Enantioselective synthesis of binaphthol derivatives by oxidative coupling of naphthol derivatives catalyzed by chiral diamine-copper complexes

Article abstract of DOI:10.1021/jo981808t

A highly efficient process of aerobic oxidative coupling of 2-naphthol derivatives catalyzed by 1 mol % of Cu(OH)Cl·TMEDA has been developed. Enantioselective oxidative coupling of naphthols was achieved by the use of 10 mol % of chiral catalysts prepared from proline-derived diamines and cuprous chloride, affording the corresponding binaphthols in good enantioselectivities of up to 78% ee. The ester moiety at the 3-position of the substrate was found to be essential for the good asymmetric induction observed in the present coupling reaction.

Full text of DOI:10.1021/jo981808t

2264
J . Org. Chem. 1999, 64, 2264-2271
En a n tioselective Syn th esis of Bin a p h th ol Der iva tives by Oxid a tive
Cou p lin g of Na p h th ol Der iva tives Ca ta lyzed by Ch ir a l
Dia m in e‚Cop p er Com p lexes
Makoto Nakajima,* Irie Miyoshi, Kumiko Kanayama, and Shun-ichi Hashimoto
Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, J apan
Masahiro Noji† and Kenji Koga‡
Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, J apan
Received September 4, 1998
A highly efficient process of aerobic oxidative coupling of 2-naphthol derivatives catalyzed by 1
mol % of Cu(OH)Cl‚TMEDA has been developed. Enantioselective oxidative coupling of naphthols
was achieved by the use of 10 mol % of chiral catalysts prepared from proline-derived diamines
and cuprous chloride, affording the corresponding binaphthols in good enantioselectivities of up to
78% ee. The ester moiety at the 3-position of the substrate was found to be essential for the good
asymmetric induction observed in the present coupling reaction.
In tr od u ction
chiometric amounts of chiral ligands,3 so far only a few
attempts at catalytic enantioselective oxidative coupling
of naphthols have been reported.4 We herein describe a
highly efficient aerobic oxidative coupling of 2-naphthols
catalyzed by a copper‚TMEDA complex and its extension
to the first successful enantioselective oxidative coupling
of 2-naphthols catalyzed by chiral amine‚copper com-
plexes.5
Homochiral 1,1′-binaphthalene derivatives have been
successfully utilized as chiral inducers for highly stereo-
selective reactions because of their axial dissymmetry
and molecular flexibility.1 From this point of view, there
has recently been an intense interest in the preparation
of optically active 1,1′-binaphthalene derivatives by
methods other than optical resolution of racemic com-
pounds.2 Since oxidative coupling of 2-naphthols has been
amply employed in the preparation of binaphthols,
extensive efforts have been made to develop asymmetric
coupling of naphthols for the past decade.3,4 Although
satisfactory selectivities were achieved employing stoi-
Resu lts a n d Discu ssion
Aer obic Oxid a tive Cou p lin g of 2-Na p h th ols Ca ta -
lyzed by Cu (OH)Cl‚TMEDA. The oxidative coupling of
naphthols are frequently performed with excess amount
of oxidizing agent such as Fe(III),6 Mn(III),7 or Cu(II)3,8
salts; however, these methods suffer from difficulty in
isolation of the coupling product and waste disposal
problem. Recently, several catalytic processes were de-
veloped by Toda,6c Smrcˇina,4a or Sakamoto.8c However,
their systems still need to be improved in terms of
catalytic activity and practicability. Aerobic oxidative
coupling catalyzed by copper‚amine complexes, known as
the Glaser-Hay coupling, is a reliable method for the
preparation of conjugate diynes from acetylenes or qui-
nones from phenols. We were intrigued by the feasibility
of this system toward the enantioselective oxidative
coupling of naphthols catalyzed by chiral amine‚copper
complexes.
† Present address: Meiji Pharmaceutical University, Kiyose 204-
8588, J apan.
‡ Present address: Nara Institute of Science and Technology, Ikoma
630-0101, J apan.
(1) For recent reviews, see: (a) Bringmann, G.; Walter, R.; Weirich,
R. Angew. Chem., Int. Ed. Engl. 1990, 29, 977-991. (b) Rosini, C.;
Franzini, L.; Raffaelli, A.; Salvadori, P. Synthesis 1992, 503-517. (c)
Noyori, R. Asymmetric Catalysis in Organic Synthesis; Wiley: New
York, 1994. (d) Zimmer, R.; Suhrbier, J . J . Prakt. Chem. 1997, 339,
758-762.
(2) For recent methods for direct optical resolution of BINOL, see:
(a) Kawashima, M.; Hirayama, A. Chem. Lett. 1990, 2299-2300. (b)
Cai, D.; Hughes, D. L.; Verhoeven, T. R.; Reider, P. J . Tetrahedron
Lett. 1995, 7991-7994. (c) Toda, F.; Tanaka, K. Chem. Commun. 1997,
1087-1088. For enantioselective synthesis of binaphthyl skeletons by
methods other than those of asymmetric oxidation, see: (d) Hayashi,
T.; Hayashizaki, K.; Kiyoi, T.; Ito, Y. J . Am. Chem. Soc. 1988, 110,
8153-8156. (e) Shindo, M.; Koga, K.; Tomioka, K. J . Am. Chem. Soc.
1992, 114, 8732-8733.
(3) For asymmetric synthesis of binaphthols including second-order
asymmetric transformation, see: (a) Feringa, B.; Wynberg, H. Bioorg.
Chem. 1978, 7, 397-408. (b) Brussee, J .; J ansen, A. C. A. Tetrahedron
Lett. 1983, 24, 3261-3262. (c) Yamamoto, K.; Fukushima, H.; Naka-
zaki, M. J . Chem. Soc., Chem. Commun. 1984, 1490-1491. (d) Brussee,
J .; Groenendijk, J . L. G.; te Koppele, J . M.; J ansen, A. C. A.
Tetrahedron 1985, 41, 3313-3319. (e) Yamamoto, K.; Fukushima, H.;
Yumioka, H.; Nakazaki, M. Bull. Chem. Soc. J pn. 1985, 58, 3633-
3634. (f) Smrcˇina, M.; Lorenc, M.; Hanusˇ, V.; Sedmera, P.; Kocˇovsky´,
P. J . Org. Chem. 1992, 57, 1917-1924. (g) Osa, T.; Kashiwagi, Y.;
Yanagisawa, Y.; Bobbitt, J . M. J . Chem. Soc., Chem. Commun. 1994,
2535-2537.
(4) For asymmetric synthesis of binaphthols by enantioselective
oxidation with catalytic amount of chiral ligand, see: (a) Smrcˇina, M.;
Pola´kova´, J .; Vyskocˇil, Sˇ.; Kocˇovsky´, P. J . Org. Chem. 1993, 58, 4534-
4537. (b) Hamada, T.; Ishida, H.; Usui, S.; Watanabe, Y.; Tsumura,
K.; Ohkubo, K. J . Chem. Soc., Chem. Commun. 1993, 909-911.
(5) For our preliminary results, see: (a) Noji, M.; Nakajima, M.;
Koga, K. Tetrahedron Lett. 1994, 35, 7983-7984. (b) Nakajima, M.;
Kanayama, K.; Miyoshi, I.; Hashimoto, S. Tetrahedron Lett. 1995, 36,
9519-9520.
(6) (a) Pummerer, R.; Prell, E.; Rieche, A. Ber. 1926, 59, 2159-2161.
(b) Feringa, B.; Wynberg, H. J . Org. Chem. 1981, 46, 2547-2557. (c)
Toda, F.; Tanaka, K.; Iwata, S. J . Org. Chem. 1989, 54, 3007-3009.
(d) Deussen, H.-J .; Frederiksen, P.; Bjørnholm, T.; Bechgaard, K. Org.
Prep. Proc. Int. 1996, 28, 484-486. (e) Ding, K.; Wang, Y.; Zhang, L.;
Wu, Y.; Matsuura, T. Tetrahedron 1996, 52, 1005-1010.
(7) (a) Dewar, M. J . S.; Nakaya, T. J . Am. Chem. Soc. 1968, 90,
7134-7135. (b) Yamamoto, K.; Fukushima, H.; Okamoto, Y.; Hatada,
K.; Nakazaki, M. J . Chem. Soc., Chem. Commun. 1984, 1111-1112.
(8) (a) Feringa, B.; Wynberg, H. Tetrahedron Lett. 1977, 4447-4450.
(b) Kantam, M. L.; Santhi, P. L. Synth. Commun. 1996, 26, 3075-
3079. (c) Sakamoto, T.; Yonehara, H.; Pac, C. J . Org. Chem. 1997, 62,
3194-3199.
10.1021/jo981808t CCC: $18.00 © 1999 American Chemical Society
Published on Web 03/11/1999

Enantioselective Synthesis of Binaphthol Derivatives
J . Org. Chem., Vol. 64, No. 7, 1999 2265
Ta ble 1. Ca ta lytic Oxid a tive Cou p lin g of 2-Na p h th ol
Ta ble 2. Ca ta lytic Aer obic Oxid a tion of 2-Na p h th ol
Der iva tives
entry
Cu salt
solvent
yield,a
%
1
2
3
4
5
6
7
8
9
CuCl
CuCl
CuCl
CuCl
CuCl
CuI
CuOTf
Cu2O
CuCl2
Cu(OAc)2
MeOH
acetone
AcOEt
benzene
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
52
47
35
56
81
50
54
0
naphthol
binaphthol
yield,a
%
entry
X
Y
Z
1
2
3
4
5
6
1a
1b
1c
1d
1e
1f
H
Me
OMe
H
H
H
H
H
H
H
H
H
2a
2b
2c
2d
2e
2f
92
95
96
95
90b
77
OMe
H
42
36
COOMe
-(CHdCH)2-
10
H
a
Isolated yield.
a
b
Isolated yield. Reaction was performed with 10 mol % of
catalyst at room temperature for 48 h. Refluxing in CH2Cl2 for 24
h with 10 mol % of catalyst or refluxing in MeOH for 12 h with 10
mol % of catalyst afforded 2e in 98% yield.
According to the procedure of the Glaser-Hay cou-
pling, we first examined oxidative coupling of 2-naphthol
(1a ) by the use of 11 mol % of TMEDA and 10 mol % of
CuCl in methanol or acetone under oxygen atmosphere
(1 atm) at room temperature (Table 1, entries 1 and 2).
Unfortunately, binaphthol (2a ) was obtained in low yield
along with quinones and other byproducts. Five different
solvents were tested, and the best result was obtained
with dichloromethane (Table 1, entry 5). Unsatisfactory
chemical yields were obtained with Cu(OAc)2 or CuCl2
(Table 1, entries 9 or 10), which had often been employed
in stoichiometric oxidative coupling.3,8a
Ta ble 3. En a n tioselective Oxid a tive Cou p lin g of
Na p h th ols Ca ta lyzed by Sp a r tein e‚Cop p er Com p lex
In view of these findings, we then undertook an aerobic
oxidative coupling exploiting Cu(OH)Cl‚TMEDA,9,10 eas-
ily prepared from CuCl, TMEDA, water, and molecular
oxygen. The reaction proceeded smoothly even in the
open air using 1 mol % of Cu(OH)Cl‚TMEDA, producing
2a in high yield. The results obtained for the reaction of
a variety of naphthol derivatives are summarized in
Table 2. Naphthols with various substituent patterns
were oxidatively coupled to produce the corresponding
binaphthols in high yield. The present protocol could be
extended to a reaction of naphthols with low reactivity
such as 1e, though the reaction was slow unless the
amount of the catalyst was increased to 10 mol % (Table
2, entry 5). No binaphthyl derivative was obtained in the
reaction of 2-methoxynaphthalene, which indicates the
phenolic hydroxy group is crucial to this oxidative
coupling. The present reaction has provided the first
efficient process of catalytic oxidative coupling of 2-naph-
thols, which could be applied to a large-scale synthesis
of binaphthols.11
naphthol
X
binaphthol
yield,a ee,b % confgnc
entry
Z
%
1
2
3
4
1a
1b Me
1d
H
H
H
2a
2b
32
54
31
38
18
10
16
47
S
S
S
S
H
OMe 2d
H 2e
1e COOMe
a
b
Isolated yield. Determined by HPLC analysis employing a
Daicel Chiralcel OJ or Chiralpak AD. c Assignment by comparison
to literature values of optical rotations.
with commercially available (-)-sparteine (3) as a chiral
ligand having two tertiary nitrogens similar to TMEDA.
According to the above procedure, 2-naphthol (1a ) was
added to the solution of the chiral catalyst prepared in
situ from CuCl (10 mol %) and sparteine (3) (11 mol %)
in dichloromethane, and the reaction mixture was heated
at reflux under oxygen of atmospheric pressure. Chro-
matography afforded unreacted starting material (58%)
and binaphthol (2a ) (32%) in low enantiomeric excess
(18% ee) (Table 3, entry 1). Among several substrates
surveyed, we were gratified to find that the reaction of
methyl 3-hydroxy-2-naphthoate (1e) afforded the corre-
sponding binaphthol 2e in 47% ee (Table 3, entry 4),12
albeit with low chemical yield.
En a n tioselective Oxid a tive Cou p lin g of 2-Na p h -
th ols Ca ta lyzed by Ch ir a l Am in e‚Cop p er Com -
p lexes. With an efficient process of catalytic oxidative
coupling of naphthols established, we then turned our
attention to the enantioselective oxidative coupling of
naphthols. We first investigated asymmetric coupling
To improve both chemical yield and enantioselectivity,
we then adopted diamines derived from L-proline as
chiral ligand because of their availability and their
(9) (a) Hay, A. S. J . Org. Chem. 1962, 27, 3320-3321. (b) de J ong,
C. R. H. I. In Organic Syntheses by Oxidation with Metal Compounds;
Mijs, W. J ., de J ong, C. R. H. I., Eds.; Plenum Press Inc.: New York,
1986; pp 423-443.
(10) Cu(OH)Cl‚TMEDA dimer (di-µ-hydroxo-bis[(N,N,N′,N′-tetra-
methylethylenediamine)copper(II)] chloride) is now commercially avail-
able (TCI, D2542).
(12) Silica gel column chromatography (hexanes-EtOAc) of 2e
furnished fractions that differ in enantiomeric excess. We employed
hexanes-EtOAc as eluent for removing unreacted 1e and then
dichloromethane for complete elution of 2e. Fractionation of nonrace-
mic chiral compound on achiral phase: Nicoud, R.-M.; J aubert, J .-N.;
Rupprecht, I.; Kinkel, J . Chirality 1996, 8, 234-243 and references
therein.
(11) Hu, Q.-S.; Vitharana, D.; Pu, L. Tetrahedron: Asymmetry 1995,
6, 2123-2126.

2266 J . Org. Chem., Vol. 64, No. 7, 1999
Ta ble 4. En a n tioselective Oxid a tive Cou p lin g of Meth yl 3-Hyd r oxy-2-n a p h th oa te
Nakajima et al.
chiral diamine
R2
2e
entry
R1
R3
yield,a
%
ee,b %
confgnc
1
2
3
4
5
6
7
8
9
10
11
12
13
14
4
5
6
7
8
Me
Me
H
H
H
H
H
H
H
H
H
H
H
-(CH2)4-
-(CH2)4-
79
77
11
82
74
76
25
49
25
69
24
78
87
66
2
4
0
S
S
Ph
H
H
H
31
30
59
58
61
34
53
27
70
65
12
S
S
S
S
S
S
S
S
S
S
S
Ph
Ph
H
9
Me
Me
Me
Me
Me
Me
Et
10
11
12
13
14
15
16
17
4-MeOC6H4
4-CF3C6H4
1-naphthyl
2-naphthyl
cHex
Ph
Ph
Ph
CH2Ph
Ph
H
a
b
Isolated yield. Determined by HPLC analysis employing a Daicel Chiralpak AD. c Assignment by comparison to literature values of
optical rotations.
sterically rigid conformation in chelation with various
metals.13 Representative results are summarized in Table
4. By analogy with the process using TMEDA or sparteine
(3), we initially examined asymmetric oxidation with the
diamine 4 bearing two tertiary nitrogens. However, the
binaphthol 2e obtained in 79% yield appeared to be a
racemic product (Table 4, entry 1). We then screened
three types of ligands 5-9 containing a combination of
one secondary and one primary nitrogens, two secondary
nitrogens, or one secondary and one tertiary nitrogen.
Clearly, the ligands 4-6 (Table 4, entries 1-3) were
inferior to the ligands 7-9 (Table 4, entries 4-6), which
suggested that a secondary nitrogen in the pyrrolidine
ring and a secondary or tertiary nitrogen in the side-
chain were crucial to the asymmetric induction. Encour-
aged by this finding, we fixed the pyrrolidine ring moiety
and investigated the substituent effect of the side-chain
nitrogen on enantioselectivities. Of various diamines
surveyed, N-ethylaniline derivative 15 was found to
induce good enantioselectivities, whereas substitution of
cyclohexyl or 1-naphthyl rings for the phenyl ring of 9
resulted in only modest selectivities and poor yields
(Table 4, entries 9 and 11). Little electronic effect of the
aromatic ring on enantioselection was observed in the
reaction with the catalysts derived from 9-11 (Table 4,
entries 6-8).
obtained for the enantioselective oxidation of a variety
of naphthols catalyzed by the complex derived from 15
are summarized in Table 5. Little variation in enantio-
selectivities was observed with the ester moiety of the
substrate (Table 5, entries 1-3), except for the tert-butyl
ester (Table 5, entry 4). It should be noted that the
enantiomeric excess up to 78% is so far the highest
reported to date for catalytic, enantioselective oxidative
coupling of naphthol derivatives.14 Oxidation of naphthols
with ketone, amide, alkyl, or alkoxy moieties at the
3-position (Table 5, entries 5-10) afforded the corre-
sponding binaphthols with low enantioselectivities, which
implies that the ester moiety is essential for the asym-
metric induction.
P ossible Mech a n ism of En a n tioselective Cou -
p lin g of 2e. Although extensive efforts have been made
for the elucidation of the mechanism of the aerobic
oxidation catalyzed by copper‚amine complexes,9b the
mechanism of the present oxidative coupling is unknown.
We postulate that our coupling reaction consists of three
successive processes: (1) exchange of the hydroxy group
on the copper complex for a phenolic hydroxy group
followed by the additional coordination of ester carbonyl
to the copper atom, (2) oxidative coupling affording a
diketone with central chirality, and (3) transfer of central
chirality to axial chirality15 through keto-enol isomerism
along with dissociation of copper‚amine complex (Scheme
1). Assuming the reversible formation of the copper‚
amine-diketone complex, the intermediacy of 18, where
the substituents of the chiral amines are in the least
sterically demanding region, might be the best explana-
tion for the present enantioselection.
With a promising diamine for enantioselective oxida-
tion in hand, we then attempted the isolation of the
copper‚diamine complex. Addition of hexane into a solu-
tion of the complex prepared from CuCl and 15 in
dichloromethane afforded a green powder. Although its
structure remains ambiguous, it might be reasonable to
suppose the complex to be Cu(OH)Cl‚15, on the analogy
of Cu(OH)Cl‚TMEDA. The isolated complex possessed
slightly better reactivity, which made it possible to
conduct the reaction at room temperature. The results
P r ep a r a tion of Hom och ir a l Bin a p h th ol. Since
homochiral binaphthol (2a ) is a reliable source of a
(14) Catalytic oxidative cross-coupling of 2-naphthol and methyl
3-hydroxy-2-naphthoate employing copper‚sparteine complex as cata-
lyst and AgCl as oxidant afforded the corresponding binaphthol of 32%
ee in 41% yield.4a Photocatalytic oxidation of 2-naphthol with chiral
Ru-complex afforded 2,2′-binaphthol in 16% ee.4b
(15) (a) Meyers, A. I.; Lutomski, K. A. J . Am. Chem. Soc. 1982, 104,
879-881. (b) Meyers, A. I.; Wettlaufer, D. G. J . Am. Chem. Soc. 1984,
106, 1135-1136.
(13) (a) Asami, M.; Ohno, H.; Kobayashi, S.; Mukaiyama, T. Bull.
Chem. Soc. J pn. 1978, 51, 1869-1873. (b) Mukaiyama, T.; Iwasawa,
N.; Stevens, R. W.; Haga, T. Tetrahedron 1984, 40, 1381-1390. (c)
Kobayashi, S.; Uchiro, H.; Fujishita, Y.; Shiina, I.; Mukaiyama, T. J .
Am. Chem. Soc. 1991, 113, 4247-4252.

Enantioselective Synthesis of Binaphthol Derivatives
J . Org. Chem., Vol. 64, No. 7, 1999 2267
Ta ble 5. En a n tioselective Oxid a tive Cou p lin g of 2-Na p h th ol Der iva tives
naphthol
binaphthol
entry
X
yield,a
%
ee,b %
confignc
[R]D (c, THF)
1
2
3
4
5
6
7
8
9
1e
1g
1h
1i
COOMe
COOEt
COOCH2Ph
COOtBu
COMe
2e
2g
2h
2i
85
77
77
69
71
65
89
93
58
95
78
73
76
58
37
24
17
12
5g
S
-125.0 (1.0)
-112.2 (1.1)
-81.3 (1.1)
-79.6 (1.0)
-78.8 (1.0)
-3.3 (0.9)
Sd
Sd
Sd
S
1j
2j
1k
1a
1b
1l
CONHCH2Ph
H
2k
2a
2b
2l
Se
S
S
-20.1 (1.0)
-3.1 (1.0)f
-1.6 (1.4)
Me
iPr
10
1m
OCH2Ph
2m
24h
Sh
-8.2 (0.8)
a
b
Isolated yield. Determined by HPLC analysis employing a Daicel Chiralcel OD, OJ , or Chiralpak AD. c Assignment by comparison
to literature values of optical rotations. Assignment after conversion to 2e. e Assignment by comparison to the values of optical rotation
d
of 2k prepared from (R)-diacid. f Optical rotation was measured in CHCl3 at 578 nm. Determined by 1H NMR analysis with Eu(hfc)3.
g
h
Determined after conversion to (S)-1,1′-binaphthalene-2,2′,3,3′-tetrol.
Sch em e 1
variety of binaphthyl compounds, the development of
efficient preparation of homochiral 2a has attracted much
attention. Toward this end, we then addressed the
enrichment of enantiomeric excess of 2e and its trans-
formation into homochiral 2a .16
of hydroxy group with BBr3 afforded homochiral 2a in
70% overall yield shown in Scheme 2.
Sch em e 2
Enantioselective oxidation of 1e was performed by the
aid of a catalyst prepared from 15. Without aqueous
workup, the solvent was evaporated and the residue was
triturated in MeOH to afford 2e as needles (85%, 78%
ee). The homochiral 2e was easily obtained by a conse-
quence of the large solubility difference between racemic
2e and homochiral 2e. Thus, trituration of the above
scalemic mixture (78% ee) in ethyl acetate gave racemic
crystals (30%, mp 278-280 °C), which were filtered off,
and the mother liquor containing 2e (70%, mp 242-244
°C) of >99% ee. Protection of the hydroxy group in 2e
(MeI, NaH, DMF), hydrolysis of ester (KOH, aqueous
EtOH), and decarboxylation (Cu-bronze, CuCO3, quino-
line) gave O-methyl protected 2a . Finally, deprotection
Con clu sion
We have demonstrated the effectiveness of Cu(OH)Cl‚
TMEDA as a catalyst for aerobic oxidative coupling of
2-naphthol derivatives affording binaphthol derivatives
in excellent yields. Enantioselective oxidative coupling
was achieved by the use of chiral amine‚copper complexes
as catalysts, which afforded binaphthol derivatives in
(16) Conversion of 2e into 2a via Curtius rearrangement has been
reported, though the chemical yield of the decarboxylation step is low.
See: Akimoto, H.; Yamada, S. Tetrahedron 1971, 27, 5999-6009.

2268 J . Org. Chem., Vol. 64, No. 7, 1999
Nakajima et al.
24.3, 30.2, 31.2, 37.6, 37.8, 46.9, 47.4, 55.3, 55.4, 56.6, 57.1,
66.7, 67.3, 114.6, 114.8, 127.5, 127.7, 128.2, 128.3, 128.4, 128.8,
135.7, 136.1, 136.6, 136.7, 154.0, 154.7, 158.8, 158.9, 172.7.
good enantioselectivities up to 78% ee. Oxidation of
naphthols without an ester moiety at the 3-position
afforded the corresponding binaphthols with low enan-
tioselectivities, which implies that the ester moiety is
essential for the asymmetric induction. The present
catalytic system has proven to be a potent addition to
the existing method for the preparation of homochiral
binaphthyl compounds.
MS m/z: 368 (M+), 204, 91 (bp), 70. HRMS: calcd for C21H24
-
N2O4 368.1732, found 368.1702. Anal. Calcd for C21H24N2O4:
C, 68.46; H, 6.57; N, 7.60. Found: C, 68.44; H, 6.63; N, 7.53.
To a solution of above amide (1.7 g, 4.6 mmol) in THF (10
mL) was added BH3‚THF (1 M in THF, 15 mL, 15 mmol), and
the reaction mixture was heated at reflux for 1 h. After
addition of 10% HCl, the mixture was neutralized with NaOH
and extracted with Et2O. Drying over Na2SO4 and concentra-
tion afforded crude amide, which was dissolved in MeOH (10
mL) with Pd-C (ca. 100 mg), and the reaction mixture was
stirred at room temperature for 12 h under a hydrogen
atmosphere. Filtration followed by silica gel column chroma-
tography (CH2Cl2-MeOH-aqueous NH3, 100:10:1) afforded 10
(1.0 g, 80%) as a pale yellow oil. [R]23D: +2.6 (c 1.0, EtOH). IR
Exp er im en ta l Section
Gen er al Exper im en tal P r ocedu r es. Reactions were moni-
tored by thin-layer chromatography (TLC). All yields reported
refer to isolated material. Solvents were dried according to
established procedures by distillation under argon atmosphere
from the appropriate drying agent. Column chromatography
purifications were carried out using silica gel (70-230 mesh).
1H NMR (270 MHz) and 13C NMR (68 MHz) were recorded in
CDCl3 unless otherwise specified. Chemical shift values are
expressed in ppm relative to tetramethylsilane (0.0 ppm) for
1H and CDCl3 (77.0 ppm) for 13C NMR. Coupling constants
(J ) are reported in hertz (Hz). Abbreviations are as follows:
s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; br,
broad. Mass spectra were obtained by electron impact (EI) with
ionization voltage of 70 eV.
Chiral amines 4-9 were prepared by the literature meth-
ods.13 Naphthols 1b,c,g-m were prepared by the literature
methods.17
P r ep a r a tion of Cu (OH)Cl‚TMEDA.5a,9b A mixture of CuCl
(8.2 g, 0.083 mol) and TMEDA (19 g, 0.16 mol) in 95%
methanol was stirred under oxygen atmosphere at room
temperature for 1 h. The resulting precipitates were collected
by filtration and washed with acetone. Drying in vacuo gave
a purple powder (19 g, 98%) of mp 137-138 °C dec.
(neat): 3331 cm-1 1H NMR (CDCl3): δ 1.32-1.45 (m, 1H),
.
1.67-1.93 (m, 3H), 2.08 (s, 3H), 2.82-2.89 (m, 1H), 2.91(s, 3H),
2.98-3.06 (m, 1H), 3.21 (d, J ) 6.7 Hz, 2H), 3.37 (d, J ) 6.7
Hz, 1H), 3.76 (s, 3H), 6.74 (d, J ) 9.2 Hz, 2H), 6.83 (d, J ) 9.2
Hz, 2H). 13C NMR (CDCl3): δ 24.7, 29.3, 39.8, 45.9, 55.6, 57.1,
59.1, 114.5, 114.6, 144.8, 151.6. MS m/z: 204 (M+), 107, 97
(bp). HRMS: calcd for C13H20N2 204.1628, found 204.1601.
(S)-N-Met h yl-N-(4-t r iflu or om et h yl)p h en yl-2-p yr r oli-
d in em eth a n a m in e (11). To a solution of N-tert-butoxy-L-
proline (1.0 g, 4.56 mmol) and N-methylmorpholine (0.61 mL,
5.6 mmol) in EtOAc (10 mL) were added ethyl chloroformate
(0.50 mL, 5.0 mmol) and 4-aminobenzotrifluoride (0.91 g, 5.6
mmol) successively at -15 °C, and the mixture was stirred
for 1 h at the same temperature. After addition of water, the
mixture was extracted with EtOAc and washed with 10% HCl,
saturated NaHCO3, and brine. Drying over Na2SO4 and
concentration followed by silica gel column chromatography
(hexanes-EtOAc 4:1) afforded (S)-1-(tert-butoxycarbonyl)-N-
(4-trifluoromethylphenyl)-2-pyrrolidinecarboxamide (1.3 g, 76%).
[R]26D: -109.0 (c 1.04, CHCl3). IR (Nujol): 1711, 1678, 844
cm-1. 1H NMR (CDCl3): δ 1.51 (s, 9H), 2.01 (bs, 3H), 2.43 (bs,
1H), 4.11-4.14 (m, 2H), 4.51 (bs, 1H), 7.48-7.60 (m, 4H), 9.92
(bs, 1H). 13C NMR (CDCl3): δ 24.8, 28.7, 29.0, 47.6, 60.8, 81.2,
119.1, 126.0, 141.8, 156.2, 171.4. MS m/z: 358 (M+), 339, 285,
170, 145, 70 (bp). HRMS: calcd for C17H21F3N2O3 358.1504,
found 358.1475. Anal. Calcd for C17H21F3N2O3: C, 56.98; H,
5.91; N, 7.82. Found: C, 56.85; H, 5.91; N, 7.71.
Gen er a l P r oced u r e for th e Oxid a tive Cou p lin g of
Na p h th ol Der iva tives Ca ta lyzed by Cu (OH)Cl‚TMEDA.
A mixture of CuCl(OH)‚TMEDA (8.0 mg, 0.035 mmol) and
naphthol derivative (3.5 mmol) in dichloromethane (35 mL)
was stirred at room temperature for 1 h in the open air.
Concentration followed by silica gel column chromatography
afforded the corresponding binaphthol derivative. The spec-
troscopic properties of the products were coincident with those
previously reported.8c,18
To a solution of above amide (1.1 g, 3.1 mmol) in THF (17
mL) was added sodium hydride (60% in oil, 0.14 g, 3.5 mmol)
at 0 °C, and the mixture was stirred at the same temperature
for 1 h. Iodomethane (0.30 mL, 5.0 mmol) was added, and the
reaction mixture was stirred for 12 h at room temperature.
After addition of 10% HCl, the mixture was extracted with
EtOAc and washed with saturated NaHCO3 and brine. Drying
over Na2SO4 and concentration followed by silica gel chroma-
tography (hexanes-EtOAc 2:1) afforded (S)-1-(tert-butoxycar-
bonyl)-N-methyl-N-(4-trifluoromethylphenyl)-2-pyrrolidine-
P r ep a r a tion of Ch ir a l Am in es 10-17. (S)-N-(4-Meth -
oxyp h en yl)-N-m et h yl-2-p yr r olid in em et h a n a m in e (10).
To a solution of N-benzyloxycarbonyl-L-proline (1.5 g, 6.0
mmol) and N-methyl-p-anisidine (0.91 g, 6.6 mmol) in THF
(10 mL) was added 1-(3-dimethylaminopropyl)-3-ethylcarbo-
diimide (EDC) (1.3 g, 6.6 mmol), and the reaction mixture was
stirred at room temperature for 12 h. After addition of water,
the mixture was extracted with EtOAc and washed with 10%
HCl, saturated NaHCO3, and brine. Drying over Na2SO4 and
concentration followed by silica gel column chromatography
(hexanes-EtOAc 1:2) afforded (S)-1-benzyloxycarbonyl-N-(4-
methoxyphenyl)-N-methyl-2-pyrrolidinecarboxamide (2.1 g,
94%) as a mixture of rotamers. [R]21D: +122.4 (c 1.0, CHCl3).
carboxamide (0.96 g, 92%) as a mixture of rotamers. [R]27
:
D
+83.0 (c 1.1, CHCl3). IR (neat): 1693, 1682 cm-1 1H NMR
.
(CDCl3): δ 1.44 and 1.47 (2 × s, 9H), 1.67-2.06 (m, 4H), 3.29
(s, 3H), 3.29-3.60 (m, 2H), 4.07-4.25 (m, 1H), 7.37 (d, J )
8.3 Hz, 1H), 7.52 (d, J ) 8.2 Hz, 1H), 7.67-7.72 (m, 2H). 13C
NMR (CDCl3): δ 23.4, 24.2, 28.5, 28.6, 30.2, 47.0, 47.1, 56.8,
57.1, 79.4, 79.8, 126.9, 127.9, 128.3, 128.3, 172.5. MS m/z: 372
(M+), 299, 271, 202, 170, 70 (bp). HRMS: calcd for C18H23F3N2O3
372.1661, found 372.1632. Anal. Calcd for C18H23F3N2O3: C,
58.06; H, 6.22; N, 7.52. Found: C, 58.01; H, 6.35; N, 7.39.
To a solution of above amide (1.0 g, 2.7 mmol) in THF (10
mL) was added BH3‚THF complex (1 M in THF, 5.0 mL, 5.0
mmol), and the reaction mixture was heated at reflux for 1 h.
After addition of 10% HCl, the mixture was neutralized with
NaOH and extracted with Et2O. Drying over Na2SO4 and
concentration gave crude amide, which was treated with
trifluoroacetic acid (2 mL) in CH2Cl2 (2 mL) at 0 °C for 1 h.
After addition of water, the mixture was neutralized with
NaOH and extracted with Et2O. Drying over Na2SO4 and
concentration followed by silica gel column chromatography
(CH2Cl2-MeOH-aqueous NH3 100:10:1) afforded 11 (0.53 g,
1
IR (Nujol): 1712, 1680 cm-1. H NMR (CDCl3): δ 1.66-2.11
(m, 4H), 3.11 and 3.26 (2 × s, 3H), 3.41-3.71 (m, 2H), 4.11-
4.32 (m, 1H), 5.01-17 (m, 2H), 6.59-6.84 (m, 2H), 6.93 (d, J
) 8.8 Hz, 1H), 7.27-7.45 (m, 6H). 13C NMR (CDCl3): δ 23.6,
(17) (a) Einhorn, J .; Demerseman, P.; Royer, R. Eur. J . Chem.-
Chim. Ther. 1983, 18, 175-180. (b) Widmer, U. Synthesis 1983, 135-
136. (c) Colquhoun, H. M.; Goodings, E. P.; Maud, J . M.; Stoddart, J .
F.; Wolstenholme, J . B. J . Chem. Soc., Perkin Trans. 2 1985, 607-
624. (d) Coll, G.; Morey, J .; Costa, A.; Saa´, J . M. J . Org. Chem. 1988,
53, 5345-5348. (e) Chang, H. M.; Chui, K. Y.; Tan, F. W. L.; Yang, Y.;
Zhong, P. J . Med. Chem. 1991, 34, 1675-1692.
(18) (a) Cram, D. J .; Helgeson, R. C.; Peacock, S. C.; Kaplan, L. J .;
Domeier, L. A.; Moreau, P.; Koga, K.; Mayer, J . M.; Chao, Y.; Siegel,
M. G.; Hoffman, D. H.; Sogah, G. D. Y. J . Org. Chem. 1978, 43, 1930-
1946. (b) Miyano, S.; Tobita, M.; Nawa, M.; Sato, S.; Hashimoto, H. J .
Chem. Soc., Chem. Commun. 1980, 1233-1234. (c) Reeder, J .; Castro,
P. P.; Knobler, C. B.; Martinborough, E.; Owens, L.; Dieterich, F. J .
Org. Chem. 1994, 59, 3151-3160.

Enantioselective Synthesis of Binaphthol Derivatives
73%) as a pale yellow oil. [R]28
J . Org. Chem., Vol. 64, No. 7, 1999 2269
:
+9.7 (c 1.1, EtOH). IR
74.01; H, 6.00; N, 7.28. 13. [R]24D: -1.3 (c 0.55, EtOH). IR
D
1
(neat): 3335, 1481 cm-1
.
1H NMR (CDCl3): δ 1.35-1.48 (m,
(neat): 3337, 862, 823, 744 cm-1. H NMR (CDCl3): δ 1.39-
1H), 1.66-1.96 (m, 3H), 2.80-3.07 (m, 2H), 3.05 (s, 3H), 3.38-
3.41 (m, 3H), 6.72 (d, J ) 8.9 Hz, 1H), 7.43 (d, J ) 8.9 Hz,
1H). 13C NMR (CDCl3): δ 24.9, 29.4, 39.2, 46.3, 57.1, 57.6,
110.9, 117.1 (q, J CF ) 33 Hz), 125.1 (q, J CF ) 270 Hz), 126.4,
151.4. MS m/z: 258 (M+), 239, 189, 145, 70 (bp). HRMS: calcd
for C13H17F3N2 258.1344, found 258.1333.
1.96 (m, 4H), 2.92 (ddd, J ) 6.5, 7.9, 10.2 Hz, 1H), 3.00 (ddd,
J ) 5.5, 7.5, 10.2 Hz, 1H), 3.09 (s, 3H), 3.43 (d, J ) 2.3 Hz,
1H), 7.03 (d, J ) 2.6 Hz, 1H), 7.18 (m, 2H), 7.35 (td, J ) 6.9,
1.4 Hz, 1H), 7.65 (t, J ) 9.1 Hz, 2H), 7.68 (d, J ) 9.1 Hz, 1H).
13C NMR (CDCl3): δ 24.8, 29.4, 39.3, 46.1, 57.3, 58.1, 105.8,
116.1, 121.8, 126.0, 126.0, 126.6, 127.3, 128.6, 135.0, 147.5.
MS m/z: 240 (M+), 171 (bp), 70. HRMS: calcd for C16H20N2
240.1626, found 240.1608. Anal. Calcd for C16H20N2‚HCl: C,
69.43; H, 7.65; N, 10.12. Found: C, 69.70; H, 7.51; N, 10.02.
(S)-N-Cycloh exyl-N-m et h yl-2-p yr r olid in em et h a n a m -
in e (14). To a solution of N-tert-butoxycarbonyl-L-proline (0.50
g, 2.3 mmol) and N-methylcyclohexylamine (0.35 g, 3.1 mmol)
in CH2Cl2 (3 mL) was added EDC (0.59 g, 3.1 mmol), and the
reaction mixture was stirred at room temperature for 12 h.
After addition of water, the mixture was extracted with EtOAc
and washed with 10% HCl, saturated NaHCO3, and brine.
Drying over Na2SO4 and concentration followed by silica gel
column chromatography (hexanes-EtOAc 1:1) afforded (S)-1-
tert-butoxycarbonyl-N-cyclohexyl-N-methyl-2-pyrrolidinecar-
boxamide (0.39 g, 54%) as a mixture of rotamers. [R]29D: -25.0
(c 1.0, CHCl3). IR (Nujol): 1699, 1685 cm-1. 1H NMR (CDCl3):
δ 1.00-1.89 (m, 16H), 1.39, 1.40, 1.45, and 1.45 (s × 4, 9H),
1.93-2.23 (m, 2H), 2.81-2.91 (m, 5H), 3.37-3.66 (m, 4H),
4.36-4.43 (m, 1H), 4.45-4.53 (m, 1H), 4.65 (td, 8.4, 2.9 Hz,
1H). 13C NMR (CDCl3): δ 23.1, 23.7, 24.9, 25.0, 25.2, 25.3, 25.4,
25.6, 27.0, 27.0, 28.1, 28.2, 28.8, 29.3, 29.4, 29.5, 29.8, 30.1,
30.3, 30.4, 30.6, 30.7, 30.7, 46.3, 46.5, 52.4, 52.5, 55.7, 55.8,
56.6, 56.9, 153.5, 153.7, 154.1, 171.6, 171.6, 172.0. MS m/z:
310 (M+), 237, 170, 70 (bp). HRMS: calcd for C17H30N2O3
310.2256, found 310.2256. Anal. Calcd for C17H30N2O3: C,
65.81; H, 9.75; N, 9.03. Found: C, 65.90; H, 9.62; N, 8.88.
To a solution of above amide (0.39 g, 0.87 mmol) in CH2Cl2
(1 mL) was added trifluoroacetic acid (1 mL) at 0 °C, and the
reaction mixture was stirred at the same temperature for 1 h.
The mixture was neutralized with saturated NaHCO3 and
extracted with CH2Cl2. Drying over Na2SO4 and concentration
gave crude amide, which was added to a solution of lithium
aluminum hydride (0.13 g, 3.3 mmol) in THF (20 mL) and the
mixture was heated at reflux for 1 h. After the addition of
water (0.13 mL), 15% NaOH (0.13 mL), and water (0.39 mL)
successively, the mixture was filtered through a Celite pad.
Concentration followed by silica gel column chromatography
(CH2Cl2-MeOH-aqueous NH3 100:10:1) afforded 14 (0.10 g,
36%) as a colorless oil. [R]26D: -3.5 (c 1.0, EtOH). IR (neat):
3319 cm-1. 1H NMR (CDCl3): δ 0.97-1.37 (m, 6H), 1.56-1.91
(m, 8H), 2.26 (s, 3H), 2.20-2.50 (m, 2H), 2.32 (d, J ) 6.8 Hz,
2H), 2.83 (dt, J ) 7.0, 9.9 Hz, 1H), 2.94 (dt, J ) 6.6, 10.0 Hz,
1H), 3.18 (dd, J ) 6.7, 6.7 Hz, 1H). 13C NMR (CDCl3): δ 25.1,
26.4, 26.7, 28.7, 29.1, 29.8, 38.7, 46.0, 56.7, 58.9, 63.7. MS
m/z: 196 (M+), 126, 84 (bp), 70. HRMS: calcd for C12H24N2
196.1940, found 196.1941.
(S)-N-Meth yl-N-(1-n a p h th yl)-2-p yr r olid in em eth a n a m -
in e (12). To a solution of (S)-1-benzyloxycarbonyl-N-(1-naph-
thyl)-2-pyrrolidinecarboxamide13 (1.5 g, 4.0 mmol) in DMF (10
mL) was added sodium hydride (60% in oil, 0.24 g, 5.0 mmol)
at 0 °C, and the mixture was stirred at the same temperature
for 15 min. Iodomethane (0.37 mL, 6.0 mmol) was added, and
the reaction mixture was stirred for 2 h at room temperature.
After addition of 10% HCl, the mixture was extracted with
EtOAc and washed with saturated NaHCO3 and brine. Drying
over Na2SO4 and concentration followed by silica gel chroma-
tography (hexanes-EtOAc 1:2) afforded (S)-1-benzyloxycar-
bonyl-N-methyl-N-(1-naphthyl)-2-pyrrolidinecarboxamide (1.3
g, 82%) as a mixture of rotamers. [R]28
:
+108.0 (c 0.56,
D
CHCl3). IR (neat): 1680, 1595, 1460, 1377 cm-1 1H NMR
.
(CDCl3): δ 1.90-2.07 (m, 4H), 3.25, 3.29, 3.38, and 3.40 (4 ×
s, 3H), 3.37-3.67 (m, 2H), 3.85-4.27 (m, 1H), 4.95-6.56 (m,
2H), 7.08-8.30 (m, 12H). 13C NMR (CDCl3): δ 23.5, 23.7, 24.4,
24.5, 29.2, 30.6, 31.1, 31.6, 32.3, 30.9, 37.3, 37.5, 37.5, 39.8,
46.8, 47.1, 47.3, 47.7, 48.1, 52.0, 53.4, 56.6, 57.1, 57.8, 58.3,
60.4, 66.7, 66.7, 66.8, 67.5, 122.3, 123.0, 123.9, 124.7, 125.3,
125.4, 125.8, 125.9, 126.0, 126.3, 126.3, 126.5, 126.6, 126.7,
126.8, 127.1, 127.2, 127.2, 127.6, 127.7, 127.8, 127.9, 128.1,
128.3, 128.3, 128.4, 128.6, 128.6, 128.7, 128.7, 129.0, 129.0,
130.0, 130.0, 130.1, 134.6, 134.7, 134.8, 136.7, 136.8, 137.3,
139.0, 139.1, 139.3, 139.4, 141.9, 154.1, 154.6, 154.8, 160.2,
172.6, 172.8, 173.4, 173.7, 206.9. MS m/z: 388 (M+), 312, 253,
204, 184, 91 (bp). HRMS: calcd for C24H24N2O3 388.1787, found
388.1816. Anal. Calcd for C24H24N2O3: C, 74.21; H, 6.23; N,
7.21. Found: C, 74.12; H, 5.98; N, 7.18.
To a solution of above amide (198 mg, 0.51 mmol) in THF
(2 mL) was added BH3‚THF complex (1 M in THF, 5.0 mL,
5.0 mmol), and the reaction mixture was heated at reflux for
1 h. After addition of 10% HCl, the mixture was neutralized
with NaOH and extracted with Et2O. Drying over Na2SO4 and
concentration gave crude amide, which was treated with 30%
HBr in acetic acid (1 mL) at 0 °C for 3 h. After addition of
water, the mixture was neutralized with NaOH and extracted
with Et2O. Drying over Na2SO4 and concentration followed by
silica gel column chromatography (CH2Cl2-MeOH-aqueous
NH3 100:10:1) afforded 12 (94 mg, 77%) as a pale yellow oil.
[R]24D: +11.0 (c 1.1, CHCl3). IR (neat): 3335, 802, 775 cm-1
.
1H NMR (CDCl3): δ 1.32-1.51 (m, 1H), 1.63-1.95 (m, 3H),
2.89 (s, 3H), 2.80-2.89 (m, 1H), 2.97 (td, J ) 6.8, 13.3 Hz,
1H), 3.13 (t, J ) 13.0 Hz, 1H), 3.15 (dd, J ) 13.9, 13.0 Hz,
1H), 3.42 (t, J ) 6.6 Hz, 1H), 3.53 (s, 1H), 7.16 (d, J ) 7.1 Hz,
1H), 7.37-7.57 (m, 4H), 7.81 (dd, J ) 6.7, 2.7 Hz, 1H), 8.36
(dd, J ) 7.5, 2.0 Hz, 1H). 13C NMR (CDCl3): δ 24.9, 29.7, 44.1,
46.0, 56.0, 61.6, 116.1, 123.4, 123.8, 125.2, 125.6, 125.7, 128.1,
129.7, 134.7, 150.3. MS m/z: 240 (M+), 171 (bp), 70. HRMS:
calcd for C16H20N2 240.1626, found 240.1638. Anal. Calcd for
(S)-N-Eth yl-N-p h en yl-2-p yr r olid in em eth a n a m in e (15).
Prepared by the same method as for 10 starting from N-
benzyloxycarbonyl-L-proline and N-ethylaniline. (S)-1-Benzyl-
oxycarbonyl-N-ethyl-N-phenyl-2-pyrrolidinecarboxamide. [R]22
:
D
+119.3 (c 1.2, CHCl3). IR (Nujol): 1730, 1668, 702 cm-1. H
NMR (CDCl3): δ 1.02-1.17 (m, 3H), 1.67-2.14 (m, 5H), 3.45-
3.87 (m, 4H), 4.06-4.26 (m, 1H), 5.09-5.19 (m, 2H), 6.72 (bs,
1H), 7.23-7.50 (m, 9H). 13C NMR (CDCl3): δ 12.8, 12.9, 23.6,
24.4, 30.3, 31.4, 44.3, 44.4, 47.0, 47.5, 57.0, 57.6, 66.8, 67.4,
127.6, 127.8, 127.9, 128.0, 128.3, 128.4, 128.5, 128.6, 128.9,
129.0, 129.5, 129.7, 136.6, 136.8, 141.4, 141.7, 154.1, 154.7,
171.8, 171.9. MS m/z: 352 (M+), 204, 148, 120, 91 (bp).
HRMS: calcd for C21H24N2O3 352.1787, found 352.1779. Anal.
Calcd for C21H24N2O3: C, 71.57; H, 6.86; N, 7.95. Found: C,
71.79; H, 6.97; N, 7.86. 15. [R]22D: +10.1 (c 1.0, EtOH). IR
1
C
16H20N2‚HCl: C, 69.43; H, 7.65; N, 10.12. Found: C, 69.28;
H, 7.70; N, 10.09.
(S)-N-Meth yl-N-(2-n a p h th yl)-2-p yr r olid in em eth a n a m -
in e (13). Prepared by the same method as for 12 starting from
(S)-1-benzyloxycarbonyl-N-(2-naphthyl)-2-pyrrolidinecarbox-
amide.13 (S)-1-benzyloxycarbonyl-N-methyl-N-(1-naphthyl)-2-
pyrrolidinecarboxamide. [R]27
: +184.6 (c 1.0, CHCl3). IR
D
(Nujol): 1712, 1680, 864, 821, 754 cm-1. H NMR (CDCl3): δ
1.66-2.11 (m, 4H), 3.23 and 3.38 (2 × s, 3H), 3.43-3.72 (m,
2H), 4.15-4.37 (m, 1H), 5.01-5.19 (m, 2H), 6.75-6.82 (m, 1H),
7.19-7.94 (m, 12H). 13C NMR (CDCl3): δ 14.1, 23.6, 24.4, 30.3,
31.4, 37.6, 37.8, 46.9, 47.4, 56.8, 57.4, 66.8, 67.4, 125.2, 125.7,
125.9, 126.1, 126.2, 126.7, 126.8, 127.6, 127.8, 128.0, 128.4,
128.6, 129.0, 129.8, 129.9, 132.3, 132.5, 133.4, 133.6, 136.7,
140.4, 140.8, 154.0, 172.6. MS m/z: 388 (M+), 204, 91 (bp).
HRMS: calcd for C24H24N2O3 388.1787, found 388.1801. Anal.
Calcd for C24H24N2O3: C, 74.21; H, 6.23; N, 7.21. Found: C,
1
(neat): 3329, 1599, 1248, 1196, 694 cm-1 1H NMR (CDCl3):
.
δ 1.14 (t, J ) 7.0 Hz, 3H), 1.38-1.51 (m, 1H), 1.68-1.98 (m,
3H), 2.83 (bs, 1H), 2.90 (ddd, J ) 6.6, 8.2, 10.3 Hz, 1H), 3.06
(ddd, J ) 5.7, 7.7, 10.3 Hz, 1H), 3.23-3.50 (m, 3H), 3.46 (q, J
) 7.0 Hz, 2H), 6.68-6.82 (m, 3H), 7.18-7.27 (m, 2H). 13C NMR
(CDCl3): δ 11.5, 24.6, 29.0, 45.5, 46.0, 55.4, 57.2, 112.2, 115.7,
129.0, 148.1. MS m/z: 204 (M+), 135, 120, 106, 70 (bp).

2270 J . Org. Chem., Vol. 64, No. 7, 1999
Nakajima et al.
HRMS: calcd for C13H20N2 204.1627, found 204.1616. Anal.
Calcd for C13H20N2‚2HCl: C, 56.32; H, 8.00; N, 10.10, Found:
C, 56.10; H, 7.93; N, 10.00.
2.42 (bs, 1H), 2.64-2.75 (m, 1H), 3.15-3.23 (m, 1H), 3.69-
3.76 (m, 1H), 7.12-7.67 (m, 10H). 13C NMR (CDCl3): δ 26.7,
31.8, 48.0, 59.5, 128.8, 129.2, 129.3, 174.9. MS m/z: 266 (M+),
196, 169, 70 (bp). HRMS: calcd for C17H18N2O 266.1420, found
266.1432. Anal. Calcd for C17H18N2O: C, 76.67; H, 6.81; N,
10.52. Found: C, 76.43; H, 6.89; N, 10.30.
(S)-N-Ben zyl-N-ph en yl-2-pyr r olidin em eth an am in e (16).
To a solution of N-benzyloxycarbonyl-L-proline (10 g, 40 mmol)
and N-benzylaniline (8.8 g, 48 mmol) in THF was added EDC
(8.3 g, 43 mmol), and the reaction mixture was stirred at room
temperature for 12 h. After addition of water, the mixture was
extracted with EtOAc and washed with 10% HCl, saturated
NaHCO3, and brine. Drying over Na2SO4 and concentration
followed by recrystallization from EtOAc-hexane afforded (S)-
1-benzyloxycarbonyl-N-phenyl-N-phenylmethyl-2-pyrrolidin-
To a solution of above amide (0.67 g, 2.5 mmol) in THF (1
mL) was added BF3‚OEt2 (0.30 mL, 2.4 mmol), and the reaction
mixture was heated at reflux for 1 h. After cooling, BH3‚SMe2
complex (1 M in THF, 1.8 mL, 1.8 mmol) was added, and the
mixture was heated at reflux for 3 h. After evaporation of the
solvent, 10% HCl (0.5 mL) was added to the residue, and the
mixture was refluxed for 1 h. The mixture was neutralized
with 10% aqueous NaOH and extracted with Et2O. Drying over
Na2SO4 and concentration followed by silica gel column
chromatography (CH2Cl2-MeOH-aqueous NH3 200:10:1) af-
forded 17 (536 mg, 65%) as a colorless oil. [R]22D: -21.5 (c 1.1,
ecarboxamide (6.9 g, 41%) as a mixture of rotamers. [R]25
:
D
+76.9 (c 1.0, CHCl3). IR (Nujol): 1696, 1662, 1593 cm-1 1H
.
NMR (CDCl3): δ 1.68-2.14 (m, 4H), 3.44-3.74 (m, 2H), 4.09-
4.29 (m, 1H), 4.64-5.18 (m, 4H), 6.56 (d, J ) 6.8 Hz, 1H),
7.06-7.39 (m, 14H). 13C NMR (CDCl3): δ 23.5, 24.4, 30.3, 31.3,
46.9, 47.4, 53.2, 53.3, 56.9, 57.5, 66.7, 67.2, 127.2, 127.3, 127.5,
127.7, 127.9, 128.0, 128.1, 128.3, 128.4, 128.5, 128.6, 128.7,
128.9, 129.0, 129.3, 129.5, 129.6, 129.7, 129.8, 136.5, 136.7,
137.2, 137.3, 141.2, 141.6, 154.0, 154.7, 172.4, 172.5. MS m/z:
414 (M+), 204, 182, 91 (bp). HRMS: calcd for C26H26N2O3
414.1945, found 414.1906. Anal. Calcd for C26H26N2O3: C,
75.34; H, 6.32; N, 6.76. Found: C, 75.44; H, 6.50; N,6.61.
To a solution of above amide (6.5 g, 15.7 mmol) in THF (16
mL) was added BH3‚THF complex (1 M in THF, 17 mL, 17
mmol), and the reaction mixture was heated at reflux for 1 h.
After addition of 10% HCl, the mixture was neutralized with
NaOH and extracted with Et2O. Drying over Na2SO4 and
concentration gave crude amide, which was treated with 30%
HBr in acetic acid (18 mL) at 0 °C for 3 h. After addition of
water, the mixture was neutralized and extracted with Et2O.
Drying over Na2SO4 and concentration followed by silica gel
column chromatography (CH2Cl2-MeOH-aqueous NH3 100:
10:1) afforded 16 (3.6 g, 85%) as a pale yellow oil. [R]28D: +9.6
1
EtOH). IR (neat): 3339, 1589, 866 cm-1. H NMR (CDCl3): δ
1.32-1.46 (m, 1H), 1.57-1.88 (m, 3H), 2.79-3.02 (m, 2H),
3.36-3.47 (m, 1H), 3.74 (d, J ) 7.0 Hz, 2H), 3.95 (bs, 1H),
6.84-7.21 (m, 10H). 13C NMR (CDCl3): δ 24.5, 29.3, 45.9, 56.6,
57.3, 121.2, 121.6, 129.3, 148.3. MS m/z: 252 (M+), 183 (bp),
70. HRMS: calcd for calcd for
C17H20N2 52.1627, found
252.1638. Treatment of 17 with picric acid afforded the
corresponding picrate as orange prisms of mp 153 °C. Anal.
Calcd for C17H20N2‚C6H3N3O7: C, 57.37; H, 4.81; N, 14.54.
Found: C, 57.07; H, 4.95; N, 14.39.
En a n tioselective Oxid a tive Cou p lin g of 1e Ca ta lyzed
by Ch ir a l Am in e‚Cop p er Com p lex P r ep a r ed in Situ . To
a solution of amine (0.15 mmol) in dichloromethane (10 mL)
was added CuCl (14 mg, 0.14 mmol), and the mixture was
sonicated to afford a green solution. A solution of 1e (400 mg,
1.4 mmol) in dichloromethane (10 mL) was added, and the
mixture was heated at reflux in oxygen of atmospheric
pressure for 24 h. Purification by silica gel column chroma-
tography12 afforded 2e, the enantiomeric excess of which was
determined by HPLC analysis (Daicel Chiralpak AD).
P r ep a r a tion of Ch ir a l Am in e‚Cop p er Com p lex. To a
solution of 15 (220 mg) in dichloromethane (20 mL) was added
CuCl (99 mg), and the mixture was sonicated in an oxygen
atmosphere to afford a green solution to which hexane (100
mL) was added at room temperature. The resultant precipitate
was collected by filtration to afford a green powder (180 mg).
Mp: 98-102 °C dec.
Gen er a l P r oced u r e for th e En a n tioselective Oxid a -
tion of 2-Na p h th ol Der iva tives. To a solution of 2-naphthol
derivative (2.5 mmol) in dichloromethane (20 mL) was added
catalyst (10 mol %), and the reaction mixture was stirred at
room temperature in an oxygen atmosphere for 24 h. The
reaction was quenched by 10% aqueous NH3 (10 mL), and the
mixture was extracted with EtOAc. The organic phase was
dried with Na2SO4 and evaporated in vacuo. The residue was
purified by silica gel column chromatography to afford the
corresponding binaphthol derivative. For purification by silica
gel column chromatography of 2e, see ref 12.
(c 1.1, EtOH). IR (neat): 3339, 1599, 1504, 1392, 1358 cm-1
.
1H NMR (CDCl3): δ 1.33-1.46 (m, 1H), 1.63-1.99 (m, 3H),
2.07 (s, 1H), 2.86 (ddd, J ) 6.7, 7.9, 10.2 Hz, 1H), 2,98 (ddd, J
) 5.7, 7.6, 10.2 Hz, 1H), 3.35-3.54 (m, 3H), 4.64 (d, J ) 22.2
Hz, 1H), 4.70 (d, J ) 22.2 Hz, 1H), 6.65-6.75 (m, 3H), 7.14-
7.36 (m, 7H). 13C NMR (CDCl3): δ 24.9, 29.5, 46.3, 55.2, 56.7,
57.4, 112.6, 116.5, 126.5, 126.7, 128.5, 129.2, 138.8, 148.8. MS
m/z: 266 (M+), 197, 190, 84 (bp). HRMS: calcd for C18H22N2
266.1783, found 266.1796. Anal. Calcd for C18H22N2: C, 81.16;
H, 8.32; N, 10.52. Found: C, 79.7; H, 8.33; N, 10.27.
(S)-N,N-Dip h en yl-2-p yr r olid in em eth a n a m in e (17). To
a solution of N-trifluoro-L-proline (3.0 g, 14 mmol) in dichlo-
romethane (10 mL) was added thionyl chloride (10 mL) at 0
°C, and the mixture was stirred at room temperature for 1 h.
After evaporation in vacuo, diphenylamine (5.0 g, 29 mmol)
was added to the solution of the residue in dichloromethane
(20 mL) at 0 °C, and the reaction mixture was stirred at room
temperature for 12 h. After addition of water, the mixture was
extracted with EtOAc and washed with 10% HCl, saturated
NaHCO3, and brine. Drying over Na2SO4 and concentration
followed by recrystallization from benzene-hexane afforded
(S)-1-trifluoro-N,N-diphenyl-2-pyrrolidinecarboxamide (1.0 g,
21%) as pale brown needles. Mp: 102-104 °C. [R]26D: -32.5
Dim eth yl 2,2′-Dih yd r oxy-1,1′-bin a p h th a len e-3,3′-d ica r -
boxyla te (2e). [R]25D: -125.0 (c 1.0, THF), for 78% ee (lit.18a
[R]25D +172 (c 0.82, THF) for (R)-2e). HPLC: Daicel Chiralpak
AD, hexane-isopropyl alcohol 9:1, 1 mL/min, 11.0 (S) and 20.0
(R) min.
(c 1.0, benzene). IR (Nujol): 1749, 1682, 906, 869 cm-1 1H
.
NMR (CDCl3): δ 1.86-2.33 (m, 4H), 3.76 (s, 2H), 3.63-3.91
(m, 2H), 4.36-4.66 (m, 1H), 7.29-7.58 (m, 8H). 13C NMR
(CDCl3): δ 25.2, 28.5, 29.0, 47.9, 59.5, 60.1, 117.8, 126.3, 129.0,
129.3, 170.8. MS m/z: 362 (M+), 166 (bp). HRMS: calcd for
calcd for C19H17F3N2O2 362.1242, found 362.1263. Anal. Calcd
for C19H17F3N2O2: C, 62.98; H, 4.73; N, 7.73. Found: C, 63.22;
H, 4.64; N, 7.65.
To a solution of above amide (1.2 g, 3.3 mmol) in EtOH (18
mL) was added sodium borohydride (0.23 g, 5.8 mmol), and
the reaction mixture was refluxed for 3 h. After addition of
water, the mixture was extracted with EtOAc and washed with
10% HCl, saturated NaHCO3, and brine. Drying over Na2SO4
and concentration followed by recrystallization from benzene-
hexane afforded (S)-N,N-diphenyl-2-pyrrolidinecarboxamide
(0.67 g, 76%) as pale brown needles. Mp: 113 °C. [R]25D: +23.4
(c 1.0, benzene). 1H NMR (CDCl3): δ 1.62-1.95 (m, 4H), 2.02-
Dieth yl 2,2′-Dih yd r oxy-1,1′-bin a p h th a len e-3,3′-d ica r -
boxyla te (2g). [R]21D: -112.2 (c 1.1, THF) for 73% ee. HPLC:
Daicel Chiralpak AD, hexane-isopropyl alcohol 9:1, 1 mL/min,
7.5 (S) and 11.6 (R) min. IR (CHCl3): 3223, 1680 cm-1 1H
.
NMR (CDCl3): δ 1.52 (t, J ) 7.1 Hz, 6H), 4.52 (q, J ) 6.6 Hz,
8H), 7.15 (dd, J ) 6.3, 3.6 Hz, 2H), 7.30-7.37 (m, 4H), 7.94
(dd, J ) 6.4, 3.1 Hz, 2H), 8.69 (s, 2H), 10.80 (s, 2H). 13C NMR
(CDCl3): δ 14.7, 62.3, 114.8, 117.4, 124.3, 125.1, 127.6, 129.6
129.8, 130.2, 133.2, 137.6, 154.6, 170.6. MS m/z: 430 (M+, bp),
412, 384, 356, 310. HRMS: calcd for C26H22O6 430.1417, found
430.1429. Anal. Calcd for C26H22O6: C, 72.55; H, 5.15. Found:
C, 72.50; H, 5.26. Absolute configuration of 2g was determined
after conversion of 2g ([R]21D -112.2 (c 1.1, THF)) into 2e ([R]21
D
-157.5 (c 1.0, THF)) by transesterification catalyzed by
dibutyltin oxide.19b

Enantioselective Synthesis of Binaphthol Derivatives
J . Org. Chem., Vol. 64, No. 7, 1999 2271
Diben zyl 2,2′-d ih yd r oxy-1,1′-bin a p h th a len e-3,3′-d ica r -
boxyla te (2h ). [R]20D: -81.3 (c 1.0, THF) for 76% ee. HPLC:
Daicel Chiralpak AD, hexane-isopropyl alcohol 9:1, 1 mL/min,
MeOH) for (R)-2d .) HPLC: Daicel Chiralpak AD, hexane-
isopropyl alcohol 9:1, 1.5 mL/min, 29 (S) and 36 (R) min.
3,3′-Diisop r op yl-1,1′-bin a p h th a len e-2,2′-d iol (2l). [R]24
:
D
15.4 (S) and 23.9 (R) min. IR (Nujol): 3194, 1672, 794 cm-1
.
-1.6 (c 1.4, THF), 5% ee determined by 1H NMR analysis
with Eu(hfc)3. IR (CHCl3): 2543 cm-1. 1H NMR (CDCl3): δ 1.19
(d, J ) 6.9 Hz, 12H), 3.07 (septet, J ) 6.9 Hz, 2H), 7.15 (s,
2H), 7.31 (d, J ) 7.5 Hz, 2H), 7.42 (ddd, J ) 7.5, 7.5, 1.2 Hz,
2H), 7.61 (ddd, J ) 7.5, 7.5, 1.2 Hz, 2H), 8.04 (d, J ) 7.5 Hz,
2H). 13C NMR (CDCl3): δ 21.5, 27.0, 129.3, 129.6, 129.7, 130.4,
135.4, 135.8, 138.3, 146.3, 179.5, 180.7. MS m/z: 370 (M+, bp).
HRMS: calcd for C26H26O2 370.1934, found 370.1940. Anal.
Calcd for C26H26O2: C, 84.29; H, 7.07. Found: C, 84.01; H,
6.95.
1H NMR (CDCl3): δ 5.48 (s, 4H), 7.12-7.17 (m, 2H), 7.29-
7.54 (m, 14H), 7.87-7.92 (m, 2H), 8.71 (s, 2H), 10.69 (s, 2H).
13C NMR (CDCl3): δ 67.4, 114.2, 117.0, 124.0, 124.7, 127.2,
128.4, 128.5, 128.7, 128.8, 129.2, 129.5, 129.8, 132.9, 135.2,
137.2, 154.1, 169.9. MS m/z: 554 (M+), 445, 356, 91 (bp). Anal.
Calcd for C36H26O6: C, 77.96; H, 4.73. Found: C, 78.10; H,
4.90. Absolute configuration of 2h was determined after
conversion of 2h ([R]21 -76.7 (c 1.0, THF)) into 2e ([R]21
D
D
-123.5 (c 1.1, THF)) by hydrogenolysis (H2/Pd-C) followed by
esterification with diazomethane.
3,3′-Diben zyloxy-1,1′-bin aph th alen e-2,2′-diol (2m ). [R]24
:
.
D
-8.2 (c 0.8, THF) for 24% ee. IR (CHCl3): 3528, 1458 cm-1
Di-ter t-bu tyl 2,2′-Dih yd r oxy-1,1′-bin a p h th a len e-3,3′-d i-
1H NMR (CDCl3): δ 5.32 (s, 4H), 5.98 (s, 2H), 7.16 (d, J ) 3.7
Hz, 4H), 7.26-7.52 (m, 14H), 7.75 (d, J ) 8.0 Hz, 2H). 13C
NMR (CDCl3): δ 71.1, 107.6, 114.8, 124.0, 124.6, 124.8, 126.9,
127.9, 128.4, 128.8, 129.0, 129.2, 136.0, 143.8, 146.4. MS m/z:
498 (M+), 407, 91 (bp). HRMS: calcd for C34H26O4 498.1831,
found 498.1856. Anal. Calcd for C34H26O4: C, 81.91; H, 5.26.
Found: C, 81.81; H, 5.33. Enantiomeric excess and absolute
configuration were determined after conversion (H2, Pd-C)
ca r boxyla te (2i). [R]25
: -79.6 (c 1.0, THF) for 58% ee.
D
HPLC: Daicel Chiralpak AD, hexane-isopropyl alcohol 9:1,
1 mL/min, 9.9 (R) and 12.0 (S) min. IR (CHCl3): 3221, 1682
1
cm-1. H NMR (CDCl3): δ 1.69 (s, 18H), 7.14 (dd, J ) 6.3, 3.4
Hz, 2H), 7.29-7.35 (m, 4H), 7.91 (dd, J ) 6.2, 3.2 Hz, 2H),
8.59 (s, 2H), 11.0 (s, 2H). 13C NMR (CDCl3): δ 52.7, 114.2,
117.0, 124.0, 124.7, 127.2, 129.5, 129.8, 132.9, 137.2, 154.0,
170.6. MS m/z: 486 (M+), 430, 374 (bp). Anal. Calcd for
C30H30O6: C, 74.06; H, 6.21. Found: C, 73.81; H, 6.55. Absolute
into 1,1′-binaphthalene-2,2′,3,3′-tetrol: [R]23 -8.2 (c 0.29,
D
configuration of 2i was determined after conversion of 2i ([R]26
THF) for 24% ee. HPLC: Daicel Chiralpak AD, EtOH, 1 mL/
min, 3.8 (S) and 4.4 (R) min.
D
-79.6 (c 1.0, THF)) into 2e ([R]26 -100 (c 1.0, THF)) by
D
P r ep a r a tion of Hom och ir a l Bin a p h th ol (2a ) fr om
Meth yl 3-Hyd r oxy-2-n a p h th oa te (1e) a s a Sta r tin g Ma te-
r ia l. To a solution of 1e (0.75 g, 3.7 mmol) in dichloromethane
(30 mL) was added chiral catalyst (0.16 g, 0.37 mmol) prepared
from 15, and the reaction mixture was stirred at room
temperature under oxygen atmosphere for 24 h. The mixture
was concentrated and then triturated in MeOH (10 mL). The
resulting precipitate was collected by filtration to afford 2e
successive treatment with trifluoroacetic acid and diaz-
omethane.
3,3′-Diacetyl-1,1′-bin aph th alen e-2,2′-diol (2j). [R]21D: -78.8
(c 1.0, THF) for 37% ee. HPLC: Daicel Chiralpak AD, hexane-
isopropyl alcohol 9:1, 1 mL/min, 13.8 (S) and 30.5 (R) min. IR
1
(CHCl3): 3532, 1647 cm-1. H NMR (CDCl3): δ 2.87 (s, 6H),
7.13-7.17(m, 2H), 7.32-7.39 (m, 4H), 7.92-7.96 (m, 2H), 8.55
(s, 2H), 11.87 (s, 2H). 13C NMR (CDCl3): δ 27.0, 117.3, 121.1,
124.1, 124.6, 127.0, 129.9, 130.0, 134.0, 137.5, 154.8, 204.9.
MS m/z: 370 (M+, bp), 352, 337. HRMS: calcd for C24H18O4
370.1206, found 370.1190. Anal. Calcd for C24H18O4: C, 77.83;
H, 4.90. Found: C, 77.71; H, 5.10. The absolute configuration
of 2j was determined after conversion of (R)-2,2′-dihydroxy-
1,1′-binaphthalene-3,3′-dicarboxylic acid18a into 2j ([R]21D +212.8
(c 1.01, THF)) by methyllithium with trimethylsilyl chloride
in THF.19a
N,N′-Diben zyl-2,2′-d ih yd r oxy-1,1′-bin a p h th a len e-3,3′-
d ica r boxa m id e (2k ). [R]26D: -27.1 (c 0.61, THF) for 24% ee.
1H NMR (CD3COCD3): δ 4.72 (d, J ) 5.8 Hz, 4H), 7.07-7.12
(m, 2H), 7.24-7.47 (m, 12H), 7.84-7.89 (m, 2H), 8.67 (s, 2H),
9.07 (bs, 2H), 12.40 (s, 2H). 13C NMR (CD3COCD3): δ 43.9,
117.7, 124.2, 125.3, 127.8, 128.0, 128.6, 129.1, 129.3, 130.1,
139.6. MS m/z: 552 (M+), 461, 446, 91 (bp). Anal. Calcd for
([R]23 -125.0 (c 1.0, THF), 78% ee) as pale yellow needles.
D
Trituration of 2e in EtOAc (10 mL) followed by filtration
afforded the filtrate containing 0.50 g of 2e ([R]28 -162.0 (c
D
1.1, THF) of >99% ee.
To a solution of optically pure 2e (0.50 g, 1.2 mmol) in DMF
(7 mL) was added sodium hydride (60% in oil, 0.11 g, 2.8 mmol)
followed by iodomethane (0.2 mL, 3.2 mmol) at 0 °C, and the
mixture was stirred at room temperature for 2 h. The reaction
was quenched with saturated NH4Cl, and the mixture was
extracted with EtOAc. Drying over Na2SO4 and evaporation
of solvent afforded dimethyl 2,2′-dimethoxy-1,1′-binaphtha-
lene-3,3′-dicarboxylate as a viscous oil, which was hydrolyzed
with KOH (0.40 g) in 10% EtOH (5 mL) at 80 °C for 1 h.
Acidification with HCl followed by extraction with EtOAc gave
the diacid, which was decarboxylated with Cu-bronze (0.20 g)
and CuCO3 (0.15 g) in quinoline (8 mL) at 180 °C for 30 min.
After cooling, the mixture was diluted with benzene and
filtered through a Celite pad. The filtrate was washed with
brine, and the organic phase was evaporated to afford the
diether, which was purified with silica gel column chromatog-
raphy (hexanes-EtOAc 10:1) to afford 2,2′-dimethoxy-1,1′-
binaphthalene (0.33 g, 85% from 2e) as colorless needles of
mp 227-229 °C. BBr3 (0.2 mL, 2.1 mmol) was added to a
solution of above diether in CH2Cl2 (3 mL) at -78 °C, and the
mixture was stirred at room temperature for 30 min. The
reaction was quenched with ice water and the mixture was
extracted with EtOAc. Evaporation of solvent followed by
recrystallization from benzene afforded 2a (0.25 g, 82%) as
colorless needles. Mp: 205-206 °C. [R]24D: -36.0 (c 1.0 THF)
C
36H28N2O4: C, 78.24; H, 5.11; N, 5.07. Found: C, 78.41; H,
5.03; N, 4.90. The enantiomeric excess was determined after
conversion of 2k into the corresponding diacetate. 1H NMR
(CDCl3): δ 1.56 (s, 6H), 4.62 (ddd, J ) 20.6, 14.6, 5.8 Hz, 4H),
6.57 (t, J ) 5.6 Hz, 2H), 7.12 (d, J ) 8.5 Hz, 2H), 7.24-7.36
(m, 12H), 7.50 (t, J ) 7.6 Hz, 2H), 7.96 (d, J ) 8.1 Hz, 2H),
8.38 (s, 2H). HPLC: Daicel Chiralpak OD, EtOH, 1 mL/min,
3.8 (S) min. and 4.6 (R) min. The absolute configuration of 2k
was determined after conversion of optically pure (R)-2,2′-
dihydroxy-1,1′-binaphthalene-3,3′-dicarboxylic acid18a into 2k
([R]25 +111.6 (c 0.78, THF)) by amide formation with benzy-
D
lamine and thionyl chloride.
1,1′-Bin a p h th a len e-2,2′-d iol (2a ). [R]29
: -20.1 (c 1.0,
D
THF) for 17% ee. (lit.18b [R]20 -35.5 (c 1.0, THF) for (S)-2a .)
D
(lit.18b [R]24 -35.5 (c 1.0 THF)), >99% by HPLC.
HPLC: Daicel Chiralpak OJ , hexane-isopropyl alcohol 9:1, 1
mL/min, 34 (S) and 49 (R) min.
D
Ack n ow led gm en t. This work was partly supported
by a Grant-in-Aid for Scientific Research from the
Ministry of Education, Science and Culture of J apan
and the Sasakawa Scientific Research Grant from the
J apan Science Society.
Su p p or t in g In for m a t ion Ava ila b le: 1H and 13C NMR
spectra of chiral amines 10-17. This material is available free
of charge via the Internet at http://pubs.acs.org.
3,3′-Dim eth yl-1,1′-bin a p h th a len e-2,2′-d iol (2b). [R]25
:
578
-3.1 (c 1.0, CHCl3) for 12% ee. (lit.18a [R]25 +37.3 (c 1.0,
578
CHCl3) for (R)-2b.) HPLC: Daicel Chiralpak AD, hexane-
isopropyl alcohol 9:1, 1 mL/min, 6.7 (S) and 8.8 (R) min.
7,7′-Dim eth oxy-1,1′-bin a p h th a len e-2,2′-d iol (2d ). [R]25
:
D
+12.1 (c 1.0, MeOH) for 16% ee. (lit.18c [R]21 -126.4 (c 1.0,
D
(19) (a) Rubottom, G. M.; Kim, C. J . Org. Chem. 1983, 48, 1550-
1552. (b) Otera, J .; Yano, T.; Kawabata, A.; Nozaki, H. Tetrahedron
Lett. 1986, 27, 2383-2386.
J O981808T