Enantioselective carbonyl-ene reaction of glyoxal derivatives catalyzed by cationic 3-oxobutylideneaminatocobalt(III) complexes

Article abstract of DOI:10.1246/bcsj.76.49

Optically active 3-oxobutylideneaminatocobalt(III) complexes were designed for the catalytic enantioselective carbonyl-ene reaction. Varieties of counter anions of cationic cobalt(III) complexes were screened and hexafluoroantimonate was found to be the m

Full text of DOI:10.1246/bcsj.76.49

c. Jpn.
e Chemical © 2003 The Chemical Society of Japan
Bull. Chem. Soc. Jpn., 76, 49–58 (2003)
49
ciety of Ja-
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e Chemical
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Headline Articles
Enantioselective Carbonyl-Ene Reaction of Glyoxal Derivatives
03
Catalyzed by Cationic 3-Oxobutylideneaminatocobalt(Ⅲ) Complexes
Enantioselective Carbonyl-Ene Reaction
SJA8
S. Kezuka et al.
09-2673
Satoko Kezuka, Youichi Kogami, Taketo Ikeno, and Tohru Yamada*
2
0
0
10
Department of Chemistry, Faculty of Science and Technology, Keio University,
Hiyoshi, Kohoku-ku, Yokohama 223-8522
2
2
(
Received July 29, 2002)
Optically active 3-oxobutylideneaminatocobalt(Ⅲ) complexes were designed for the catalytic enantioselective car-
bonyl-ene reaction. Varieties of counter anions of cationic cobalt(Ⅲ) complexes were screened and hexafluoroanti-
monate was found to be the most effective. In the presence of cobalt(Ⅲ) hexafluoroantimonate complex 1f, the enantio-
selective carbonyl-ene reaction of various alkenes with glyoxal derivatives was carried out to afford the corresponding
homoallylic alcohols in high yields and with high enantioselectivities. Even in the presence of 0.2 mol% cobalt(Ⅲ) com-
plexes, the reaction proceeded in high yield and with maintained high enantioselectivity. The absolute configuration of
the optically active product was determined and a reasonable explanation for the enantioselection in the present carbon-
yl-ene reaction catalyzed by the cobalt complex was proposed.
1
The enantioselective carbonyl-ene reaction is one of the
most reliable and convenient processes to prepare optically ac-
tive homoallylic alcohols because it could be performed with-
out any pretreatment of carbonyl compounds such as enoliza-
tion or preparation of allylmetallic reagents. The resulting ho-
moallylic alcohol could be furthermore transformed into vari-
ous functionalized compounds by taking advantage of its hy-
droxy group and its carbon–carbon double bond. The carbon-
yl-ene reaction is categorized as a 6π-electrocyclic concerted
effectively regulate the stereochemistry in the formation of the
homoallylic alcohol. On the basis of these features, a wide va-
riety of metal complexes have been investigated as chiral
Lewis acid catalysts for this purpose. The achievement of
high performance has been reported, e.g. the chiral BINOL
ligands with various conventional Lewis-acid-metals, such as
1
3
4
5
aluminum and titanium, or rare-earth metal. Several com-
plexes with other than BINOL ligands were recently reported
to be available as chiral Lewis acid catalysts for this type of re-
2
6
7
8
reaction, similar to the Diels–Alder reaction. Therefore, it is
action; bis(oxazoline)copper, BINAP palladium or platinum,
and DPPF-nickel catalyst, etc.
9
expected that a Lewis acid would remarkably catalyze the re-
action by lowering the LUMO energy of the carbonyl com-
pounds and that the optically active Lewis acid catalyst would
The optically active 3-oxobutylideneaminatocobalt com-
plexes (Fig. 1) were originally developed as effective catalysts
Fig. 1. Varieties of 3-oxobutylideneaminatocobalt complex catalysts.

5
0
Bull. Chem. Soc. Jpn., 76, No. 1 (2003)
HEADLINE ARTICLES
Scheme 1. Enantioselective reactions catalyzed by 3-oxobutylideneaminato complexes.
of the enantioselective tetrahydroborate reductions of ke-
Table 1. Various Cobalt Complex Catalysts for the Enantio-
selective Carbonyl-Ene Reaction
10
11
tones, imines, and α,β-unsaturated carboxamides (Scheme
1
2
1
). It was recently reported that this type of complex effec-
tively catalyzed the cyclopropanation of styrenes and
13
diazoacetates to afford the corresponding cyclopropane de-
rivatives with high stereoselectivities. The enantioselectivities
and diastereoselctivities in the above-mentioned reactions
could be tuned by the structure of the 3-oxobutylideneaminato
ligands. These complexes were prepared from the correspond-
ing 1,3-dicarbonyl compounds and the optically active 1,2-
diaryl-1,2-ethanediamines and isolated before use. The X-ray
a)
b)
c)
Entry
Catalysts
Time/h
Yield/%
Ee/%
1
2
3
4
5
6
1a
1b
1c
1d
1e
1f
125
125
48
48
48
3
trace
trace
9
25
34
—
—
2
56
69
93
1
4
analyses of several 3-oxobutylideneaminatocobalt complexes
provided helpful knowledge for ligand design. In the course of
our continuing study of these cobalt complexes, they were
found to act as chiral Lewis acid catalysts for a 6π-electro-
93
a) Reaction conditions: cobalt catalyst 0.025 mmol (5.0
mol%), phenylglyoxal 1.0 mmol, and 2-phenylpropene 0.5
mmol in CHCl (2.5 mL). b) Isolated yield. c) Determined
3
by HPLC analysis using Daicel Chiralcel OB-H (3% 2-pro-
panol in hexane).
1
5
cyclic concerted hetero Diels–Alder reaction. In addition,
the corresponding cationic cobalt(Ⅲ) complexes could be em-
ployed more effectively than the original cobalt(Ⅱ) complex
and their counter anions significantly influenced their Lewis
1
6
acidities and catalytic abilities.
These cationic cobalt(Ⅲ)
complexes also catalyzed the enantioselective carbonyl-ene
reaction of glyoxal derivatives to afford the corresponding ho-
1
7
moallylic alcohols with high enantioselectivities.
In this article, we would like to fully disclose the enantiose-
lective carbonyl-ene reaction of various terminal alkenes with
glyoxal derivatives catalyzed by cationic cobalt(Ⅲ) complexes
with optically active 3-oxobutylideneaminato ligands.
Results and Discussion
Examinations of the Central Cobalt Atom and Effective
-Oxobutylideneaminato Ligands for the Optically Active
Cobalt Complexes. On the basis of the previous observa-
tions for the 3-oxobutylideneaminatocobalt complexes which
catalyzed hetero Diels–Alder reaction, the cationic character
of the central cobalt atom would have a crucial effect on the
3

S. Kezuka et al.
Bull. Chem. Soc. Jpn., 76, No. 1 (2003)
51
1
6
reaction rate and enantioselectivity; therefore, various 3-
oxobutylideneaminatocobalt(Ⅱ) and cobalt(Ⅲ) complex cata-
lysts were examined for the enantioselective carbonyl-ene re-
action of phenylglyoxal (6a) and 2-phenylpropene (7a) (Table
highly active cationic cobalt(Ⅲ) complex catalyst and that the
resulting homoallylic alcohol with 93% ee was obtained in
93% yield (Entry 6). It was confirmed by X-ray analysis that
the central cobalt(Ⅲ) atom in the complexes was completely
1
6
1
). The cobalt(Ⅱ) complex 1a and the corresponding iodo
separated from the counter anions. The catalytic activities of
cobalt(Ⅲ) complex 1b did not catalyze the carbonyl-ene reac-
tions very well (Entries 1 and 2). The cationic cobalt(Ⅲ) com-
plexes with various counter anions 1c–1f were synthesized by
treatment of the iodo cobalt(Ⅲ) complex 1b with the corre-
these series of cationic cobalt(Ⅲ) complexes could be correlat-
1
8
ed to the acidity of the conjugate base of their counter anions;
the cationic cobalt(Ⅲ) complex with a counter anion derived
from the stronger conjugate acid achieved the higher yield of
the carbonyl-ene product. For instance, the carbonyl-ene prod-
uct was obtained in low yield in the presence of catalytic
1
6
sponding silver salts; then they were used in the reaction.
The cobalt(Ⅲ) triflate complex 1c, one of the most effective
catalysts for the cobalt complex-catalyzed hetero Diels–Alder
19
amount of cobalt(Ⅲ) trifluoromethanesulfonate [H
trifluoromethanesulfonic acid (CF SO H) is −14.1], whereas
the corresponding cobalt(Ⅲ) hexafluoroantimonate [H value
of hexafluoroantimonic acid (HF–SbF ) is −27.9] afforded the
0
value of
16
reaction, catalyzed the present carbonyl-ene reaction to pro-
duce the adduct in only 9% yield and with 2% ee (Entry 3).
The corresponding cobalt(Ⅲ) tetrafluoroborate 1d and hexaflu-
orophosphate 1e more effectively catalyzed the carbonyl-ene
reaction to obtain the corresponding homoallylic alcohol with
good enantioselectivities in moderate yields (Entries 4 and 5).
Screening of the counter anions revealed that the cobalt(Ⅲ)
hexafluoroantimonate 1f could be significantly employed as a
3
3
0
5
resulting homoallylic alcohol in high yield.
A variety of optically active 3-oxobutylideneaminato
ligands for cobalt(Ⅲ) hexafluoroantimonate complexes were
next examined (Table 2). The chiral diaryl diamine parts of the
1
1,13,14
complexes were firstly examined.
When the complex 2f
Table 2. Various Ligands of the Cationic Cobalt(Ⅲ) Complex Catalyst for the Enantioselective
Carbonyl-Ene Reaction
a)
b)
c)
Entry
Catalyst
Time/h
3
Yield/%
Ee/%
1
1f
2f
93
93
2
3
24
48
97
22
92
13
3f
4
5
9f
48
48
16
64
64
63
10f
6
11f
48
79
88
a) Reaction conditions: cobalt catalyst 0.025 mmol (5.0 mol%), phenylglyoxal 0.5 mmol, and
-phenylpropene 1.0 mmol in CHCl (2.5 mL). b) Isolated yield. c) Determined by HPLC
analysis using Daicel Chiralcel OB-H (3% 2-propanol in hexane).
2
3

5
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Bull. Chem. Soc. Jpn., 76, No. 1 (2003)
HEADLINE ARTICLES
Table 4.
derived from 1,2-bis(3,5-dimethylphenyl)ethylenediamine was
employed as the catalyst, the product was obtained in 24 hours
in a similar yield and with similar enantioselectivity, as com-
pared to that obtained in 3 hours using complex 1f derived
from 1,2-diphenylethylenediamine (Entry 2). When the com-
plex 3f derived from 1,2-bis(2,4,6-trimethylphenyl)ethylenedi-
amine was used, both the activity and enantioselectivity were
unexpectedly decreased (Entry 3). The side chains in the 3-ox-
obutylideneaminato ligands were then examined. Two cationic
cobalt(Ⅲ) complexes having acetyl or cyclopentyloxycarbonyl
groups in place of the mesitoyl groups were prepared and used
in the reaction; however, the corresponding homoallylic alco-
hols were obtained with low ee (Entries 4 and 5). Optically ac-
tive cyclohexanediamine was tested as a chiral diamine to pre-
pare the corresponding cationic cobalt(Ⅲ) hexafluoroanti-
monate 11f; the corresponding homoallyl alcohol was obtained
in 79% yield and with 88% ee (Entry 6) although a longer
reaction time was required.
Temperature Effect in the Enantioselective
Carbonyl-Ene Reaction
a)
b)
c)
Entry
Temp/°C
Time/h
Yield/%
Ee/%
1
2
3
4
5
r.t.
0
−20
−40
−60
20
20
3
18
40
61
77
93
95
90
53
92
93
94
95
a) Reaction conditions: Co(Ⅲ)–SbF
6
complex catalyst
0
.025 mmol (5.0 mol%), 2-phenylpropene 0.5 mmol, and
phenylglyoxal 1.0 mmol in CHCl (2.5 mL). b) Isolated
3
yield. c) Determined by HPLC analysis using Chiralcel
OB-H (3% 2-propanol in hexane).
Optimization of the Solvents and Temperature for the
Enantioselective Carbonyl-Ene Reaction.
Reaction sol-
vents and temperature influence the catalytic activities and
enantioselectivities for Lewis acid catalyzed reactions. For the
enantioselective hetero Diels–Alder reaction catalyzed by 3-
oxobutylideneaminatocobalt complexes, dichloromethane and
fluorobenzene were effective for enhancing reactivities and
enantioselectivities; therefore, various solvents were exam-
ined for the enantioselective carbonyl-ene reaction. The yields
and enantiomeric excesses of the resulting product are shown
in Table 3. The cationic cobalt catalyst did not dissolve
enough in hexane, and the reaction did not proceed (Entry 1).
Donative solvents, such as acetonitrile and diethyl ether, de-
creased the catalytic activity and the stereoselectivity because
of their coordination to the cationic cobalt complexes (Entries
toluene (Entry 4). In fluorobenzene and dichloromethane, the
reaction proceeded more rapidly and the enantioselectivities
were 70% and 90%, respectively (Entries 5 and 6). Moreover,
in chloroform, the reaction was completed within 3 hours to
afford the corresponding homoallylic alcohol with 93% ee
(Entry 7). These examinations indicated that chloroform was
the most suitable solvent for the present enantioselective car-
bonyl-ene reaction.
The reaction temperature was next examined and the results
are shown in Table 4. The yields and enantioselectivities at
room temperature and at 0 °C were both lower than those at
−20 °C (Entries 1–3). The enantioselectivity was slightly im-
proved at −40 °C and −60 °C, though the reaction rate was
decreased (Entries 4 and 5). Therefore, the reaction tempera-
ture could be selected from −20 °C to −60 °C according to
the reactivity of the substrates.
16
2
and 3), and the product was obtained in a moderate yield in
Table 3. Various Solvents for the Enantioselective Carbonyl-
Ene Reaction
Enantioselective Carbonyl-Ene Reaction of Various Gly-
oxals and Alkenes. The highly active catalyst, cobalt(Ⅲ)
hexafluoroantimonate complex 1f, was successfully applied to
the enantioselective carbonyl-ene reaction of various phenyl-
glyoxal derivatives and benzyl glyoxylate (6g) with 2-phenyl-
propene (7a) (Table 5). Phenylglyoxal derivatives with elec-
tron-withdrawing groups, p-nitro-, p-fluoro-, p-chloro-, and p-
bromophenylglyoxals (6b–e), were attempted at −40 °C; the
enantioselectivities of the resulting products were over 90%
(
Entries 2–5). In addition, p-methylphenylglyoxal (6f) was
a)
b)
c)
Entry
Solvent
Hexane
Time/h
Yield/%
Ee/%
examined and the corresponding homoallylic alcohol was
achieved with high enantioselectivity, though the yield was
only 45% (Entry 6). The reaction with benzyl glyoxylate (6g)
smoothly proceeded at −60 °C and the corresponding homoal-
lylic alcohol was obtained in 91% yield and with 85% ee
(Entry 7).
The carbonyl-ene reaction of phenylglyoxal (6a) with vari-
ous alkenes was then attempted in the presence of 5 mol% co-
balt(Ⅲ) hexafluoroantimonate 1f at −20 °C (Table 6). The 2-
phenylpropenes substituted with 4-fluoro-, 4-methyl-, and 2-
fluoro- on the benzene ring (7a–c) also smoothly reacted with
phenylglyoxal (6a) to afford the corresponding homoallylic al-
cohols in high yields with high enantioselectivities (Entries 1,
1
2
3
4
5
6
7
96
96
96
96
38
14
3
trace
trace
26
31
50
—
—
16
26
70
90
93
3
CH CN
Et
2
O
Toluene
PhF
CH
2
Cl
2
82
93
CHCl
3
a) Reaction conditions: Co(Ⅲ)–SbF
.025 mmol (5.0 mol%), 2-phenylpropene 0.5 mmol, and
phenylglyoxal 1.0 mmol at −20 °C. b) Isolated yield.
c) Determined by HPLC analysis using Chiralcel OB-H
6
complex catalyst
0
(
3% 2-propanol in hexane).

S. Kezuka et al.
Bull. Chem. Soc. Jpn., 76, No. 1 (2003)
53
Table 5. The Enantioselective Carbonyl-Ene Reaction of
Various Glyoxal Derivatives
Table 6. The Enantioselective Carbonyl-Ene Reaction of
Various Alkenes
a)
b)
Entry
Glyoxal
X = H (6a)
X = NO (6b)
Yield/%
Ee/%
1
2
3
4
5
6
95
80
81
89
80
45
94
92
92
92
91
91
a)
b)
Entry
R
Alkene
Yield/%
92
Ee/%
2
1
2
3
Ph (6a)
X = F (7b)
X = H (7a)
X = Me (7c)
88
93
84
X = F (6c)
X = Cl (6d)
X = Br (6e)
X = Me (6f)
93
70
4
5
7d
7e
87
87
92
89
c)
7
6g
91
85
a) Reaction conditions: Co(Ⅲ)–SbF
6
catalyst 0.025 mmol
(
5.0 mol%), glyoxal derivative 1.0 mmol, and 2-phenyl-
3
propene 0.5 mmol in CHCl (2.5 mL). b) Isolated yield.
c) Reaction was carried out at −60 °C.
6
7
7f
81
56
91
84
7g
3
, and 4). The reaction of 2-(2-naphthyl)propene (7e) was
8
9
7h
7i
75
60
91
94
94
85
completed in 48 hours and the optical yield of the correspond-
ing product was 89% ee (Entry 5). In the presence of co-
balt(Ⅲ) complex 1f, the carbonyl-ene reaction of 1,1-dialkyl
substituted ethenes, such as 2,4,4-trimethyl-1-pentene (7f),
c)
2
,3-dimethyl-1-butene (7g), methylenecyclohexane (7h) and
OBn (6g)
1
0
7a
O-protected methallyl alcohol (7i), with phenylglyoxal (6a)
proceeded and the corresponding products were obtained with
high enantioselectivities (Entries 6–9). In these cases, two
geometrical isomers could be produced, though the regioselec-
tivity in the present carbonyl-ene reaction was totally superior
c)
1
1
7e
7f
93
70
85
56
1
2
(> 99:1, NMR analysis) (Entries 6, 7, and 9). In addition,
benzyl glyoxylate (6g) reacted with various ethenes to afford
the product with good to high enantioselectivity. In the reac-
tion with 2-phenylpropene (7a) and 2-(2-naphthyl)propene
13
7j
50
62
(
7e), the corresponding α-hydroxy esters was obtained in high
a) Reaction conditions: Co(Ⅲ)–SbF
mol%), glyoxal derivative 1.0 mmol, and alkene 0.5 mmol in
CHCl (2.5 mL) at −20 °C. b) Isolated yield. c) Reaction
6
catalyst 0.025 mmol (5.0
yields with high enantioselectivities (Entries 10 and 11). The
reaction of benzyl glyoxylate (6g) with 2,4,4-trimethyl-1-pen-
tene (7f) and 1-isopropenyladamantane (7j) also proceeded,
and the corresponding products were obtained with good enan-
tioselectivities (Entries 12 and 13).
3
was carried out at −60 °C.
Catalytic Amount of the Cationic Cobalt(Ⅲ) Complex.
Lewis acid catalysts are generally moisture-sensitive since
contaminants such as water or amines could occupy the coor-
dination sites of the central metal to prevent the substrate from
approaching the catalyst. Therefore, perfectly anhydrous con-
ditions, loading of more than 10 mol% catalyst, or coexistence
of dehydrating agents should be required to achieve high reac-
tivities and enantioselectivities. Pre-synthesized and readily
isolated transition-metal and/or moisture-stable complex cata-
lysts were expected to be among the most promising solutions
for these difficulties. Using these concepts, researchers have
cobalt complexes are prepared in water-methanol and can be
isolated prior to use; therefore, the loading amount of the cata-
lyst was expected to be decreased. In Table 7, the loading
amount of the cationic cobalt(Ⅲ) complex catalyst 1f was ex-
amined in the reaction of 2-phenylpropene (7a) with phenyl-
glyoxal (6a). The smaller the amount of complex catalyst
loaded, the longer the reaction time required for complete con-
sumption of the glyoxal. The yield and enantioselectivity of
the products in each reaction were maintained in the ranges of
80–93% yields and 93–95% ee regardless of the amount of
complex catalyst employed (0.2–5 mol%). These observations
show that the optically active 3-oxobutylideneaminatoco-
balt(Ⅲ) hexafluoroantimonate complex could act as a Lewis
acid for the carbonyl-ene reaction even with a 0.2 mol% cata-
lyst loading.
2
0
recently developed the enantioselective Diels–Alder and het-
21
ero Diels–Alder reactions and enantioselective cyano-
22
hydration to achieve high enantioselections and high catalyt-
ic efficiencies. The optically active 3-oxobutylideneaminato-

5
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Bull. Chem. Soc. Jpn., 76, No. 1 (2003)
HEADLINE ARTICLES
Scheme 2.
Table 7.
Loading Amount of 3-Oxobutylideneaminato-
cobalt(Ⅲ) Complex Catalysts
a)
b)
c)
Entry
Cat./mol%
Time/h
Yield/%
Ee/%
1
2
3
4
5
5
2
1
0.5
0.2
3
8
21
45
80
93
80
84
80
80
93
94
95
95
94
6
a) Reaction conditions: Co(Ⅲ)–SbF complex catalyst
0
.025 mmol (5.0 mol%), 2-phenylpropene 0.5 mmol, and
phenylglyoxal 1.0 mmol at −20 °C. b) Isolated yield.
c) Determined by HPLC analysis using Chiralcel OB-H
Fig. 3. Reasonable explanation for the enantioselection in
the carbonyl-ene reaction catalyzed by the (S,S)-cobalt
complex.
(
3% 2-propanol in hexane).
those of the corresponding hetero Diels–Alder reaction.
Conclusions
In summary, the cationic cobalt(Ⅲ) hexafluoroantimonate
complex with a optically active 3-oxobutylideneaminato
ligand effectively catalyzed the asymmetric carbonyl-ene reac-
tion of various alkenes with glyoxal derivatives to afford the
corresponding homoallylic alcohols in high yield with high
enantioselectivities.
Fig. 2. ∆δ(δ
S
R
− δ ) values (ppm) obtained for (R)- and (S)-
MTPA esters of secondary alcohols.
Absolute Configuration of the Optically Active Homoal-
lylic Alcohols. The absolute configuration of the obtained
Experimental
1
product 12f was determined by the ∆δ values of H NMR ana-
lysis obtained for the corresponding (R)- and (S)-MTPA esters
General. Infrared (IR) spectra were recorded on a JASCO
2
3
Model FT/IR-410 infrared spectrometer on KBr pellets or liquid
(
Scheme 2) described in the literature. We confirmed that the
1
13
film on NaCl. H NMR spectra and C NMR spectra were mea-
sured on a JEOL Model GX-400 spectrometer using CDCl or
as a solvent and with tetramethylsilane as an internal
homoallylic alcohol of the (S)-configuration corresponding to
the (S,S)-cobalt complex catalyst was obtained (Fig. 2). On the
basis of this observation, the plausible transition states of the
present carbonyl-ene reaction are proposed as follows (Fig. 3);
it could be assumed that the lone pair of oxygen atoms anti to
the benzoyl or benzyloxycarbonyl group in glyoxals contribut-
ed to coordination of the cobalt atom, and that the phenyl or
benzyloxy group are oriented between two coordinating oxy-
gen atoms on the planar 3-oxobutylideneaminato ligand, be-
3
6 6
C D
standard. High-resolution mass spectra were obtained with a
HITACHI M-8013. For the thin-layer chromatography (TLC)
analysis throughout this work, Merck precoated TLC plates (silica
gel 60 F254, 0.25 mm) were used. The products were purified by
preparative column chromatography on silica gel (silica gel 60N).
High-performance liquid chromatography (HPLC) analyses were
performed with a Shimadzu LC-6A chromatograph using an opti-
cally active column (Chiralcel OB-H, Chiralcel OD-H, and
Chiralpak AD-H columns, Daicel Ltd., Co.); the peak areas were
obtained with a Shimadzu chromatopack CR-4A or Varian
Dynamax MacIntegrator. Optical rotations were measured with a
JASCO DIP-370 digital polarimeter.
2
4
cause of their bulkiness. The alkene should approach the si-
face of the activated glyoxals mentioned above to afford the
(S)-homoallylic alcohols in high selectivities because the re-
face is blocked by the aryl group of the chiral diamine and the
bulky alkyl or aryl group on the side chain of the 3-oxobutyl-
ideneaminato ligand. This postulated transition state can clear-
ly explain the observed stereochemistry of the present carbon-
yl-ene reaction. Moreover, these results are consistent with
Phenylglyoxal (6a) was purchased from Tokyo Kasei Kogyo
(TCI) Co., Ltd. p-Nitrophenylglyoxal (6b), p-fluorophenylgly-
oxal (6c), p-chlorophenylglyoxal (6d), p-bromophenylglyoxal

S. Kezuka et al.
6e), p-methylphenylglyoxal (6f), and benzyl glyoxylate (6g),
Bull. Chem. Soc. Jpn., 76, No. 1 (2003)
55
2
5
26
cm−1. HRMS: Calcd for C17
+
(
H
16
O
2
: (M ), 252.1150. Found: m/z
were prepared by a reported method. 2-Phenylpropene (7a), 2-(4-
fluorophenyl)propene (7b), 2,4,4-trimethyl-1-pentene (7f), 2,3-
dimethyl-1-butene (7g), and methylenecyclohexane (7h) were
purchased from Tokyo Kasei Kogyo (TCI) Co., Ltd. 2-(4-Meth-
ylphenyl)propene (7c), 2-(2-fluorophenyl)propene (7d), 2-(2-
naphthyl)propene (7e), 3-(t-butyldimethylsilyloxy)-2-methylpro-
pene (7i), and 1-isopropenyladamantane (7j) were prepared by a
252.1166. HPLC: Chiralcel OB-H (3.0% 2-propanol in hexane,
Flow 1.0 mL/min), 17.9 min (minor), 31.3 min (major) [(R,R)-
cobalt complex 1f was employed].
2-Hydroxy-1-(4-nitrophenyl)-4-phenyl-4-penten-1-one (8b):
2
8
1
[α]
D
+33.0° (c 0.320, CHCl
3
). H NMR (400 MHz) δ 2.75 (1H,
dd, J = 7.3, 14.7 Hz), 2.98 (1H, dd, J = 4.4, 14.7 Hz), 3.37 (1H,
d, J = 6.8 Hz), 5.02–5.14 (2H, m), 5.27 (1H, d, J = 1.2 Hz), 7.17–
7.26 (5H, m), 7.80 (2H, d, J = 8.8 Hz), 8.19 (1H, d, J = 8.8 Hz);
2
7
reported method.
Preparation of Optically Active 3-Oxobutylideneaminatoco-
13
C NMR (100 MHz) δ 41.6, 72.2, 117.0, 123.8, 126.5, 127.9,
balt Complexes. Complexes 1f, 2f, 3f, 9f, 10f, and 11f were
128.4, 129.4, 138.7, 139.9, 143.0, 150.4, 200.1; IR (neat) 3482,
3108, 3082, 3054, 3030, 2930, 2860, 1950, 1809, 1692, 1628,
1603, 1574, 1525, 1495, 1444, 1402, 1348, 1318, 1254, 1216,
1
6
prepared by a reported method.
1S,2S)-1,2-Bis(3,5-dimethylphenyl)-N,Nꢀ-bis[3-oxo-2-(2,4,6-
(
−
1
trimethylbenzoyl)butylidene]ethylenediaminatocobalt(Ⅲ) He-
xafluoroantimonate (2f): IR (KBr) 3012, 2921, 2863, 1586,
1190, 1111, 1089, 1073, 978, 908, 854, 780, 707, 541, 508 cm .
+
4
HRMS: Calcd for C17H15NO : (M ), 297.1001. Found: m/z
1
8
472, 1398, 1355, 1299, 1262, 1200, 1125, 1074, 1032, 997, 875,
297.1030. HPLC: Chiralcel OD-H (10.0% 2-propanol in hexane,
Flow 1.0 mL/min), 16.9 min (major), 20.4 min (minor) [(R,R)-
cobalt complex 1f was employed].
−
1
51, 745, 725, 700, 665, 640, 601, 567 cm . MS (FAB(positive))
+
−
6 6
m/z 754 (M−SbF +H) , (FAB(negative)) m/z 235 (SbF ) .
(
1S,2S)-N,Nꢀ-Bis[3-oxo-2-(2,4,6-trimethylbenzoyl)butylidene]-
1-(4-Fluorophenyl)-2-hydroxy-4-phenyl-4-penten-1-one (8c):
25
1
1
,2-bis(2,4,6-trimethylphenyl)ethylenediaminatocobalt(Ⅲ)
Hexafluoroantimonate (3f):
466, 1400, 1356, 1288, 1268, 1199, 1124, 1083, 1035, 994, 878,
50, 746, 665, 641, 595 cm
M−SbF
(
ylenediaminatocobalt(Ⅲ) Hexafluoroantimonate (9f):
KBr) 2932, 1585, 1534, 1492, 1474, 1397, 1359, 1300, 1268,
193, 1084, 1000, 948, 763, 705, 661, 607, 549 cm
FAB(positive)) m/z 490 (M−SbF
[α]
D
−42.0° (c 0.177, CHCl
3
). H NMR (400 MHz) δ 2.71 (1H,
IR (KBr) 2922, 2863, 1591,
dd, J = 7.3, 14.7 Hz), 3.05 (1H, dd, J = 3.9, 14.7 Hz), 3.59 (1H,
d, J = 7.3 Hz), 5.09 (1H, dt, J = 3.9, 7.3 Hz), 5.16 (1H, d, J = 1.0
Hz), 5.34 (1H, d, J = 1.0 Hz), 7.08–7.16 (2H, m), 7.25–7.36 (5H,
1
8
(
−
1
.
MS (FAB(positive)) m/z 782
+
−
13
6
+ H) , (FAB(negative)) m/z 235 (SbF
6
) .
m), 7.76–7.84 (2H, m); C NMR (100 MHz) δ 42.1, 71.5, 116.0
1S,2S)-N,Nꢀ-Bis(2-acetyl-3-oxobutylidene)-1,2-diphenyleth-
(d, JCF = 22 Hz), 116.4, 126.5, 127.7, 128.3, 130.2 (d, JCF = 3
Hz), 131.1 (d, JCF = 10 Hz), 140.3, 143.6, 166.0 (d, JCF = 256
Hz), 199.8; IR (neat) 3471, 3081, 3058, 3026, 2932, 1683, 1599,
1508, 1299, 1235, 1157, 1113, 1092, 1072, 977, 906, 845, 778,
IR
(
1
(
2
−
1
.
MS
+
−1
+
6
+ H) , (FAB(negative)) m/z
2
705, 601 cm . HRMS: Calcd for C17H15FO : (M ), 270.1056.
−
35 (SbF
1S,2S)-N,Nꢀ-Bis(2-cyclopentyloxycarbonyl-3-oxobutylidene)-
,2-diphenylethylenediaminatocobalt(Ⅲ) Hexafluoroantimo-
6
) .
Found: m/z 270.1043. HPLC: Chiralcel OD-H (1.0% 2-propanol
in hexane, Flow 1.0 mL/min), 21.0 min (major), 22.9 min (minor)
[(R,R)-cobalt complex 1f was employed].
(
1
nate (10f): IR (KBr) 2966, 2874, 1672, 1615, 1436, 1409, 1362,
1-(4-Chlorophenyl)-2-hydroxy-4-phenyl-4-penten-1-one (8d):
25
1
1
5
323, 1263, 1199, 1168, 1086, 1035, 1003, 965, 759, 702, 665,
[α]
D
+35.1° (c 1.063, CHCl
3
). H NMR (400 MHz) δ 2.71 (1H,
99, 547 cm− . MS (FAB(positive)) m/z 630 (M−SbF
1
+ H) ,
+
dd, J = 7.8, 14.6 Hz), 3.04 (1H, dd, J = 3.9, 14.6 Hz), 3.57 (1H,
brs), 5.04–5.11 (1H, m), 5.15 (1H, d, J = 1.0 Hz), 5.34 (1H, d, J
= 1.0 Hz), 7.27–7.35 (5H, m), 7.42 (2H, d, J = 8.3 Hz), 7.70 (2H,
6
−
(
FAB(negative)) m/z 235 (SbF
6
) .
(
1R,2R)-N,Nꢀ-Bis[3-oxo-2-(2,4,6-trimethylbenzoyl)butyl-
13
idene]-cyclohexylethylenediaminatocobalt(Ⅲ) Hexafluoroanti-
monate (11f): IR (KBr) 2938, 2864, 1638, 1584, 1454, 1398,
d, J = 8.3 Hz); C NMR (100 MHz) δ 42.0, 71.6, 116.4, 126.5,
127.7, 128.3, 129.0, 129.8, 132.1, 140.27, 140.32, 143.5, 200.2;
IR (neat) 3465, 3083, 3059, 3032, 2934, 1683, 1591, 1571, 1491,
1445, 1399, 1285, 1259, 1092, 1012, 976, 906, 833, 778, 703, 531
1
7
353, 1299, 1281, 1246, 1199, 1165, 1030, 996, 930, 881, 850,
−
1
95, 745, 662, 640, 586, 558 cm . MS (FAB(positive)) m/z 600
+
−
−1
+
(
M−SbF
6
+ H) , (FAB(negative)) m/z 235 (SbF
6
) .
2
cm . HRMS: Calcd for C17H15ClO : (M ), 286.0761. Found:
General Procedure for the Enantioselective Carbonyl-Ene
Reaction. To a solution of the cobalt complex 1f (23.3 mg, 5.4
mol%) in chloroform (0.5 mL) was added 2-phenylpropene (7a)
m/z 286.0741. HPLC: Chiralcel OD-H (1.0% 2-propanol in hex-
ane, Flow 1.0 mL/min), 20.3 min (minor), 22.2 min (major)
[(R,R)-cobalt complex 1f was employed].
(
54.5 mg, 0.46 mmol) in chloroform (1.0 mL). A solution of the
1-(4-Bromophenyl)-2-hydroxy-4-phenyl-4-penten-1-one (8e):
25
1
phenylglyoxal (6a) (133.3 mg, 0.99 mmol) in chloroform (1.0
mL) was then added at −20 °C. The mixture was stirred for 3 h at
−
afforded 1,4-diphenyl-2-hydroxy-4-penten-1-one (108.6 mg) in
9
1
[α]
D
−38.0° (c 0.932, CHCl
3
). H NMR (400 MHz) δ 2.70 (1H,
dd, J = 7.8, 14.7 Hz), 3.03 (1H, dd, J = 3.9, 14.7 Hz), 3.56 (1H,
d, J = 6.8 Hz), 4.99 (1H, ddd, J = 3.9, 6.8, 7.8 Hz), 5.15 (1H, d, J
= 1.0 Hz), 5.34 (1H, d, J = 1.0 Hz), 7.26–7.35 (5H, m), 7.57 (2H,
20 °C. A standard workup and chromatography on silica gel
13
3% yield. [Chiralcel OB-H, 3.0% 2-propanol in hexane, Flow
.0 mL/min, 17.9 min (minor), 31.3 min (major)].
d, J = 8.3 Hz), 7.61 (2H, d, J = 8.3 Hz); C NMR (100 MHz) δ
41.9, 71.6, 116.4, 126.5, 127.7, 128.3, 129.0, 129.8, 132.0, 132.5,
140.2, 143.5, 200.4; IR (neat) 3469, 3083, 3057, 3031, 2932,
1684, 1586, 1487, 1394, 1258, 1070, 1010, 975, 906, 824, 778,
3
1
1
,4-Diphenyl-2-hydroxy-4-penten-1-one (8a): [α]
D
+40.1°
1
(
1
c 0.370, CHCl ). H NMR (400 MHz) δ 2.59 (1H, dd, J = 8.3,
3
703 cm−
1
.
+
4.7 Hz), 3.02 (1H, dd, J = 2.9, 14.7 Hz), 3.59 (1H, brs), 5.00–
.10 (2H, m), 5.28 (1H, d, J = 7.8 Hz), 7.15–7.33 (5H, m), 7.39
2
HRMS: Calcd for C17H15BrO : (M ), 330.0256.
5
Found: m/z 330.0280. HPLC: Chiralcel OB-H (5.0% 2-propanol
in hexane, Flow 1.0 mL/min), 14.9 min (minor), 17.5 min (major)
[(R,R)-cobalt complex 1f was employed].
(
2H, t, J = 7.8 Hz), 7.54 (1H, t, J = 7.8 Hz), 7.71 (2H, d, J = 7.8
1
3
Hz); C NMR (100 MHz) δ 42.0, 71.6, 116.1, 126.5, 127.6,
1
3
1
28.3, 128.4, 128.7, 133.6, 133.8, 140.3, 143.8, 201.3; IR (neat)
471, 3082, 3058, 3030, 2928, 1682, 1629, 1598, 1578, 1494,
448, 1408, 1259, 1178, 1112, 1092, 1072, 975, 905, 779, 699
2-Hydroxy-1-(4-methylphenyl)-4-phenyl-4-penten-1-one (8f):
2
8
1
[α]
D
+26.1° (c 0.412, CHCl
3
). H NMR (400 MHz) δ 2.43 (3H,
s), 2.63 (1H, dd, J = 8.3, 14.6 Hz), 3.08 (1H, dd, J = 3.4, 14.6

5
6
Bull. Chem. Soc. Jpn., 76, No. 1 (2003)
HEADLINE ARTICLES
1
Hz), 3.67 (1H, d, J = 6.8 Hz), 5.08 (1H, ddd, J = 3.4, 6.8, 8.3
Hz), 5.17 (1H, s), 5.35 (1H, s), 7.21–7.42 (7H, m), 7.70 (2H, d, J
1449, 1407, 1290, 1262, 1215, 1094, 975, 914, 824, 763, 692 cm−
.
+
HRMS: Calcd for C17
H15FO
2
: (M ), 270.1056. Found: m/z
1
3
=
1
(
8.3 Hz); C NMR (100 MHz) δ 21.8, 42.2, 71.4, 116.0, 126.5,
27.6, 128.3, 128.6, 129.4, 131.1, 140.5, 144.0, 144.9, 200.9; IR
neat) 3468, 3082, 3056, 3031, 2923, 1678, 1606, 1444, 1401,
270.1071. HPLC: Chiralpak OB-H (3.0% 2-propanol in hexane,
Flow 1.0 mL/min), 11.6 min (major), 14.5 min (minor) [(R,R)-
cobalt complex 1f was employed].
−
1
1
288, 1266, 1179, 1111, 1092, 1073, 973, 903, 822, 778, 706 cm
.
2-Hydroxy-4-(2-naphtyl)-1-phenyl-4-penten-1-one
(12e):
+
25
1
HRMS: Calcd for C18
H
18
O
2
: (M ), 266.1307. Found: m/z
[α] +59.5° (c 0.558, CHCl ). H NMR (400 MHz) δ 2.78 (1H,
dd, J = 8.3, 14.5 Hz), 3.19 (1H, d, J = 14.5 Hz), 3.69 (1H, brs),
D
3
2
66.1313. HPLC: Chiralcel OB-H (10.0% 2-propanol in hexane,
Flow 1.0 mL/min), 7.6 min (major), 10.3 min (minor) [(R,R)-
cobalt complex 1f was employed].
5.16 (1H, br), 5.27 (1H, s), 5.49 (1H, s), 7.38–7.62 (7H, m), 7.73–
13
7.85 (5H, m); C NMR (100 MHz) δ 42.1, 71.6, 116.7, 124.8,
125.3, 125.9, 126.1, 127.4, 127.9, 128.0, 128.4, 128.7, 132.8,
133.1, 133.7, 133.8, 137.5, 143.5, 201.4; IR (KBr) 3421, 3383,
3059, 2937, 1683, 1596, 1447, 1408, 1258, 1212, 1197, 1173,
1132, 1109, 1005, 945, 901, 865, 832, 755, 692, 647, 633, 617,
25
Benzyl 2-Hydroxy-4-phenyl-4-pentenoate (8g):
[α]
D
1
+
3.9° (c 1.197, CHCl ). H NMR (400 MHz) δ 2.72–2.88 (1H,
3
br), 2.85 (1H, dd, J = 7.3, 14.7 Hz), 3.06 (1H, dd, J = 4.4, 14.7
Hz), 4.31 (1H, s), 4.95 (1H, d, J = 12.2 Hz), 5.09 (1H, d, J = 12.2
Hz), 5.17 (1H, d, J = 12.2 Hz), 5,36 (1H, s), 7.21–7.42 (10H, m);
476 cm− . HRMS: Calcd for C21
1
H O : (M ), 302.1307. Found:
+
18 2
1
3
C NMR (100 MHz) δ 40.5, 67,2, 69.2, 116.2, 126.3, 127.6,
28.25, 128.29, 128.4, 128.5, 134.9, 140.1, 143.3, 174.1; IR (neat)
469, 3084, 3060, 3033, 2953, 1738, 1629, 1600, 1574, 1496,
455, 1377, 1266, 1199, 1113, 1092, 1028, 906, 780, 738, 698
m/z 302.1313. HPLC: Chiralcel OB-H (10.0% 2-propanol in hex-
ane, Flow 1.0 mL/min), 16.4 min (minor), 25.9 min (major).
6,6-Dimethyl-2-hydroxy-4-methylene-1-phenylheptan-1-one
1
3
1
2
6
1
(12f): [α]
D
−9.5° (c 0.762, CHCl
3
). H NMR (400 MHz) δ
−
1
+
cm . HRMS: Calcd for C18
H
18
O
3
: (M ), 282.1256. Found: m/z
0.80 (9H, s), 1.89 (1H, d, J = 13.0 Hz), 1.95 (1H, d, J = 13.0 Hz),
2.17 (1H, dd, J = 8.8, 14.7 Hz), 2.56 (1H, dd, J = 2.4, 14.7 Hz),
3.61 (1H, brs), 4.80 (1H, s), 4.94 (1H, s), 5.14 (1H, dd, J = 2.4,
8.8 Hz), 7.44 (2H, t, J = 7.3 Hz), 7.56 (1H, t, J = 7.3 Hz), 7.86
2
1
82.1214. HPLC: Chiralcel OB-H (2.0% ethanol in hexane, Flow
.0 mL/min), 18.5 min (minor), 20.1 min (major) [(R,R)-cobalt
complex 1f was employed].
13
4
-(4-Fluorophenyl)-2-hydroxy-1-phenyl-4-penten-1-one (12b):
(2H, d, J = 7.3 Hz); C NMR (100 MHz) δ 29.9, 31.7, 44.1, 49.5,
72.6, 116.3, 128.5, 128.7, 133.6, 133.8, 142.8, 201.4; IR (neat)
3475, 3071, 2952, 1682, 1639, 1598, 1477, 1449, 1363, 1263,
2
5
1
[
α]
D
+20.7° (c 0.732, CHCl
3
). H NMR (400 MHz) δ 2.61 (1H,
dd, J = 8.3, 14.6 Hz), 2.97 (1H, dd, J = 3.4, 14.6 Hz), 3.63 (1H,
brs), 5.00–5.12 (2H, m), 5.22 (1H, s), 6.90 (1H, d, J = 8.8 Hz),
900, 775, 692 cm−
1
.
+
22 2
HRMS: Calcd for C16H O : (M ),
6
=
.92 (1H, d, J = 8.8 Hz), 7.21 (1H, d, J = 8.8 Hz), 7.22 (1H, d, J
8.8 Hz), 7.39 (2H, t, J = 7.3 Hz), 7.54 (1H, t, J = 7.3 Hz), 7.69
246.1620. Found: m/z 246.1595. HPLC: Chiralcel OD-H (1.0%
2-propanol in hexane, Flow 1.0 mL/min), 9.9 min (major), 15.3
min (minor).
1
3
(
J
2H, d, J = 7.3 Hz); C NMR (100 MHz) δ 42.0, 71.6, 115.1 (d,
CF = 21 Hz), 116.2, 128.1 (d, JCF = 8 Hz), 128.5, 130.0, 133.5,
2-Hydroxy-4-isopropyl-1-phenyl-4-hepten-1-one
D 3
[α] −3.1° (c 0.255, CHCl ). H NMR (400 MHz) δ 0.95 (3H, d,
(12g):
22
1
1
2
1
33.9, 136.5 (d, JCF = 3 Hz), 142.7, 162.2 (d, JCF = 246 Hz),
01.1; IR (neat) 3469, 3065, 2932, 1683, 1600, 1509, 1449, 1403,
227, 1111, 1076, 975, 841, 711, 691 cm . HRMS: Calcd for
J = 6.8 Hz), 0.96 (3H, d, J = 6.8 Hz), 2.13 (1H, dd, J = 9.8, 15.1
Hz), 2.24 (1H, q, J = 6.8 Hz), 2.55 (1H, dd, J = 2.5, 15.1 Hz),
3.60 (1H, d, J = 6.8 Hz), 4.83 (1H, s), 4.87 (1H, s), 5.16 (1H, ddd,
J = 2.5, 6.8, 9.8 Hz), 7.44 (2H, t, J = 7.3 Hz), 7.56 (1H, t, J = 7.3
−
1
+
C
17
H
15FO
2
: (M ), 270.1056. Found: m/z 270.1033. HPLC:
Chiralcel OB-H (5.0% 2-propanol in hexane, Flow 1.0 mL/min),
8.4 min (minor), 31.4 min (major).
13
1
Hz), 7.86 (2H, d, J = 7.3 Hz); C NMR (100 MHz) δ 21.6, 21.8,
33.6, 41.0, 72.2, 109.6, 128.4, 128.7, 133.5, 133.8, 151.0, 201.4;
IR (neat) 3468, 3065, 2962, 2932, 2873, 1717, 1683, 1598, 1450,
2
-Hydroxy-4-(4-methylphenyl)-1-phenyl-4-penten-1-one (12c):
2
8
1
[α]
D
+37.4° (c 0.507, CHCl
3
). H NMR (400 MHz) δ 2.35 (3H,
−
1
s), 2.64 (1H, dd, J = 7.8, 14.7 Hz), 3.05 (1H, dd, J = 2.9, 14.7
Hz), 3.64 (1H, d, J = 6.8 Hz), 5.07–5.16 (2H, m), 5.31 (1H, d, J =
1263, 1091, 974, 899, 713, 695 cm
.
HRMS: Calcd for
+
C H O : (M ), 218.1307. Found: m/z 218.1305. HPLC: Chiral-
14 18 2
1
.0 Hz), 7.12 (2H, d, J = 7.8 Hz), 7.25 (2H, d, J = 7.8 Hz), 7.45
cel OD-H (0.8% 2-propanol in hexane, Flow 0.5 mL/min), 28.4
min (major), 59.7 min (minor).
(
2H, t, J = 7.3 Hz), 7.59 (1H, t, J = 7.3 Hz), 7.79 (2H, d, J = 7.3
13
Hz); C NMR (100 MHz, C
28.9, 129.0, 129.5, 133.6, 134.8, 137.5, 138.6, 144.5, 201.8; IR
neat) 3472, 3085, 3059, 3028, 2922, 1682, 1627, 1598, 1578,
6
D
6
) δ 21.4, 42.5, 72.3, 115.7, 127.2,
3-(1-Cyclohexenyl)-2-hydroxy-1-phenyl-4-propen-1-one (12h):
1
9
1
1
(
1
6
[α]
D
−2.9° (c 0.386, CHCl
3
). H NMR (400 MHz) δ 1.42–1.60
(4H, m), 1.82–2.04 (4H, m), 2.08 (1H, dd, J = 8.3, 14.7 Hz), 2.41
(1H, d, J = 14.7 Hz), 3.57 (1H, d, J = 6.4 Hz), 5.07–5.16 (1H, m),
5.40 (1H, s), 7.43 (2H, t, J = 7.3 Hz), 7.54 (1H, t, J = 7.3 Hz),
513, 1449, 1406, 1259, 1179, 1110, 1076, 974, 907, 824, 733,
95 cm− . HRMS: Calcd for C18
1
H O : (M ), 266.1307. Found:
+
18 2
13
m/z 266.1302. HPLC: Chiralcel OB-H (5.0% 2-propanol in hex-
ane, Flow 1.0 mL/min), 9.5 min (minor), 13.7 min (major).
7.84 (2H, d, J = 7.3 Hz); C NMR (100 MHz) δ 22.1, 22.8, 25.3,
28.7, 44.5, 72.0, 124.8, 128.4, 128.6, 133.0, 133.6, 133.7, 201.7;
IR (neat) 3453, 3061, 2931, 2858, 1717, 1684, 1598, 1449, 1262,
4
-(2-Fluorophenyl)-2-hydroxy-1-phenyl-4-penten-1-one (12d):
2
5
1
−1
+
[α]
D
+42.0° (c 0.177, CHCl
3
). H NMR (400 MHz) δ 2.58 (1H,
18 2
1096, 1070, 976, 703 cm . HRMS: Calcd for C15H O : (M ),
dd, J = 8.8, 14.7 Hz), 3.11 (1H, dd, J = 2.0, 14.7 Hz), 3.60 (1H,
d, J = 6.4 Hz), 4.95–5.06 (1H, m), 5.20 (1H, s), 5.24 (1H, s), 6.92
230.1307. Found: m/z 230.1291. HPLC: Chiralcel OD-H (1.0%
2-propanol in hexane, Flow 1.0 mL/min), 12.4 min (major), 20.9
min (minor).
(
(
(
1H, dd, J = 8.8, 10.5 Hz), 7.04 (1H, t, J = 7.3 Hz), 7.14–7.26
2H, m), 7.37 (2H, t, J = 7.8 Hz), 7.52 (1H, t, J = 7.8 Hz), 7.70
5-(t-Butyldimethylsilyloxy)-2-hydroxy-4-methylene-1-phen-
1
3
25
1
2H, d, J = 7.8 Hz); C NMR (100 MHz) δ 42.7 (d, JCF = 3 Hz),
D 3
ylpentan-1-one (12i): [α] +2.1° (c 0.766, CHCl ). H NMR
71.7, 115.5 (d, JCF = 22 Hz), 119.5, 124.2 (d, JCF = 3 Hz), 128.4,
128.69, 128.70 (d, JCF = 13 Hz), 129.2, 130.7 (d, JCF = 4 Hz),
133.4, 133.8, 140.3, 159.7 (d, JCF = 246 Hz), 201.1; IR (neat)
3474, 3084, 3062, 3036, 2928, 1683, 1632, 1598, 1578, 1488,
(400 MHz) δ 0.08 (3H, s), 0.10 (3H, s), 0.92 (9H, s), 2.20 (1H, dd,
J = 8.8, 14.7 Hz), 2.76 (1H, d, J = 14.7 Hz), 3.79 (1H, brs), 4.14
(1H, d, J = 13.7 Hz), 4.28 (1H, d, J = 13.7 Hz), 4.91 (1H, s), 5.13
(1H, s), 5.19–5.31 (1H, br), 7.50 (2H, t, J = 7.3 Hz), 7.62 (1H, t, J

S. Kezuka et al.
Bull. Chem. Soc. Jpn., 76, No. 1 (2003)
57
1
3
=
−
1
2
1
7.3 Hz), 7.99 (2H, d, J = 7.3 Hz); C NMR (100 MHz) δ
5.25, −5.21, 18.5, 26.0, 39.6, 66.3, 72.2, 113.0, 128.7, 128.8,
4
K. Mikami, M. Terada, and T. Nakai, J. Am. Chem. Soc.,
111, 1940 (1989); K. Mikami, M. Terada, and T. Nakai, J. Am.
Chem. Soc., 112, 3949 (1990); K. Mikami, Pure Appl. Chem., 68,
639 (1996); K. Mikami, M. Terada, M. Shimizu, and T. Nakai, J.
Synth. Org. Chem. Jpn., 48, 292 (1990); K. Mikami and M.
Shimizu, Chem. Rev., 92, 1021 (1992).
33.5, 133.9, 144.2, 201.2; IR (neat) 3478, 3068, 2955, 2928,
885, 2857, 1683, 1598, 1579, 1471, 1463, 1450, 1404, 1361,
258, 1177, 1104, 1005, 975, 903, 838, 777, 693 cm . HRMS:
−
1
+
28 3
Calcd for C18H O Si: (M ), 320.1808. Found: m/z 320.1811.
HPLC: Chiralcel OD-H (1.0% ethanol in hexane, Flow 1.0 mL/
min), 6.4 min (minor), 10.5 min (major) [(R,R)-cobalt complex 1f
was employed].
5
C. Qian and T. Huang, Tetrahedron Lett., 38, 6721 (1997);
C. Qian and T. Huang, Tetrahedron: Asymmetry, 11, 2347 (2000).
D. A. Evans, C. S. Burgey, N. A. Paras, T. Vojkovsky, and
6
25
Benzyl 2-Hydroxy-4-(2-naphtyl)-4-pentenoate (13e): [α]
D
S. W. Tregay, J. Am. Chem. Soc., 120, 5824 (1998); D. A. Evans,
S. W. Tregay, C. S. Burgey, N. A. Paras, and T. Vojkovsky, J. Am.
Chem. Soc., 122, 7936 (2000).
7
(2000).
8
1
+
3
8.2° (c 1.541, CHCl ). H NMR (400 MHz) δ 2.83 (1H, brs),
2
4
1
.96 (1H, dd, J = 7.8, 14.2 Hz), 3.17 (1H, dd, J = 3.9, 14.2 Hz),
.30–4.43 (1H, br), 4.92 (1H, d, J = 12.2 Hz), 5.05 (1H, d, J =
J. Hao, M. Hatano, and K. Mikami, Org. Lett., 2, 4059
13
2.2 Hz), 5.26 (1H, s), 5.49 (1H, s), 7.21–7.82 (12H, m);
C
NMR (100 MHz) δ 40.6, 67,3, 69.3, 116.7, 124.6, 125.0, 125.9,
J. H. Koh, A. O. Larsen, and M. R. Gagné, Org. Lett., 3,
1
1
2
6
26.1, 126.9, 127.4, 127.6, 127.9, 128.1, 128.3, 128.4, 128.5,
32.8, 133.1, 134.9, 137.4, 143.1, 174.1; IR (neat) 3480, 3058,
953, 1737, 1498, 1455, 1265, 1196, 1102, 896, 860, 821, 752,
1233 (2001).
9
K. Mikami and K. Aikawa, Org. Lett., 4, 99 (2002).
10 T. Nagata, K. Yorozu, T. Yamada, and T. Mukaiyama,
Angew. Chem., Int. Ed. Engl., 34, 2145 (1995).
98 cm− . HRMS: Calcd for C18
1
+
18 3
H O : (M ), 332.1412. Found:
m/z 332.1424. HPLC: Chiralcel OD-H (10.0% 2-propanol in hex-
ane, Flow 1.0 mL/min), 11.9 min (minor), 13.5 min (major)
11 K. D. Sugi, T. Nagata, T. Yamada, and T. Mukaiyama,
Chem. Lett., 1997, 493.
[
(R,R)-cobalt complex 1f was employed].
12 T. Yamada, Y. Ohtsuka, and T. Ikeno, Chem. Lett., 1998,
1129.
Benzyl 6,6-Dimethyl-2-hydroxy-4-methylene-1-phenylhep-
1
tanoate (13f): H NMR (400 MHz) δ 0.90 (9H, s), 1.91 (1H, d,
J = 13.2 Hz), 1.97 (1H, d, J = 13.2 Hz), 2.39 (1H, dd, J = 7.8,
1
4
7
6
13 T. Yamada, T. Ikeno, H. Sekino, and M. Sato, Chem. Lett.,
1999, 719; T. Ikeno, M. Sato, and T. Yamada, Chem. Lett., 1999,
1345; T. Ikeno, A. Nishizuka, M. Sato, and T. Yamada, Synlett,
2001, 406; T. Ikeno, M. Sato, H. Sekino, A. Nishizuka, and T.
Yamada, Bull. Chem. Soc. Jpn., 74, 2139 (2001).
14 T. Yamada, T. Nagata, T. Ikeno, Y. Ohtsuka, A. Sagara, and
T. Mukaiyama, Inorg. Chim. Acta, 296, 86 (1999).
15 T. Yamada, S. Kezuka, T. Mita, and T. Ikeno, Heterocycles,
52, 1041 (2000). The hetero Diels-Alder reaction using the salen-
cobalt complexes; L. S. Li, Y. K. Wu, Y. J. Hu, L. J. Xia, and Y. L.
Wu, Tetrahedron: Asymmetry, 9, 2271 (1998).
4.4 Hz), 2.60 (1H, d, J = 3.9, 14.4 Hz), 2.70 (1H, d, J = 6.4 Hz),
.31–4.41 (1H, m), 4.85 (1H, s), 4.97 (1H, s), 5.21 (1H, s), 7.28–
1
3
.45 (5H, m); C NMR (100 MHz) δ 29.9, 31.6, 42.7, 49.3, 67.3,
9.7, 70.3, 116.6, 128.3, 128.5, 128.6, 135.0, 142.5, 174.4; IR
(
1
neat) 3480, 3058, 3061, 2953, 1737, 1625, 1597, 1498, 1455,
375, 1265, 1196, 1133, 1102, 1028, 953, 896, 860, 821, 752, 698
−
1
+
24 3
cm . HRMS: Calcd for C17H O : (M ), 276.1725. Found: m/z
2
0
76.1746. HPLC: Chiralcel OB-H (1.0% ehtanol in hexane, Flow
.9 mL/min), 10.9 min (major), 11.3 min (minor) [(R,R)-cobalt
complex 1f was employed].
16 S. Kezuka, T. Mita, N. Ohtsuki, T. Ikeno, and T. Yamada,
Chem. Lett., 2000, 824; S. Kezuka, T. Mita, N. Ohtsuki, T. Ikeno,
and T. Yamada, Bull. Chem. Soc. Jpn., 74, 1333 (2001).
17 S. Kezuka, T. Ikeno, and T. Yamada, Org. Lett., 3, 1937
(2001).
Benzyl 2-Hydroxy-4-(1-adamantyl)-4-pentenoate (13j):
2
8
1
[
(
α]
D
+13.5° (c 0.367, CHCl
3
). H NMR (400 MHz) δ 1.54–1.78
1H, m), 1.99 (1H, brs), 2.35 (1H, dd, J = 8.3, 15.4 Hz), 2.60 (1H,
dd, J = 3.9, 15.4 Hz), 2.72 (1H, d, J = 5.4 Hz), 4.39 (1H, ddd, J
3.9, 5.4, 8.3 Hz), 4.91 (1H, s), 4.96 (1H, s), 5.19 (1H, d, J =
=
18 G. A. Olah, G. K. S. Prakash, and J. Sommer, “Super-
acids,” John Wiley & Sons., New York (1985).
13
1
2.2 Hz), 5.23 (1H, d, J = 12.2 Hz), 7.29–7.44 (5H, m); C NMR
(
100 MHz) δ 28.5, 35.4, 36.8, 37.9, 40.8, 67.2, 70.3, 109.4, 128.2,
19 P. L. Fabre, J. Devynck, and B. Tremillon, Chem. Rev., 82,
591 (1982); J. Grondin, R. Sagnes, and A. Commeyras, Bull. Soc.
Chim. Fr., 1976, 1779.
1
3
9
3
2
28.4, 128.5, 135.1, 152.9, 174.6; IR (neat) 3479, 3090, 3065,
033, 2902, 2848, 1739, 1632, 1497, 1454, 1262, 1195, 1096,
02, 750, 697 cm−
1
.
HRMS: Calcd for C22
H
O
3
: (M ),
+
20 S. Kanemasa, Y. Oderaotoshi, S. Sakaguchi, H. Yamamoto,
J. Tanaka, E. Wada, and D. P. Curran, J. Am. Chem. Soc., 120,
3074 (1998); E. P. Kündig, C. M. Saudan, and G. Bernardinelli,
Angew. Chem., Int. Ed., 38, 1219 (1999); D. A. Evans, S. J. Miller,
T. Lectka, and P. von Matt, J. Am. Chem. Soc., 121, 7559 (1999);
D. A. Evans, D. M. Barnes, J. S. Johnson, T. Lectka, P. von Matt,
S. J. Miller, J. A. Murry, R. D. Norcross, E. A. Shaughnessy, and
K. R. Campos, J. Am. Chem. Soc., 121, 7582 (1999); Y. Huang, T.
Iwama, and V. H. Rawal, J. Am. Chem. Soc., 124, 5950 (2002).
21 S. L. Yao, M. Johannsen, H. Audrain, R. G. Hazell, and K.
A. Jørgensen, J. Am. Chem. Soc., 120, 8599 (1998); J. Long, J.
Hu, X. Shen, B. Ji, and K. Ding, J. Am. Chem. Soc., 124, 10
(2002).
28
40.2038. Found: m/z 340.2009. HPLC: Chiralcel OD-H (10.0%
-propanol in hexane, Flow 1.0 mL/min), 5.7 min (minor), 7.5
min (major) [(R,R)-cobalt complex 1f was employed].
References
1
K. Mikami and M. Terada, “Comprehensive Asymmetric
Catalysis,” ed by E. N. Jacobsen, A. Pfaltz, and H. Yamamoto,
Springer-Verlag, Berlin and Heiderberg (1999), Vol. 3, p. 1143.
2
A zwitter ionic intermediate was also proposed for the
Lewis acid catalyzed carbonyl-ene reaction: B. B. Snider, D. J.
Rodini, T. C. Kirk, and R. Cordova, J. Am. Chem. Soc., 104, 555
(
(
1982); B. B. Snider and G. B. Phillips, J. Org. Chem., 48, 464
1983).
22 Y. N. Belokonꢀ, S. Caveda-Cepas, B. Green, N. S.
Ikonnikov, V. N. Khrustalev, V. S. Larichev, M. A. Moscalenko,
M. North, C. Orizu, V. I. Tararov, M. Tasinazzo, G. I. Timofeeva,
and L. V. Yashkina, J. Am. Chem. Soc., 121, 3968 (1999).
3
K. Maruoka, Y. Hoshino, T. Shirasaka, and H. Yamamoto,
Tetrahedron Lett., 29, 3967 (1988).

5
8
Bull. Chem. Soc. Jpn., 76, No. 1 (2003)
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2
3
I. Ohtani, T. Kusumi, Y. Kashnan, and H. Kakisawa, J. Am.
Chem. Soc., 113, 4092 (1991).
The intermediate of the resulting cobalt-aldehyde complex
was rationalized by a semi-empirical method; Ref. 16.
H. A. Riley and A. R. Gray, Org. Synth., Coll. Vol. 2, 509
(1966).
26 T. K. Kelly, T. E. Schmidt, and J. G. Haggerty, Synthesis,
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27 A. H. Schmidt, G. Kircher, J. Zylla, and S. Veit, J. Chem.
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2
4
2
5