003, 1641Ϫ1651

Double Addition of Anionic C-Nucleophiles to Cobalt-Stabilized Acetylenedicarbaldehyde
FULL PAPER
Table 1. Crystal data and structure refinement for complex 4 (Refinement method: Full-matrix least-squares on F2)
3
˚
Empirical formula
Formula mass
C10H2Co2O8
367.98
293(2)
V (A )
Z
620.6(2)
2
1.969
2.706
360
2.15 to 26.16
Ϫ9 Յ h Յ 9
Ϫ11 Յ k Յ 11
Ϫ11 Յ l Յ 11
R(int)
0.0325
Completeness
to 2θ ϭ 26.16
No of data
Ϫ restraints
Ϫ parameters
R1 [I Ͼ 2σ(I)]
wR2 [I Ͼ 2σ(I)]
R1 (all data)
wR2 (all data)
Temperature (K)
ρ (g cmϪ3
)
91.6%
2275
0
˚
λ (A)
0.71073
triclinic
PϪ1
7.4070(10)
8.990(2)
9.599(2)
82.84(3)
83.54(3)
79.32(3)
Abs. coef. µ(mmϪ1
F(000)
)
Cryst. syst.
Space group
θ range (deg)
Index ranges
189
˚
a (A)
0.0287
0.0729
0.0369
0.0797
0.362
Ϫ0.362
˚
b (A)
˚
c (A)
α (deg)
β (deg)
γ (deg)
Reflections
Ϫ collected
Ϫ unique
Ϫ3
˚
˚
5743
2275
ρmax (e·A
ρmin (e·A
)
Ϫ3
)
Scheme 4. Nucleophilic addition to a protected acetylenedicarbal-
dehyde equivalent.
Table 2. Preparation of 9 from 4 and two equivalents of organoli-
thium reactant
RLi
9:8[a] % de % yield
a MeLi
b EtLi
91:09 12[a] 22
94:06 04[a] 23
c
tert-BuLi
Ϫ
Ϫ
Ϫ
d PhLi
100:0 54[a] 37
100:0 n.d.[b] 09
100:0 n.d.[c] 63
100:0 n.d.[d] 16
e
f
PhCϵCLi
Me3Si-CϵCLi
g rac-(MeC2)CPh(OMe)-CϵCLi (11g)
h rac-(Me3SiC2)CPh(OMe)ϪCϵCLi (11h) 100:0 n.d.[d] 15
i
(Me3SiC2)CH(OTHP)ϪCϵCLi (11i)[e]
100:0 n.d.
15
[a]
[b]
Determined by 1H NMR spectroscopy.
Integration of two
slightly split signals in a resolved 13C NMR spectrum afforded a
[c]
rough estimate of 20 Ϯ 10%.
Formal integrations of four split
signals in a resolved 13C NMR spectrum gave the same excesses
[d]
of the main signals, 22%.
diastereoisomers could not be resolved by NMR spectroscopy.
50:50 mixture of racemic epimers.
Signals of the a priori possible six
[e]
of the former one (dl:meso, 23:77). Assuming that the
stereochemistry of 10 was preserved during its com-
plexation with Co2(CO)6, the preparation of free ligand 10
thus favored the dl epimer in 26% de.
sp-Hybridized carbanions also reacted with 4. In accord-
ance with the moderate nucleophilicity of acetylide reac-
Figure 2. X-ray-crystal structures of meso complexes 9b and 9d;
˚
selected bond lengths in A and bond angles in degrees for 4 (tri-
˚
clinic, PϪ1); selected bond lengths in A and bond angles in degrees.
meso-9b: Co(1)ϪC(1)
Co(1)ϪCo(2)
ϭ
1.961(2); Co(1)ϪC(2)
ϭ
1.949(2);
1.960(2);
ϭ
2.4798(10);
Co(2)ϪC(2) ϭ
Co(2)ϪC(1) ϭ 1.956(2); O(1)ϪC(3) ϭ 1.441(3); O(2)ϪC(6) ϭ
tants, reaction of 4 with PhC2Li gave complex 9e in rather 1.439(3); C(1)ϪC(2)
ϭ
1.348(3); C(2)ϪC(3)
ϭ
1.492(3);
C(1)ϪC(6) ϭ1.487(3); C(3)ϪC(4)
ϭ
1.520(3); O(1)ϪH(1) ϭ
low yield (9%). Stronger nucleophilicity, however, is re-
stored in Me3SiC2Li, which afforded complex 9f in 63%
yield. The diastereoselectivity of the nucleophilic attack by
acetetylides could not be determined in a reliable fashion.
Indeed, because of the presence of paramagnetic impurities
released from cobalt carbonyl units, it was not possible to
resolve the two epimers of 9e or 9f by 1H NMR spec-
O(2)ϪH(2) ϭ 0.93(7); C(3)ϪC(5) ϭ1.529(12); C(2)ϪC(1)ϪC(6) ϭ
136.56(19); C(1)ϪC(2)ϪC(3) ϭ 137.41(19); O(1)ϪC(3)ϪC(2) ϭ
107.67(17);
O(2)ϪC(6)ϪC(7)
ϭ
107.93(17).
meso-9d:
Co(1)ϪC(1) ϭ 1.942(8); Co(1)ϪC(2) ϭ 1.943(8); Co(1)ϪCo(2) ϭ
2.4678(18); Co(2)ϪC(2) ϭ 1.945(8); Co(2)ϪC(1) ϭ 1.923(7);
O(1)ϪC(3) ϭ 1.406(11); O(2)ϪC(4) ϭ 1.423(10); C(1)ϪC(2) ϭ
1.328(11); C(2)ϪC(3)
O(1)ϪH(1) ϭ 0.70(3); O(2)ϪH(2) ϭ 0.73(3); C(3)ϪC(4) ϭ1.520(3);
C(2)ϪC(1)ϪC(4) 133.0(7); C(1)ϪC(2)ϪC(3) 137.1(7);
ϭ
1.540(11); C(1)ϪC(4) ϭ1.530(10);
ϭ
ϭ
troscopy. Moreover, despite several attempts, crystals of 9e O(1)ϪC(3)ϪC(2) ϭ 108.0(7); O(2)ϪC(6)ϪC(7) ϭ 107.0(6).
Eur. J. Org. Chem. 2003, 1641Ϫ1651
www.eurjoc.org
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1643

R. Chauvin et al.
FULL PAPER
and 9f were not suitable for X-ray crystal structure determi- their values of de are improved from 12% to 22% and from
nation. 4% to 60%, respectively. To a lesser extent, switching from
Symmetrical carbinol-skipped triynes and pentaynes are PhLi to PhMgBr also resulted in improved yield and stereo-
key intermediates for the synthesis of functional ring car- selectivity in 9d and 9e. Thus, for sp3- and sp2-hybridized
bomers of cycloalkanes or pericyclynes.[21] As a first appli- carbanions, the magnesium bromide salts are more selective
cation of the results above, tertiary and secondary carbinol- at the aldehyde function than their lithium counterparts,
skipped pentayne complexes 9g, 9h, and 9i were isolated in but overall, however, are less reactive. Indeed, appreciable
one step, albeit in moderate yields, by reaction of 4 with the amounts of monoadducts 8 were obtained.
lithium salts of diynes 11g, 11h, and 11i, respectively
For sp-hybridized carbanions, the cation effect is much
(Table 2, Scheme 5).[22] The secondary carbinol-tetra- weaker. It is even reversed for trimethylsilylacetylide, which
skipped pentayne complex 11i was found to be particularly afforded 9f in lower yield (15%) than did its lithium
stable with respect to its tautomeric rearrangements. In all counterpart (63%), and even led repeatedly to the recovery
three cases, the signals of possible stereoisomers could not of unchanged complex 4.
be assigned in NMR spectra and the stereoselectivity was
not determined. It is noteworthy, however, that all carbon
atoms of a given chemical type give sharp 13C NMR reson-
ances, but without resolved stereochemical fine structures;
Discussion
as previously noted for related structures, the remote dialky-
The origin of the stereochemical induction is tentatively
nyl stereogenic centers appear to be virtually indepen-
proposed on the basis of a simple model. Let us first recall
dent.[21]
that the bending around the alkyne sp-carbon atoms
brought about by Co2(CO)6 complexation (ca. 180° Ϫ
145° ϭ 35°) draws the two reacting propargylic carbon
atoms nearer. Whereas diacylacetylene complexes 4 and 6
display quasi-C2 molecular symmetry in their crystals,
meso-1,4-disubstituted but-2-yne-1,4-diol complexes 9a, 9b,
and 9f display quasi-Cs molecular symmetries. In the latter
complexes, the short intramolecular HO···OH distances (ca.
˚
2.70 A) reveal intramolecular hydrogen bonding, which is
evidenced further by the positions of the refined OH pro-
˚
tons. In 9b, for example, the values OϪH ϭ 0.93 A,
Scheme 5. Preparation of carbinol-skipped pentanyne complexes
from lithium 1,4-heptadiynes and complex 4.
˚
[H···O] ϭ1.78 A and [OϪH···O] ϭ 172.8°, are typical for
hydrogen bonds. Replacement of the OH proton for Mϩ
(Liϩ or MgBrϩ) gives a likely approximate structure for the
Both the yields and diastereoselectivities of these reac-
tions should depend on the countercation of the nucleoph-
ile. Indeed, we found that reactions of organomagnesium
bromides with 4 gave compounds 9 with higher isolated
yields and diastereoselectivities than do the corresponding
reactions of organolithiums (Table 3). This feature is par-
ticularly interesting for alkyl nucleophiles, since the yields
of 9a and 9b are both improved from ca. 20% to 80%, and
metal salt of the primary monoaddition product 8. In this
structure, the cation acts as a Lewis acid for the second
aldehyde function, thus closing a seven-membered metalla-
cycle by a CHϭOǞ[M] dative bond. Assuming that the
first added nucleophile (e.g., ethylide) prefers a pseudo-
equatorial orientation (anti to the triple bond), two kinds
of conformations can be envisioned (Scheme 6): a quasi-Cs
conformation (pseudo-chair C[M] or pseudo-boat B[M])
and a quasi-C2 conformation (twisted, T[M]), which upon
exo attack by the second nucleophile would lead to the
meso and dl epimer of 9, respectively.
Table 3. Preparation of 9 from 4 and two equivalents of organom-
agnesium bromide reactant (compared with the preparation from
the corresponding organolithium reactant)
RMgBr
% conver- 9:8
sion[a]
% de[a] % isolated
yield
a
b
d
e
f
MeMgBr
EtMgBr
PhMgBr
Ph-CϵCMgBr
Me3Si-CϵCMgBr 62
100
100
100
100
87:13 22(12) 81 (22)
73:27 60(04) 71 (23)
88:12 66(54) 48 (37)
52:48 n.d.[b]
67:33 n.d.
16 (09)
15 (63)
[a] Determined by 1H NMR spectroscopy (see Exp. Sect. The values
of de in brackets were obtained from reactions with lithium nucleo-
Scheme 6. Putative conformations of the intermediate lithium salt
of primary products 8, and associated stereochemistries of the se-
cond nucleophilic attack by NuM. M ϭ Li, MgBr. The first entered
Nu group is assumed to lie in a pseudo-equatorial position.
[b]
1
philes (see Table 2)).
Although the H NMR spectra could not
be resolved, the separation of the epimers by TLC allowed for the
estimation: 36 Ͻ de ഠ 68% (see Exp. Sect.).
1644
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2003, 1641Ϫ1651

Double Addition of Anionic C-Nucleophiles to Cobalt-Stabilized Acetylenedicarbaldehyde
FULL PAPER
To fit the experimental conditions closer, the model was configuration of the asymmetric propargylic carbinol center
refined by adding two THF ligands on lithium and one would allow the preservation of the stereochemical infor-
THF ligand on magnesium bromide. With this model, mation gained in the first addition step. Secondly, owing
ESFF molecular mechanic calculations showed that in both to the availability of various known methods for oxidative
cases [i.e., M ϭ Li(THF)2 and M ϭ MgBr(THF)] the mini- deprotection of Nicholas’ cobalt complexes,[24] the triple
mum-energy structures had quasi-Cs conformations, while bond of the symmetrical 1,4-difunctional but-2-yne deriva-
no quasi-C2 conformations exist as minima. The minimum tives could be used in further classical functionalization
Cs conformations are of the pseudo-boat type B[M] (Fig- (e.g., semi-hydrogenation to cis-meso bisallylic diol deriva-
ure 3).
tives). Thirdly, a cyclizing version of this methodology can
be applied to the synthesis of five- and six-membered ring
carbomers of carbocycles, which will be reported shortly.[25]
Experimental Section
THF and diethyl ether were distilled over Na/benzophenone. Pen-
tane and dichloromethane were distilled over P2O5. Commercial
organomagnesium bromide and organolithium reactants were used:
EtMgBr (3  in diethyl ether), MeMgBr (3  in diethyl ether),
PhMgBr (3  in ether), nBuLi (2.5  in hexanes), MeLi (1.6  in
ether), and PhLi (1.6Ϫ1.8  in cyclohexane/diethyl ether). Solu-
tions of ethyllithium in diethyl ether were prepared according to a
described procedure.[26] Alkyllithium solutions were titrated with
2,2,2Ј-trimethylpropionanilide.[27] Dibenzoylacetylene 5,[28] its com-
plex 6,[6] and racemic 1-trimethylsilyl-3-hydroxy-3-phenylpenta-1,4-
diyne 11h,[21] were prepared according to described procedures.
TLC was performed on a 60F254 silica gel phase. Mass spectra
(DCI/NH3) were recorded on a Nermag R10Ϫ10H apparatus. IR
spectra were recorded on a PerkinϪElmer Spectrum GX FT-IR
spectrometer using a CaF2 cell. 1H NMR spectra were recorded on
Bruker AC 200, AM 250, and AMX 400 spectrometers at 200, 250,
and 400 MHz, respectively; 13C spectra were recorded at 50 MHz,
62.9, and 100 MHz, respectively. Positive chemical shifts at low
field are expressed in ppm by internal reference to TMS. Samples
of cobalt complexes for NMR spectroscopy were filtered through
celite before recording their spectra.
Figure 3 MM(ESFF) model for the intermediate resulting from the
first attack of acetylene dicarbaldehyde complex 4 by EtLi [M ϭ
Li(THF)2] and EtMgBr [M ϭ MgBr(THF)]. [Co] ϭ Co(CO)3. In
both cases, a single minimum conformation is found. They are of
pseudo-boat type, B[M] (Scheme 6). These conformations account
for the observed meso diastereoselectivity of the nucleophilic attack
by the second equivalent of EtM.
Acetylenedicarbaldehyde Bis(diethyl acetal) Complex 3: A solution
of 1,1,4,4-tetraethoxybut-2-yne 2 (3.56 g, 15.5 mmol) in diethyl
ether (30 mL) was poured into a solution of dicobaltoctacarbonyl
(5.30 g, 15.5 mmol) in diethyl ether (30 mL). After stirring for 3 h,
the solution was filtered and the solvents were evaporated to dry-
ness. Complex 3 was obtained as a brown oil (7.61 g, 95%). TLC
(heptane/EtOAc, 7:3): Rf ϭ 0.50. MS (DCI/NH3): m/z ϭ 534 ([M
ϩ NH4]ϩ), 471 ([MH Ϫ EtOH]ϩ). IR (CDCl3): νsp3-CH ϭ 2980 (m),
2931 (w), 2875 (w) cmϪ1; νCϵO ϭ 2097 (s), 2060 (vs), 2034 (vs)
Since the sterically favored exo attack of the remaining
aldehyde function in the B[M] conformation would indeed
provide a meso configuration for the bisaddition product 9,
the experimental meso stereoselectivity is explained simply
by this model.
1
cmϪ1. H NMR (CDCl3, 250 MHz): δ ϭ 1.22 (t, 12 H, CH3); 3.73
(q, 8 H, CH2); 5.44 [s, 2 H, CH(OEt)2] ppm. 13C NMR (CDCl3,
1
62.9 MHz): δ ϭ 13.95 (q, JC,H ϭ 125.9 Hz, CH3), 63.27 (dt-like,
Conclusion
2
1JC,H ϭ 141.2, JC,H ϭ 3.9 Hz, CH2O), 91.68 (s, CϵC), 101.81 (d,
1JC,H ϭ 161.5 Hz, CH(OEt)2], 199.47 [br s, Co2(CO)6] ppm.
Complex 4 reacts quite efficiently with alkyl and aryl
Grignard reagents. The lower reactivity of alkynyl nucleo-
philes has been challenged with Carreira’s zinc reactant, but
without success.[23] Nevertheless, though optimization of
yields is required in a few cases, the present results show
that use of this attractive, highly functional C4 synthon is
henceforth possible. These compounds are potentially valu-
able at three levels. Firstly, the introduced Co2(CO)6 metal
core could be reused as an activator for a further Nicholas
reaction of the primary 1,4-butyndiols products with neu-
Acetylenedicarbaldehyde Complex 4: Bis(diethyl acetal) complex 3
(7.60 g, 14.73 mmol) was dissolved in formic acid (120 mL) at 0 °C.
After stirring for 2.5 h between 0 °C and room temp., the solution
was filtered, evaporated, and dried under vacuum for 1.5 h. The
red-brown residue was dissolved in CH2Cl2 and the solution was
filtered through a small pad of silica gel. The filtrate was again
evaporated, the residue dissolved in diethyl ether and the resulting
solution filtered though celite. After evaporation, complex 4 was
obtained as a red-orange microcrystalline solid (4.80 g, 89%).
TLC (pentane/Et2O, 9:1): Rf ϭ 0.52. MS (DCI/NH3): m/z ϭ 386
tral C-nucleophiles, such as enol ethers; overall retention of ([M ϩ NH4]ϩ), 369 ([MH]ϩ). IR (CDCl3): νΟCϪH ϭ 2814 (w) cmϪ1
;
Eur. J. Org. Chem. 2003, 1641Ϫ1651
www.eurjoc.org  2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 1645

R. Chauvin et al.
FULL PAPER
νCϵO ϭ 2114 (s), 2081 (vs), 2057 (vs) cmϪ1; νHCϭO ϭ 1671 (s) 1H NMR (CDCl3, 200 MHz): δ ϭ 0.96 (m, 6 H, CH3), 1.95 (m ഠ
cmϪ1. 1H NMR (CDCl3, 250 MHz): δ ϭ 10.30 (s, CHO) ppm. 13C 2q, 4 H, diastereoisotopic CH2Me), 3.12 (br, 2 H, OH), 7.27Ϫ7.39
3
NMR (CDCl3, 62.9 MHz): δ ϭ 85.88 (d, JC,H ϭ 36 Hz, CϵC-
(m, 6 H, o-, m-CH), 7.58Ϫ7.64 (m, 4 H, o-CH) ppm. 13C{1H}
1
CHO), 191.30 (d, JC,H ϭ 187 Hz, CHO), 199.47 [s, Co2(CO)6] NMR (CDCl3, 50 MHz): δ ϭ 9.04 (CH3), 38.21 (CH2Me), 73.81
ppm. Recrystallization from CH2Cl2/pentane afforded crystals of 4 (CHOH), 88.16 (CϵC), 125.40, 127.98 (o-, m-CH), 127.49 (p-CH),
suitable for an X-ray structure determination.
Reaction of Complex with EtMgBr: BF3·OEt2 (0.097 mL,
144.12 (ipso-C) ppm. Further elution gave 7c as a mixture with the
reduced side product 10, identified by comparison with the 1H
NMR spectrum of an authentic sample (see below).
6
0.77 mmol) was added by syringe into a solution of diketone com-
plex 6 (0.200 g, 0.385 mmol) in diethyl ether (20 mL) at Ϫ78 °C.
After stirring for 1.5 h, a solution of EtMgBr in diethyl ether (3 ,
0.256 mL, 0.77 mmol) was added by syringe. The resulting deep-red
solution was kept at Ϫ15 °C for 17 h, then quenched with saturated
aqueous NH4Cl (20 mL). The organic layer was separated, washed
with aqueous NH4Cl and the solvents evaporated to dryness. Three
products were identified in the 1H NMR spectrum of the crude
material: starting material 6 (73%), reduced product 7a (5%), and
acylated product 7b (22%). The reddish residue (0.107 g) was chro-
matographed over silica gel eluting with pentane/diethyl ether mix-
tures of increasing polarity (starting at 95:5). After recovering un-
changed 6, triketone 7b was obtained as a yellow oil (0.007 g, ca.
6%) containing 20% of reduced product 7a (δH ϭ 3.46 ppm).[14]
TLC (pentane/Et2O, 1:1): Rf ϭ 0.72. MS (DCI/NH3): m/z ϭ 312
1-Trimethylsilyl-3-methoxy-3-phenylhexa-1,4-diyne (MeC2)(OMe)-
PhC(C2SiMe3): This compound was obtained as a byproduct
formed during the preparation of 11h by exhaustive methylation of
1-trimethylsilyl-3-hydroxy-3-phenylpenta-1,4-diyne (HC2)PhC(OH)-
(C2SiMe3) with CH3I.[21]
TLC (hexane/EtOAc, 9:1): Rf
ϭ
0.67. 1H NMR (CDCl3,
250 MHz): δ ϭ 0.21 [s, 9 H, Si(CH3)3], 1.93 (s, 3 H, ϵC-CH3), 3.44
(s, 3 H, OCH3), 7.33Ϫ7.37 (m, 3 H, m- and p-CH), 7.75 (dd,
3
2JH,H ഠ 7.8, JH,H ഠ 1.7 Hz, 2 H, o-CH) ppm. 13C NMR (CDCl3,
1
62.9 MHz): δ ϭ Ϫ0.19 [q, JC,H ϭ 120 Hz, Si(CH3)3], 3.90 (q,
1
1JC,H ϭ 132 Hz, ϵCϪCH3), 52.64 (q, JC,H ϭ 143 Hz, OCH3),
71.97 (s, COMe), (76.49Ϫ77.51, masked signal of ϵCϪMe ?), 83.22
(s, CϵCMe), 91.17 (s, CϵCϪSiMe3), 102.35 (s, ϵCϪSiMe3),
1
1
126.60 (dt-like, JC,H ϭ 160 Hz, m-CH), 128.21 (dm, JC,H
ϭ
1
160 Hz, o-CH), 128.51 (dm, JC,H ϭ 161 Hz, p-CH), 141 (s, ipso-
C) ppm.
([M ϩ NH4]ϩ), 295 ([MH]ϩ). IR (CDCl3): νEtCϭO ϭ 1723 (s) cmϪ1
PhCϭO ϭ 1675 (s br) cmϪ1; νArCϭC ϭ 1598 (m), 1581 (w), 1449 (m)
;
ν
cmϪ1. 1H NMR (CDCl3, 400 MHz): δ ϭ 1.07 (t, 3JH,H ϭ 7.2 Hz, 3
H, CH3), 2.63 (second-order m, from the decoupling of the Me
resonance at δ ϭ1.07 ppm: 2JH,H ϭ 18.8 Hz, 2 H, OϭC-CHH-Me),
2.56 (second-order m, from the decoupling of the Me resonance at
3-Methoxy-3-phenylhexa-1,4-diyne (11g): 1-Trimethylsilyl-3-meth-
oxy-3-phenylhexa-1,4-diyne (2.30 g, 8.97 mmol) was dissolved in
methanol (100 mL) at room temp. and K2CO3 (18.54 g, 134 mmol)
was added. After stirring for 4 h the mixture was filtered and the
solution was diluted with diethyl ether, washed with water, and then
the solvents were evaporated to dryness. The crude residue (1.71 g)
was chromatographed over silica gel (pentane/acetone, 95:5). Diyne
11g was obtained as an orange oil (1.17 g, 71%).
2
δ ϭ 1.07 ppm: JH,H ϭ 18.8 Hz, 2 H, OϭC-CHH-Me), 3.62 (dd,
2JH,H ϭ 18.3, 3JH,H ϭ 6.2 Hz, 1 H, CHHCOPh), 3.85 (dd, 2JH,H ϭ
3
3
18.3, JH,H ϭ 7.0 Hz, 1 H, CHHCOPh), 5.34 (t-like, JH,H
ഠ
3
6.6 Hz, 1 H, CHCOEt), 7.49 (t-like, JH,H ഠ 7.8 Hz, 2 H, m-CH),
7.55 (t-like, JH,H ഠ 7.7 Hz, 2 H, m-CH), 7.61 (t-like, JH,H
7.3 Hz, 1 H, p-CH), 7.66 (t-like, JH,H ഠ 7.3 Hz, 1 H, p-CH), 8.01
3
3
ഠ
TLC (pentane/acetone, 95:5): Rf ϭ 0.75. MS (DCI/NH3) m/z ϭ 202
([M ϩ NH4]ϩ), 185 ([MH]ϩ), 170 ([M ϩ NH4 Ϫ MeOH]ϩ), 153
([MH Ϫ MeOH]ϩ). C13H12O (184.2): calcd. C 84.75, H 6.57; found
C 84.57, H 6.82. 1H NMR (CDCl3, 250 MHz): δ ϭ 1.95 (s, 3 H,
ϵCϪCH3), 2.74 (s, ϵCϪH), 3.48 (s, 3 H, OCH3), 7.35Ϫ7.38 (m,
3
3
3
(d, JH,H ϭ 7.6 Hz, 2 H, o-CH), 8.11 (d, JH,H ϭ 7.6 Hz, 2 H,
o-CH) ppm. 13C{1H} NMR (CDCl3, 100 MHz): δ ϭ 8.09 (Oϭ
CCH2CH3), 36.28 (OϭCCH2Me), 38.60 (CH2COPh), 56.28
(CHCOPh), 128.66, 129.11, 129.85, 130.04 (o- and m-CH), 134.01,
134.30 (p-CH), 136.41, 136.52 (ipso-C-CO), 196.88 (Et-
COCH(Ph)CϭO), 197.53 (CH2(Ph)CϭO), 205.45 (EtCϭO) ppm.
1H and 13C assignments were confirmed by 13C 140 Hz-J-MOD,
1H-1H COSY-DQF-GS, 1H-13C 1J-HMQC, 1H-13C LR-HMQC,
3 H, m- and p-CH), 7.76 (dd, 2JH,H ഠ 7.9, 3JH,H ഠ 1.7 Hz, 2 H, o-
1
CH) ppm. 13C NMR (CDCl3, 62.9 MHz): δ ϭ 3.98 (q, JC,H
ϭ
1
132 Hz, ϵCϪCH3), 52.64 (q, JC,H ϭ 143 Hz, OCH3), 71.76 (s,
COMe), 72.48 (d, 1JC,H ϭ 254 Hz, ϵCH), 76.85 (partly masked m,
ϵCϪMe), 81.90 (d, 2JC,H ഠ 49 Hz, CϵCH), 83.87 (br s, CϵCMe),
1
and H-13C HMBC experiments.
1
1
126.63 (dt-like, JC,H ϭ 159 Hz, m-CH), 128.51 (dd, JC,H ഠ159,
2JC,H ഠ 7 Hz, o-CH), 128.88 (dt, JC,H ϭ 161, JC,H ഠ 8 Hz, p-
1
2
Reaction of 5 with EtMgBr/CeCl3, 3,6-Diphenyl-oct-4-yne-3,6-diol
(7c): A solution of EtMgBr in diethyl ether (3.0 , 0.81 mL,
2.4 mmol) was added by syringe into a solution of CeCl3 (0.60 g,
2.43 mmol) in THF (5 mL) at 0 °C. After stirring for 1.5 h, the
CH), 140.51 (s, ipso-C) ppm.
1-Trimethylsilyl-3-(2-tetrahydropyranyl)oxypenta-1,4-diyne (11i): A
mixture of racemic 1-trimethylsilylpenta-1,4-diyn-3-ol (1.006 g,
mixture was cooled to Ϫ78 °C and a solution of diketone 5 6.62 mmol), dihydropyran (1.8 mL, 20 mmol) and p-toluenesul-
(0.285 g, 1.21 mmol) in THF (5 mL) was added. The mixture was fonic acid (22.9 mg, 0.12 mmol) in toluene (40 mL) was stirred for
warmed to room temp. over 5 h, and the resulting suspension was
stirred overnight at room temp. The mixture was then cooled to
Ϫ40 °C and treated with aqueous acetic acid (10%, 10 mL). The
orange solution was extracted with diethyl ether. The ethereal
6 h at room temp. The reaction was quenched by addition of tri-
ethylamine. After removal of the solvent under reduced pressure,
dichloromethane (100 mL) and water (100 mL) were added. The
organic layer was washed with water, dried over MgSO4, and con-
phase was washed sequentially with aqueous NH4Cl, aqueous centrated to produce a 50:50 mixture of the epimers of 11i as an
NaHCO3, and brine, then dried over MgSO4 and the solvents eva-
porated to dryness. The residue (0.325 g) was chromatographed
over silica gel eluting with pentane/diethyl ether (90:10). Diol 7c
was obtained as a yellow oil (0.087 g, 24%). TLC (pentane/Et2O,
orange oil (1.212 g, 77%). IR (CDCl3) νOϪH ϭ 3308 (s) cmϪ1
νCϪH ϭ 3018, 2947, 2874, 2854 (s) cmϪ1; νCϵC ϭ 2248 (s) cmϪ1
;
;
ν
CϪSi ϭ 1252 (m) cmϪ1. MS (DCI/NH3): m/z ϭ 254 ([M ϩ NH4]ϩ).
1H NMR (CDCl3, 250 MHz): δ ϭ 0.13, 0.14 [2 s, 9 H, Si(CH3)3],
9:1): Rf ϭ 0.42. IR (CDCl3): νOϪH ϭ 3591 (s) cmϪ1; νCϪH ϭ 2974 1.48Ϫ1.81 (m, 6 H, CH2CH2CH2), 2.48, 2.51 (2 d, JH,H ϭ 2.3,
4
(s), 2938 (m) cmϪ1; νarCϭC ϭ 1601 (m), 1449 (s) cmϪ1; νCOH
1326 (m) cmϪ1. MS (DCI/NH3): m/z ϭ 312 ([M ϩ NH4]ϩ), 294
ϭ
2.4 Hz, 1 H, ϵC-H), 3.47Ϫ3.54 and 3.80Ϫ3.84 (2 m, 2 H, dia-
stereoisotopic CH2O), 4.91Ϫ4.96 (m, 1 H, CHO2), 5.13 and 5.15
([M ϩ NH4 Ϫ H2O]ϩ), 277 ([MH Ϫ H2O]ϩ), 259 ([MH Ϫ 2H2O]ϩ). (2 d, JH,H ϭ 2.3, 2.4 Hz, 1 H, CHOTHP) ppm. 13C{1H} NMR
4
1646
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2003, 1641Ϫ1651

Double Addition of Anionic C-Nucleophiles to Cobalt-Stabilized Acetylenedicarbaldehyde
(CDCl3, 62.9 MHz. Assignment from the 13C{1H} gated spec-
9a from 4 and MeLi: A solution of methyllithium in diethyl ether
FULL PAPER
trum): δ ϭ Ϫ0.37 [Si(CH3)3], 18.51, 18.70, 25.42, 29.84, 29.90 (1.6 , 0.421 mL, 0.674 mmol) was added by syringe into a solution
(CH2CH2CH2), 54.63, 54.78 (CHOTHP), 61.72, 61.99 (CH2O), of acetylene dicarbaldehyde complex 4 (0.124 g, 0.337 mmol) in
72.35, 73.34 (ϵCH), 78.76, 79.20 (CϵCϪH), 89.50, 90.47 THF (13 mL) at Ϫ78 °C. The mixture was warmed to room temp.
(CϵCϪSi), 95.08, 95.45 (CHO2), 99.23, 99.73 (ϵCϪSi) ppm.
and then stirred for 2 h. The mixture was diluted with diethyl ether
(50 mL) and then quenched and extracted with saturated aqueous
NH4Cl (50 mL). The organic phase was separated, dried over
MgSO4, and concentrated. The de (12%) was determined by decon-
volution of the 400-MHz 1H NMR spectrum of the crude material
in CDCl3 at 40 °C. The crude material was chromatographed over
silica gel (pentane/EtOAc, 7:3). Complex 9a was isolated over sev-
eral fractions with varying values of de (0.030 g, 22%). TLC (pen-
1,4-Diphenylbut-2-yne-1,4-diol (10): Bis(trimethylsilyl)acetylene
(3.94 mmol, 17.6 mmol) was added to a mixture of KF (30.7 mg,
0.53 mmol, 3 mol%) and [18]crown-6 (0.139 g, 0.53 mmol) at 0 °C.
Benzaldehyde (3.6 mL, 35.2 mmol) was then slowly added, and the
solution was heated under reflux overnight. Because of the presence
of unchanged benzaldehyde, KF (0.012 mg, 0.2 mmol) was added
again, and the mixture was heated under reflux for another 1 h.
After cooling, the solvent was evaporated and the residue (6.519 g)
tane/EtOAc, 7:3): Rf ϭ 0.66 (single spot). IR (CDCl3): νOϪH
ϭ
3305 (s, H-bonded), 3602 (s, free), 2933 (w) cmϪ1; νCϵO ϭ 2094
(vs), 2056 (vs), 2030 (vs) cmϪ1. MS (DCI/NH3): m/z ϭ 418 ([M ϩ
NH4]ϩ), 383 ([MH Ϫ H2O]ϩ), 355 ([MH Ϫ H2O Ϫ CO]ϩ), 327
([MH Ϫ H2O Ϫ 2CO]ϩ), 299 ([MH Ϫ H2O Ϫ 3CO]ϩ).
1
was analyzed by H NMR spectroscopy and found to contain the
bis(trimethylsilyl)diether of 10. Thus, the residue was dissolved in
methanol (60 mL), potassium carbonate (9.70 g, 70 mmol) was ad-
ded, and then the mixture was stirred for 2 h at room temp. The
solution was filtered and evaporated, and the residue (7.41 g) was
partitioned between saturated aqueous NH4Cl (100 mL) and di-
chloromethane (100 mL). The organic layer was separated, washed
with water until pH 7 was reached, dried over MgSO4, filtered, and
then the solvents were evaporated. The orange residue (2.203 g) was
chromatographed over silica gel (CH2Cl2/THF, 95:5).
meso-9a: 1H NMR (400 MHz, 40 °C, CDCl3): δ ϭ 1.38 (d, 3JH,H ϭ
6.0 Hz, 6 H, CH3), 2.38 (s, 2 H, OH), 4.75 (large, 2 H, CH) ppm.
1H NMR (200 MHz, 21 °C, CDCl3): δ ϭ 1.55 (br, 6 H, CH3), 2.89
(s, 2 H, OH), 5.03 (br, 2 H, CHOH) ppm. 13C{1H} NMR (50 MHz,
21 °C, CDCl3): δ ϭ 24.73 (CH3), 68.47 (CHOH), 101.68 (η2-
CϵC),199.36 [Co2(CO)6] ppm.
Pure 1-phenylbut-2-yn-1-ol eluted first and was obtained as an or-
threo-9a: 1H NMR (400 MHz, 40 °C, CDCl3): δ ϭ 1.35 (d, 3JH,H ϭ
6.4 Hz, 6 H, CH3), 2.24 (s, 2 H, OH), 4.75 (br, 2 H, CHOH) ppm.
13C{1H} NMR (50 MHz, 21 °C, CDCl3): δ ϭ 25.18 (CH3), 68.91
(CHOH), 101.24 (η2-CϵC),199.36 [Co2(CO)6] ppm.
1
ange oil (0.241 g, 10%). TLC (CH2Cl2/THF, 95:5): Rf ϭ 0.72. H
4
NMR (CDCl3, 200 MHz): δ ϭ 2.67 (d, JH,H ϭ 2.4 Hz, 1 H,
ϵCH), 3.41 (br s, exchangeable with D2O, 1 H, OH), 5.43 (br s, 1
H, CHOH), 7.36Ϫ7.46 (m, 6 H, m- and p-CH), 7.54Ϫ7.59 (m, 4
H, o-CH) ppm.
Monoaddition Product 8a: 1H NMR (200 MHz, 21 °C, CDCl3): δ ϭ
1.55 (br, 6 H, CH3), 2.93 (s, 2 H, OH), 5.03 (br, 2 H, CHOH),
10.31 (s, 1 H, HCϭO).
Diol 10 was obtained as a white solid (0.280 g, 20%). TLC
(CH2Cl2/THF, 95:5): Rf ϭ 0.35. 1H NMR (CDCl3, 250 MHz): δ ϭ
3
2.22 (d, JH,H ϭ 6.0 Hz, exchangeable with D2O, 2 H, OH), 5.56
9a from 4 and MeMgBr: A solution of methylmagnesium bromide
in diethyl ether (3.0 , 0.362 mL, 1.087 mmol) was added by syr-
inge into a solution of acetylene dicarbaldehyde complex 4 (0.200 g,
0.543 mmol) in THF (26 mL) at Ϫ78 °C. The mixture was warmed
to room temp. and then stirred for 2 h. The mixture was quenched
with saturated aqueous NH4Cl (50 mL) and then extracted with
diethyl ether. The organic layer was washed with water until pH 7
was reached, dried over MgSO4, and concentrated. The de (22%)
3
(d, JH,H ϭ 5.9 Hz, 2 H, CHOH), 7.33Ϫ7.41 (m, 6 H, m- and p-
CH), 7.52Ϫ7.56 (m, 4 H, o-CH) ppm.
9d from Co2(CO)8 and 10: Solid Co2(CO)8 (0.436 g, 1.26 mmol) was
added to a suspension of 1,4-diphenylbut-2-yne-1,4-diol 10 (3.00 g,
1.26 mmol) in dichloromethane (20 mL) at room temp. The me-
dium turned red and CO evolved. After stirring overnight, the sol-
vent was evaporated and the residue dissolved in diethyl ether. The
solution was filtered through celite and the solvents were evapo-
rated to dryness. Pure complex 9d was obtained as a brown foam
(0.638 g, 97%).
1
was determined by deconvolution of the 400-MHz H NMR spec-
trum of the crude material in C6D6 at 40 °C (meso-9a: δ ϭ 1.41
(d), 2.62 (br), 4.77 (m) ppm. threo-9a: δ ϭ 1.37 (d), 2.47 (br), 4.78
(m) ppm). The crude material was chromatographed over silica gel
eluting with pentane/Et2O mixture of increasing polarity (from
70:30 to 50:50). Complex 9a was isolated in several fractions of
varying de (0.176 g, 81%). C12H10O8Co2 (400.1): calcd. C 36.01, H
2.52, Co 29.47, O 31.0; found 36.05, H 2.71, O 31.68, Co 28.43.
TLC (pentane/Et2O, 7:3): Rf ϭ 0.73. IR (CDCl3): νOϪH ϭ 3588 (s,
free), 3448 (s, hydrogen bonded OH) cmϪ1; νCϪH ϭ 3032 (w) cmϪ1
;
νCϵO ϭ 2095 (vs), 2059 (vs), 2034 (vs) cmϪ1; νarCϭC ϭ 1603 (m),
1494 (m), 1453 (m) cmϪ1. MS (DCI/NH3): m/z ϭ 542 ([M ϩ
NH4]ϩ), 507 ([MH Ϫ H2O]ϩ), 479 ([MH Ϫ H2O Ϫ CO]ϩ).
9b from 4 and EtLi: A solution of ethyllithium in diethyl ether (1.3
, 0.418 mL, 0.544 mmol) was added by syringe into a solution of
acetylene dicarbaldehyde complex 4 (0.100 g, 0.272 mmol) in THF
(10 mL) at Ϫ78 °C. After stirring for 15 min at Ϫ78 °C, the mixture
was stirred for 1 h at Ϫ25 °C, then quenched with saturated aque-
ous NH4Cl and diluted with diethyl ether. The organic layer was
dried over MgSO4, filtered through a small pad of celite, and con-
meso-9d: 1H NMR (CDCl3, 200 MHz): δ ϭ 3.44 (br, 2 H, OH),
5.96 (s, 2 H, CHOH), 7.30Ϫ7.47 (m, 10 H, aromatic CH) ppm.
13C{1H} NMR (CDCl3, 62.9 MHz): δ ϭ 74.52 (CHOH), 102.38
(η2-CϵC), 125.57 (o-CH), 128.22 (p-CH), 128.63 (m-CH), 143.14
(ipso-C), 198.49 [Co2(CO)6] ppm.
threo-9d: 1H NMR (CDCl3): δ ϭ 3.55 (d, 3JH,H ഠ 2 Hz, 2 H, OH),
5.89 (d, 3JH,H ഠ 2 Hz, 2 H, CHOH), 7.30Ϫ7.47 (m, 10 H, aromatic centrated. The crude material was chromatographed over silica gel
CH) ppm. 13C{1H} NMR (CDCl3, 62.9 MHz): δ ϭ 75.10 (CHOH), (pentane/EtOAc, 90:10). Complex 9b was isolated over several frac-
100.82 (η2-CϵC), 125.57 (o-CH), 125.71 (p-CH), 128.63 (m-CH), tions with varying de (0.027 g, 23%). Elemental analysis for the
1
143.63 (ipso-C), 198.49 [br, Co2(CO)6] ppm. Integration of the H
NMR spectra gave threo:meso, 63:37. The meso and threo configu-
rations were assigned by comparison with the spectrum of 9d,
which was prepared by addition of PhLi or PhMgBr to complex 4
(see below).
complex 9b·0.5 pentane (half an equivalent of pentane measured
by NMR spectroscopy). C16.5H20O8Co2 (463.98):calcd. C 42.67, H
4.34, Co 25.40, O 27.58; ; found C 42.40, H 4.07, Co 23.81, O
27.32. The de could not be determined from the 1H NMR spectrum
of the crude material. The better resolution of the 13C NMR spec-
Eur. J. Org. Chem. 2003, 1641Ϫ1651
www.eurjoc.org
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1647

R. Chauvin et al.
trum allowed for a crude estimation of de of ca. 10%. A more Analyses were consistent with those of the product obtained by
FULL PAPER
precise value (de 4%) was obtained as the weighted mean of the
values of de (measured by integration of H NMR spectra) of the
three chromatographed fractions containing 9b.
reaction of the diol 10 with Co2(CO)8 (see above).
1
meso-9d: TLC (pentane/EtOAc, 9:1): Rf ϭ 0.40. 1H NMR (CDCl3,
250 MHz): δ ϭ 3.54 (br, 2 H, OH), 5.95 (s, 2 H, CHOH), 7.34Ϫ7.43
(m, 10 H, aromatic CH) ppm.
9b from 4 and EtMgBr: A solution of ethylmagnesium bromide in
THF (3.0 , 0.181 mL, 0.544 mmol) was added by syringe into a
threo-9d: TLC (pentane/EtOAc, 9:1): Rf ϭ 0.53. 1H NMR (CDCl3,
250 MHz): δ ϭ 3.65 (d, 3JH,H ϭ 2.7 Hz, 2 H, OH), 5.88 (d, 3JH,H ϭ
2.7 Hz, 2 H, CHOH), 7.32Ϫ7.48 (m, 10 H, aromatic CH) ppm.
solution of acetylene dicarbaldehyde complex
4
(0.100 g,
0.272 mmol) in THF (10 mL) at Ϫ78 °C. The mixture was warmed
to room temp., stirred for 2 h, quenched with saturated aqueous
NH4Cl, and then extracted with diethyl ether. The organic layer
was washed with water until pH 7 was reached, then dried over
MgSO4 and concentrated. The crude material was chromato-
graphed over silica gel eluting with pentane/EtOAc mixtures of in-
creasing polarity (from 90:10 to 50:50). The de (60%) was deter-
mined as the weighted mean of the values of de (measured by inte-
1
Monoaddition Product 8d: H NMR (CDCl3, 250 MHz): δ ϭ 2.80
(d, 3JH,H ϭ 3.1 Hz, 1 H, OH), 5.92 (s, 1 H, CHOH), 7.32Ϫ7.48 (m,
5 H, aromatic CH), 10.24 (s, 1 H, CHO) ppm.
9e from 4 and PhCϵCLi: A solution of n-butyllithium in toluene
(2.1 , 1.04 mL, 2.18 mmol) was added by syringe into a solution
of phenylacetylene (0.144 mL, 2.18 mmol) in THF (20 mL) at Ϫ78
°C. After stirring for 1 h, during which time the temperature rose
to Ϫ25 °C, the resulting pink solution was cooled down to Ϫ78
°C. A solution of acetylenedicarbaldehyde complex 4 (0.400 g,
1.09 mmol) in THF (36 mL) was added. The mixture was warmed
to room temp., stirred for 3.5 h, quenched with saturated aqueous
NH4Cl, and then extracted with diethyl ether. The organic layer
was washed with water, dried over MgSO4, filtered through a small
pad of celite, and concentrated. The crude material was chromato-
graphed over silica gel with pentane/EtOAc (90:10 then 80:20).
Complex 9e was isolated as an orange oil (0.055 g, 9%) correspond-
ing to a single spot on TLC.
TLC (pentane/EtOAc, 8:2): Rf ഠ 0.25. TLC (pentane/EtOAc, 7:3):
Rf ഠ 0.54. IR (CDCl3) νOϪH ϭ 3601 (s, free), 3408 (s, hydrogen-
bonded) cmϪ1; νCϪH ϭ 2927 (w), 2855 (w) cmϪ1; νCϵO ϭ 2099
(vs), 2063 (vs), 2039 (vs) cmϪ1; νarCϭC ϭ 1600 (m), 1490 (m), 1457
(m) cmϪ1. MS (DCI/NH3/Et2O): m/z ϭ 586 ([M Ϫ 2H2 ϩ NH4]ϩ),
569 ([M Ϫ 2H2 ϩ H]ϩ), 553 ([M Ϫ H2 ϩ H Ϫ H2O]ϩ), 499 ([M
ϩ H Ϫ H2O Ϫ 2CO), 481 ([M ϩ H Ϫ 2H2O Ϫ 2CO]ϩ. The invoked
oxidation processes are explained by the stabilization of the doubly
propargylic carbenium centers:
1
gration of H NMR spectra) of the three fractions containing 9b.
Pure meso-9b was isolated as an orange-red solid (0.083 g, 71%).
IR (CDCl3): νOϪH ϭ 3603 (s, free OH), 3452 (s, hydrogen bonded)
cmϪ1; νCϪH ϭ 2968 (w), 2935 (w), 2878 (w) cmϪ1; νCϵO ϭ 2094
(vs), 2056 (vs), 2030 (vs) cmϪ1. MS (DCI/NH3): m/z ϭ 446 ([M ϩ
NH4]ϩ), 411 ([MH Ϫ H2O]ϩ), 383 ([MH Ϫ H2O Ϫ CO]ϩ), 355
([MH Ϫ H2O Ϫ 2CO]ϩ), 327 ([MH Ϫ H2O Ϫ 3CO]ϩ).
meso-9b: TLC (pentane/EtOAc, 9:1): Rf ϭ 0.40. 1H NMR (CDCl3):
3
δ ϭ 1.15 (t, JH,H ϭ 7.3 Hz, 6 H, CH3), 1.80 (m, 4 H, CH2Me),
3
2.96 (d, JH,H ϭ 3.6 Hz, 2 H, OH), 4.71 (m, 2 H, CHOH) ppm.
13C NMR: δ ϭ 11.23 (q, 1JC,H ϭ 126.1 Hz, CH3), 32.50 (t, 1JC,H ϭ
124.7 Hz, CH2Me), 74.06 (d, 1JC,H ϭ 143.9 Hz, CHOH), 100.78 (s,
η2-CϵC), 199.43 [br s, Co2(CO)6] ppm.
threo-9b: TLC (pentane/EtOAc, 9:1): Rf ϭ 0.49. 1H NMR (CDCl3):
3
δ ϭ 1.15 (t, JH,H ϭ 7.3 Hz, 6 H, CH3), 1.67 (m, 4 H, CH2Me),
3
2.66 (d, JH,H ϭ 4.7 Hz, 2 H, OH), 4.71 (m, 2 H, CHOH) ppm.
13C{1H} NMR (62.9 MHz, CDCl3): δ ϭ 11.14 (CH3), 32.86 (CH2),
74.06 (CHOH), 100.86 (η2-CϵC), 199.57 [Co2(CO)6] ppm.
9d from 4 and PhLi: A solution of phenyllithium in cyclohexane/
diethyl ether (1.6 , 0.340 mL, 0.544 mmol) was added by syringe
into a solution of acetylene dicarbaldehyde complex 4 (0.100 g,
0.272 mmol) in THF (10 mL) at Ϫ78 °C. The mixture was warmed
to room temp., stirred for 1.5 h, quenched with saturated aqueous
NH4Cl, and then extracted with diethyl ether. The organic layer
was washed with water, dried over MgSO4, and concentrated. The
1
Scheme 7
de (54%) was determined by integration of the resolved H NMR
spectrum of the crude material in CDCl3. The crude material was
chromatographed over silica gel (pentane/EtOAc, 80:20). Complex
9d was isolated as a red amorphous solid (0.053 g, 37%).
If the sample is injected as a CH2Cl2 solution, instead of in Et2O,
the isotope pattern analysis allowed for the following assignments:
MS (DCI/NH3/CH2Cl2): m/z ϭ 586 ([M Ϫ 2CO ϩ 2HCl Ϫ H2O
ϩ NH3 Ϫ H·]ϩ), 569 ([M Ϫ 2CO ϩ 2HCl Ϫ H2O Ϫ H·]ϩ), 553
([M Ϫ 2CO ϩ 2HCl Ϫ 2H2O ϩ H]ϩ).
9d from 4 and PhMgBr: A solution of phenylmagnesium bromide
in diethyl ether (3.0 , 0.181 mL, 0.544 mmol) was added by syr-
inge into a solution of acetylene dicarbaldehyde complex 4 (0.100 g,
0.272 mmol) in THF (20 mL) at Ϫ78 °C. The mixture was warmed
to room temp., stirred at room temp. for 2.5 h, quenched with satu-
rated aqueous NH4Cl, and then extracted with diethyl ether. The
organic layer was washed with water until pH 7 was reached, then
dried over MgSO4 and concentrated. The crude material was chro-
matographed over silica gel eluted with pentane/EtOAc mixtures of
increasing polarity (from 90:10 to 80:20). Complex 9d (mixture of
diastereoisomers) was isolated as a brown solid (0.069 g, 48%). El-
emental analysis for 9d·H2O C22H16Co2O9: calcd. C 48.71, H 2.98,
Co 21.74; found C 48.41, H 2.83.
1H NMR (CDCl3, 200 MHz): δ ϭ 2.98 (br s, 2 H, OH), 5.87 (s, 2
H, CHOH), 7.30 (sharp signal, 6 H; m- and p-CH), 7.39Ϫ7.43 (m,
4 H, o-CH) ppm. 13C{1H} NMR (CDCl3, 62.9 MHz): δ ϭ 64.08
(CHOH), 85.96 and 88.08 (CϵCPh), 96.39 (η2-CϵC), 122.00 (ipso-
C), 128.50 (m-CH), 128.99 (p-CH), 131.88 (o-CH), 198.91 [s,
Co2(CO)6] ppm. Elemental analysis for 9e·icosane (1 equivalent of
C20 alkane in the sample was confirmed by NMR spectroscopy):
C46H56O8Co2 (854.26): calcd. C 64.62, H 6.62; found C 64.50, H
6.44.
NMR spectroscopic data for the minor epimer of 9e [TLC (pen-
tane/EtOAc, 7:3): Rf ϭ 0.63] were extracted from spectra of the
crude material. 13C{1H} NMR (CDCl3, 62.9 MHz): δ ϭ 64.08
(CHOH), 86.04 and 88.00 (CϵCPh), 96.39 (η2-CϵC), 122.00 (ipso-
The stereoselectivity (de ϭ 66%) was determined as the weighted
mean of the values of de (measured by integration of the 1H NMR
spectra) of all the three chromatographed fractions containing 9d.
1648
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2003, 1641Ϫ1651

Double Addition of Anionic C-Nucleophiles to Cobalt-Stabilized Acetylenedicarbaldehyde
C), 128.50 (m-CH), 128.99 (p-CH), 131.88 (o-CH), 198.91 [s, 0.544 mmol) in THF (20 mL) was added. The resulting dark-brown
FULL PAPER
Co2(CO)6] ppm. Formal integration of the spectrum gave 12 and
28% excesses for the major components of two split CϵCPh sig-
nals; a rough estimation gives de of ca. 20 Ϯ10%.
solution was stirred for 1 h at room temp., then quenched with
saturated aqueous NH4Cl and extracted with diethyl ether. The
organic layer was washed with water until pH 7 was reached, dried
over MgSO4, and concentrated. The crude brown solid (0.155 g)
9e from 4 and PhCϵCMgBr: A solution of ethylmagnesium bro-
mide in THF (3.0 , 0.181 mL, 0.544 mmol) was added to a solu-
tion of phenylacetylene (0.037 mL, 0.544 mmol) in THF (10 mL)
at Ϫ78 °C. After stirring for 0.5 h, during which time the mixtute
warmed to room temp., the solution was cooled to Ϫ78 °C. A solu-
tion of acetylenedicarbaldehyde complex 4 (0.100 g, 0.272 mmol)
in THF (13 mL) was added. The mixture was warmed to room
temp., stirred for 2.5 h, quenched with saturated aqueous NH4Cl,
and then extracted with diethyl ether. The organic phase was
washed with water, dried over Na2SO4, and concentrated. The
crude material was chromatographed over silica gel (pentane/Et2O,
80:20). Complex 9e (0.025 g, 16%) was isolated as an orange oil
corresponding to the same (more polar) TLC spot observed for the
reaction using Ph2C2Li. The less-polar spot corresponds to the
minor epimer of 9e, which was obtained in mixture (0.017 g) with
8e and the first epimer of 9e in a ratio 9e:8e, 66:33. Assuming that
9e here occurs either as a 1:1 mixture of the two epimers (de ϭ 0)
or, at worst, as a single minor epimer (de ϭ Ϫ100%), the weighted
mean of the values of de in the two extreme cases gives the esti-
mated range: 36 Ͻ de ഠ 68%.
1
was analyzed by H NMR spectroscopy and integration of the re-
spective signals gave the ratio 4:8f:9f, 38:20:42. The crude material
was then chromatographed over silica gel with pentane/Et2O
(80:20). A first product [TLC (pentane/Et2O, 80:20): Rf ϭ 0.56],
1
likely containing complex 8d (according to its H NMR spectrum,
δCHO ϭ 9.97 ppm), was obtained as an impure orange oil (0.007 g,
ca. 2%). Subsequently, complex 9f, as a reddish oil (0.046 g, ca.
15%), and unchanged 4, as a red powder (0.009 g, 5%), were iso-
lated.
9g from 4 and the Lithium Salt of 11g: A solution of n-butyllithium
in toluene (2.2 , 0.197 mL, 0.434 mmol) was added by syringe
into a solution of diyne (MeC2)(OMe)PhC-CϵCH 11g (0.080 g,
0.544 mmol) in THF (6 mL) at Ϫ78 °C. The mixture was warmed
to 0 °C, and then cooled to Ϫ78 °C. A solution of acetylenedicar-
baldehyde complex 4 (0.080 g, 0.217 mmol) in THF (10 mL) was
added. The mixture was then stirred at room temp. for 1 h,
quenched with saturated aqueous NH4Cl, and extracted with di-
ethyl ether. The organic layer was washed with water, dried over
MgSO4, and concentrated. The brown residue was chromato-
graphed over silica gel with pentane/Et2O mixtures of increasing
polarity (from 80:20 to 50:50). Complex 9g (mixture of dia-
stereoisomers) was isolated as a brown oil (0.024 g, 15%).
NMR spectroscopic data for 8e: 1H NMR (CDCl3, 250 MHz): δ ϭ
3
3
2.91 (d, JH,H ϭ 5.9 Hz, 1 H, OH), 5.81 (d, JH,H ϭ 5.8 Hz, 1 H,
CHOH), 7.30Ϫ7.41 (m, assumed 5 H, aromatic CH), 10.36 (s, 1 H,
CHO) ppm.
IR (CDCl3): νOϪH ϭ 3585 (s) cmϪ1; νCϪH ϭ 2958 (w), 2935 (w),
2826 (w) cmϪ1; νCϵO ϭ 2100 (vs), 2064 (vs), 2038 (vs) cmϪ1; νar.Cϭ
9f from 4 and Me3SiCϵCLi: A solution of n-butyllithium in toluene
(2.5 , 0.218 mL, 0.544 mmol) was added by syringe into a solution
of trimethylsilylacetylene (0.077 mL, 0.544 mmol) in THF (10 mL)
at Ϫ78 °C. The mixture was warmed to room temp. and then co-
oled to Ϫ78 °C. A solution of acetylenedicarbaldehyde complex 4
(0.100 g, 0.272 mmol) in THF (13 mL) was added. The mixture was
warmed to room temp., stirred for 3.5 h, quenched with saturated
aqueous NH4Cl, and then extracted with diethyl ether. The organic
layer was washed with water until pH 7 was reached, dried over
MgSO4, and concentrated. The crude material was chromato-
graphed over silica gel with pentane/EtOAc (90:10 then 80:20).
Complex 9f was isolated over several fractions, corresponding to
ϭ 1591 (m), 1489 (m), 1449 (m) cmϪ1; νCϪO ϭ 1063 (m) cmϪ1
.
C
MS (DCI/NH3): m/z ϭ 754 ([M ϩ NH4]ϩ). 1H NMR (CDCl3,
250 MHz): δ ϭ 1.91 (s, 6 H, ϵCϪCH3), 2.97 (br, 2 H, OH),
3.44Ϫ3.49 (m, 6 H, OCH3), 5.54Ϫ5.61 (m, 2 H, CHOH), 7.33 (m,
6 H, m- and p-CH), 7.71 (m, 4 H, o-CH) ppm. Surprisingly, the
13C NMR spectrum can be assigned entirely to that of a pseudo-
diastereoisomerically pure compound. 13C NMR (CDCl3,
1
62.9 MHz): δ ϭ 3.64 (q, JC,H ϭ 132 Hz, ϵCϪCH3), 52.83 (q,
1
1JC,H ϭ 143 Hz, OϪCH3), 63.28 (d, JC,H ϭ 151 Hz, CHOH),
71.77 [s, C(OMe)Ph), 84.32 (br, CϵCMe), 95.35 (s, η2-CϵC),
126.47 (d, o-CH), 128.27 (d, m-CH), 128.64 (d, p-CH), 140.32 (s,
ipso-C), 198.37 [s, Co2(CO)6] ppm.
1
two spots on TLC (each affording the same H NMR spectrum),
that were combined to give a red amorphous solid (0.082 g, 63%).
TLC (pentane/Et2O, 80:20): Rf ϭ 0.40 and 0.53. IR (CDCl3):
νOϪH ϭ 3588 (s) cmϪ1; νCϪH ϭ 2962 (w) cmϪ1; νCϵCSi ϭ 2173 (w)
cmϪ1; νCϵO ϭ 2099 (vs), 2063 (vs), 2038 (vs) cmϪ1; νCϪSi ϭ 1252
(m) cmϪ1. MS (DCI/NH3): m/z ϭ 582 ([M ϩ NH4]ϩ), 547 ([MH
Ϫ H2O]ϩ), 491 ([MH Ϫ H2O Ϫ 2CO]ϩ). 1H NMR (CDCl3,
250 MHz): δ ϭ 0.16 [br s, 18 H, Si(CH3)3], 2.95 (br, 2 H, OH), 5.57
(br, 2 H, CHOH). Because of this broadness, the de could not be
determined by 1H NMR spectroscopy. 13C{1H} NMR (CDCl3,
62.9 MHz; formal integration of four split signals gave the same
22% excess of the main signals, and allowed for the following as-
signments): major epimer, δ ϭ Ϫ0.45 [Si(CH3)3], 63.69 (CHOH),
90.82 (η2-CϵC), 95.97 (CϵCϪSi), 103.74 (CϵCϪSi), 198.64 [s,
Co2(CO)6] ppm; minor epimer, δ ϭ Ϫ0.45 [Si(CH3)3], 63.61
(CHOH), 90.90 (η2-CϵC), 95.84 (CϵCϪSi), 103.82 (CϵCϪSi),
198.64 [s, Co2(CO)6] ppm.
9h from 4 and the Lithium Salt of 11h: A solution of n-butyllithium
in toluene (2.5 , 0.217 mL, 0.544 mmol) was added by syringe into
a solution of diyne (Me3SiC2)(OMe)PhCϪCϵCH 11h (0.132 g,
0.544 mmol) in THF (10 mL) at Ϫ78 °C. The mixture was warmed
to room temp. and then the resulting violet solution was cooled to
Ϫ68 °C. A solution of complex 4 (0.100 g, 0.272 mmol) in THF
(13 mL) was added. The mixture was then stirred at room temp.
for 2.5 h, quenched with saturated aqueous NH4Cl, and extracted
with diethyl ether. The organic layer was washed with water, dried
over MgSO4, and concentrated. The brown residue was chromato-
graphed over silica gel with pentane/EtOAc mixtures of increasing
polarity (from 90:10 to 50:50). Complex 9h (mixture of dia-
stereoisomers) was isolated as a brown oil (0.039 g, 16%).
IR (CDCl3): νOϪH ϭ 3585 (s, free), 3410 (hydrogen bonded) cmϪ1
;
ν
CϪH ϭ 2961 (w), 2936 (w), 2902 (w), 2827 (w) cmϪ1; νCϵO ϭ 2100
(vs), 2064 (vs), 2040 (vs) cmϪ1; νar.CϭC ϭ 1587 (w), 1489 (m), 1450
(m) cmϪ1; νCϪO ϭ 1064 (m) cmϪ1; νCϪSi ϭ 1252 (m) cmϪ1. MS
(DCI/NH3): m/z ϭ 870 ([M ϩ NH4]ϩ), 835 ([MH Ϫ H2O]ϩ). 1H
9f from 4 and Me3SiCϵCMgBr: A solution of EtMgBr in THF (3
, 0.362 mL, 1.09 mmol) was added by syringe into a solution of
phenylacetylene (0.154 mL, 1.09 mmol) in THF (20 mL) at room NMR (CDCl3, 250 MHz): δ ϭ 0.21 [s, 18 H, Si(CH3)3], 2.82 (br, 2
temp. and then the solution was heated at 55 °C for 0.5 h. The
solution was cooled to 5 °C, and a solution of complex 4 (0.200 g,
H, OH), 3.45Ϫ3.47 (m, 6 H, OCH3), 5.57Ϫ5.60 (m, 2 H, CHOH),
7.36 (m, 6 H, m- and p-CH), 7.72 (m, 4 H, o-CH) ppm. Surpris-
Eur. J. Org. Chem. 2003, 1641Ϫ1651
www.eurjoc.org
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1649

R. Chauvin et al.
FULL PAPER
ingly, the 13C NMR spectrum can be assigned almost entirely as
geometries were designed starting from the X-ray crystal structure
that of a pseudo-diastereomerically pure compound (except for two
of 8b, appending a frozen Co2(CO)6 core at the triple bond, and
CϵC signals). 13C{1H} NMR (CDCl3, 62.9 MHz): δ ϭ Ϫ0.37 replacing one of the sp3 carbinol groups for a sp2 formyl group.
[Si(CH3)3], 53.01 (O-CH3), 63.12 (CHOH), 71.88 [C(OMe)Ph],
The remaining OH proton of 8b was then replaced by a metal unit
83.62, 84.83, 85.00 (diastereoisomeric CϵCϪSi), 95.18 (η2-CϵC), [M ϭ Li(THF)2 or MgBr(THF)], placed at nonbonding distances
101.00 (ϵCϪSiMe3), 126.47 (o-CH), 128.32 (m-CH), 128.76 (p-
CH), 139.44 (ipso-C), 198.34 [Co2(CO)6] ppm.
from the formyl function and diversely oriented. Finally, ESSF op-
timization led to the closure of a seven-membered metallacycle by
a new OǞ[M] bond in a pseudo-boat conformation B[M].
9i from 4 and the Lithium Salt of 11i: A solution of n-butyllithium
in hexane (2.5 , 0.850 mL, 2.12 mmol) was added by syringe into a
solution of 1-trimethylsilyl-3-(tetrahydropyranyloxy)pent-1,4-diyne
(11i, 0.500 g, 2.12 mmol) in THF (15 mL) at Ϫ80 °C. After stirring
for 15 min, a solution of complex 4 (0.390 g, 1.06 mmol) in THF
(10 mL) was added. The mixture was then stirred at Ϫ80 °C for 1 h
and at room temp. for 1 h, before being quenched with a saturated
aqueous solution of NH4Cl and extracted with diethyl ether. The
organic layer was washed with water, dried over MgSO4 and con-
centrated. The brown residue was purified by flash chromatography
through a plug of silica gel eluting with heptane/EtOAc (80:20).
Complex 9i (mixture of diastereoisomers) was isolated as a brown
amorphous solid (167 mg, 15%).
Supporting Information: (see footnote on the first page of this arti-
cle) Cartesian coordinates for the ESFF-optimized structures
B[Li(THF)2] and B[MgBr(THF)].
Acknowledgments
´
The authors wish to thank Cecile Lamirand, Antonetta Mohanu,
´
and Cecile Destombes for experimental assistance, and the Minis-
`
tere de lЈEducation Nationale de la Recherche et de la Technologie
for ACI financial support.
IR (CDCl3): νOϪH ϭ 3408 (w) cmϪ1; νCϪH ϭ 2951, 2854 (m) cmϪ1
νCϵC ϭ 2247 (w) cmϪ1; νCϵO ϭ 2098, 2063, 2035 (vs) cmϪ1
;
;
[1] [1a]
A. Gorgues, A. Le Coq, Chem. Commun. 1979, 767Ϫ768.
νCϪSi ϭ 1251 (m) cmϪ1; νCϪO ϭ 1117 (m) cmϪ1. MS (DCI/NH3):
m/z ϭ 839 ([M Ϫ H]ϩ). 1H NMR (CDCl3, 250 MHz): δ ϭ 0.13 [m,
18 H, Si(CH3)3], 1.22 and 1.51 (2 m, 12 H, CH2CH2CH2), 3.49
and 3.83 (2 m, 4 H, CH2O), 4.91 (m, 2 H, CHO2), 5.20 (m, 2
H, CHϪOTHP), 5.63 (m, 2 H, CHOH) ppm. 13C NMR (CDCl3,
62.9 MHz): δ: Ϫ0.43 [Si(CH3)3], 18.35, 18.58, 19.66, 25.23, 25.39,
29.63, 29.86, 30.26, 30.62 (CH2CH2CH2), 54.92Ϫ55.26
[1b]
A. Gorgues, A. Le Coq, Tetrahedron Lett. 1979, 50,
[1c]
4825Ϫ4828.
1979, 50, 4829Ϫ4832.
mine, A. Khanous, A. Le Coq, Tetrahedron 1990, 465,
A. Gorgues, A. Le Coq, Tetrahedron Lett.
[1d]
A. Gorgues, D. Stephan, A. Belyas-
2817Ϫ2820.
[2]
A. Meyer, A. Gorgues, Y. Le Floc’h, Y. Pineau, J. Guilleviv, J.
Y. Le Marouille, Tetrahedron Lett. 1981, 22, 5181Ϫ5182.
A. Meyer, M. Bigorgne, Organometallics 1984, 3, 1112Ϫ1118.
M. Badri, J.-P. Majoral, A.-M. Caminade, M. Delmas, A. Ga-
set, A. Gorgues, J. Jaud, J. Am. Chem. Soc. 1990, 112,
5618Ϫ5623.
[3]
[4]
(CHOTHP),
61.61Ϫ62.01
(CHOTHP),
62.83
(CHOH),
94.57Ϫ95.67 (CHO2, CϵC), 98.76Ϫ99.00 (ϵCϪSi), 198.53
[Co2(CO)6] ppm.
[5]
[6]
A. Khanous, A. Gorgues, M. Jubault, Tetrahedron Lett. 1990,
31, 7311Ϫ7314.
X-ray Analysis of 4, 9b, and 9d: Data were collected at low tempera-
ture on a Stoe Imaging Plate Diffraction System (IPDS), equipped
with an Oxford Cryosystems Cryostream Cooler Device and by
M. Soleilhavoup, L. Maurette, C. Lamirand, B. Donnadieu,
M. J. McGlinchey, R. Chauvin, Eur. J. Org. Chem. 2003,
1652Ϫ1660 following paper.
˚
using graphite-monochromated Mo-K radiation (λ ϭ 0.71073 A).
The final unit cell parameters were obtained by means of a least-
squares refinement of a set of 5000 well-measured reflections. Crys-
tal decay was monitored in the course of data collection by measur-
ing 200 reflections by image; no significant fluctuations of intensit-
ies have been observed during all measurements. All structures have
been solved by Direct Methods using SIR92,[29] and refined by le-
ast-squares procedures on F2 with the aid of SHELXL.[30] The
Atomic Scattering Factors were taken from International Tables
for X-ray Crystallography.[31] All hydrogen atoms were located on
difference Fourier maps, and refined by using a riding model with
an isotropic thermal parameter fixed at 20% higher to carbons
atoms to which they are connected. Exceptions are the hydrogens
atoms H(3) and H(4) of the CHO function of 4, and the hydrogens
atoms H(1) and H(2) of the -OH groups of 9b and 9d, which were
isotropically refined. A semi-empirical correction absorption was
applied for all models (DIFABS-N),[32] all non-hydrogens atoms
were anisotropically refined, and in the last cycles of refinement a
weighting scheme was used,[33] where weights are calculated from
[7] [7a]
[7b]
K. M. Nicholas, Acc. Chem. Res. 1987, 207Ϫ214.
O.
Kuhn, D. Rau, H. Mayr, J. Am. Chem. Soc. 1998, 120,
[7c]
900Ϫ907.
J. R. Green, Current Org. Chem. 2001, 809Ϫ826.
[8]
[9]
R. Tester, V. Varghese, A. M. Montana, M. Khan, K. M. Nich-
olas, J. Org. Chem. 1990, 55, 186Ϫ192.
S. Padmanabhan, K. M. Nicholas, J. Organomet. Chem. 1981,
212, 115Ϫ124.
[10]
K. M. Nicholas, J. Siegel, J. Am. Chem. Soc. 1985, 107,
4999Ϫ5001.
[11] [11a]
M. Gruselle, V. Philomin, F. Chaminant, G. Jaouen, K.
M. Nicholas, J. Organomet. Chem. 1990, 399, 317Ϫ326. [11b] S.
Takano, T. Sugihara, K. Ogasawara, Synlett 1992, 70Ϫ72.
[11c]
J. R. Green, Chem. Commun. 1998, 1751Ϫ1752.
[12]
J. Bach, R. Berenger, J. Garcia, T. Loscertales, J. Manezanal, J.
Vilarrasa, Tetrahedron Lett. 1997, 38, 1091Ϫ1094.
[13] [13a]
C. Mukai, K. Nagami, M. Hanaoka, Tetrahedron Lett.
1989, 41, 5627Ϫ5630. [13b] A. J. Fletcher, R. Fryatt, D. T. Ruth-
erford, M. R. J. Elsegood, D. R. Steven, Synlett 2001,
1711Ϫ1714.
[14]
X. Lu, J. Ji, D. Ma, W. Shen, J. Org. Chem. 1991, 56,
2
the following formula: w ϭ 1/[2(Fo ) ϩ (aP)2 ϩ bP] where P ϭ
5774Ϫ5778.
2
(Fo2 ϩ 2Fc )/3. Molecules were drawn using the program ZORTEP
[15] [15a]
T. Imamoto, N. Takiyama, K. Nakamura, T. Hatajima, Y.
[15b]
with 50% probability displacement ellipsoids for non-hydrogen
Kamiya, J. Am. Chem. Soc. 1989, 111, 4392Ϫ4398.
J.
atoms.[34]
March, Advanced Organic Chemistry. Reactions, Mechanisms
and Structures, 4th ed., John Wiley & Sons, New York, 1992,
chapter 16, p. 926, and references therein.
MM Modeling of Intermediates B[Li(THF)2] and B[MgBr(THF)]:
Optimization of the geometry of lithium and magnesium bromide
salts of 8b have been carried out with ESSF (Extensive Systematic
Force Field) implemented in the Discover software.[35] The input
[16]
The characterization of 7b was guided by that of the previously
[16a]
known 1-acetyl-1,2-dibenzoylethane homolog:
H. Stetter,
[16b]
F. Jonas, Tetrahedron Lett. 1981, 22, 4945Ϫ4948.
P.-K.
1650
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2003, 1641Ϫ1651

Double Addition of Anionic C-Nucleophiles to Cobalt-Stabilized Acetylenedicarbaldehyde
FULL PAPER
Chiu, M. P. Sammes, Tetrahedron 1988, 44, 3531Ϫ3538. [16c] S.
Sayama, Y. Inamura, Bull. Chem. Soc. Jpn. 1991, 64, 306Ϫ308.
M. Soleilhavoup, C. Saccavini, C. Lepetit, G. Lavigne, L. Mau-
rette, B. Donnadieu, R. Chauvin, Organometallics 2002, 21,
871Ϫ883.
T. F. Kelton, J. E. Mathews, R. S. Huber, J. P. Davidson, J. Org.
[24b]
Chem. 1997, 62, 9379Ϫ9381.
D. S. Davis, S. C. Shadinger,
[17]
Tetrahedron Lett. 1999, 40, 7749Ϫ7752.
[25] [25a]
[25b]
R. Chauvin, Tetrahedron Lett. 1995, 36, 397Ϫ400.
R.
Chauvin, Tetrahedron Lett. 1995, 36, 401Ϫ404. [25c] C. Godard,
C. Lepetit, R. Chauvin, Chem. Commun. 2000, 1833Ϫ1834.
[18]
[19]
H. G. Alt, H. E. Engelhardt, R. D. Rogers, S. T. Abu-Orabi, J.
Organomet. Chem. 1989, 378, 33Ϫ43.
[25d]
C. Lepetit, C. Godard, R. Chauvin, New. J. Chem. 2001,
´
M. Gruselle, B. Malezieux, J. Vaissermann, H. Amouri, Or-
25, 572Ϫ580.
[26]
[27]
[28]
ganometallics 1998, 17, 2337Ϫ2343.
R. G. Jones, H. Gilman, Org. React. 1951, 6, 339Ϫ366.
J. Suffert, J. Org. Chem. 1989, 54, 509Ϫ510.
J.-J. Zhang, G. B. Schuster, J. Am. Chem. Soc. 1989, 111,
7149Ϫ7155.
A. Altomare, G. Cascarano, G. Giacovazzo, A. Guagliardi, M.
C. Burla, G. Polidori, M. Camalli, J. Appl. Cryst. 1994, 27,
435Ϫ436.
[20] [20a]
A. B. Holmes, C. L. D. Jennings-White, A. H. Schulthess,
B. Akinde, D. R. M. Walton, Chem. Commun. 1979, 840Ϫ842.
[20b]
E. Abele, K. Rubina, J. Popelis, I. Mazeika, E. Lukevics,
[29]
J. Organomet. Chem. 1999, 586, 184Ϫ190.
[21] [21a]
L. Maurette, C. Godard, S. Frau, C. Lepetit, M. Soleil-
[21b]
havoup, R. Chauvin, Chem. Eur. J. 2001, 1165Ϫ1170.
C.
[30]
[31]
[32]
[33]
[34]
[35]
Tedeschi, C. Saccavini, L. Maurette, M. Soleilhavoup, R.
Chauvin, J. Organomet. Chem. 2003, 670, 151.
G. M. Sheldrick, SHELXL-97. Program for the Refinement of
Crystal Structures, University of Göttingen, Germany, 1997.
International Tables for X-ray Crystallography, Vol. IV, Kynoch
Press, Birmingham, England, 1974.
N. Walker, D. Stuart, Acta Crystallogr. Sect A 1983, 39,
158Ϫ166.
[22]
Alkynylation has been reported of acetoxy propargylic Nichol-
as’ complexes with twofold excess of the alkynyl nucleophile
with respect to the trisalkynylalane reactants: S. Padmanabhan,
K. M. Nicholas, Tetrahedron Lett. 1983, 24, 2239Ϫ2242.
[23] [23a]
D. E. Frantz, R. Fässler, E. M. Carreira, J. Am. Chem.
J. R. Carruthers, D. J. Watkin, Acta Crystallogr. Sect. A 1979,
35, 698Ϫ699.
[23b]
Soc. 2000, 122, 1806Ϫ1807.
Examples have been recently
reported of asymmetric addition of diethylzinc to dicobalthexa-
carbonyl complexes of acetylenic aldehydes: M. Fontes, X. Ver-
daguer, L. Sola, A. Vidal-Ferran, K. S. Reddy, A. Riera, M.
A. Perquas, Organic Letters 2002, 4, 2381Ϫ2383.
L. Zolna¨ı, ZORTEP, Graphical Program for X-ray Structures
Analysis, University of Heidelberg, Germany, 1998.
Discover 95.0, Molecular Simulation Inc., Cambridge, U. K.,
1996.
[24] [24a]
G. B. Jones, J. M. Wright, T. M. Rush, G. W. Plourde II,
Received October 23, 2002
Eur. J. Org. Chem. 2003, 1641Ϫ1651
www.eurjoc.org
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1651