Selective hydroboration of alkenes and alkynes in the presence of aldehydes and ketones

Article abstract of DOI:10.1139/v98-042

The reactions of terminal alkenes in the presence of ketones or aldehydes with a variety of borane reagents have been investigated. It was found that the selective hydroboration of a terminal alkene in the presence of a ketone or an aldehyde is most efficient when dicyclohexylborane is used as the hydroborating agent. The hydroboration of olefinic ketones and olefinic aldehydes with dicyclohexylborane generates the corresponding hydroxyaldehydes and hydroxyketones in good yields after oxidation with sodium perborate. The hydroboration of alkynyl ketones and alkynyl aldehydes with dicyclohexylborane yields the corresponding olefinic carbonyl compounds after protonation, or dicarbonyl compounds after oxidation.

Full text of DOI:10.1139/v98-042

800
Selective hydroboration of alkenes and alkynes
in the presence of aldehydes and ketones
George W. Kabalka, Su Yu, and Nan-Sheng Li
Abstract: The reactions of terminal alkenes in the presence of ketones or aldehydes with a variety of borane reagents have
been investigated. It was found that the selective hydroboration of a terminal alkene in the presence of a ketone or an aldehyde
is most efficient when dicyclohexylborane is used as the hydroborating agent. The hydroboration of olefinic ketones and
olefinic aldehydes with dicyclohexylborane generates the corresponding hydroxyaldehydes and hydroxyketones in good
yields after oxidation with sodium perborate. The hydroboration of alkynyl ketones and alkynyl aldehydes with
dicyclohexylborane yields the corresponding olefinic carbonyl compounds after protonation, or dicarbonyl compounds after
oxidation.
Key words: hydroboration, reduction, dicyclohexylborane, hydroxyaldehyde, hydroxyketone.
Résumé : On a étudié les réactions des alcènes terminaux, en présence de cétones ou d’aldéhydes, avec une variété de boranes
comme réactifs. On a trouvé que le dicyclohexylborane est le meilleur agent pour effectuer l’hydroboration sélective d’un
alcène terminal en présence d’une cétone ou d’un aldéhyde. L’hydroboration des cétones ou des aldéhydes oléfiniques suivie
d’une oxydation avec du perborate de sodium conduit aux hydroxyaldéhydes et aux hydroxycétones correspondants avec de
bons rendements. L’hydroboration des alcynylcétones et des alcynylaldéhyes par le dicyclohexylborane conduit aux composés
carbonylés oléfiniques correspondants après protonation ou aux composés dicarbonylés après oxydation.
Mots clés : hydroboration, réduction, dicyclohexylborane, hydroxyaldéhyde, hydroxycétone.
[Traduit par la rédaction]
related examples such as one involving a hydroboration with
catecholborane in the presence of Wilkinson’s catalyst (9),
indicate that it might be possible to selectively hydroborate
alkenes in the presence of aldehydes and ketones. Recently, we
reported the preliminary results of our studies, which focused
on the selective hydroboration of alkenes (Fig. 1) and alkynes
(Fig. 2) in the presence of ketones and aldehydes (10). We now
wish to report the details of these studies.
Introduction
Boron hydride reagents have been utilized extensively in or-
ganic synthesis. They have proven to be valuable for the selec-
tive reduction of carbonyl compounds as well as for the
stereoselective hydroboration of alkenes and alkynes (1, 2).
Because of the effectiveness of borane reagents in reducing
aldehydes and ketones, hydroboration reactions involving sub-
strates containing these functional groups are often carried out
by either converting the carbonyl group to a less reactive func-
tionality (3, 4) or modifying the hydroborating agent (5). Oth-
erwise, reduction of the carbonyl moiety might compete with
the desired hydroboration reaction. For example, α,β-unsatu-
rated aldehydes and ketones are reduced rapidly and quantita-
tively to the corresponding allylic alcohols by 9-BBN (6).
Similarly, the hydroboration of allyl ketones with diisopino-
campheyborane produces enantiomerically enriched 1,4-diols
via an intramolecular reduction (7). Diols are also the final
products (after oxidation) when olefinic ketones are reduced
by either borane or thexylborane (8). These latter reports, and
Results and discussion
Brown and his co-workers (11) have carried out extensive re-
search on the reactions of alkenes and carbonyl compounds
with a variety of boron hydrides. Their kinetic data indicates
that both the hydroboration of terminal alkenes as well as the
reduction of most aldehydes and some ketones by 9-BBN fol-
low first-order kinetics (12). Although they exhibit first-order
rate constants when reduced by borane reagents, the alde-
hydes, ketones, and alkenes exhibit different overall reaction
rates. For example, aldehydes are more reactive toward 9-BBN
than alkenes but 9-BBN reacts faster with certain alkenes than
with ketones. We felt that these reactivity differences might be
amplified if more hindered borane reagents were utilized.
As a probe, we allowed a mixture of 1-octene and 2-hep-
tanone to react with a variety of common borane reagents at
various temperatures (0, 25, 68°C). The mixtures were then
oxidized to the corresponding alcohols using sodium perborate
(13); the results of the study are presented in Table 1.
Received February 12, 1998.
This paper is dedicated to Professor E. Buncel in recognition of
his contributions to Canadian chemistry.
G.W. Kabalka,1 S. Yu, and N.-S. Li. Departments of
Chemistry and Radiology, The University of Tennessee,
Knoxville, TN 37996-1600, U.S.A.
1
Analysis of the data in Table 1 indicates that the reactivities
of a terminal alkene and an acyclic aliphatic ketone toward
boron hydrides are quite different; in fact, a terminal alkene
Author to whom correspondence may be addressed.
Telephone: (423) 974-3260. Fax: (423) 974-2997. E-mail:
kabalka@utk.edu
Can. J. Chem. 76: 800–805 (1998)
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Kabalka et al.
Fig. 1.
Fig. 2.
Table 1. The reaction of 1-octene and 2-heptanone with
various borane reagents: a competitive study.a
Table 2. The reaction of 1-octene and cyclopentanone
with various borane reagents.a
Rxn.
Borane
reagent
Ratio of 1-octanol
to 2-heptanolb,c
Ratio of 1-octanol
to cyclopentanolb,c
Entry
temp. (°C)
Entry
Borane reagent
1
2
0
25
68
0
BH3 THF
BH3 THF
BH3 THF
BMS
97:3d
99:1d
98:2d
96:4d
97:3d
93:7
1
2
3
4
5
BH3 THF
BMS
94:6d
89:11d
34:66
92:8
3
9-BBN
4
Sia2BH
5
25
25
68
0
BMS
(c-C6H11)2BH
100:0
a Reactions were carried out using 1 equiv. each of
6
9-BBN
7
9-BBN
89:11
100:0
100:0
96:4
hydride, alkene, and ketone.
b Ratios obtained by GC analysis after aqueous sodium
perborate oxidation.
8
(c-C6H11)2 BH
(c-C6H11)2 BH
Sia2BH
9
25
0
c Overall combined yields ranged from 90 to 100%.
d 2-Octanol was also formed in small quantities.
10
11
25
Sia2BH
97:3
a Reactions were carried out using 1 equiv. each of hydride,
alkene, and ketone.
b Ratios obtained by GC analysis after aqueous sodium perborate
oxidation.
c Overall combined yields ranged from 90 to 100%.
d 2-Octanol was also formed in small quantities.
slightly more reactive than 1-octene toward 9-BBN. Dicyclo-
hexylborane is the most effective at hydroborating a terminal
alkene in the presence of a cyclic ketone.
We also carried out a competitive study of reactions of
alkenes and an aromatic ketone using various borane reagents.
The results of the study are presented in Table 3. The data
indicate that a terminal alkene can be selectively hydroborated
in the presence of an aromatic ketone. Consistent with the
earlier studies, 9-BBN is the least chemoselective.
can be successfully hydroborated in the presence of a ketone
utilizing essentially all of the common hydroborating agents.
As anticipated from earlier studies, 9-BBN is less chemoselec-
tive than the more hindered hydroborating reagents (entries
6–11); but dicyclohexylborane is quite effective at hydrobo-
rating a terminal alkene in the presence of a ketone. Also note-
worthy is the fact that temperature had little effect on the
selectivity of the reagents.
Cyclic ketones are present in a number of important natu-
rally occuring molecules. Since cyclic ketones are more reac-
tive toward 9-BBN than acyclic ketones (11), they might
compete more effectively with terminal alkenes. As a probe,
we allowed 1-octene and cyclopentanone to react with a lim-
ited quantity of the various borane reagents. The mixtures were
then oxidized with sodium perborate, and the results are pre-
sented in Table 2.
As noted earlier, aldehydes are more reactive than terminal
alkenes toward 9-BBN (11). 1-Octene and heptanal were used
as model substrates and allowed to react with a limited quantity
of the borane reagent. The results are presented in Table 4. The
data reveal that hydroboration is the major reaction when hin-
dered borane reagents are utilized, while reduction predomi-
nates in reactions using unhindered borane reagents.
Dicyclohexylborane is once again the most effective at hy-
droborating a terminal alkene in the presence of an aldehyde.
We then examined the ability of dicyclohexylborane to se-
lectively hydroborate olefinic aldehydes and ketones (Ta-
ble 5). The results indicate that hydroxyaldehydes and
hydroxyketones can be prepared in good yields after oxidation.
Interestingly, no “simple” reduction products (olefinic alco-
hols) were detectable in any of the reactions except when 11-
undecylenic aldehyde was used as the substrate. However,
As shown in Table 2, cyclopentanone competes more ef-
fectively than 2-heptanone for the borane reagents. However,
hydroboration is still the major reaction except when 9-BBN
is used as the hydroborating reagent. Cyclopentanone is
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Can. J. Chem. Vol. 76, 1998
Table 3. The reaction of 1-octene and acetophenone
with various borane reagents.a
Table 4. The reaction of 1-octene and heptanal with
various borane reagents.a
Borane
reagent
Ratio of 1-octanol to
1-phenylethanolb,c
Ratio of 1-octanol
to 1-heptanolb,c
Entry
Entry
Borane reagent
1
2
3
4
5
BH3 THF
BMS
100:0d
94:6d
76:24
100:0
100:0
1
2
3
4
5
BH3 THF
BMS
45:55d
53:47d
16:84
71:29
82:18
9-BBN
9-BBN
Sia2BH
Sia2BH
(c-C6H11)2BH
(c-C6H11)2BH
a Reactions were carried out using 1 equiv. each of
a Reactions were carried out using 1 equiv. each of
hydride, alkene, and ketone.
b Ratios obtained by GC analysis after aqueous sodium
perborate oxidation.
c Overall combined yields ranged from 90 to 100%.
d 2-Octanol was also formed in small quantities.
hydride, alkene, and ketone.
b Ratios obtained by GC analysis after aqueous sodium
perborate oxidation.
c Overall combined yields ranged from 90 to 100%.
d 2-Octanol was also formed in small quantities.
overreduction to the diol product (up to 10%) was observed in
some cases.
13C NMR (CDCl3/TMS), δ (ppm): 209.38, 61.96, 43.15, 31.87,
19.73, 19.72.
A variety of unconjugated alkynyl carbonyl compounds
were then hydroborated with dicyclohexylborane to probe the
ability of dicyclohexylborane to selectively hydroborate al-
kynes in the presence of both aldehydes and ketones. The re-
sults are summarized in Table 6. Both terminal and internal
alkynyl carbonyl compounds can be hydroborated in the pres-
ence of the carbonyl group. The reaction affords the corre-
sponding olefins in high yields (71–94%) after protonation, or
dicarbonyl compounds in good yields (50–76%) after oxida-
tion with sodium perborate.
2-Methyl-5-(1-methyl-2-hydroxylethyl)cyclohexanone (16)
Yield: 77%; 1H NMR (CDCl3/TMS), δ (ppm): 3.59–3.44 (m,
2H), 2.49–1.26 (m, 9H), 1.01 (d, J = 6.4 Hz, 2H), 0.94 (d, J =
6.9 Hz), 0.91 (d, J = 6.9 Hz) (total 3H); 13C NMR
(CDCl3/TMS), δ (ppm): 213.72, 213.45, 65.45, 65.36, 46.17,
44.83 (44.83), 43.91, 41.57, 41.37, 40.19, 40.00, 34.97 (34.97),
29.71, 27.51, 14.20 (14.20), 13.05, 12.71.
1-Methoxy-2-oxabicyclo[4.4.0]decane (17)
Yield: 70%; 1H NMR (CDCl3/TMS), δ (ppm): 3.72–3.56 (m,
2H), 3.22–3.16 (m, 3H), 1.98–1.12 (m, 13H); 13C NMR
(CDCl3/TMS), δ (ppm): 98.34, 60.87, 46.34, 44.44, 31.74,
29.45, 26.36, 25.88, 24.72, 22.67.
Experimental section
Alkenyl ketones and alkenyl aldehydes, obtained from Aldrich
Chemical Company, were used as received or purified by dis-
tillation prior to use. Alkynyl ketones and alkynyl aldehydes
were synthesized from the alkynyl alcohols by oxidation with
PCC (14). Alkynyl alcohols were either obtained commer-
cially or prepared via Grignard reactions (14).1H NMR spectra
and 13C NMR spectra were run at 250 MHz. Elemental analy-
ses were performed by Atlantic Microlab Inc., Atlanta, Ga.
6-Hydroxy-5-methyl-2-hexanone
Yield 80%; a cyclic and acyclic mixture (50:50) of 6-hydroxy-
5-methyl-2-hexanone was produced. 1H NMR (CDCl3/TMS),
δ (ppm): 3.55–3.42 (m, 2H), 2.97 (br s, 0.5H) 2.61–2.46 (m,
1.5H), 2.16 (s, 1.5H), 1.81–1.35 (m, 5.5H), 0.91 (d, J = 6.6 Hz,
1.5H), 0.82 (d, J = 6.3 Hz, 1.5H); 13C NMR (CDCl3/TMS), δ
(ppm): 209.58, 94.50, 67.18, 60.50, 41.06, 35.15, 34.85, 30.06,
29.94, 29.72, 27.56, 26.65, 17.05, 16.39. HRMS calcd. for
C7H14O2: 130.099; found: 130.096.
General procedure for the preparation of
hydroxyketones and hydroxyaldehydes
4-(2-Propenoxy)-2-hydroxybenzophenone
1
6-Hydroxy-2-hexanone
Yield 78%; H NMR (CDCl3/TMS), δ (ppm): 12.66 (s, 1H),
Borane tetrahydrofuran (5.0 mmol, 5.0 mL of a 1.0 M solution
in THF) was placed in a dry, argon-flushed, round-bottomed
flask, which was then immersed in an ice-water bath. Cyclo-
hexene (10.0 mmol, 0.82 g, 1.0 mL) was added dropwise and
the mixture stirred at 0°C for 1 h. 5-Hexen-2-one (5.0 mmol,
0.49 g, 0.58 mL) was then added to the slurry of dicyclohexyl-
borane in THF. The cooling bath was removed and the mixture
stirred for 2 h at room temperature. Oxidation was achieved by
adding NaBO3 4H2O (15 mmol, 2.3 g) and water (5 mL) and
stirring the mixture at room temperature for 2 h. The product
was extracted into ether (3 × 15 mL), the solvent removed
under pressure, and 6-hydroxy-2-hexanone (15) (0.44g, 76%
yield) was isolated by flash chromatography. 1H NMR
(CDCl3/TMS), δ (ppm): 3.62 (t, J = 6.1 Hz, 2H), 2.59 (br s,
1H), 2.49 (t, J = 6.8 Hz, 2H), 2.16 (s, 3H), 1.73–1.50 (m, 4H);
7.61–7.44 (m, 6H), 6.50 (d, J = 2.2 Hz, 1H), 6.38 (dd, J = 8.9,
2.2 Hz, 1H), 4.13 (t, J = 6.0 Hz, 2H), 3.80 (t, J = 6.0 Hz, 2H),
2.66 (s, 1H), 2.02 (p, J = 6.0 Hz, 2H); 13C NMR (CDCl3/TMS),
δ (ppm): 199.85, 166.04, 165.40, 138.01, 135.13, 131.32,
128.64, 128.12, 112.93, 107.42, 101.53, 65.32, 59.14, 31.61.
Anal. calcd. for C16H16O4: C 70.57, H 5.92; found: C 70.66, H
5.91.
2-Acetyl-5-hydroxynorbornane and 2-acetyl-6-hydroxy-
norbornane (18)
1
Yield 68%; H NMR (CDCl3/TMS), δ (ppm): 3.85–3.62 (m,
1H), 3.05–1.12 (m, 13H); 13C NMR (CDCl3/TMS), δ (ppm):
209.79, 209.64, 209.28, 73.98, 73.68, 73.38, 69.72, 60.20,
53.39, 52.79, 51.43, 50.13, 47.30, 47.03, 44.65, 43.70, 41.70,
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Kabalka et al.
Table 5. The hydroboration of olefinic carbonyl compounds with dicyclohexylborane.
Entry Substrate
Producta Yield (%)b
a Known compounds exhibited physical and spectral characteristics in accord with literature values, and
new compounds were characterized by spectral and elemental analysis or HRMS.
b Isolated yield.
c Up to 10% of the corresponding diols were isolated.
d Acetal formed by the reaction of the crude product with methanol in the presence of TsOH.
e Two equiv. of dicyclohexylborane were utilized.
f A trace of 11-undecylenic alcohol was detected by TLC.
41.21, 39.17, 38.85, 36.27, 34.93, 32.07, 31.63, 31.17, 29.44,
29.23, 28.63, 28.42, 26.76, 25.06.
0.41 mL) was added dropwise and the mixture stirred at 0°C
for 1 h. 11-Dodecyn-2-one (2.0 mmol, 0.36 g) was then added
to the slurry of dicyclohexylborane in THF. The cooling bath
was removed and the mixture stirred for 1 h at room tempera-
ture. Protonation was achieved by adding glacial acetic acid
(1.0 mL) and stirring the mixture at room temperature for 1 h.
11-Dodecen-2-one (20) (0.34 g, 94% yield) was isolated after
work-up. 1H NMR, δ (ppm): 5.88–5.72 (m, 1H), 5.02–4.90 (m,
2H), 2.41 (t, J = 7.4 Hz, 2H), 2.13 (s, 3H), 2.03 (q, J = 6.8 Hz,
2H), 1.56 (m, 2H), 1.28 (m, 10H); 13C NMR (CDCl3/TMS), δ
(ppm): 209.08, 139.05 114.06, 43.70, 33.71, 29.72, 29.25
(29.25), 29.09, 29.00, 28.83, 23.78. Alternatively, oxidation
could be achieved by adding of NaBO3 4H2O (6.0 mmol,
0.92 g) and water (2 mL) and stirring the mixture at room
temperature for 2 h. 11-Oxododecanal (21) (0.30 g, 76%
11-Hydroxyundecanal (19)
1
Yield 50%; H NMR (CDCl3/TMS), δ (ppm): 9.76 (t, J =
1.6 Hz, 1H), 3.61 (t, J = 6.6 Hz, 2H), 2.65 (s, 1H), 2.43 (dt, J
= 7.3, 1.6 Hz, 2H), 1.65–1.53 (m, 4H), 1.29 (br s, 12H); 13C
NMR (CDCl3/TMS), δ (ppm): 202.71, 62.47, 43.63, 32.51,
29.26, 29.11 (29.11), 28.90, 25.54, 21.82, 13.89.
General procedure for the preparation of alkenyl
carbonyl compounds and dicarbonyl compounds
The hydroboration of 11-dodecyn-2-one is representative:
BH3 THF (2.0 mmol, 2.0 mL of a 1.0 M solution in THF) was
placed in a dry, argon-flushed flask, which was then immersed
in an ice-water bath. Cyclohexene (4.0 mmol, 0.33 g,
1
yield) was isolated after work-up. H NMR, δ (ppm): 9.76
© 1998 NRC Canada

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Can. J. Chem. Vol. 76, 1998
Table 6. Preparation of olefinic carbonyl compounds and dicarbonyl compounds.
Entry
Substrate
Work-up
Producta
Yield (%)b
92
1
2
CH3C;C(CH2)8C(O)Ph
CH3C;C(CH2)8C(O)CH3
CH3C;C(CH2)8CHO
HC;C(CH2)8C(O)CH3
HC;C(CH2)8C(O)CH3
HC;C(CH2)8C(O)CH2CH3
HC;C(CH2)8C(O)CH2CH3
HC;C(CH2)8CHO
Protonation
Protonation
Protonation
Protonation
Oxidation
(Z)-CH3CHTCH(CH2)8C(O)Ph
(Z)-CH3CHTCH(CH2)8C(O)CH3
(Z)-CH3CHTCH(CH2)8 CHO
CH2TCH(CH2)8C(O)CH3
HC(O)(CH2)9C(O)CH3
88
71
94
76
83
68
90
50
85
66
3
4
5
6
Protonation
Oxidation
CH2TCH(CH2)8C(O)CH2CH3
HC(O)(CH2)9C(O)CH2CH3
CH2TCH(CH2)8CHO
7
8
Protonation
Oxidation
9
HC;C(CH2)8CHO
HC(O)(CH2)9CHO
10
11
HC;C(CH2)3C(O)Ph
HC;C(CH2)3C(O)Ph
Protonation
Oxidation
CH2TCH(CH2)3C(O)Ph
HC(O)(CH2)4C(O)Ph
a Products exhibited physical and spectral characteristics in accord with literature values or gave acceptable elemental analyses.
b Isolated yield.
(t, J = 1.9 Hz, 1H), 2.45–2.39 (m, 4H), 2.14 (s, 3H), 1.62–1.56
(m, 4H), 1.29 (m, 10H); 13C NMR (CDCl3/TMS), δ (ppm):
209.07, 202.64, 43.71, 43.58, 29.65, 29.10, 28.95, 23.65,
21.89.
10-Undecenal (23)
1
Yield 90%; H NMR (CDCl3/TMS), δ (ppm): 9.76 (t, J =
1.9 Hz, 1H), 5.89–5.73 (m, 1H), 5.03–4.90 (m, 2H), 2.42 (dt, J
= 7.3, 1.9 Hz, 2H), 2.08–2.00 (m, 2H), 1.66–1.57 (m, 2H), 1.30
(m, 10H); 13C NMR (CDCl3/TMS), δ (ppm): 202.80, 139.08,
114.12, 43.87, 33.73, 29.23 (29.23), 29.11, 29.00, 28.84,
22.03.
1-Phenyl-(Z)-10-dodecen-1-one
1
Yield 92%; H NMR (CDCl3/TMS), δ (ppm): 7.98–7.94 (m,
2H), 7.58–7.41 (m, 3H), 5.47–5.35 (m, 2H), 2.96 (t, J = 7.2 Hz,
2H), 2.04–1.99 (m, 2H), 1.78–1.68 (m, 2H), 1.61–1.58 (m,
3H), 1.43–1.20 (m, 10H); 13C NMR (CDCl3/TMS), δ (ppm):
200.49, 137.07, 132.77, 130.77, 128.47, 127.99, 123.56, 38.55,
29.33 (29.33, 29.33), 29.18 (29.18), 26.77, 24.32, 12.50. Anal.
calcd. for C18H26O: C 83.67, H 10.14; found: C 83.73, H 10.20.
1,11-Undecanedial (24)
1
Yield 50%; H NMR (CDCl3/TMS), δ (ppm): 9.76 (t, J =
1.6 Hz, 2H), 2.42 (dt, J = 7.3, 1.6 Hz, 4H), 1.62 (m, 4H), 1.30
(br s, 10H); 13C NMR (CDCl3/TMS), δ (ppm): 202.74, 43.72,
29.10, 29.01, 28.97, 21.89.
(Z)-11-Tridecen-2-one
1
1-Phenyl-5-hexen-1-one (25)
1
Yield 88%; H NMR (CDCl3/TMS), δ (ppm): 5.47–5.32 (m,
Yield 85%; H NMR (CDCl3/TMS), δ (ppm): 7.94 (m, 2H),
2H), 2.41 (t, J = 7.4 Hz, 2H), 2.13 (s, 3H), 2.03–1.98 (m, 2H),
1.61–1.54 (m, 5H), 1.28 (br s, 10H); 13C NMR (CDCl3/TMS),
δ (ppm): 209.19, 130.72, 123.53, 43.70, 29.72, 29.42, 29.27
(29.27), 29.10 (29.10), 26.72, 23.78, 12.64. HRMS calcd. for
C13H24O: 196.182; found: 196.182.
7.57–7.41 (m, 3H), 5.90–5.74 (m, 1H), 5.08–4.97 (m, 2H),
2.97 (t, J = 7.3 Hz, 2H), 2.15 (q, J = 7.3 Hz, 2H), 1.84 (p, J =
7.3 Hz, 2H); 13C NMR (CDCl3/TMS), δ (ppm): 200.07,
137.95, 136.98, 132.80, 128.46, 127.92, 115.18, 37.60, 33.10,
23.21.
6-Oxo-6-phenylhexanal (26)
1
(Z)-10-Dodecenal
1
Yield 66%; H NMR (CDCl3/TMS), δ (ppm): 9.78 (t, J =
Yield 71%; H NMR, δ (ppm): 9.76 (t, J = 1.9 Hz, 1H),
1.4 Hz, 1H), 7.96–7.93 (m, 2H), 7.59–7.43 (m, 3H), 3.03 (t, J
= 6.8 Hz, 2H), 2.53–2.48 (m, 2H), 1.76–1.72 (m, 4H); 13C
NMR (CDCl3/TMS), δ (ppm): 202.19, 199.69, 136.77, 132.94,
128.49, 127.89, 43.61, 38.00, 23.50, 21.59.
5.43–5.41 (m, 2H), 2.42 (dt, J = 7.3, 1.9 Hz, 2H), 2.07–1.98
(m, 2H), 1.78–1.53 (m, 5H), 1.30 (br s, 10H); 13C NMR, δ
(ppm): 202.82, 130.76, 123.63, 43.86, 29.45, 29.30 (29.30),
29.16, 26.79, 23.80, 22.06, 12.50. HRMS calcd. for C12H22O:
182.167; found: 182.167.
Acknowledgement
12-Tridecen-3-one (19)
1
We wish to thank the Department of Energy and the Robert H.
Cole Foundation for support of this research.
Yield 83%; H NMR (CDCl3/TMS), δ (ppm): 5.85–5.72 (m,
1H), 5.03–4.90 (m, 2H), 2.46–2.36 (m, 4H), 2.03 (q, J =
6.9 Hz, 2H), 1.62–1.54 (m, 2H), 1.28 (m, 10H), 1.05 (t, J =
7.3 Hz, 3H); 13C NMR (CDCl3/TMS), δ (ppm): 211.81,
139.08, 114.06, 42.36, 35.78, 33.72, 29.23 (29.23), 29.00
(29.00), 28.84, 23.87, 7.77.
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© 1998 NRC Canada

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