Bu4N[Fe(CO)3(NO)]-catalyzed hydrosilylation of aldehydes and ketones

Article abstract of DOI:10.1002/ejoc.201100717

The nucleophilic Fe complex Bu₄N[Fe(CO)₃(NO)] (TBAFe) has been used as a highly active catalyst for the mild hydrosilylation of a variety of functionalized aldehydes and ketones using inexpensive PMHS as stoichiometric reductant. The corresponding alcohols were obtained in good-to-excellent yields at low catalyst loadings of only 1 mol-% and reaction temperatures of 30-50 °C.

Full text of DOI:10.1002/ejoc.201100717

FULL PAPER
DOI: 10.1002/ejoc.201100717
Bu4N[Fe(CO)3(NO)]-Catalyzed Hydrosilylation of Aldehydes and Ketones
André P. Dieskau,[a] Jeanne-Marie Begouin,[b] and Bernd Plietker*[a]
Keywords: Iron / Hydrosilylation / Reduction / Ketones / Aldehydes / Alcohols
The nucleophilic Fe complex Bu4N[Fe(CO)3(NO)] (TBAFe)
ant. The corresponding alcohols were obtained in good-to-
has been used as a highly active catalyst for the mild hydro- excellent yields at low catalyst loadings of only 1 mol-% and
silylation of
a
variety of functionalized aldehydes and
reaction temperatures of 30–50 °C.
ketones using inexpensive PMHS as stoichiometric reduct-
cleophilicity of this ferrate we wondered whether this com-
plex would also catalyze the hydrosilylation of carbonyl
groups. This transformation would not only extend the re-
action scope of TBAFe but also be a test for its ability to
activate the Si–H σ bond. Herein we describe our investi-
gations that led to the development of a practical, widely
applicable hydrosilylation of aldehydes and ketones in the
presence of only 1 mol-% of TBAFe at ambient or slightly
elevated temperatures.
Introduction
The reduction of carbonyl groups in the presence of
other oxidized functional groups, for example, alkenes/
alkynes, nitro groups, or carboxylic acid derivatives, using
established procedures based on active metal hydrides often
faces chemoselectivity issues. Furthermore, the strong basic
character of some of the most common metal hydrides
leads to undesired side-reactions such as epimerization or
deprotonation. Hence there is a serious demand for new,
mild, and chemoselective reducing methods.
Catalytic hydrosilylation is an attractive alternative for
the reduction of carbonyl groups. Apart from anion-cata-
lyzed protocols,[1,2] the metal-catalyzed version has evolved
as a particularly powerful tool for the transformation of
aldehydes or ketones into alcohols. High enantioselectivities
in hydrogen atom transfer to the carbonyl carbon atom
have been achieved by employing chiral ligands.[3] Most of
the methods reported to date employ metal complexes[4]
based on Ru,[5] Rh,[6] Ir,[7] and Cu.[8] Within the past
10 years, Fe-catalyzed versions of the hydrosilylation of car-
bonyl groups have been described.[9,10] The low prices of
these catalysts and the fact that Fe-containing complexes
are metabolizable make these catalytic transformations par-
ticularly amenable to applications in medicinal or industrial
chemistry.[11]
Results and Discussion
Our investigations started with a screening of different
solvents using TBAFe as the catalyst, triphenylphosphane
as the ligand, and polymethylhydrosiloxane (PMHS) for the
hydrosilylation of acetophenone (Table 1). In this two-step
process acetophenone is first reduced to the polymeric silyl
ether intermediate, which delivers 1-phenylethanol upon
treatment with aqueous NaOH. We wanted to focus on a
cheap, readily available silane source like PMHS[15] to keep
this process as economical as possible. At a reaction tem-
perature as low as 30 °C, 1,4-dioxane was identified as the
best solvent.
Subsequently, different phosphane ligands were screened
at a catalyst loading of only 1 mol-% (Scheme 1). In anal-
ogy to previously reported Fe-catalyzed hydrosilylation re-
actions,[10] electron-rich phosphanes such as PCy3 or PMes3
gave the best results. Notably, only 1 mol-% of the catalyst/
ligand system successfully converts the ketone into the
alcohol.
Electron-rich phosphanes are known to undergo oxi-
dation reactions. To exclude the possibility of the ligand or
the oxidized ligand being the active catalyst in the hydro-
silylation reactions, control experiments were conducted in
the absence of the iron catalyst under otherwise identical
conditions. In no case was a conversion of acetophenone
into 1-phenylethanol observed. Thus, the new protocol was
subsequently applied to the hydrosilylation of different
ketones (Table 2).
Recently we added Bu4N[Fe(CO)3(NO)] (TBAFe) as a
nucleophilic catalyst to the portfolio of Fe catalysts.[12] This
complex, which is available in one step from [Fe(CO)5],
NaNO2, and Bu4NBr as an air- and moisture-stable solid,
proved to be a potent catalyst in allylic substitution[13] or
transesterification[14] reactions. With regard to the high nu-
[a] Institut für Organische Chemie, Universität Stuttgart,
Pfaffenwaldring 55, 70569 Stuttgart, Germany
Fax: +49-711-685-64285
E-mail: bernd.plietker@oc.uni-stuttgart.de
[b] Current address: Institut für Organische Chemie, RWTH
Aachen,
Landoltweg 1, 52074 Aachen, Germany
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201100717.
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A. P. Dieskau, J.-M. Begouin, B. Plietker
Table 2. TBAFe-catalyzed hydrosilylation of ketones.
FULL PAPER
Table 1. Solvent and temperature effects in the TBAFe-catalyzed
hydrosilylation of ketones.
Entry[a]
Solvent
T [°C]
Conversion [%][b]
1
2
3
4
5
6
7
THF
THF
THF
THF
80
60
40
30
30
30
30
30
30
100
100
69
51
54
39
31
65
0
DME
toluene
hexane
1,4-dioxane
1,4-dioxane
8
9[c]
[a] All reactions were performed on a 1-mmol scale in dry solvents
(1 mL) under N2 in the presence of TBAFe (0.01 mmol) and PPh3
(0.011 mmol) at the given temperature. [b] Conversions determined
by GC after basic work-up using dodecane as internal standard.
[c] Reaction in the absence of TBAFe.
[a] All reactions were performed on a 1-mmol scale in dry 1,4-
dioxane (1 mL) under N2 in the presence of TBAFe (0.01 mmol)
and PCy3 (0.011 mmol) at 30 °C. [b] Isolated yields after basic
work-up. [c] 2.5 mol-% catalyst, reaction at 50 °C. [d] 2.5 mol-%
catalyst, reaction at 30 °C.
The results show that this reaction is broadly applicable
to a variety of different aromatic and aliphatic ketones. All
the substrates were fully converted into the corresponding
alcohols essentially in quantitative yields. Aliphatic and
very electron-rich aromatic ketones required a slightly
higher catalyst loading and/or reaction temperature (en-
tries 3, 5, 6, 8–10, Table 2). Interestingly the benzyloxy-
methyl (BOM) protecting group, which is known to be sus-
ceptible to hydrogenative cleavage, is tolerated (entry 5,
Table 2).
More complex ketones 24 and 26 were subjected to the
standard conditions to analyze both the chemo- and stereo-
selective course of the hydrosilylation reaction. The corre-
sponding alcohols 25 and 27 were obtained in moderate-
to-excellent yields but only moderate diastereoselectivities.
However, no 1,4-reduction or π-bond isomerization of
ketone 26 was observed (Scheme 2).
Subsequent attempts to hydrosilylate aldehydes under the
aforementioned conditions were initially not successful.
Fortunately, an increase of the reaction temperature to
50 °C led to the full conversion of a variety of different
aldehydes (Table 3).
Scheme 1. Ligand effects in the TBAFe-catalyzed hydrosilylation
reaction of acetophenone.
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Hydrosilylation of Aldehydes and Ketones
an aldehyde and a methyl ketone failed. However, the corre-
sponding diol was obtained in good yield as the only prod-
uct (entry 13, Table 3).
Conclusions
We have presented herein our results of the TBAFe-cata-
lyzed chemoselective hydrosilylation of aldehydes and
ketones. The reaction is characterized by a very low catalyst
loading of only 1 mol-% TBAFe,[16] a low reaction tempera-
ture, its operational simplicity, and high yields of the de-
sired alcohols. A variety of functional groups are tolerated
and 1,4-reductions were not observed. We are currently in-
vestigating the mechanism of this new reaction to shed light
on the question of how the nucleophilic ferrate activates Si–
H bonds. In future work we will also concentrate on identi-
fying complexes that might allow for an efficient asymmet-
ric induction as well as on extending this method to further
unsaturated starting materials.
Scheme 2. Chemo- and stereoselective course of the reaction.
Table 3. TBAFe-catalyzed hydrosilylation of aldehydes.
Experimental Section
General: All the reactions and manipulations that are sensitive to
air or moisture were performed under dry nitrogen by using stan-
dard Schlenk techniques. All solvents were purified prior to use.
Commercial reagents were used as received; all liquid aldehydes
were distilled prior to use. Thin-layer chromatography (TLC) was
conducted on aluminium sheets (silica gel 60 F254) with visualiza-
tion performed by exposure to UV light or staining with anisal-
dehyde. Flash chromatography was performed with silica gel. The
eluent used is reported in parentheses. 1H NMR spectra were re-
corded with 500, 360, or 250 MHz spectrometers. 13C NMR spec-
tra were recorded at 126, 90.6, or 63 MHz. Chemical shifts are
reported in ppm relative to the solvent signal. Multiplicity is indi-
cated as follows: s (singlet), d (doublet), t (triplet), q (quartet), m
(multiplet), and dd (doublet of doublets); J values are given in
Hertz. Low-resolution mass spectra were recorded by using GC–
MS, EI, or ESI technique. High-resolution mass spectra were ob-
tained by using the EI or ESI ionization method.
General Procedure for the TBAFe-Catalyzed Hydrosilylation Reac-
tions:
A Schlenk tube was charged with TBAFe (4.12 mg,
0.01 mmol, 1 mol-%) and PCy3 (3.1 mg, 0.011 mmol, 1.1 mol-%)
under argon at ambient temperature. Dry 1,4-dioxane (0.5 mL) was
added and the mixture was stirred at 80 °C for 1 h. The reaction
medium was cooled to room temperature and PMHS (0.18 mL,
3 mmol, 3 equiv.), the ketone or aldehyde (1 mmol), and dry 1,4-
dioxane (0.5 mL) were added and the resulting mixture was stirred
at the given temperature until TLC indicated complete conversion.
The reaction medium was then allowed to cool to ambient tem-
perature. MeOH (1 mL) was added to the reaction mixture and an
aqueous solution of 2 n NaOH (1.5 mL) was added dropwise. The
resulting mixture was stirred at room temperature for 1.5 h and
then extracted with ethyl acetate (3ϫ 20 mL). The organic layers
were washed with brine (1ϫ 10 mL), dried with anhydrous
Na2SO4, and the solvent was removed in vacuo. The crude product
was purified by column chromatography on silica gel using petro-
leum ether/ethyl acetate as eluent.
[a] All reactions were performed as indicated in Table 2 at 50 °C.
[b] Isolated yields. [c] 2.5 mol-% of catalyst, reaction at 50 °C. [d]
The corresponding diol was obtained as the sole product.
The TBAFe-catalyzed hydrosilylation of aldehydes dis-
plays remarkable functional group tolerance. Even at the
slightly elevated temperature, functional groups that are
susceptible to reduction, such as NO2, CN, and CO2Me,
remained intact (entries 3, 4, and 6, Table 3). Electron-rich
aldehydes required slightly higher catalyst loadings.
Furthermore, synthetically useful heterocyclic compounds
known to coordinate to metal centers with concomitant in-
hibition of the catalytic activity are tolerated (entries 8–10,
Table 3). The corresponding alcohols were obtained in al-
1-Phenylethanol (2): Alcohol 2 was obtained according to the gene-
1
ral procedure as a yellow oil (121 mg, 99%). H NMR (300 MHz,
most quantitative yield. Attempts to differentiate between CDCl3): δ = 7.40–7.27 (m, 5 H), 4.91 (q, 1 H), 1.77 (s, 1 H), 1.50
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A. P. Dieskau, J.-M. Begouin, B. Plietker
(d, 3 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 145.8, 128.5, 127.5, (s) cm–1. MS (EI, 70 eV): m/z (%) = 150 (77), 131 (30), 121 (100),
FULL PAPER
125.4, 70.5, 25.2 ppm. IR: ν = 3344 (m), 3029 (w), 2972 (m), 1451
105 (25), 77 (27), 65 (25), 51 (20).
˜
(m), 1076 (m), 898 (m), 760 (m), 698 (s) cm–1. MS (EI, 70 eV): m/z
1,2,3,4-Tetrahydronaphthalen-1-ol (21): Alcohol 21 was obtained
according to the general procedure as a pale-yellow oil (147 mg,
95%). Rf = 0.37 (petroleum ether/ethyl acetate, 5:1). 1H NMR
(300 MHz, CDCl3): δ = 7.28 (m, 1 H), 7.04–6.95 (m, 3 H), 4.62 (t,
J = 4.1 Hz, 1 H), 2.72–2.51 (m, 2 H), 1.85–1.61 (m, 5 H) ppm. 13C
NMR (75 MHz, CDCl3): δ = 138.7, 137.0, 128.9, 128.6, 127.4,
(%) = 122 (43), 107 (100), 79 (80), 77 (42), 51 (18), 43 (20).
1-(4-Methoxyphenyl)ethanol (15): Alcohol 15 was obtained accord-
ing to the general procedure as a yellow oil (143 mg, 94%). Rf =
0.20 (petroleum ether/ethyl acetate, 5:1). 1H NMR (300 MHz,
CDCl3): δ = 7.33–7.28 (m, 2 H), 6.91–6.86 (m, 2 H), 4.86 (q, 1 H),
3.81 (s, 3 H), 1.48 (d, 3 H) ppm. 13C NMR (75 MHz, CDCl3): δ =
126.0, 68.0, 32.2, 29.2, 18.8 ppm. IR: ν = 3342 (s), 2916 (s), 1605
˜
(w), 1443 (m), 1278 (m), 1200 (w), 1045 (s), 961 (w), 745 (w) cm–1.
MS (EI, 70 eV): m/z (%) = 148 (43), 147 (42), 130 (98), 129 (41),
120 (100), 119 (65), 115 (26), 104 (40), 91 (67), 77(18).
159.0, 138.0, 126.7, 113.9, 70.0, 55.3, 25.0 ppm. IR: ν = 3346 (m),
˜
2969 (m), 2836 (w), 1611 (m), 1510 (s), 1240 (s), 1173 (s), 1032 (s),
895 (m), 829 (s) cm–1. MS (EI, 70 eV): m/z (%) = 152 (4), 137 (100),
109 (38), 94 (12), 77 (17), 43 (10).
Cyclopentanol (22): Alcohol 22 was obtained according to the gene-
ral procedure as a pale-yellow oil (86 mg, 99%). Rf = 0.52 (petro-
leum ether/ethyl acetate, 2:1). 1H NMR (300 MHz, CDCl3): δ =
4.19 (m, 1 H), 1.63 (m, 1 H), 1.42 (m, 4 H) ppm. 13C NMR
Cyclopropyl(phenyl)methanol (16): Alcohol 16 was obtained accord-
ing to the general procedure as a yellow oil (147 mg, 99%). Rf =
0.35 (petroleum ether/ethyl acetate, 5:1). 1H NMR (300 MHz,
CDCl3): δ = 7.43–7.24 (m, 5 H), 3.99 (d, 1 H), 2.08 (s, 1 H), 1.26–
1.15 (m, 1 H), 0.67–0.48 (m, 4 H) ppm. 13C NMR (75 MHz,
CDCl3): δ = 143.9, 128.4, 127.5, 126.0, 78.6, 19.2, 3.6, 2.8 ppm. IR:
(75 MHz, CDCl ): δ = 74.0, 35.5, 23.3 ppm. IR: ν = 3368 (m), 2960
˜
3
(m), 1214 (s), 751 (s) cm–1. MS (EI, 70 eV): m/z (%) = 86 (10), 58
(14), 57 (100), 44 (33), 41 (15), 39 (12).
ν = 3355 (w), 3005 (w), 1493 (w), 1452 (w), 1023 (s), 919 (w), 737
˜
Cyclohexanol (23): Alcohol 23 was obtained according to the gene-
ral procedure as a pale-yellow oil (93 mg, 93%). Rf = 0.53 (petro-
leum ether/ethyl acetate, 2:1). 1H NMR (300 MHz, CDCl3): δ =
3.64–3.58 (m, 1 H), 1.91–1.14 (m, 10 H) ppm. 13C NMR (75 MHz,
(m), 697 (s) cm–1. MS (EI, 70 eV): m/z (%) = 147 (1), 120 (100),
104 (19), 91 (38), 77 (30).
1-(2-Naphthyl)ethanol (17): Alcohol 17 was obtained according to
the general procedure as a colorless solid (171 mg, 99%). Rf = 0.18
(petroleum ether/ethyl acetate, 5:1); m.p. 69–71 °C. 1H NMR
(300 MHz, CDCl3): δ = 7.85–7.81 (m, 4 H), 7.52–7.43 (m, 2 H),
5.07 (q, 1 H), 1.87 (s, 1 H), 1.58 (m, 3 H) ppm. 13C NMR (75 MHz,
CDCl3): δ = 143.2, 133.3, 132.9, 128.3, 127.7, 126.2, 125.8, 123.8,
CDCl ): δ = 70.3, 35.5, 25.5, 24.2 ppm. IR: ν = 3400 (m), 2360 (w),
˜
3
1113 (s), 745 (s) cm–1. MS (EI, 70 eV): m/z (%) = 100 (3), 82 (46),
71 (13), 67 (27), 57 (100), 54 (15), 44 (24), 41 (22), 39 (11), 29 (10),
27(11).
(1S,2S,5R)-2-Isopropyl-5-methylcyclohexanol (25): Alcohol 25 was
obtained according to the general procedure as a colorless oil as a
mixture of diastereomers (25a + 25b: 78 mg, 50%; 25a/25b 60:40).
70.6, 25.2 ppm. IR: ν = 3301 (m), 3052 (m), 2970 (m), 1599 (m)
˜
1362 (m), 1274 (m), 1122 (m), 1071 (s), 822 (s), 740 (s) cm–1. MS
1
(EI, 70 eV): m/z (%) = 172 (30), 157 (35), 129 (100), 77 (10).
Rf = 0.53 (26a), 0.50 (26b) (petroleum ether/ethyl acetate, 1:1). H
NMR (300 MHz, CDCl3) a: δ = 4.04 (m, 1 H), 2.31–2.21 (m, 2 H),
1.67–1.57 (m, 5 H), 1.20–1.19 (m, 2 H), 0.93–0.77 (m, 10 H); b: δ
= 3.45–3.37 (m, 1 H), 2.20–2.14 (m, 1 H), 2.00–1.93 (m, 1 H), 1.64–
1.59 (m, 3 H), 1.41 (m, 2 H), 1.27–1.22 (m, 2 H), 0.97–0.80 (m, 10
H) ppm. 13C NMR (75 MHz, CDCl3): δ = 66.8, 48.1, 42.6, 35.2,
4-[4-(Benzyloxymethoxy)phenyl]butan-2-ol (18): Alcohol 18 was ob-
tained according to the general procedure as a yellow oil (263 mg,
92%). Rf = 0.49 (petroleum ether/ethyl acetate, 2:1). 1H NMR
(300 MHz, CDCl3): δ = 7.33–7.28 (m, 5 H), 7.14–7.10 (m, 2 H),
7.03–7.00 (m, 2 H), 5.26 (s, 2 H), 4.72 (s, 2 H), 3.87–3.76 (m, 1 H),
2.76–2.57 (m, 2 H), 1.78–1.70 (m, 2 H), 1.49 (s, 1 H), 1.22 (d, 3
H) ppm. 13C NMR (75 MHz, CDCl3): δ = 155.5, 137.3, 135.5,
129.3, 128.5, 128.1, 127.9, 116.4, 92.5, 69.9, 67.5, 41.0, 31.3,
29.2, 25.9, 24.2, 22.5, 21.2, 20.7 ppm. IR: ν = 3451 (w), 2922 (m),
˜
2854 (m), 1731 (w), 1268 (m), 1114 (s), 769 (s) cm–1. MS (EI,
70 eV): m/z (%) = 156 (0.9), 138 (30), 123 (48), 109 (17), 95 (87),
81 (90), 71 (100), 67 (40), 55(48).
23.7 ppm. IR: ν = 3369 (w), 2963 (w), 1611 (w), 1509 (s), 1216 (s),
˜
1072 (s), 1000 (s), 826 (m), 735 (s), 696 (s) cm–1. MS (EI, 70 eV):
m/z (%) = 286 (1), 256 (9), 91 (100), 77 (5), 65 (8). HRMS (ESI):
calcd. for C18H22O3 [M + Na]+ 309.1467; found 309.1461.
4-(2,6,6-Trimethylcyclohex-2-enyl)but-3-en-2-ol
(α-Ionol,
27):
Alcohol 27 was obtained according to the general procedure as a
colorless oil (182 mg, 94%). Rf = 0.81 (petroleum ether/ethyl acet-
ate, 1:1). 1H NMR (300 MHz, CDCl3): δ = 5.56–5.38 (m, 3 H),
4.30 (quint., J = 6.2 Hz, 1 H), 2.10–1.98 (m, 3 H), 1.59–1.57 (m, 4
H), 1.44–1.37 (m, 1 H), 1.27 (d, J = 6.2 Hz, 3 H), 1.14–1.16 (m, 1
H), 0.89 (2 s, 3 H), 0.78 (2 s, 3 H) ppm. 13C NMR (75 MHz,
CDCl3): δ = 135.9, 133.9, 131.3, 121.01, 69.0, 53.9, 31.9, 31.4, 27.6,
1-(2,4-Dimethoxyphenyl)ethanol (19): Alcohol 19 was obtained ac-
cording to the general procedure as a yellow oil (180 mg, 99%). Rf
= 0.42 (petroleum ether/ethyl acetate, 2:1). 1H NMR (300 MHz,
CDCl3): δ = 7.26–7.22 (m, 1 H), 6.49–6.45 (m, 2 H), 5.04 (q, 1 H),
3.83 (s, 3 H), 3.80 (s, 3 H), 2.59 (s, 1 H), 1.48 (d, 3 H) ppm. 13C
NMR (75 MHz, CDCl3): δ = 160.6, 157.8, 131.3, 119.9, 104.0, 98.2,
27.0, 23.0, 22.9, 22.8 ppm. IR: ν = 3340 (m), 2927 (s), 1650 (w),
˜
1455 (m), 870 (s) cm– 1. MS (EI, 70 eV): m/z (%) = 194 (1), 138
68.8, 66.0, 55.3, 22.8 ppm. IR: ν = 3350 (m), 2968 (m), 2836 (w),
˜
(35), 123 (19), 95 (92), 43(100).
1610 (m), 1510 (s), 1240 (s), 1173 (s), 1032 (s), 895 (m), 829 (s) cm–1.
MS (EI, 70 eV): m/z (%) = 182 (7), 137 (100), 109 (38), 94 (12), 77
(17), 43 (9).
Benzyl Alcohol (29): Alcohol 29 was obtained according to the ge-
neral procedure as a colorless oil (102 mg, 94%). Rf = 0.45 (petro-
leum ether/ethyl acetate, 2:1). 1H NMR (300 MHz, CDCl3): δ =
7.32–7.18 (m, 5 H), 4.61 (s, 2 H), 1.92 (s, 1 H) ppm. 13C NMR
Chroman-4-ol (20): Alcohol 20 was obtained according to the gene-
ral procedure as a colorless solid (143 mg, 99%). Rf = 0.38 (petro-
(75 MHz, CDCl ): δ = 139.8, 127.5, 126.6, 126.0, 64.3 ppm. IR: ν
˜
1
3
leum ether/ethyl acetate, 2:1); m.p. 41–42 °C. H NMR (300 MHz,
= 3310 (w), 3030 (w), 2872 (w), 1495 (w), 1453 (m), 1206 (w), 1008
(s), 731 (s), 694 (s) cm–1. MS (EI, 70 eV): m/z (%) = 108 (90), 91
(17), 79 (100), 51 (26).
CDCl3): δ = 7.32–7.18 (m, 2 H), 6.95–6.82 (m, 2 H), 4.77 (t, 1 H),
4.28–4.24 (m, 2 H), 2.19–1.98 (m, 2 H), 1.88 (s, 1 H) ppm. 13C
NMR (75 MHz, CDCl3): δ = 154.6, 129.7, 129.7, 124.3, 120.6,
117.1, 63.2, 61.9, 30.8 ppm. IR: ν = 3336 (w), 2882 (w), 1608 (w),
1583 (w), 1486 (s), 1454 (m), 1219 (s), 1059 (s), 1014 (m), 751
(Biphenyl-4-yl)methanol (30): Alcohol 30 was obtained according
to the general procedure as a yellow solid (166 mg, 90%). Rf = 0.10
˜
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Hydrosilylation of Aldehydes and Ketones
1
(petroleum ether/ethyl acetate, 5:1); m.p. 103–106 °C. 1H NMR (ethyl acetate). H NMR (250 MHz, CDCl3): δ = 8.54–8.88 (m, 1
(300 MHz, CDCl3): δ = 7.47–7.41 (m, 4 H), 7.38–7.32 (m, 5 H), H), 7.69 (m, 1 H), 7.18–7.29 (m, 2 H), 4.75 (s, 2 H), 3.16 (br. s, 1
4.75 (s, 2 H), 1.63 (s, 1 H) ppm. 13C NMR (75 MHz, CDCl3): δ = H) ppm. 13C NMR (250 MHz, CDCl3): δ = 159.6, 148.4, 136.9,
140.8, 140.7, 139.9, 128.8, 127.5, 127.3, 127.1, 65.1 ppm. IR: ν =
122.3, 120.8, 64.3 ppm. IR (film): ν = 3206, 2853, 1595, 1572, 1478,
˜
˜
3238 (m), 3031 (w), 2923 (w), 1484 (m), 1404 (m), 1122 (w), 1037
1434, 1053, 755, 728 cm–1. MS (EI, 70 eV): m/z (%) = 108 (100),
(s), 995 (s), 817 (m), 749 (s), 730 (s), 683 (s) cm–1. MS (EI, 70 eV): 80 (71), 109 (49), 78 (37), 52 (36), 79 (31), 51 (31), 53 (27).
m/z (%) = 184 (100), 165 (24), 155 (90), 128 (16), 115 (17), 77 (40).
(Furan-2-yl)methanol (38): Alcohol 38 was obtained according to
4-(Hydroxymethyl)benzonitrile (31): Alcohol 31 was obtained ac-
cording to the general procedure as a colorless oil (114 mg, 90%).
Rf = 0.05 (petroleum ether/ethyl acetate, 5:1). 1H NMR (300 MHz,
CDCl3): δ = 7.61 (d, 2 H), 7.46 (d, 2 H), 4.75 (s, 2 H), 2.65 (s, 1
H) ppm. 13C NMR (75 MHz, CDCl3): δ = 146.5, 132.3, 127.0,
the general procedure as a yellow oil (91 mg, 93%). Rf = 0.81 (ethyl
acetate). 1H NMR (250 MHz, CDCl3): δ = 7.49–7.52 (m, 1 H),
6.33–6.6.36 (m, 1 H), 6.28 (m, 1 H), 4.59 (s, 2 H), 2.04 (s, 1 H) ppm.
13C NMR (250 MHz, CDCl3): δ = 154.1, 142.5, 110.3, 107.7,
57.4 ppm. IR (film): ν = 2931, 1504, 1417, 1259, 1190, 1076, 1002,
˜
912 cm–1. MS (EI, 70 eV): m/z (%) = 98 (100), 81 (74), 53 (73), 69
118.9, 110.9, 64.0 ppm. IR: ν = 3312 (s), 3068 (w), 2924 (w), 2232
˜
(s), 1610 (w), 1415 (m), 1208 (m), 1028 (s), 1017 (s), 816 (s), 643
(m) cm–1. MS (EI, 70 eV): m/z (%) = 133 (34), 104 (100), 77 (40),
51 (25).
(55).
Decan-1-ol (39): Alcohol 39 was obtained according to the general
procedure as a colorless oil (103 mg, 65%). Rf = 0.55 (petroleum
ether/ethyl acetate, 3:1). 1H NMR (250 MHz, CDCl3): δ = 3.50–
3.91 (m, 2 H), 2.45 (br. s, 1 H), 1.15–1.66 (m, 16 H), 0.81 (m, 3
H) ppm. 13C NMR (250 MHz, CDCl3): δ = 63.0, 32.7, 31.7, 29.6,
Methyl 4-(Hydroxymethyl)benzoate (32): Alcohol 32 was obtained
according to the general procedure as a colorless solid (147 mg,
89%). Rf = 0.08 (petroleum ether/ethyl acetate, 5:1); m.p. 49–50 °C.
1H NMR (300 MHz, CDCl3): δ = 8.04–8.01 (m, 2 H), 7.45–7.42
(m, 2 H), 4.77 (s, 2 H), 3.92 (s, 3 H), 1.89 (s, 1 H) ppm. 13C NMR
(75 MHz, CDCl3): δ = 167.0, 146.0, 129.9, 129.3, 126.5, 64.7,
29.5, 29.4, 29.3, 25.8, 22.7, 14.1 ppm. IR (film): ν = 3341, 2922,
˜
1711, 1465, 1377, 1032 cm–1. MS (EI, 70 eV): m/z (%) = 158 (3),
55 (100), 83 (79), 69 (78), 70 (51), 56 (48).
52.1 ppm. IR: ν = 3294 (m), 2959 (w), 1718 (s), 1431 (m), 1278 (s),
˜
trans-2,6-Dimethyl-2,6-octadien-8-ol (40): Alcohol 40 was obtained
according to the general procedure as a colorless liquid (148 mg,
96%). Rf = 0.87 (ethyl acetate). H NMR (250 MHz, CDCl3): δ =
1191 (m), 1176 (m), 1105 (s), 1044 (s), 952 (m), 750 (m) cm–1. MS
(EI, 70 eV): m/z (%) = 166 (50), 135 (100), 107 (95), 89 (48), 77
(80), 51 (30).
1
5.45–5.50 (m, 1 H), 5.05–5.15 (m, 1 H), 4.05–4.20 (m, 2 H), 2.00–
2.15 (m, 4 H), 1.61–1.69 (m, 9 H) ppm. 13C NMR (250 MHz,
CDCl3): δ = 139.6, 131.7, 124.4, 123.8, 58.9, 39.5, 26.4, 25.7, 17.7,
[4-(Trifluoromethyl)phenyl]methanol (33): Alcohol 33 was obtained
according to the general procedure as a yellowish oil (175 mg,
99%). Rf = 0.15 (petroleum ether/ethyl acetate, 5:1). 1H NMR
(300 MHz, CDCl3): δ = 7.59 (d, 2 H), 7.45 (d, 2 H), 4.73 (s, 2 H),
2.25 (s, 1 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 144.7, 129.7
16.3 ppm. IR (film): ν = 3316, 2967, 2915, 1445, 1377, 1087 cm–1.
˜
MS (EI, 70 eV): m/z (%) = 154 (2), 69 (100), 68 (21), 123 (15), 93
(14).
(q), 126.8, 125.5 (q), 124.2 (q), 64.4 ppm. IR: ν = 3318 (w), 1621
˜
1-[4-(Hydroxymethyl)phenyl]ethanol (41): Alcohol 41 was obtained
according to the general procedure as a pale-yellow oil (114 mg,
75%). Rf = 0.20 (petroleum ether/ethyl acetate, 2:1). 1H NMR
(300 MHz, CDCl3): δ = 7.31–7.26 (m, 4 H), 4.83 (q, J = 6.5 Hz, 1
H), 4.59 (s, 2 H), 2.58 (s, 2 H), 1.44 (d, J = 6.5 Hz, 3 H) ppm. 13C
NMR (75 MHz, CDCl3): δ = 145.3, 140.1, 127.2, 125.6, 70.2, 65.0,
(w), 1419 (w), 1321 (s), 1160 (m), 1107 (s), 1064 (s), 1014 (s), 816
(m) cm–1. MS (EI, 70 eV): m/z (%) = 176 (68), 157 (28), 145 (28),
127 (100), 107 (78), 79 (55).
(4-Nitrophenyl)methanol (34): Alcohol 34 was obtained according
to the general procedure as a dark-orange solid (145 mg, 95%). Rf
= 0.10 (petroleum ether/ethyl acetate, 5:1); m.p. 89–91 °C. 1H NMR
(300 MHz, CDCl3): δ = 8.24–8.20 (m, 2 H), 7.53 (d, 2 H), 4.84 (s,
2 H), 1.93 (s, 1 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 148.1,
29.7 ppm. IR: ν = 3355 (m), 2924 (m), 2362 (w), 1663 (w), 1420
˜
(w), 1720 (w), 1214 (s), 1088 (w), 1009 (w), 749 (s) cm–1. MS (EI,
70 eV): m/z (%) = 152 (10), 137 (94), 121 (13), 107 (24), 103 (7), 91
(50), 83 (7), 79 (100), 74 (5), 63 (8), 51(21).
147.3, 127.0, 123.8, 64.0 ppm. IR: ν = 3505 (m), 3111 (w), 2924
˜
(w), 1599 (m), 1503 (s), 1328 (s), 1195 (m), 1054 (s), 828 (s), 733
(s) cm–1. MS (EI, 70 eV): m/z (%) = 153 (18), 136 (14), 107 (53), 89
(35), 77 (100), 63 (20), 51 (37).
Supporting Information (see footnote on the first page of this arti-
1
cle): H NMR spectra for all reported compounds.
(4-tert-Butylphenyl)methanol (35): Alcohol 35 was obtained accord-
ing to the general procedure as a yellow oil (157 mg, 99%). Rf =
0.57 (petroleum ether/ethyl acetate, 5:1). 1H NMR (300 MHz,
CDCl3): δ = 7.42–7.22 (m, 4 H), 4.60 (s, 2 H), 2.16 (s, 1 H), 1.31
(s, 9 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 150.7, 138.0, 126.9,
Acknowledgments
Financial support by the Studienstiftung des Deutschen Volkes
(Ph. D. grant to A. P. D.) and the Deutsche Forschungsgemein-
schaft (DFG) are gratefully acknowledged. We thank D. Oschetzki
and M. Messner for experimental support.
125.5, 65.1, 34.6, 31.4 ppm. IR: ν = 3317 (m), 2960 (s), 2867 (m),
˜
1513 (w), 1362 (m), 1268 (m), 1107 (s), 1012 (s), 802 (s) cm–1. MS
(EI, 70 eV): m/z (%) = 164 (18), 149 (100), 91 (30), 77(11).
(Pyridin-3-yl)methanol (36): Alcohol 36 was obtained according to
the general procedure as a yellow oil (106 mg, 97%). Rf = 0.23
(ethyl acetate). H NMR (250 MHz, CDCl3): δ = 8.5 (s, 1 H), 8.43
[1] For fluoride-mediated or -catalyzed hydrosilylation reactions,
see: a) C. Chuit, R. J. P. Corriu, R. Perz, C. Reyé, Synthesis
1982, 981; b) J. Boyer, R. J. P. Corriu, R. Perz, C. Reyé, Tetra-
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1
(m, 1 H), 7.73 (m, 1 H), 7.25–7.33 (m, 1 H), 4.72 (s, 2 H), 3.77 (s,
1 H) ppm. 13C NMR (250 MHz, CDCl3): δ = 148.0, 147.8, 137.3,
137.2, 123.6, 61.9 ppm. IR (film): ν = 3206, 1596, 1580, 1426 cm–1.
˜
MS (EI, 70 eV): m/z (%) = 108 (78), 80 (100), 109 (66), 53 (37), 51
(32), 52 (20), 78 (17), 81 (16), 91 (14).
(Pyridin-2-yl)methanol (37): Alcohol 37 was obtained according to
the general procedure as a yellow liquid (103 mg, 94%). Rf = 0.21
Eur. J. Org. Chem. 2011, 5291–5296
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5295

A. P. Dieskau, J.-M. Begouin, B. Plietker
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Received: May 23, 2011
Published Online: July 28, 2011
5296
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© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2011, 5291–5296