Barbier-type addition of alkyl halides to aldehydes promoted by pentacarbonyliron

Article abstract of DOI:10.1023/A:1020857730190

The yield and structure of products of the Barbier-type addition of alkyl halides (perfluorobutyl iodide, allyl bromide, allyl iodide, and hexyl iodide) to para-substituted benzaldehydes in the presence of pentacarbonyliron are essentially determined, on the one hand, by the ability of alkyl halide to be reduced to carbanion and, on the other, by the electrophilicity of the aldehyde reaction center which in turn depends on the nature of para-substituent in the aromatic ring.

Full text of DOI:10.1023/A:1020857730190

Russian Journal of Organic Chemistry, Vol. 38, No. 7, 2002, pp. 1014 1017. Translated from Zhurnal Organicheskoi Khimii, Vol. 38, No. 7, 2002,
pp. 1056 1059.
Original Russian Text Copyright
2002 by Vasil’eva, Mysova, Chakhovskaya, Terent’ev.
Barbier-Type Addition of Alkyl Halides to Aldehydes
Promoted by Pentacarbonyliron
T. T. Vasil’eva, N. E. Mysova, O. V. Chakhovskaya, and A. B. Terent’ev
Nesmeyanov Institute of Organometallic Compounds, Russian Academy of Sciences,
ul. Vavilova 28, Moscow, 119991 Russia
e-mail: terent@ineos.ac.ru
Received September 20, 2001
Abstract The yield and structure of products of the Barbier-type addition of alkyl halides (perfluorobutyl
iodide, allyl bromide, allyl iodide, and hexyl iodide) to para-substituted benzaldehydes in the presence of
pentacarbonyliron are essentially determined, on the one hand, by the ability of alkyl halide to be reduced to
carbanion and, on the other, by the electrophilicity of the aldehyde reaction center which in turn depends on
the nature of para-substituent in the aromatic ring.
We previously showed [1] that pentacarbonyliron is
an efficient promotor of the addition of halogen-
substituted esters to aldehydes and ketones, following
a Reformatsky-like reaction pattern. We revealed
a considerable effect on the process of substituents
both in aromatic aldehyde and in halogen-containing
carboxylic acid ester: Electron-acceptor substituents
Alkyl halides, namely perfluorobutyl iodide (I),
allyl bromide (IIa), allyl iodie (IIb), and hexyl iodide
(III) were brought into reactions with benzaldehyde
(IVa), p-chlorobenzaldehyde (IVb), and p-methoxy-
benzaldehyde (IVc). The reaction of iodide I with
2-furaldehyde (V) was also examined. Perfluorobutyl
iodide (I) reacted with aldehydes IVa IVc in the
(
such as Cl and Br) favor the reaction, while electron-
presence of Fe(CO) and pyridine, following a usual
5
donor groups (Me, MeO) decelerate the process [2].
No such effect was observed when analogous reac-
tions were carried out under usual conditions [3].
Barbier-type addition scheme and resulting in forma-
tion of secondary alcohols VIa VIc (Scheme 1).
A specific effect of para-methoxy group in the
aromatic ring was observed. The yields of adducts
VIa and VIb from benzaldehyde (IVa) and p-chloro-
benzaldehyde (IVb), respectively, were 18 20% or
65 90% on the reacted aldehyde, whereas from alde-
hyde IVc only 6% of addition product VIc was
obtained (18% on the reacted aldehyde). Iodide I
reacted with 2-furaldehyde (V) in a way similar to
the reaction with benzaldehyde (IVa). As a result,
In the present communication we report on the
first examples of pentacarbonyliron-promoted addition
of alkyl halides to aldehydes, following the Barbier-
like reaction pattern. We used a set of reactants which
allowed us to elucidate the possibility for Barbier-type
reaction to occur in the presence of Fe(CO) , as well
5
as to reveal a significant effect of substituents in
both alkyl halide and aldehyde on the yield and struc-
ture of the products; this effect is untypical of such
reactions [4].
2
,2,3,3,4,4,5,5,5-nonafluoro-1-(2-furyl)pentanol (VII)
was obtained (Scheme 2).
Scheme 1.
Scheme 2.
Allyl iodide (IIb) reacted with benzaldehyde on
IV, VI, X = H (a), p-Cl (b), p-MeO (c).
heating in boiling benzene to afford a mixture of
1
070-4280/02/3807-1014$27.00 2002 MAIK Nauka/Interperiodica

BARBIER-TYPE ADDITION OF ALKYL HALIDES TO ALDEHYDES
1015
alcohol VIIIa and product of its dehydration, phenyl-
butadiene IXa (Scheme 3). An analogous reaction
with p-chlorobenzaldehyde gave 1-(p-chlorophenyl)-
aldehyde. In the reaction of iodide III with Fe(CO)5
nucleophilic hexyl radical is formed, and its oxidation
to the corresponding carbocation is more probable.
As a result, a different reaction path is observed.
3-buten-1-ol (VIIIb) and 1-p-chlorophenyl)-1,3-buta-
diene (IXb) in an overall yield of 30%. No corre-
sponding adducts were formed from p-methoxybenz-
aldehyde under the same conditions.
Presumably, just favorable combination of polar
factors in the transition state like A in the case of
perfluorobutyl iodide (which is unfavorable in the
case of hexyl iodide) determines the final result of
the reaction with aldehydes.
Scheme 3.
Probably, allyl halides occupy an intermediate
place between perfluoroalkyl and alkyl iodides, and
the electrophilicity of aldehyde is significant. Elec-
tron-donor methoxy group reduces the electrophilicity
of the reaction center, and no reaction occurs.
II, Z = Br (a), I (b); IV, VIII, IX, X = H (a), p-Cl (b),
p-MeO (c).
The results of the present work led us to conclude
that the nature of substituents in both reactants,
aldehyde and alkyl halide, exerts a considerable effect
In a control experiment, iodide IIb was brought
into reaction with an equimolar mixture of aldehydes
IVa and IVc. Only benzaldehyde adduct VIIIa was
detected in the reaction mixture. We succeeded in
obtaining adducts of allyl bromide (IIa) with alde-
hydes IVa and IVb only in HMPA, while aldehyde
IVc failed to react with bromide IIa.
In the reactions of hexyl iodide (III) with alde-
hydes IVa IVc in the presence of Fe(CO)5 we
isolated about 30% of dihexyl ketone (X) instead of
the expected adducts like VIII (Scheme 4). Ketone
X was also obtained in a blank experiment (with no
aldehyde).
on Fe(CO) -promoted Barbier-type reactions.
5
sec-Perfluoropropylarylcarbinols are known to be
obtained in 40% yield with the use of preliminarily
prepared (perfluoroalkyl)(tetracarbonyl)iron iodides
which are fairly difficultly accessible [5, 6]; moreover,
organometallic syntheses require low temperatures
( 20 to 80 C) and long time (30 50 h), while the
yields of the target products are poor (10 30%) [7].
We believe that the proposed procedure involving
pentacarbonyliron, despite relatively low yields, can
be regarded as an alternative to the known methods.
Its advantages are experimental simplicity (heating
of a mixture of reactants in benzene at 65 70 C for
Scheme 4.
2
3 h) and sufficiently high selectivity.
EXPERIMENTAL
We previously [1, 2] proposed and substantiated
The mass spectra were obtained on a Magnum
a scheme of reactions promoted by Fe(CO) . Accord-
Finnigan MAT mass spectrometer coupled with a gas
chromatograph (25-m Ultra-2 column; oven tempera-
ture programming from 30 to 220 C at 2.5 deg/min).
GLC analysis was performed on an LKhM-80 chrom-
atograph (1300 3-mm steel column packed with
15% of SKTFT-50Kh on Chromaton-N-AW; carrier
5
ing to this scheme, organohalogen substrate initially
gives rise to the corresponding radical which is
reduced to carbanion. The latter reacts with relatively
electrophilic aldehyde carbonyl group inside the
iron carbonyl complex. In reactions with iodide I,
perfluorobutyl radical generated in the first stage is
strongly electrophilic. It is capable of being reduced to
3
gas helium at a flow rate of 60 cm /min; thermal-
conductivity detector; oven temperature programming
1
carbanion which could attack carbonyl carbon atom of from 50 to 250 C at 6 deg/min). The H NMR spectra
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 38 No. 7 2002

1
016
VASIL’EVA et al.
were recorded on a Bruker WP-200 spectrometer at
00 MHz using CDCl as solvent; the chemical shifts
were measured relative to tetramethylsilane. All
4.68 t (1H, CH, J = 6 Hz); 5.08 5.17 m (2H, CH );
2
2
5.68 5.88 m (1H, CH ); 7.30 7.35 m (5H, C H ).
3
6
5
1
3
C NMR spectrum, C, ppm: 127.4 (CH ); 118.2
(CH ); 73.2 (CHO); 43.7 (CH ); 143.7, 134.4,
organic reagents were purified by distillation; Fe(CO)5
2
2
(97%, Fluka) was used without additional purification.
128.3, 125.7 (C H ). Mass spectrum, m/z (I , %):
6 5 rel
130 [M H O] (9.5), 107 [M C H ] (100), 77 (47).
2 3 5
+
+
The yields of the products were determined from the
GLC data using ethyl benzoate as reference.
Found, %: C 79.55; H 8.25; C H O. Calculated, %:
1
0
12
Reaction of perfluorobutyl iodide (I) with benz-
C 81.04; H 8.16.
aldehydes in the presence of Fe(CO) . A solution
of 1 mmol of perfluorobutyl iodide (I), 1 mmol of
5
1-Phenyl-1,3-butadiene (IXa). Yield 3%. Mass
+
spectrum, m/z (I , %): 130 [M] (100), 115 (44), 103
rel
aldehyde IVa IVc, 2 mmol of Fe(CO) , and 4 mmol
5
(6), 77 (10).
of pyridine in 1 ml of benzene was heated for 3 h
at 65 C. The mixture was treated with dilute hydro-
chloric acid and extracted with benzene, the extract
was dried over Na SO , and the solvent and unreacted
1
-(p-Chlorophenyl)-3-buten-1-ol (VIIIb). Yield
+
1
1
9.5%. Mass spectrum, m/z (I , %): 182 [M] (6),
64 [M H O] (95), 141 [M C H ] (100); 77 (60).
1
isomers at a ratio of 1:1). Yield 11%. Mass spectrum,
m/z (I , %): 164 [M] (95), 129 [M Cl] (100),
11 [M C H ] (5); 77 (10).
According to the GLC data, no product was formed
in the reaction of allyl iodide with p-methoxybenz-
aldehyde (IVc). In the reaction mixture obtained from
a 1 : 1 mixture of aldehydes IVa and IVc, only
-phenyl-3-buten-1-ol (VIIIa) was identified by GLC
(by comparison with an authentic sample).
Reaction of allyl bromide (IIa) with benzalde-
hydes in the presence of Fe(CO) . All reactions were
carried out by heating a solution of 1 mmol of allyl
bromide (IIa), 1 mmol of aldehyde IVa IVc, 2 mmol
of Fe(CO) , and a catalytic amount of CBrCl in 1 ml
rel
+
2
3
5
2
4
-(p-Chlorophenyl)-1,3-butadiene (IXb) (two
initial compounds were distilled off.
,2,3,3,4,4,5,5,5-Nonafluoro-1-phenyl-1-pentanol
VIa). Yield 18%; conversion of aldehyde IVa 20%;
yield on the reacted aldehyde IVa 90%. Mass spec-
2
+
+
rel
(
+
1
4 5
+
+
trum, m/z (I , %): 326 [M] (1.2), 107 [M C F ]
rel
4 9
(100), 79 (55), 77 (35), 69 (5).
1
-(p-Chlorophenyl)-2,2,3,3,4,4,5,5,5-nonafluoro-
1
-pentanol (VIb). Yield 20%; conversion of aldehyde
1
IVb 30%; yield on the reacted aldehyde IVb 65%.
+
Mass spectrum, m/z (I , %): 360 [M] (10), 141, 143
rel
+
[
M C F ] (100), 77 (57), 69 (15).
4
9
2
,2,3,3,4,4,5,5,5-Nonafluoro-1-(p-methoxy-
5
phenyl)-1-pentanol (VIc). Yield 6%; converson of
aldehyde IVc 35%; yield on the reacted aldehyde IVc
+
1
1
8%. Mass spectrum, m/z (I , %): 356 [M] (20),
5
3
rel
+
of HMPA at 60 C for 5 h.
37 [M C F ] (100), 77 (10), 69 (1).
4
9
1
-Phenyl-3-buten-1-ol (VIIIa). Yield 19%.
2
,2,3,3,4,4,5,5,5-Nonafluoro-1-(2-furyl)-1-pen-
2
0
20
tanol (VII). Yield 18%. n = 1.3760, d4 = 1.5789.
H NMR spectrum, , ppm: 2.69 br.s (1H, OH);
.20 m (1H, CH); 5.40 s, 6.60 s, and 7.40 s (1H each,
CH, furyl). Mass spectrum, m/z (I , %): 316 [M]
10), 97 [M C F ] (100), 69 (20). Found, %:
C 34.11; H 1.62; F 52.00. C H F O . Calculated, %:
1-(p-Chlorophenyl)-3-buten-1-ol (VIIIb). Yield
18%. In the reaction with aldehyde IVc, the mixture
contained no any product (GLC).
Reaction of hexyl iodide (III) with pentacar-
bonyliron. A solution of 1 mmol of hexyl iodide
D
1
5
+
rel
+
(
4
9
(III), 2 mmol of Fe(CO) , and 2 mmol of HMPA in
9
5
9
2
5
C 34.19; H 1.59; F 54.09.
1 ml of benzene was heated for 3 h at 80 C. The
mixture was treated with dilute hydrochloric acid and
extracted with benzene, the extract was dried over
Reaction of allyl iodide (IIb) with benzaldehyde
(IVa) in the presence of Fe(CO) . A solution of
5
Na SO , and the solvent and unreacted initial com-
0
.17 g (1 mmol) of allyl iodide (IIb), 0.11 g (1 mmol)
2
4
pounds were distilled off.
of benzaldehyde (IVa), and 0.39 g (2 mmol) of
1
Fe(CO) in 1 ml of benzene was refluxed for 2 h.
Tridecan-7-one (X). Yield 32%. H NMR spec-
5
The mixture was treated with dilute hydrochloric acid
and extracted with benzene, and the extract was dried 2.0 m (22H, C H ). Mass spectrum, m/z (I , %): 198
trum, , ppm: 2.34 t (4H, CH CO, J = 2 Hz); 1.1
2
5
11
rel
+
+
+
over Na SO and evaporated. The reactions of IIb
[M] (5), 169 [M C2H5] (1), 141 [M C4H9] (15),
2
4
+
+
with aldehydes IVb and IVc were carried out in
128 [C H COCH ] (30), 113 [M C H ] (100),
6 13 3 6 13
+
+
a similar way.
85 [C H ] (45), 43 [C H ] (95).
6 13 3 7
1
-Phenyl-3-buten-1-ol (VIIIa). Yield 11%. 1H
The same product was obtained when the reaction
NMR spectrum, , ppm: 2.48 2.55 m (3H, OH, CH2);
was carried out in the presence of aldehyde IVa IVc.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 38 No. 7 2002

BARBIER-TYPE ADDITION OF ALKYL HALIDES TO ALDEHYDES
1017
REFERENCES
4. Bandini, M., Cozzi, P.G., Melchiorre, P., and
Ronchi, A.U., Angew. Chem., 1999, vol. 111, no. 22,
pp. 3558 3561.
1
.
Terent’ev, A.B., Vasil’eva, T.T., Kuz’mina, N.A.,
Mysov, E.I., Kuznetsov, N.Yu., and Belokon’, Yu.N.,
Izv. Ross. Akad. Nauk, Ser. Khim., 1999, no. 6,
pp. 1132 1138.
5
.
Ratner, V.G., Korolev, V.B., and Pashkevich, K.I.,
Zh. Org. Khim., 1993, vol. 29, no. 9, pp. 1907 1908.
6
.
King, R.B., Stafford, S.I., Treichel, P.M., and
Stone, F.G.A., J. Am. Chem. Soc., 1961, vol. 83,
no. 17, pp. 3604 3608.
2
3
.
.
Terent’ev, A.B., Vasil’eva, T.T., Kuz’mina, N.A.,
Mysova, N.E., and Chakhovskaya, O.V., Russ. J. Org.
Chem., 2001, vol. 37, no. 9, pp. 1273 1275.
Zhang, Y. and Wu, W., Tetrahedron: Asymmetry,
7. Henne, A.L. and Franci, M.C., J. Am. Chem. Soc.,
1
997, vol. 8, no. 21, pp. 3575 3578.
1953, vol. 75, no. 3, pp. 992 994.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 38 No. 7 2002