Synthesis of unsymmetrical alkyl acetals via addition of primary alcohols to allyl ethers mediated by ruthenium complexes

Article abstract of DOI:10.1007/s00706-011-0638-8

Ru-catalyzed synthesis of mixed alkyl-alkyl acetals via addition of primary alcohols to allyl ethers has been extended to include long-chain and/or functionalized substrates. The catalytic systems for these reactions were generated from RuCl₂(PPh₃)₃ and [RuCl ₂(1,5-COD)]_x and phosphines [PPh₃ or P(p-chlorophenyl)₃] or SbPh₃. Of particular importance is the almost quantitative elimination of transacetalization. The addition proceeds through allyl complexes, not via isomerization of allyl ethers - subsequent addition of ROH to vinyl ethers. The Author(s) 2011.

Full text of DOI:10.1007/s00706-011-0638-8

Monatsh Chem (2011) 142:1241–1247
DOI 10.1007/s00706-011-0638-8
ORIGINAL PAPER
Synthesis of unsymmetrical alkyl acetals via addition of primary
alcohols to allyl ethers mediated by ruthenium complexes
•
Stanisław Krompiec Mateusz Penkala Ewelina Kowalska Robert Penczek
•
•
•
•
Piotr Bujak Witold Danikiewicz Grzegorz Spolnik Andrzej Kita
•
•
•
´
Iwona Grudzka
Received: 24 May 2010 / Accepted: 25 August 2011 / Published online: 27 October 2011
Ó The Author(s) 2011. This article is published with open access at Springerlink.com
Abstract Ru-catalyzed synthesis of mixed alkyl–alkyl
acetals via addition of primary alcohols to allyl ethers has
been extended to include long-chain and/or functionalized
substrates. The catalytic systems for these reactions were
generated from RuCl2(PPh3)3 and [RuCl2(1,5-COD)]x and
phosphines [PPh3 or P(p-chlorophenyl)3] or SbPh3. Of
particular importance is the almost quantitative elimination
of transacetalization. The addition proceeds through allyl
complexes, not via isomerization of allyl ethers––sub-
sequent addition of ROH to vinyl ethers.
in the literature. Also, synthesis of some mixed acetals
(e.g., tetrahydropyranyl ethers, dioxane and dioxolane
derivatives obtained from unsymmetrical diols) is quite
simple because of the substrate structure. However,
selective synthesis of mixed acetals of the type
R1CH(OR2)(OR3) (where R1, R2, and R3 is alkyl group) is
still difficult. Application of classical methods for the
synthesis of these compounds is not satisfactory, as a
concomitant transacetalization reaction leads to a mixture
of symmetrical and unsymmetrical acetals, which can be
difficult to separate. So far, only two reports describing a
selective method for the preparation of several mixed
acetals have been published. Fujioka and co-workers
obtained mixed acetals by reaction of dimethyl acetals of
the type R1CH(OMe)2 with TESOTf and 2,4,6-collidine
and then by treating the salt obtained with R2OH [9, 10].
However, only alkyl methyl acetals were obtained with
their method. Also a few attempts using transition metal
complexes for the synthesis of mixed alkyl alkyl acetals
have not been successful because of a transacetalization
side reaction [11, 12]. Recently, we have obtained alkyl-
aryl acetals via addition of alcohols and phenols to allyl
ethers [13, 14] and cyclic acetals via cyclization of ally-
loxyalcohols [15]. In the present study, we wish to report
an extension of this methodology to include more func-
tionalized substrates.
Keywords Chemoselectivity Á Homogeneus catalysis Á
Metal complexes Á Mixed acetals
Introduction
Alkyl acetals R1CH(OR2)(OR3) (R1–R3 = alkyl) are
widely used in synthetic organic chemistry as good
protecting groups for aldehydes and ketones [1] in asym-
metric synthesis [2], and also as ‘‘green solvents’’ in the
lacquer and paint industry [3] or as diesel fuel additives
[4]. Likewise, in the food (e.g., green pepper flavor) [5],
fragrance (e.g., lemon or cardamom fragrance) [6, 7], and
pharmaceutical [8] industries, acetals are used both as
intermediates and as end products. There are many
methods for the synthesis of symmetrical acetals reported
Results and discussion
S. Krompiec (&) Á M. Penkala Á E. Kowalska Á R. Penczek Á
P. Bujak Á A. Kita Á I. Grudzka
Mixed acetals of the type CH3CH2CH(OR1)(OR2) were
obtained in the addition of alkyl alcohols to allyl alkyl
ethers. Some of the starting allyl ethers were obtained
under phase transfer catalysis (PTC) conditions, according
to the procedure developed by us enabling practically
Institute of Chemistry, University of Silesia, Katowice, Poland
e-mail: stanislaw.krompiec@gmail.com
´
W. Danikiewicz Á G. Spolnik
Institute of Organic Chemistry, Polish Academy of Science,
Warsaw, Poland
123

1242
S. Krompiec et al.
quantitative conversion of alcohol into allyl ether. This is
of particular importance in the case when ether and alcohol
have similar boiling points. PTC methods described in the
literature do not assure such a quantitative conversion of
ROH into RO-allyl. The mixed acetals prepared from allyl
butyl ether and several primary alcohols are presented in
Table 1. Usually, the most effective catalyst for these
transformations was RuCl2(PPh3)3–[Ru1], but sometimes
better results were obtained in the presence of complexes
generated in situ from [RuCl2(1,5-COD)]x and phosphines
(PPh3–[Ru2] or P(p-chlorophenyl)3–[Ru3] or SbPh3–[Ru4]).
We observed similiar effects during isomerization of allyl
ethers and N-allyl amines: complexes generated in situ
from [RuCl2(1,5-COD)]x and phosphines or phosphites
were extremely effective [16, 17]. Other catalytic systems,
[Ru3(CO)12, [RuCl2(1,5-COD)]x lacking outside ligands,
Ru(acac)3], turned out to be ineffective. The reaction
products were: mixed acetals (products of addition), sym-
metrical acetals (products of transacetalization), and (E)-
and (Z)-butyl (1-propenyl) ethers (products of isomeriza-
tion of BuO-allyl), and cyclic acetal (only for entry 4).
Conversion of the allyl ethers was practically quantitative
and reaction selectivity was very good (entries 4, 7, 8) or
excellent (entries 1, 2, 3, 5, 6).
It is noteworthy that some of the acetals (e.g., 2 and 3)
may be obtained alterable in the reaction of R1Oallyl with
R2OH or R2Oallyl with R1OH.
As reported before [14, 15], addition of tertiary alcohol
(t-BuOH and [Ru1] were investigated) does not occur at
all––probably due to steric factors. In the case of addition of
secondary alcohols, intensive transacetalization was
observed. For example, in the reaction of pentan-2-ol with
allyl butyl ether in the presence of [Ru1], 33% of mixed
acetal and 67% of both symmetrical acetals were obtained
(very similiar results were obtained for cyclohexanol). In
the addition reaction of 9-decen-1-ol to allyl butyl ether, the
stereoselective migration of the double bond in the chain
was observed––but only from the terminal site 9 to the site 8
(8E), with 95% conversion (Table 1, entry 5). Moreover,
the addition of (9Z)-9-octadecene-1-ol to allyl butyl ether
was not accompanied by either double bond migration or
Z/E isomerization (Table 1, entry 6). Obviously, those are
kinetic effects. Significant prolongation of reaction time (5
times more) makes double bond migration along the chain
and Z/E isomerization noticable. It is well known that
double bond migration is much faster if the bond is terminal
rather than internal [18–20]. Also, the Z/E isomerization is
usually much slower than double bond migration [18–20].
Table 1 Synthesis of mixed acetals: addition of different primary alcohols to allyl butyl ether catalysed by ruthenium complexes (120 °C, 3 h)
[Ru]
120 OC, 3h
R2OH
+
+
+
+
R1O
R1O
R2O
OR2
R1O
OR2
R1O
OR1
A
B
C
D
R1, R2 - alkyl
1-13
Entry
R1
R2
Product A
[Ru]
A/%
B/%
C/%
D/%
1
2
3
4
n-Bu
n-Bu
n-Bu
n-Bu
n-C5H11
1
2
3
4
[Ru1], [Ru1a], [Ru2]
[Ru1]
[Ru1]
[Ru1]
[Ru3]
100
100
100
85
0
0
0
0
n-C10H21
0
0
n-C18H37
0
0
0
H3CCHCHO(CH2)2
15
4
0
0
58a
38
0
5
6
7
8
n-Bu
n-Bu
n-Bu
n-Bu
H2CCH(CH2)8
(Z)-H3C(CH2)7CHCH(CH2)8
PhCH2
5
6
7
8
[Ru1]
[Ru1], [Ru1a]
[Ru4]
100b
100
94
0
0
0
0
0
0
2
2
2
F3CCH2
[Ru3], [Ru1a]
96
0
2
2
48
22
15
15
[Ru1] = 1% RuCl2(PPh3)3; [Ru1a] = 0.1% RuCl2(PPh3)3
[Ru2] = 1% [RuCl2(1,5-COD)]x ? PPh3
[Ru3] = 1% [RuCl2(1,5-COD)]x ? P(p-chlorophenyl)3
[Ru4] = 1% [RuCl2(1,5-COD)]x ? SbPh3
a
2-Ethyl-1,3-dioxolane (product of cyclization of alcohol)
b
95% (E)-10-(1-Butoxypropoxy)dec-2-ene and 5% 10-(1-butoxypropoxy)dec-1-ene
123

Synthesis of unsymmetrical alkyl acetals via addition of primary alcohols
1243
Table 2 Synthesis of mixed acetals: addition of 1-butanol to several allyl ethers catalysed by ruthenium complexes (120 °C, 3 h)
Entry
R1Oallyl
Acetal (A)
[Ru]
a/%
A/%
B/%
C/%
D/%
0
9
9
2
[Ru1]
100
90
10
0
OBu
O
O
10
[Ru1]a
[Ru1]b
100
100
72
28
0
0
0
0
0
OBu
Me
100
O
O
8
Me
Me
O
O
8
11
12
3
[Ru1]
[Ru1]a
46
79
21
0
0
0
0
0
OBu
OBu
Me
100
100
16
16
10
[Ru1]
100
100
0
0
0
O
O
13
11
[Ru3]c
[Ru3]e
100
74
76d
100
0
0
0
0
0
0
OBu OBu
O
O
a
130 °C, 3 h
b
c
d
e
130 °C, 20 h
ether:alcohol = 1:2
24% stands for monoacetal (1-[1-(prop-2-en-1-yloxy)propoxy]butane)
ether:alcohol = 1:4
Table 3 Addition of alcohols to 1,4-dibutoxy-2-butene catalyzed by ruthenium complexes (allyl substrate:alcohol:[Ru]:P = 100:100:1:1).
Conversion was quantitative
OBu
OBu
[Ru]
neat
+
ROH
+
BuO
OBu
12, 13
OR
A
OBu
OBu
B
Entry
R
Acetal (A)
Catalytic system
T/°C
t/h
Products
A/%
B/%
14
n-C10H21
12
[Ru1]
[Ru3]
130
130
130
120
120
6
42
58
10
7
12
20
3
90
93
15
9-Decen-1-yl
13
74a
98a
26
2
6
a
95% (E)-10-(1,4-dibutoxybutoxy)dec-2-ene and 5% 10-(1,4-dibutoxybutoxy)dec-1-ene (stereoselective double bond migration was observed)
123

1244
S. Krompiec et al.
Scheme 1
R1O
H
R1O
R2O
H
P2
[Ru]
R1O
R1O
R2O
I4
Ru
H
I1
Ru
H
H
H
L
Ru
R1O
L
O
H
R1O
R2OH
R2
P1
R1O
TS
R1O
R2O
H
H
H
H
Ru
Ru
H
R2O
I3
I2
Mixed acetals were also obtained in the addition reac-
tion of butan-1-ol to allyl ethers of various structures
(Table 2). The bulky allyl t-butyl ether was converted to
the mixed acetal in high yield with good selectivity
(Table 2, entry 9). In the case of synthesis of long chain
acetals, the full conversion was achieved by raising the
temperature from 120 to 130 °C (Table 2, entry 11).
It is also very interesting that the addition of R2OH
(R2 = n-decyl, 9-decen-1-yl) to an ether of the type
R1OCH2CH=CHCH2OR1 (R1 = n-Bu) was possible
(Table 3).
p-allyl complexes, which may occur from ROCH2CH=CH2
(or slowly from ROCH=CHCH3 [15]) but not from
ROCH=CH2. Therefore, the reaction cannot be the two-
step addition of R2OH to R1O-allyl: first, the isomerization
of R1O-allyl to R1O-(1-propenyl), followed by the addition
of R2OH to R1O-(1-propenyl).
What is worth mentioning is that we also developed
methods for the separation of mixed acetals from the
reaction mixtures. It turned out that ruthenium complexes
can be almost quantitatively removed by sorption on the
activated carbon Norit CN-1 (Acros). Traces of ruthenium
were determined by the ICP-OES method. Less than
0.2 ppm of Ru was detected in the acetals. The removal of
ruthenium complexes is of great consequence at higher
temperatures (e.g., at distillation), because if they are not
removed, they can catalyze the transacetalization reaction.
What is of great importance is that we did not observe
any transacetalization during these reactions and that the
isomerized product could be separated from the addition
product by simple distillation.
According to our previous reports [14, 15], the proposed
mechanism of the studied reaction of the addition of
alcohols to allyl ethers is presented in Scheme 1. The first
step consists of the oxidative addition of the allyl ether to
[Ru] through a C(allyl)–H bond, and the hydrido-p-allyl
complex I1 is formed. Reductive elimination of allyl/H
ligands generates the vinyl ether, while the reaction with
R2OH results in the formation of the complex I2. Migration
of R2O to the coordinated allyl ligand leads to the complex
I3 containing the coordinated, unsaturated acetal and two
hydride ligands. Rapid hydrogenation follows through the
complex I4 and the mixed acetal P2 is formed. The com-
plex I3 can also be formed directly from I1 through the
transition state TS.
Experimental
Qualitative and quantitative analyses were performed by the
following methods: nuclear magnetic resonance (1H, 13C
NMR), gas chromatography, mass spectrometry, electro-
spray (ESI) mass spectrometry, and ICP-OES. NMR spectra
were recorded at room temperature on Bruker Avance 400
and Varian Unity 300 apparatus. Chemical shifts of 1H and
13C NMR spectra were related to tetramethylsilane. GC and
GC–MS analyses were performed on Thermo Finnigan
apparatus equipped with a 30-m MDN 5S column and a
mass detector (EI, 40/70 eV). Melting point measurements
were conducted on a Stuart automatic melting point SMP40
apparatus. The sequential spectrometer with an excitation in
the ICP plasma (Spectro Analytical Instruments, Germany)
was used with the following parameters: frequency
27.12 MHz, power 1.1 kW, nebulizer concentric Meinhard,
The proposed mechanism presented above is supported
by the following observations: the addition of alcohols to
vinyl butyl ether does not occur, and 2-vinyloxyethanol
does not undergo cyclization towards 2-methyl-1,3-dioxo-
lane (but 2-allyloxyethanol easily forms 2-ethyl-1,3-
dioxolane [15]). In our opinion, the reaction runs through
123

Synthesis of unsymmetrical alkyl acetals via addition of primary alcohols
1245
sample rate 1.0 cm3 min-1, analytical lines (integration
time) Ru 240.272 nm (3 s). The standard calibration pro-
cedure using five standards (1 mg cm-3 solutions
purchased from Merck, Germany) was adopted and all the
measurements were done in triplicate. The relative standard
deviation of the technique was 3–5%. Accurate mass
measurements were performed using a Mariner ESI-TOF
(Applied Biosystems) mass spectrometer at the resolving
power 5,000. Samples were injected using a syringe pump
as methanolic solutions also containing polyethylene glycol
200 or 400 as an internal standard. For all samples
[M ? Na]? ions were measured. The accuracy of the mass
measurements was better than 5 ppm.
hexane or petroleum ether and the mixture was cooled to
-30 °C. After 24 h, the solid residue was quickly filtered
off, and activated carbon (Norit CN-1, Acros; 1 g/10 mg
Ru) was added. The mixture was stirred for 24 h, the sor-
bent was filtered off, and volatile fractions were
evaporated. The content of Ru was \0.2 ppm. The crude
acetals 1, 2, 4, 5, 7–9, and 11 were purified by vacuum
distillation. In some cases (3, 6, 10, 12, 13), distillation was
ineffective (decomposition of the acetal was observed).
1-(1-Butoxypropoxy)pentane (1, C12H26O2)
B.p.: 114–115 °C (20 mbar); 1H NMR (400 MHz, CDCl3):
d = 0.90 (t, J = 7.2 Hz, 3H), 0.91 (t, J = 7.5 Hz, 3H),
0.93 (t, J = 7.3 Hz, 3H), 1.28–1.45 (m, 6H), 1.51–1.67 (m,
6H), 3.38–3.44 (m, 2H), 3.54–3.61 (m, 2H), 4.39 (t,
J = 5.8 Hz, 1H) ppm; 13C NMR (100 MHz, CDCl3): d
= 9.1, 13.9, 14.0, 19.5, 22.6, 26.6, 28.6, 29.7, 32.1, 65.3,
65.5, 104.4 ppm; GC–MS (70 eV): m/z (%) = 202 (\1),
173 (20), 129 (52), 115 (86), 103 (30), 71 (80), 59 (100), 57
(90), 43 (82); HRMS (ESI?): calcd for C12H26O2Na
[M ? Na]? 225.1830, found 225.1825.
Reagents and catalysts
Allyl t-butyl ether was synthesized according to [21].
Synthesis of 1,4-dibutoxy-(Z)-2-butene was described in
our previous work [22]. Allyl ethers: allyl n-decyl, allyl
n-octadecyl, and allyl geranyl ether were obtained in typ-
ical PTC method [23].
RuCl2(PPh3)3 [24] and [RuCl2(1,5-COD)]x [25] were
synthesized according to the procedures described in the
literature. 2-(1-Propenyloxy)-ethanol was prepared via
isomerization of 2-allyloxyethanol with RuClH(CO)(PPh3)3,
as we described in our previous paper [15]. All other
chemicals are commercially available reagents (Acros,
Aldrich, Merck).
1-(1-Butoxypropoxy)decane (2, C17H36O2)
1
B.p.: 123 °C (0.45 mbar); H NMR (400 MHz, CDCl3):
d = 0.88 (t, J = 7.0 Hz, 3H), 0.91 (t, J = 7.5 Hz, 3H),
0.93 (t, J = 7.3 Hz, 3H), 1.21–1.44 (m, 16H), 1.50–1.67
(m, 6H), 3.36–3.46 (m, 2H), 3.53–3.60 (m, 2H), 4.39 (t,
J = 5.7 Hz, 1H) ppm; 13C NMR (100 MHz, CDCl3):
d = 9.1, 13.9, 14.1, 19.5, 22.7, 26.4, 26.6, 29.6, 29.7, 29.7,
30.0, 32.0, 32.1, 65.3, 65.6, 104.3 ppm; GC–MS (70 eV):
m/z (%) = 272 (\1), 243 (8), 199 (14), 141 (10), 115 (84),
102 (42), 85 (52), 71 (48), 59 (80), 57 (100), 43 (52), 41
(52); HRMS (ESI?): calcd for C17H36O2Na [M ? Na]?
295.2608, found 295.2614.
Catalytic test reactions
All reagents (molar ratios of the reaction mixture compo-
nents and the temperature are shown in the Tables and
Schemes) were placed in a glass screw-capped ampoule,
purged with argon (by bubbling through the solution for
10 min), then tightly capped and heated in an oil bath at
given temperature ( 0.5 °C) for a given period of time.
Then, the ampoule was cooled to room temperature and the
obtained residue was used in NMR (0.15 cm3 in 0.6 cm3
CDCl3) and GC and MS analyses. Before the GC, GC–MS,
and MS analyses, ruthenium was removed from the sam-
ples using activated carbon (Norit CN-1, Acros; 1 g/10 mg
Ru).
1-(1-Butoxypropoxy)octadecane (3, C25H52O2)
1
M.p.: 34.7 °C; H NMR (400 MHz, CDCl3): d = 0.90 (t,
J = 7.0 Hz, 3H), 0.91 (t, J = 7.5 Hz, 3H), 0.94 (t,
J = 7.3 Hz, 3H), 1.24–1.46 (m, 32H), 1.53–1.70 (m, 6H),
3.39–3.47 (m, 2H), 3.52–3.65 (m, 2H), 4.41 (t, J = 5.7 Hz,
1H) ppm; 13C NMR (100 MHz, CDCl3): d = 8.9, 13.8,
14.0, 19.4, 22.7, 25.8, 26.3, 29.4, 29.5, 29.6 (2C), 29.7
(7C), 29.9, 31.9, 32.0, 32.8, 65.11, 65.42, 104.23 ppm.
(E/Z)-1-[1-[2-(1-Prop-1-enyloxy)ethoxy]propoxy]butane
(4, C12H24O3)
Reaction on preparative scale
Mixture of isomers; b.p.: 91 °C (1.2 mbar); GC–MS
(70 eV): m/z (%) = 187 (3), 115 (30), 77 (63), 59 (100),
57 (52), 46 (31), 41 (35), 29 (20); 187 (2), 115 (37), 77
(85), 59 (100), 57 (56), 46 (33), 41 (54), 29 (35).
Allyl ether, alcohol, and catalyst were placed in a thick
round-bottomed flask. The mixture was purged with argon
(by bubbling through the solution for 15 min), then tightly
capped, heated, and vigorously stirred (Spinplus stir bar) in
an oil bath at a given temperature ( 0.5 °C) for a given
period of time. After that, the flask was cooled to room
temperature, and the obtained residue was diluted in
(E)-isomer 1H NMR (400 MHz, CDCl3): d = 0.89–
0.93 (m, 3H), 0.94 (t, J = 7.5 Hz), 1.35–1.45 (m, 4H), 1.55
(dd, J = 6.7 Hz, J = 1,6 Hz, 3H), 1.64–1.71 (m, 2H), 3.62
(t, J = 6.5 Hz, 2H), 3.83–3.87 (m, 2H), 3.95–3.98 (m, 2H),
123

1246
S. Krompiec et al.
1-(1-tert-Butoxypropoxy)butane (9, C11H24O2)
4.47 (t, J = 4.8 Hz), 4.75 (dq, J = 12.6 Hz, J = 6.7 Hz,
1H), 6.22 (dq, J = 12.6 Hz, J = 1.6 Hz, 1H) ppm; 13C
NMR (100 MHz, CDCl3): d = 9.2, 12.5, 13.9, 19.2, 26.3,
31.5, 65.5, 68.5, 71.3, 98.2, 104.4, 146.7 ppm;
(Z)-isomer 1H NMR (400 MHz, CDCl3): d = 0.89–0.93
(m, 3H), 0.97 (t, J = 7.5 Hz), 1.35–1.45 (m, 4H), 1.58 (dd,
J = 6.7 Hz, J = 1.7 Hz, 3H), 1.64–1,71 (m, 2H), 3.72 (t,
J = 6.6 Hz, 2H), 3.83–3.87 (m, 2H), 3.95–3.98 (m, 2H),
4.36 (dq, J = 6.2 Hz, J = 6.7 Hz, 1H), 4.82 (t,
J = 4.6 Hz), 5.94 (dq, J = 6.2 Hz, J = 1.7 Hz, 1H) ppm;
13C NMR (100 MHz, CDCl3): d = 8.0, 12.6, 13.9, 19.1,
27.0, 31.9, 64.9, 68.9, 71.8, 100.7, 105.5, 145.7 ppm;
B.p.: 65 °C (1.73 mbar); 1H NMR (300 MHz, CDCl3):
d = 0.91 (t, J = 7.5 Hz, 3H), 0.93 (t, J = 7.3 Hz, 3H),
1.24 (s, 9H), 1.33–1.45 (m, 2H), 1.51–1.67 (m, 4H), 3.42
(dt, J = 9.4, 6.6 Hz, 1H), 3.58 (dt, J = 9.4, 6.6 Hz, 1H),
4.39 (t, J = 5.8 Hz, 1H) ppm; 13C NMR (75 MHz,
CDCl3): d = 9.1, 13.9, 19.5, 26.5, 28.7, 32.1, 65.2, 74.8,
104.3 ppm.
1-(1-Butoxypropoxy)-3,7-dimethylocta-2,6-diene
(10, C17H32O2)
Colorless oil; 1H NMR (400 MHz, CDCl3): d = 0.81–0.83
(dd, J = 4.0 Hz, J = 2.5 Hz, 3H), 0.91 (t, J = 7.3 Hz,
3H), 1.25–1.29 (m, 2H), 1.36–1.40 (m, 2H), 1.51–1.56 (m,
2H), 1.58 (s, 3H), 1.66 (s, 6H), 1.99–2.12 (m, 4H), 3.55 (t,
J = 6.6 Hz), 4.11 (d, J = 7.9 Hz), 4.43 (t, J = 5.7 Hz),
5.08 (t, J = 6.6 Hz), 5.34 (t, J = 7.9 Hz) ppm; 13C NMR
(100 MHz, CDCl3): d = 9.2, 11.5, 14.0, 14.4, 20.6, 22.7,
27.8, 29.2, 41.5, 62.0, 65.3, 103.7, 121.1, 124.2, 131.6,
139.8 ppm; HRMS (ESI?): calcd for C17H32O2Na
[M ? Na]? 291.2295, found 291.2309.
(E)-10-(1-Butoxypropoxy)dec-2-ene (5, C17H34O2)
1
B.p.: 118 °C (0.39 mbar); H NMR (400 MHz, CDCl3):
d = 0.86–0.97 (m, 9H), 1.23–1.44 (m, 10H), 1.51–1.66 (m,
6H), 1.92–2.04 (m, 2H), 3.37–3.43 (m, 2H), 3.53–3.63 (m,
2H), 4.39 (t, J = 5.7 Hz, 1H), 5.36–5.44 (m, 2H) ppm; 13
C
NMR (100 MHz, CDCl3): d = 9.0, 13.9, 17.8, 19.4, 25.6,
26.3, 26.5, 27.0, 31.6, 31.9, 32.0, 32.6, 65.2, 65.5, 104.3,
124.5, 131.6 ppm.
1-[1-(1-Butoxypropoxy)propoxy]butane (11, C14H30O3)
B.p.: 74 °C (7 mbar); 1H NMR (400 MHz, CDCl3):
d = 0.91 (t, J = 7.4 Hz, 6H), 0.93 (t, J = 7.4 Hz, 6H),
1.34–1.44 (m, 4H), 1.51–1.66 (m, 8H), 3.42 (dt, J = 9.4,
6.6 Hz, 2H), 3.58 (dt, J = 9.4, 6.6 Hz, 2H), 4.39 (t,
J = 5.8 Hz, 2H) ppm; 13C NMR (100 MHz, CDCl3):
d = 8.9, 13.7, 19.3, 26.4, 31.9, 65.0, 104.2 ppm.
(Z)-1-(1-Butoxypropoxy)octadec-9-ene (6, C25H50O2)
1
Colorless oil; H NMR (400 MHz, CDCl3): d = 0.88 (t,
J = 7.1 Hz, 3H), 0.91 (t, J = 7.7 Hz, 3H), 0.92 (t,
J = 7.3 Hz, 3H), 1.26–1.40 (m, 26H), 1.52–1.66 (m, 4H),
1.94–2.05 (m, 4H), 3.37–3.44 (m, 2H), 3.52–3.64 (m, 2H),
4.39 (t, J = 5.7 Hz, 1H), 5.33–5.43 (m, 2H) ppm; 13C
NMR (100 MHz, CDCl3): d = 9.1, 13.9, 14.0, 19.4, 22.7,
25.8, 26.5, 27.17, 29.1, 29.2, 29.43, 29.43, 29.45, 29.6,
29.6, 29.6, 31.8, 32.0, 32.6, 65.2, 65.5, 104.2, 128.1,
128.9 ppm; HRMS (ESI?): calcd for C25H50O2Na
[M ? Na]? 405.3708, found 405.3703.
1-(1,4-Dibutoxybutoxy)decane (12, C22H46O3)
1
Colorless oil; H NMR (400 MHz, CDCl3): d = 0.86-0.95
(m, 9H), 1.27–1.41 (m, 18H), 1.51–1.68 (m, 10H),
3.37–3.44 (m, 6H), 3.54–3.61 (m, 2H), 4.48 (t, 1H,
J = 5.4 Hz) ppm; 13C NMR (100 MHz, CDCl3):
d = 13.8, 13.8, 14.0, 19.4, 22.6, 25.0, 26.2, 29.3, 29.4,
29.5, 29.6, 29.8, 29.8, 30.2, 31.8, 31.8, 31.9, 65.2, 65.5,
70.4, 70.5, 102.9 ppm; HRMS (ESI?): calcd for
C22H46O3Na [M ? Na]? 381.3339, found 381.3349.
[(1-Butoxypropoxy)methyl]benzene (7, C14H22O2)
B.p.: 98 °C (7 mbar); 1H NMR (300 MHz, CDCl3):
d = 0.93 (t, J = 7.3 Hz, 3H), 0.94 (t, J = 7.4 Hz, 3H),
1.34–1.47 (m, 2H), 1.52–1.63 (m, 2H), 1.66–1.75 (m, 2H),
3.46 (dt, J = 9.4, 6.5 Hz, 1H), 3.60 (dt, J = 9.4, 6.5 Hz,
1H), 4.52 (d, J = 11.8 Hz, 1H), 4.53 (t, J = 5.8 Hz, 1H),
4.64 (d, J = 11.8 Hz, 1H), 7.38–7.22 (m, 5H) ppm; 13C
NMR (75 MHz, CDCl3): d = 9.1, 13.9, 19.5, 26.4, 32.0,
65.2, 67.1, 103.8, 127.5, 127.7, 128.4, 138.6 ppm; GC–MS
(70 eV): m/z (%) = 221 (5), 193 (24), 148 (18), 108 (20),
92 (20), 91 (100), 79 (20), 57 (23).
(E)-10-(1,4-Dibutoxybutoxy)dec-2-ene (13, C22H44O3)
Colorless oil; 1H NMR (400 MHz, CDCl3): d = 0.87–0.97
(m, 9H), 1.26–1.42 (m, 12H), 1.52–1.67 (m, 10H),
1.90–2.04 (m, 2H), 3.37–3.43 (m, 6H), 3.54–3.59 (m,
2H), 4.48 (t, J = 5.5 Hz, 1H), 5.37–5.42 (m, 2H) ppm; 13
C
NMR (100 MHz, CDCl3): d = 13.9, 14.0, 17.9, 19.4, 19.5,
25.1, 26.3, 29.2, 29.4, 29.6, 30.0, 30.3, 31.9, 32.1, 32.6,
65.3, 65.6, 70.6, 70.7, 103.1, 124.6, 131.6 ppm.
1-[1-(2,2,2-Trifluoroethoxy)propoxy]butane
(8, C9H17F3O2)
B.p.: 66 °C (27 mbar); 1H NMR (400 MHz, CDCl3):
d = 0.91–0.95 (m, 6H), 1.34–1.44 (m, 2H), 1.52–1.59
(m, 2H), 1.61–1.68 (m, 2H), 3.44 (dt, J = 6.6, 9.4 Hz, 1H),
3.60–3.64 (m, 1H), 3.84 (q, J = 8.8 Hz, 1H), 3.85 (q,
J = 8.8 Hz, 1H), 4.56 (t, J = 5.9 Hz, 1H) ppm; 13C NMR
(100 MHz, CDCl3): d = 8.7, 13.8, 19.3, 26.0, 31.7, 61.4,
65.9, 104.4, 124.2 (q, J = 277.8 Hz) ppm.
Acknowledgments This work was supported by The State Com-
mittee for Scientific Research, Project No. N N204 272237. Mateusz
Penkala is a participant in UPGOW project, co-financed by the
European Union within the European Social Fund.
Open Access This article is distributed under the terms of the
Creative Commons Attribution Noncommercial License which
123

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1247
permits any noncommercial use, distribution, and reproduction in any
medium, provided the original author(s) and source are credited.
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