Aluminum-controlled reactivity and diastereoselectivity toward radical reactions of optically active aldimines with metallic samarium

Article abstract of DOI:10.1021/jo0014616

The intermolecular pinacol-type coupling reaction and allylation reaction of optically active imines bearing a β-hydroxy group were performed stereoselectively with metallic samarium after treatment of the imines with trimethylaluminum.

Full text of DOI:10.1021/jo0014616

J . Org. Chem. 2001, 66, 1283-1286
1283
Alu m in u m -Con tr olled Rea ctivity a n d Dia ster eoselectivity tow a r d
Ra d ica l Rea ction s of Op tica lly Active Ald im in es w ith Meta llic
Sa m a r iu m
Reiko Yanada,* Masanori Okaniwa, Akira Kaieda, Toshiro Ibuka,† and Yoshiji Takemoto
Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida,
Sakyo-ku, Kyoto 606-8501, J apan
ryanada@pharm. kyoto-u.ac.jp
Received October 10, 2000
The intermolecular pinacol-type coupling reaction and allylation reaction of optically active imines
bearing a â-hydroxy group were performed stereoselectively with metallic samarium after treatment
of the imines with trimethylaluminum.
Ta ble 1. Red u ctive Dim er iza tion of Im in es
Recently, it has been shown that acyclic radicals can
be used for highly stereoselective reactions.1 The stere-
ochemical aspect of these reactions has been particularly
studied during the past decade. A new dimension was
opened up by the use of Lewis acids, which have been
employed for controlling the reactivity and diastereose-
lectivity.2 The use of chiral auxiliaries in radical reactions
in the presence of Lewis acids also has been reported
recently.3 Several chelation-controlled radical reactions
of ketyl radicals generated by single electron reduction
of ketones with samarium iodide are also reported.4
Recently, we have reported the intermolecular pinacol-
type dimerization of optically active imines 1 with
metallic samarium (Sm) and a catalytic amount of iodine
(Scheme 1, path A).5 The observed stereochemistry can
be predicted by assuming a radical intermediate on the
basis of chelation to the Sm(III) cation generated during
the reductive imine coupling reaction. We applied this
reaction to the imines bearing â-hydroxy group 2-5 in
order to obtain dimerization products 9-11 (N- and
O-free) directly (Scheme 1, path B). These products are
expected to become chiral ligands in stereoselective
reactions. They also might possibly be changed to C2-
ethylenediamines 12, which are used increasingly in
several fields, for instance, stereoselective organic syn-
thesis.6 We would like to report here the novel effects of
trimethylaluminum on reactivity and diastereoselectivity
a
d. r.: diastereomeric ratio.
of the Sm-mediated radical dimerization and allylation
reactions of optically active aldimines 2-5. To the best
of our knowledge, the stereoselective radical reactions
with Sm on the basis of chelation control of Lewis acids,
except for Sm3+, has not been investigated.
First, we attempted the reaction of imine 2 with Sm
and a catalytic amount of iodine (the conditions of path
A). Only the amine 13 was produced by the reduction of
the C-N double bond. Then we tried a variety of
methods. At last, we obtained the dimeric compounds
bearing â-hydroxy group 9-11 stereoselectively. The
general dimerization procedure is as follows. A mixture
of the imine 2, Sm (1 equiv) and Me3Al (1.1 equiv) in
hexane was stirred until the evolution of methane ceased.
After hexane was removed, a catalytic amount of iodine
in THF was added to the mixture, giving the desired
coupling product 9 (SRRS)5 in 83% yield. The same
reaction of other imines 3 and 4 proceeded smoothly.
Table 1 summarizes the results. The reductive coupling
products 9-11 were obtained with high diastereoselec-
tivity. Some amount of amines 13 were obtained as
byproducts. Only the reaction employing 5 failed to give
the expected product, but, instead, afforded a complex
mixture which was not characterized. The diastereose-
lectivity of these reductive coupling reactions on the basis
of the chelation control of Al3+ is slightly lower than that
of the coupling reactions of the ether type imine 1 on the
basis of the chelation control of Sm3+.5 We were able to
obtain N- and O-free C2-symmetric compounds 9-11
directly from imines 2-4 in high yield (Table 1).
† Deceased on J anuary 20, 2000.
(1) (a) Giese, B. Angew. Chem., Int. Ed. Engl. 1989, 28, 969-1146.
(b) RajanBabu, T. V. Acc. Chem. Res. 1991, 24, 139-145. (c) Porter,
N. A.; Giese, B.; Currn, D. P. Acc. Chem. Res. 1991, 24, 296-304. (d)
Smadja, W. Synlett 1994, 1-26.
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Soc. 1994, 116, 421-422. (b) Sibi, M. P.; J i, J . Angew. Chem., Int. Ed.
Engl. 1996, 35, 190-192. (c) Sibi, M. P.; J i, J . G. J . Am. Chem. Soc.
1996, 118, 3063-3064. (d) Katsumata, A.; Iwaki, T.; Fukumoto, K.;
Ihara, M. Heterocycles 1997, 46, 605-616. (e) Lee, E.; J eong, J .-W.;
Yu, Y. Tetrahedron Lett. 1997, 38, 7765-7768. (f) Kise, N.; Kumada,
K.; Terao, Y.; Ueda, N. Tetrahedron 1998, 54, 2697-2708.
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(b) Molander, G. A.; Harris, C. R. Chem. Rev. 1996, 96, 307-338. (c)
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(5) (a) Yanada, R.; Negoro, N.; Okaniwa, M.; Miwa, Y.; Taga, T.;
Yanada, K.; Fujita, T. Synlett 1999, 537-540. (b) Yanada, R.; Ibuka,
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The four types of C2-symmetric compounds 6-11 (N-
free, O-protected, O-free, N- and O-free) could be em-
ployed as chiral ligands for a variety of asymmetric
10.1021/jo0014616 CCC: $20.00 © 2001 American Chemical Society
Published on Web 01/30/2001

1284 J . Org. Chem., Vol. 66, No. 4, 2001
Yanada et al.
Sch em e 1
Ta ble 2. Allyla tion of Im in es
reactions. The diamines 6 and 9-11 were treated with
formaldehyde to give the compounds 7 and 8 quantita-
tively (Scheme 1). The O-free compound 8 could be
obtained from the dealkylation of the compound 7 by
BBr3, but this step gave low yield and was poorly
reproducible. Now we can obtain C2-symmetric ligands
6-11 in short steps, high yields, high diastereoselectivity
by a combination of paths A and B. For example, as we
expected, C2-symmetric compound 8 gave high enantio-
meric excess in the enantioselective addition of diethylz-
inc to several aldehydes.7
a
d. r.: diastereomeric ratio.
Next, we applied this method mentioned above to the
allylation reaction of imines (2-5).
system (Sm/I2). This method represents the first example
of the dimerization of imines with Sm based on the
chelation control of aluminum for the N-benzylidene-
amino alcohol radical. Optically active amino alcohols
have been extensively used as catalysts in alkylation of
aldehyde with alkyllithium12 or dialkylzinc,13 reduction
of ketones with borane or borates,14 and dihydroxylation
of a double bond with osmium tetraoxide.15 We are trying
now to use our C2-chiral compounds for these reactions
as asymmetric ligands.
Previously, we have reported the allylation of ether-
type imine 1 with Sm (2 equiv) and iodine (0.1 equiv)
(Scheme 1, path C).8 The allylation of imine 2 bearing a
free hydroxy group by the same method gave the allylated
diastereomers 159 [(SS): (SR) ) 62:38] in 47% yield. The
protection of the free hydroxy group of 2 by Me3Al, prior
to the Sm-mediated allylation, increased the reactivity
and diastereoselectivity to give the allylated amines 15
[(SS): (SR) ) 99:1] in 97% yield (Scheme 1, path D),
(Table 2).10 Other imines 3-5 also gave allylated products
16-18, which were versatile compounds for synthesizing
optically active homoallylamines 19. For an example, the
optically active amine 15 was used for the synthesis of
â-amino acid derivative (R)-21 (Scheme 2, 78% overall
yield, >99% (R)-enantiomer).11
Exp er im en ta l Section
All reactions were carried out under a positive pressure of
1
argon or nitrogen. H NMR spectra were recorded on a J EOL
J NM-EX-270 spectrometer using tetramethylsilane (TMS) as
an internal standard. 13C NMR spectra were recorded on a
In conclusion, we have achieved highly diastereoselec-
tive intermolecular coupling reactions of optically active
imines bearing a â-hydroxy group with a combination of
a Lewis acid (Me3Al) and the single-electron reduction
(12) Mukaiyama, T.; Suzuki, K. Chem. Lett. 1980, 255-256.
(13) (a) Kitamura, M.; Suga, S.; Kawai, K.; Noyori, R. J . Am. Chem.
Soc. 1986, 108, 6071-6072. (b) Soai, K.; Yokoyama, S.; Ebihara, K.;
Hayasaka, T. J . Chem. Soc., Chem. Commun. 1987, 1690-1691. (c)
Soai, K.; Ookawa, A.; Kaba, T.; Ogawa, K. J . Am. Chem. Soc. 1987,
109, 7111-7115. (d) Bolm, C.; Zehnder, M.; Bur, D. Angew. Chem.,
Int. Ed. Engl. 1990, 29, 205-207. (e) Kunieda, T.; Ishizuka, T. J . Synth.
Org. Chem., J pn. 1997, 55, 1018-1028.
(7) Okaniwa, M.; Yanada, R.; Ibuka, T. Tetrahedron Lett. 2000, 41,
1047-1050.
(8) Negoro, N.; Yanada, R.; Okaniwa, M.; Yanada, K.; Fujita, T.
Synlett 1998, 835-836.
(9) (a) Bocoum, A.; Savoia, D.; Umani-Ronchi, A. J . Chem. Soc.,
Chem. Commun. 1993, 1542-1544. (b) Basile, T.; Bocoum, A.; Savoia,
D.; Umani-Ronchi, A. J . Org. Chem. 1994, 59, 7766-7773.
(10) This allylation reaction proceeded without iodine (0.1 equiv).
(11) Determined by HPLC analysis using Chiralcel OD (hexane:
AcOEt ) 20:1).
(14) (a) Corey, E. J .; Bakshi, R. K.; Shibata, S. J . Am. Chem. Soc.
1987, 109, 5551-5553. (b) Corey, E. J .; Shibata, S.; Bakshi, R. K. J .
Org. Chem. 1988, 53, 2861-2863.
(15) (a) Yamada, T.; Narasaka, K. Chem. Lett. 1986, 131-134. (b)
Tomioka, K.; Shinmi, Y.; Shiina, K.; Nakajima, M.; Koga, K. Chem.
Pharm. Bull. 1990, 38, 2133-2135. (c) Ogino, Y.; Chen, H.; H.-Kwong,
L.; Sharpless, K. B. Tetrahedron Lett. 1991, 32, 3965-3968.

Radical Reactions of Aldimines with Metallic Samarium
Sch em e 2
J . Org. Chem., Vol. 66, No. 4, 2001 1285
J EOL J NM-EX-270 (67.8 MHz) spectrometer. Optical rotations
were measured with a J ASCO DIP-360 digital polarimeter.
Nominal (LRMS) and exact mass (HRMS) spectra were
recorded on a J EOL J MS-HX/HX-110A instrument. Metallic
samarium was purchased from Kojundo Chemical Laboratory
Co., Ltd. For flash chromatography, silica gel FL60D (Fuji
Silysia Chemical Ltd.) was employed.
1.41-1.49 (q, J ) 6.6 Hz, 2H), 2.11 (s, 6H), 2.35-2.48 (br s,
2H), 3.54-3.67 (m, 4H), 3.80 (s, 2H), 6.75-6.95 (br s, 8H). 13
C
NMR (CDCl3) δ: 19.0, 19.3, 21.0, 29.9, 64.2, 64.6, 68.8, 126.8,
129.1, 136.4, 139.2. Anal. Calcd for C26H40N2O2: C, 75.68; H,
9.77; N, 6.79%. Found: C, 75.41; H, 9.80; N, 6.71%.
(R,S)-1,2-Di-p -t olyl-N,N′-b is((S)-1-(h yd r oxym et h yl)-2-
m eth ylp r op yl)eth ylen ed ia m in e (10), (SRSS). Colorless oil;
[R]28 29.2 (c 2.00, CHCl3). 1H NMR (CDCl3) δ: 0.44 (d, J )
Gen er a l P r oced u r e for th e Dim er iza tion of Im in es. To
a stirred solution of the imine 2 (95.5 mg, 0.5 mmol) and Sm
(75 mg, 0.5 mmol) in hexane (1 mL) were added 1 M Me3Al in
hexane (0.55 mL, 0.55 mmol) at 0 °C under argon atmosphere.
The mixture was stirred until the evolution of methane ceased.
Hexane was removed under reduced pressure. A catalytic
amount of iodine (13 mg, 0.05 mmol) in THF (1 mL) was added
to the residue at 0 °C under argon. The color changes of the
mixture during the reaction served as indicator of the progress
of the reaction. After a short induction period, the color of the
solution turned to black-purple and then dark blue-green. The
reaction mixture was stirred vigorously for 1 h. After the
reaction was quenched with 1 N hydrochloric acid, and the
resulting mixture was made basic with 10% NaOH aq, the
product was extracted with diethyl ether, washed with brine,
dried over anhydrous potassium carbonate, and concentrated
under reduced pressure. Flash silica gel column chromatog-
raphy with hexanes-EtOAc (5:1) afforded the title compound
9 (SRRS) (79.5 mg, 83%).
D
6.9 Hz, 3H), 0.61-0.71 (m, 9H), 1.42-1.50 (m, 1H), 1.67-1.97
(m, 6H), 2.18-2.25 (m, 1H), 2.34 (s, 3H), 2.36 (s, 3H), 2.97 (dd,
J ) 9.2, 9.9 Hz, 1H), 3.19 (dd, J ) 3.6, 10.7 Hz, 2H), 3.34 (dd,
J ) 3.6, 11.2 Hz, 1H), 3.64 (d, J ) 8.6 Hz, 1H), 3.74 (d, J )
8.6 Hz, 1H), 7.15-7.28 (m, 8H). 13C NMR (CDCl3) δ: 16.6, 18.9,
19.1, 19.4, 21.0, 21.1, 27.5, 29.0, 59.4, 60.2, 60.6, 61.3, 65.9,
66.2, 127.6, 127.8, 128.0, 129.3, 137.4, 137.5, 138.4, 138.9.
Anal. Calcd for C26H40N2O2: C, 75.68; H, 9.77; N, 6.79%.
Found: C, 75.63; H, 9.49; N, 6.57%.
(S,S)-1,2-Dip h en yl-N,N′-b is((R)-1-(h yd r oxym et h yl)-2-
p h en ylm eth yl)eth ylen ed ia m in e (11), (RSSR). Colorless oil;
[R]28 -81.1 (c 2.00, CHCl3). 1H NMR (CDCl3) δ: 3.73-3.93
D
(m, 8H), 4.05 (br s, 4H), 6.93-7.26 (m, 20H). 13C NMR (CDCl3)
δ: 63.2, 66.6, 67.8, 127.1, 127.2, 127.5, 127.7, 128.1, 128.5,
141.0, 141.2. LRMS (FAB) m/z, 453 (MH+), 316, 226, 106.
HRMS Calcd for
453.2548.
C
30H33N2O2 (MH+): 453.2544. Found:
(S,R)-1,2-d ip h en yl-N,N′-b is((R)-1-(h yd r oxym et h yl)-2-
p h en ylm et h yl)et h ylen ed ia m in e (11), (RSRR). Colorless
Syn t h esis
of
(R,R)-1,2-Dip h en yl-N,N′-b is((S)-1-
oil; [R]28 -75.9 (c 2.00, CHCl3). 1H NMR (CDCl3) δ: 2.03-
(h yd r oxym et h yl)-2-m et h ylp r op yl)et h ylen ed ia m in e (9),
D
(SRRS). Colorless prisms; mp 149 °C (hexane-CHCl3); [R]30
2.40 (br s, 4H), 3.23-3.51 (m, 6H), 3.64 (d, J ) 7.6 Hz, 1H),
3.72 (d, J ) 7.6 Hz, 1H), 6.80-7.35 (m, 20H). 13C NMR (CDCl3)
δ: 60.8, 61.6, 64.0, 65.2, 66.1, 66.5, 126.6, 127.0, 127.2, 127.2,
127.4, 127.6, 127.7, 128.0, 128.2, 128.3, 128.4, 128.4, 139.9,
140.7, 140.8, 141.0. LRMS (FAB) m/z, 453 (MH+), 316, 226,
196, 106. HRMS Calcd for C30H33N2O2 (MH+): 453.2544.
Found: 453.2547. Anal. Calcd for C30H32N2O2: C, 79.60; H,
7.13; N, 6.19%. Found: C, 79.67; H, 7.10; N, 5.92%.
D
-58.2 (c 1.14, CHCl3). 1H NMR (CDCl3) δ: 0.69 (d, J ) 6.6
Hz, 6H), 0.72 (d, J ) 6.6 Hz, 6H), 1.57 (ddd, J ) 6.6, 6.6, 6.6
Hz, 2H), 2.51 (ddd, J ) 3.6, 6.6, 7.3 Hz, 2H), 3.69 (dd, J ) 7.3,
11.4 Hz, 2H), 3.77 (dd, J ) 3.6, 11.4 Hz, 2H), 3.94 (s, 2H),
7.03-7.16 (m, 10H). 13C NMR (CDCl3) δ: 19.0, 19.3, 29.9, 64.2,
64.7, 69.3, 127.0, 127.0, 128.4, 142.1. LRMS (CI) m/z, 385
(MH+), 367, 282, 192. HRMS Calcd for C24H37N2O2 (MH+):
385.2857. Found: 385.2859. Anal. Calcd for C24H36N2O2: C,
74.96; H, 9.44; N, 7.29%. Found: C, 74.84; H, 9.51; N, 7.14%.
(R,S)-1,2-Dip h en yl-N,N′-b is((S)-1-(h yd r oxym et h yl)-2-
m et h ylp r op yl)et h ylen ed ia m in e (9), (SRSS). Colorless
Gen er a l P r oced u r e for th e P r ep a r a tion of Allyla ted
Am in es. To a stirred solution of the imine 2 (95.5 mg, 0.5
mmol) and Sm (75 mg, 0.5 mmol) in hexane (1 mL) were added
1 M Me3Al in hexane (0.55 mL, 0.55 mmol) at 0 °C under argon
atmosphere. The mixture was stirred until the evolution of
methane ceased. Hexane was removed under reduced pressure.
Allyl bromide (121 mg, 1 mmol) in THF (4 mL) was added to
the residue at 0 °C under argon. The color changed to black-
purple and then dark blue-green. The reaction mixture was
stirred vigorously for 30 min. After the reaction was quenched
with 1 N hydrochloric acid, the resulting mixture was made
basic with 10% NaOH aq, the product was extracted with
diethyl ether, washed with brine, dried over anhydrous potas-
sium carbonate, and concentrated under reduced pressure.
Usual workup followed by flash silica gel column chromatog-
raphy with CHCl3 gave the title compound 15 (112.1 mg, 96%).
Syn th esis of (2S)-3-Meth yl-2-(1S)-1-p h en ylbu t-3-en yl-
needles; mp 130-132 °C (hexane-CHCl3); [R]26 30.2 (c 1.00,
D
CHCl3). 1H NMR (CDCl3) δ: 0.43 (d, J ) 6.9 Hz, 3H), 0.64
(dd, J ) 6.9, 6.9 Hz, 6H), 0.69 (d, J ) 6.9 Hz, 3H), 1.46 (qq, J
) 6.9, 6.9 Hz, 1H), 1.10-1.70 (br s, 3H), 1.73 (qq, J ) 6.9, 6.9
Hz, 1H), 1.95-1.99 (m, 1H), 2.21-2.25 (m, 1H), 2.50-2.70 (br
s, 1H), 2.98 (dd, J ) 8.6, 10.2 Hz, 1H), 3.17-3.22 (m, 2H), 3.32
(dd, J ) 3.6, 11.2 Hz, 1H), 3.68 (d, J ) 8.8 Hz, 1H), 3.80 (d, J
) 8.8 Hz, 1H), 7.29-7.40 (m, 10H). 13C NMR (CDCl3) δ: 16.5,
18.9, 19.0, 19.3, 27.5, 29.1, 59.6, 60.4, 60.9, 61.6, 66.5, 66.7,
127.9, 128.0, 128.1, 128.4, 128.6, 128.7, 141.6, 142.1. Anal.
Calcd for C24H36N2O2: C, 74.96; H, 9.44; N, 7.29%. Found: C,
74.94; H, 9.24; N, 7.32%.
(R,R)-1,2-Di-p-tolyl-N,N′-bis((S)-1-(h yd r oxym eth yl)-2-
m eth ylp r op yl)eth ylen ed ia m in e (10), (SRRS). Colorless
prisms; mp 133-135 °C (hexane-CHCl3); [R]26D -33.2 (c 2.00,
a m in o)bu ta n -1-ol (15). Colorless oil; [R]24 -32.4 (c 2.00,
D
1
CHCl3). H NMR (CDCl3) δ: 0.81 (d, J ) 6.6 Hz, 3H), 0.86 (d,
J ) 6.9 Hz, 3H), 1.69 (dd, J ) 6.6, 6.9 Hz, 1H), 1.80-2.60 (br
s, 1H), 2.21-2.28 (m, 1H), 2.34-2.52 (br s, 1H), 2.43 (ddd, J
1
CHCl3). H NMR (CDCl3) δ: 0.58 (d, J ) 6.6 Hz, 6H), 0.62 (d,
J ) 6.6 Hz, 6H), 0.75-0.85 (br s, 2H), 1.10-1.25 (br s, 2H),

1286 J . Org. Chem., Vol. 66, No. 4, 2001
Yanada et al.
) 6.6, 6.9, 7.3 Hz, 2H), 3.38 (dd, J ) 4.2, 10.9 Hz, 1H), 3.61
(dd, J ) 4.2, 10.9 Hz, 1H), 3.72 (dd, J ) 6.6, 6.9 Hz, 1H), 4.99-
5.09 (m, 2H), 5.62-5.78 (m, 1H), 7.20-7.36 (m, 5H). 13C NMR
(CDCl3) δ: 18.9, 19.4, 29.3, 42.6, 59.7, 59.9, 61.0, 117.2, 126.9,
3H), 1.77 (qq, J ) 6.6, 6.9 Hz, 1H), 2.10-2.40 (m, 4H), 2.43-
2.49 (m, 1H), 3.26-3.35 (m, 1H), 3.42 (dd, J ) 3.6, 10.7 Hz,
1H), 3.58 (dd, J ) 4.1, 10.7 Hz, 1H), 5.07-5.16 (m, 2H), 5.78-
5.89 (m, 1H), 5.98 (dd, J ) 8.6, 15.8 Hz, 1H), 6.43 (d, J ) 15.8
Hz, 1H), 7.23-7.39 (m, 5H). 13C NMR (CDCl3) δ: 18.9, 19.6,
29.4, 40.8, 58.2, 60.1, 60.9, 117.5, 126.2, 127.4, 128.5, 131.0,
132.4, 134.9, 136.8. Anal. Calcd for C17H25O: C, 78.72; H, 9.71;
N, 5.40%. Found: C, 78.81; H, 9.51; N, 5.14%.
N-((S)-1-P h en ylb u t -3-en yl)a cet a m id e (20). Colorless
needles; mp 68.0-69.5 °C (hexane-AcOEt).1H NMR (CDCl3)
δ:1.94 (s, 3H), 2.53 (dd, J ) 6.9, 6.9 Hz, 2H), 5.00-5.12 (m,
3H), 5.59-5.75 (m, 1H), 6.34 (br d, J ) 7.6 Hz, 1H), 7.20-
7.34 (m, 5H). 13C NMR (CDCl3) δ: 23.1, 40.4, 52.5, 117.9, 126.4,
127.2, 128.4, 134.0, 141.7, 169.4. Anal. Calcd for C12H15NO:
C, 76.16; H, 7.99; N, 7.40%. Found: C, 75.84; H, 8.01; N, 7.35%.
3-Acet yla m in o-(R)-3-p h en ylp r op ion ic Acid Met h yl
Ester (21). Colorless prisms; mp 78.0 °C (decomp) (Et2O).1H
NMR (CDCl3) δ:1.99 (s, 3H), 2.81 (dd, J ) 6.1, 15.7 Hz, 1H),
2.92 (dd, J ) 6.1, 15.7 Hz, 1H), 3.60 (s, 3H), 5.42 (dd, J ) 6.1,
6.1 Hz), 6.80 (br d, J ) 7.9 Hz, 1H), 7.24-7.35 (m, 5H). 13C
NMR (CDCl3) δ: 23.2, 39.7, 49.5, 51.7, 126.2, 127.5, 128.6,
140.5, 169.3, 171.6. Anal. Calcd for C12H15NO3: C, 65.14; H,
6.83; N, 6.33%. Found: C, 65.06; H, 6.86; N, 6.38%.
127.0, 127.1, 128.0, 128.3, 135.3, 143.8. Anal. Calcd for C15H23
-
NO: C, 77.21; H, 9.93; N, 6.00%. Found: C, 77.27; H, 10.06;
N, 5.88%.
(2S)-3-Met h yl-2-(1S)-1-p -t olylb u t -3-en yla m in o)bu t a n -
1
1-ol (16). Colorless oil; [R]29 -26.3 (c 1.00, CHCl3). H NMR
D
(CDCl3) δ: 0.81 (d, J ) 6.6 Hz, 3H), 0.86 (d, J ) 6.9 Hz, 3H),
1.68 (qq, J ) 6.6, 6.9 Hz, 1H), 2.09-2.15 (br s, 1H), 2.22-2.29
(m, 1H), 2.33 (s, 3H), 2.37-2.49 (m, 3H), 3.36 (dd, J ) 4.6,
10.9 Hz, 1H), 3.60 (dd, J ) 4.1, 10.9 Hz, 1H), 3.69 (t, J ) 6.9
Hz, 1H), 4.98-5.08 (m, 2H), 5.61 (m, 1H), 7.13 (s, 4H). 13C
NMR (CDCl3) δ: 19.4, 19.5, 21.0, 29.4, 42.6, 59.7, 61.0, 117.1,
126.9, 129.1, 135.4, 136.7, 140.7. Anal. Calcd for C16H25NO:
C, 77.63; H, 10.19; N, 5.66%. Found: C, 77.36; H, 10.06; N,
5.37%.
(2R)-2-P h en yl-2-(1R)-1-p h en ylb u t -3-en yla m in o)et h a -
1
n ol (17). Colorless oil; [R]29 -42.3 (c 4.00, CHCl3). H NMR
D
(CDCl3) δ: 2.40 (br s, 2H), 2.35-2.57 (m, 2H), 3.46-3.56 (m,
1H), 3.69-3.87 (m, 3H), 4.97-5.06 (m, 2H), 5.57-5.76 (m, 1H),
7.15-7.35 (10H, m). 13C NMR (CDCl3) δ: 41.3, 60.0, 61.2, 65.5,
117.4, 127.1, 127.1, 127.3, 127.4, 128.3, 128.5, 134.9, 141.0,
143.5. Anal. Calcd for C18H21NO: C, 80.86; H, 7.92; N, 5.24%.
Found: C, 80.98; H, 8.02; N, 4.95%.
Su p p or t in g In for m a t ion Ava ila b le: 1H and 13C NMR
spectra and spectral data for 11. This material is available
free of charge via the Internet at http://pubs.acs.org.
(2S)-3-Meth yl-2-[(1S)-1-(4-styr ylp h en yl)bu t-3-en yla m i-
n o]bu ta n -1-ol (18). Colorless oil; [R]29D -46.1 (c 2.00, CHCl3).
1H NMR (CDCl3) δ:0.85 (d, J ) 6.9, 3H), 0.94 (d, J ) 6.6 Hz,
J O0014616