Highly efficient synthesis of optically pure 5,5′,6,6′,7, 7′,8,8′-octahydro-1,1′-bi-2-naphthol and -naphthylamine derivatives by partial hydrogenation of 1,1′-binaphthyls with carbon nanofiber supported ruthenium nanoparticles

Article abstract of DOI:10.1021/jo702015j

(Chemical Equation Presented) Use of Ru/CNF-P, nanoruthenium particles dispersed on a nanocarbon fiber support, realizes highly efficient catalytic partial hydrogenation of 1,1′-bi-2-naphthol and -naphthylamine derivatives. The reactions proceed in high turnover numbers without racemization of the axial chirality, offering a practical procedure for the production of optically pure 5,5′,6,6′,7,7′,8,8′-octahydro-1,1′- binaphthyls in good to high yields.

Full text of DOI:10.1021/jo702015j

oxy derivative (BINOL-Piv) are efficient chiral auxiliaries or
precursors for the synthesis of non-C2-symmetric 1,1′-binaph-
thyls.4 Chemical modification of naphthyl units in these chiral
binaphthyls sometimes enhances the properties as chiral lig-
ands.2,3 In particular, 5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaph-
thyls (H8-binaphthyls, II) have recently received considerable
attention from organic chemists; they are more soluble and better
electron-donors than the corresponding binaphthyls.5
Highly Efficient Synthesis of Optically Pure
5,5′,6,6′,7,7′,8,8′-Octahydro-1,1′-bi-2-naphthol and
-naphthylamine Derivatives by Partial
Hydrogenation of 1,1′-Binaphthyls with Carbon
Nanofiber Supported Ruthenium Nanoparticles
Mikihiro Takasaki, Yukihiro Motoyama,* Seong-Ho Yoon,
Isao Mochida, and Hideo Nagashima
Graduate School of Engineering Sciences, Institute for Materials
Chemistry and Engineering, Kyushu UniVersity, Kasuga,
Fukuoka 816-8580, Japan
motoyama@cm.kyushu-u.ac.jp
ReceiVed September 13, 2007
In the complexes containing a ligated metal center at the 2,2′-
positions, the H8-binaphthyls show larger bite angles than the
binaphthyls.6f,g These properties sometimes provide higher
asymmetric induction than the parent 1,1′-binaphthyls.5,6 As
typical examples, H8-binaphthyls are effective for alkylation of
aldehydes,6a,b hetero-Diels-Alder reaction of Danishefsky’s
diene,6c,d and hydrogenation of alkenes.6e-g Despite their
potential as better chiral auxiliaries, synthetic procedures for
H8-binaphthyls are problematic. Although partial hydrogenation
of 1,1′-binaphthyls with transition metal catalysts is a simple
method for the synthesis of H8-binaphthyls, the catalysts reported
in literature showed poor activity and sometimes formation of
an intermediary 5,6,7,8-tetrahydro-1,1′-binaphthyl (H4-binaph-
thyls) as a byproduct.2a,7 Moreover, the reactions were often
accompanied by racemization of the axial chirality.8 For
example, catalytic hydrogenation of BINOL to H8-BINOL over
Raney-Ni/Al alloy, Ru/C,7d or Pd/C7a,d requires a high substrate/
Use of Ru/CNF-P, nanoruthenium particles dispersed on a
nanocarbon fiber support, realizes highly efficient catalytic
partial hydrogenation of 1,1′-bi-2-naphthol and -naphthyl-
amine derivatives. The reactions proceed in high turnover
numbers without racemization of the axial chirality, offering
a practical procedure for the production of optically pure
5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyls in good to high
yields.
(4) (a) Maruoka, K.; Saito, S.; Yamamoto, H. J. Am. Chem. Soc. 1995,
117, 1165. (b) Ishihara, K.; Nakamura, S.; Kaneeda, M.; Yamamoto, H. J.
Am. Chem. Soc. 1996, 118, 12854. (c) Taniguchi, T.; Ogasawara, K.
Tetrahedron Lett. 1997, 38, 6429. (d) Yamada, Y. M. A.; Shibasaki, M.
Tetrahedron Lett. 1998, 39, 5561. (e) Hocke, H.; Uozumi, Y. Tetrahedron
2003, 59, 619.
Optically pure 1,1′-binaphthyls with C2-symmetry such as
1,1′-bi-2-naphthol(BINOL),2,2′-diamino-1,1′-binaphthyl(DABN),
2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP), and their
derivatives (I) have been widely used as chiral ligands for
catalytic asymmetric syntheses.1-3 It is also recognized that
monoprotected BINOL derivatives such as 2-hydroxy-2′-meth-
oxy-1,1′-binaphthyl (BINOL-Me) and 2-hydroxy-2′-(pivaloyl)-
(5) Review: Au-Yeung, T. T.-L.; Chan, S.-S.; Chan, A. S. C. AdV. Synth.
Catal. 2003, 345, 537 and references therein.
(6) Representative papers. H8-BINOL derivatives: (a) Chan, A. S. C.;
Zhang, F.-Y.; Yip, C.-W. J. Am. Chem. Soc. 1997, 119, 4080. (b) Lu, G.;
Li, X.; Chan, W. L.; Chan, A. S. C. Chem. Commun. 2002, 172. (c) Long,
J.; Hu, J.; Shen, X.; Ji, B.; Ding, K. J. Am. Chem. Soc. 2002, 124, 10. (d)
Wang, B.; Feng, X.; Huang, Y.; Liu, H.; Cui, X.; Jiang, Y. J. Org. Chem.
2002, 67, 2175. H8-DABN derivatives: (e) Zhang, F.-Y.; Pai, C.-C.; Chan,
A. S. C. J. Am. Chem. Soc. 1998, 120, 5808. H8-BINAP derivatives: (f)
Zhang, X.; Matsumura, K.; Koyano, K.; Sayo, N.; Kumobayashi, H.;
Akutagawa, S.; Takaya, H. J. Chem. Soc., Perkin Trans. 1 1994, 2309. (g)
Uemura, T.; Zhang, X.; Matsumura, K.; Sayo, N.; Kumobayashi, H.; Ohta,
T.; Nozaki, K.; Takaya, H. J. Org. Chem. 1996, 61, 5510. (h) Xiao, J.;
Nefkens, S. C. A.; Jessop, P. G.; Ikariya, T.; Noyori, R. Tetrahedron Lett.
1996, 37, 2813.
(7) Representative papers: (a) Zhang, X.; Mashima, K.; Koyano, K.;
Sayo, N.; Kumobayashi, H.; Akutagawa, S.; Takaya, H. Tetrahedron Lett.
1991, 32, 7283. (b) Guo, H.; Ding, K. Tetrahedron Lett. 2000, 41, 10061.
(c) Shen, X.; Guo, H.; Ding, K. Tetrahedron: Asymmetry 2000, 11, 4321.
(d) Korostylev, A.; Tararov, V. I.; Fischer, C.; Monsees, A.; Bo¨rner, A. J.
Org. Chem. 2004, 69, 3220.
* Corresponding author. Tel. & Fax: +81-92-583-7821.
(1) Reviews: (a) Rosini, C.; Franzini, L.; Raffaelli, A.; Salvadori, P.
Synthesis 1992, 503. (b) Pu, L. Chem. ReV. 1998, 98, 2405. (c) McCarthy,
M.; Guiry, P. J. Tetrahedron 2001, 57, 3809. (d) Catalytic Asymmetric
Synthesis, 2nd ed.; Ojima, I., Ed.; Wiley-VCH: Weinheim, Germany, 2000,
and references therein.
(2) 2,2′-Dimethoxy- and 2,2′-di(methoxymethy)oxy-1,1′-binaphthyl are
well known as precursors for the 3,3′-disubstituted BINOL derivatives. (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. G.; Sogah, D. Y. J. Org. Chem. 1978, 43, 1930. (b) Lingenfelter, D.
S.; Helgeson, R. C.; Cram, D. J. J. Org. Chem. 1981, 46, 393. (c) Maruoka,
K.; Itoh, T.; Araki, Y.; Shirasaka, T.; Yamamoto, H. Bull. Chem. Soc. Jpn.
1988, 61, 2975. (d) Simonsen, K. B.; Gothelf, K. V.; Jørgensen, K. A. J.
Org. Chem. 1998, 63, 7536. (e) Cox, P. J.; Wang, W.; Snieckus, V.
Tetrahedron Lett. 1992, 33, 2253.
(3) 6,6′-Disubstituted BINOL derivatives: (a) Mikami, K.; Motoyama,
Y.; Terada, M. Inorg. Chim. Acta 1994, 222, 71. (b) Sasai, H.; Tokunaga,
T.; Watanabe, S.; Suzuki, T.; Itoh, N.; Shibasaki, M. J. Org. Chem. 1995,
60, 7388. (c) Ueno, M.; Ishitani, H.; Kobayashi, S. Org. Lett. 2002, 4, 3395.
(d) Saruhashi, K.; Kobayashi, S. J. Am. Chem. Soc. 2006, 128, 11232.
(8) Both BINOL and H8-BINOL lose their optical rotations by heating
in alcohols over 100 °C (∼2%), and such partial racemization accelerates
under acidic or basic conditions (∼56%). Encyclopedia of Reagents for
Organic Synthesis; Paquette, L. A., Ed.; John Wiley & Sons: New York,
1995; Vol. 1, p 397. Also see ref 2a.
10.1021/jo702015j CCC: $37.00 © 2007 American Chemical Society
Published on Web 11/29/2007
J. Org. Chem. 2007, 72, 10291-10293
10291

TABLE 1. Hydrogenation of (R)-BINOL 1a, BINOL-derived (R)-1a-e, and (R)-DABN 1fa
yield (%)
ee (%)
yield (%)
entry
substrate
catalyst
S/C
conditions
of 2b
of 2c
of 3b
1
2
3
BINOL (1a)
BINOL (1a)
BINOL (1a)
BINOL (1a)
BINOL (1a)
BINOL (1a)
BINOL-Me2 (1b)
BINOL-Me2 (1b)
BINOL-MOM2 (1c)
BINOL-Me (1d)
BINOL-Piv (1e)
DABN (1f)
Ru/CNF-P
Ru/CNF-P
Ru/Cd
300
300
100
100
300
1390
300
300
300
300
300
150
70 °C, 3 h
92
>95
7-19
>99.9
>99.9
>99.9
>99.9
>99.9
>99.9
-
7
70 °C, 5.5 h
70 °C, 5.5 h
70 °C, 5.5 h
50 °C, 7 h
50 °C, 48 h
70 °C, 5.5 h
100 °C, 5.5 h
50 °C, 7 h
not detected
41-57
41-62
4
Ru/Ce
11-21
>95 (95)
>95 (99)
37
>95 (95)
>95 (98)
>95 (96)
>95 (92)
83 (80)
5
Ru/CNF-P
Ru/CNF-P
Ru/CNF-P
Ru/CNF-P
Ru/CNF-P
Ru/CNF-P
Ru/CNF-P
Ru/CNF-P
not detected
not detected
37
not detected
not detected
not detected
not detected
i
6f
7
8
9
10
11
12h
>99.9g
>99.9
>99.9
>99.9
>99.9
50 °C, 7 h
50 °C, 7 h
100 °C, 24 h
a All reactions were carried out with 0.5 mmol of (R)-1, 10 mg of Ru/CNF-P (1.7 wt % Ru) in 10 mL of EtOH under H2 (initial pressure ) 40 atm).
1
b Determined by H NMR analysis. The yield in parentheses was the isolated yield. c Determined by HPLC analysis of the crude product. d Ru/C (5 wt %)
was used. e Ru/C (5 wt %, dry type) was used. f One gram of 1a and 15 mg of catalyst were used. g Determined by HPLC of 2a after demethylation of 2b
with TMSI. h 1f (0.25 mmol) was used. i Some unidentified compounds were formed as byproducts.
catalyst mole ratio of S/C < 14.9 The reaction of methoxy-
methyl-protected BINOL (BINOL-MOM2) with Raney-Ni/Al
alloy afforded H4-BINOL-MOM2 selectively.7c Higher temper-
ature and/or addition of acids or bases accelerate the reaction,
but racemization of the axial chirality is commonly observed.2a,7b,d
In spite of a lengthy reaction time (rt for a week) and large
amounts of the catalyst (S/C < 7), therefore, Cram’s hydrogena-
in 92 and 7% yield, respectively (entry 1). Prolonged reaction
time to 5.5 h resulted in formation of 2a as a single product in
quantitative yield with >99.9% ee (entry 2). The catalytic
efficiency of the Ru/CNF-P was much higher than that of two
commercially available Ru/C catalysts as shown in entries 3
and 4; even with the S/C ratio of 100, conversion of 1a was
lower than 80% and a major product was H4-BINOL 3a (2a/3a
) 1:6-1:2) after 5.5 h. The Ru/CNF-P-catalyzed reaction can
also be performed at 50 °C, and the optically pure 2a was
obtained as a single product in 95% isolated yield after 7 h
(entry 5). Ru/CNF-P does not have a reproducibility problem
of heterogeneous catalysis; the desired 2a was obtained in
quantitative yields over five experiments under the conditions
shown in entry 2. This is in sharp contrast to the results using
commercially available Ru/C catalysts, in which conversion of
1a was varied from 48 to 77% in three independent experiments
under the conditions shown in entries 3 and 4. Application of
the hydrogenation using a minimum amount of the Ru/CNF-P
catalyst to a gram-scale production of 2a was successful; the
hydrogenation of 1a (1.00 g, 3.5 mmol) using 15 mg of
Ru/CNF-P (255 µg of Ru) at 50 °C for 48 h afforded the
optically pure 2a in 99% isolated yield (1.02 g). The turnover
number of this reaction was calculated to be 1390 (entry 6).
The Ru/CNF-P catalyst is also useful for production of
derivatives of BINOL and DABN as shown in entries 7-12.
In all cases, the partial hydrogenation proceeds at 50-100 °C
to afford the corresponding H8 product in almost quantitative
yield without loss of optical purity. The BINOL-derived 1c-e
were completely converted to the corresponding H8 derivatives
at 50 °C for 7 h, and optically pure 2c-e were obtained in
92-98% isolated yields (entries 9-11). In the reaction of 1e,
the reduction of ester function was not observed under these
conditions. It is noteworthy that the present procedure is useful
2a
tion procedure using PtO2 is widely used for the production
of optically pure H8-binaphthyls.10 Thus, a hydrogenation
catalyst, which can apply a variety of binaphthyl derivatives
with high efficiency and no loss of optical purity, is a target to
be developed. We have recently synthesized carbon nanofiber
supported ruthenium nanoparticles (Ru/CNF-P) by pyrolysis of
Ru3(CO)12 in the presence of platelet-type CNF (CNF-P) and
found that they show high catalytic performance for the arene
hydrogenation.11,12 Here, we report use of Ru/CNF-P as a
practical solution for problematic production of H8-binaphthyls
by catalytic partial hydrogenation of 1,1′-binaphthyls.
Hydrogenation of BINOL (1a) was carried out in a 100 mL
autoclave with 1 (0.5 mmol) and Ru/CNF-P (1.7 wt % Ru; 0.34
mol % of metal loadings; S/C ) 300) in ethanol under hydrogen
(initial pressure: PH2 ) 40 atm) (Table 1).13 At 70 °C, (R)-
BINOL 1a (>99.9% ee) was completely consumed in 3 h. At
this stage, H8-BINOL 2a and H4-BINOL 3a were both formed
(9) The Pd/C-catalyzed reaction of (R)-BINOL can be performed at S/C
) 100, but severe reaction conditions (100 °C, 80 atm) are required to
obtain H8-BINOL (99.7% ee) in high yields; see ref 7d.
(10) Optically pure H8-BINAP is generally obtained by optical resolution
of racemic H8-bis(diphenylphosphinyl)-1,1′-binaphthyl (H8-BINAPO), which
is prepared from (()-BINOL, followed by reduction with trichlorosilane;
see ref 7a.
(11) Motoyama, Y.; Takasaki, M.; Higashi, K.; Yoon, S.-H.; Mochida,
I.; Nagashima, H. Chem. Lett. 2006, 35, 876.
(12) The CNFs are classified into three types: graphite layers are
perpendicular (platelet: CNF-P), parallel (tubular: CNF-T), and stacked
obliquely (herringbone: CNF-H). These three CNFs can be synthesized
selectively in large scales; see: (a) Rodriguez, N. M. J. Mater. Res. 1993,
8, 3233. (b) Tanaka, A.; Yoon, S.-H.; Mochida, I. Carbon 2004, 42, 591
and 1291.
(13) The solvent strongly affected the reaction rate; the hydrogenations
of BINOL in THF and dichloroethane were both sluggish, and the
H8-BINOL was obtained in <10% yields along with the formation of
H4-BINOL in ca. 20 and 50% yields, respectively.
10292 J. Org. Chem., Vol. 72, No. 26, 2007

temperature, the insoluble Ru/CNF-P was removed by filtration,
and the filtrate was concentrated under reduced pressure. The optical
purity of the produced H8-1,1′-binaphthyls 2a-e was determined
by chiral HPLC analysis.17
for the production of oily binaphthyls, in which optical purity
of the partially racemized product cannot be improved by
recrystallization. Optically pure H8-BINOL-MOM2 2c is a
typical compound of such oily binaphthyls, which can be
effectively synthesized by the Ru/CNF-P-catalyzed hydrogena-
tion in high yield (entry 9). Poor solubility of the dimethylether
1b to ethanol retarded the reaction.14 The conversion of 1b was
74% at 70 °C for 5.5 h, and only 37% of H8-BINOL-Me2 2b
was obtained along with the formation of H4-BINOL-Me2 3b
(37% yield, entry 7). Preparation of optically pure 2b in 95%
isolated yield was accomplished by the reaction at 100 °C; no
byproduct was observed (entry 8).
The solubility problem was also observed in the reaction of
2,2′-diamino-1,1′-binaphthyl 1f.14 DABN is less soluble in
ethanol than BINOL-Me2 1b, and the hydrogenation reaction
is quite sluggish under the conditions of [1f] ) 50 mM in
EtOH: S/C ) 300; below 70 °C.15 When the reaction was
carried out with a lower concentration of 1f ([1f] ) 25 mM)
and higher catalyst loading (S/C ) 150) at 100 °C, (R)-DABN
1f was successfully hydrogenated in ethanol to give 2f in 80%
isolated yield with over 99.9% ee (entry 12). Preparation of
H8-BINAP by hydrogenation of BINAP is a problem and has
not yet been achieved with conventional catalysts. We also
attempted the hydrogenation of BINAP in several organic
solvents (S/C ) 150); however, no reaction took place even at
120 °C for 48 h; BINAP was recovered quantitatively after the
reaction.
Utility of the Ru/CNF catalyst in the production of H8-binaph-
thyls is enhanced by its reusability. After the reaction of (R)-
BINOL-MOM2 1c ([1c] ) 50 mM in EtOH, S/C ) 300) was
performed at 70 °C, the catalyst was recovered by filtration and
subjected to a further run of hydrogenation. H8-BINOL-MOM2
2c was obtained in almost quantitative yields for the repeated
uses of the catalyst (first; >99%, second; >99%, third; 96%)
without loss of optical purity (>99.9% ee in all cases).
In summary, the results shown in this paper clearly demon-
strate that the Ru/CNF-P-catalyzed hydrogenation of binaphthyls
is useful for practical synthesis of optically pure H8-BINOL
derivatives and H8-DABN. Although hydrogenation of BINAP
has not yet been achieved, the desired H8-BINAP is easily
synthesized from H8-DABN.16
(R)-2,2′-Di[(methoxymethyl)oxy]-5,5′,6,6′,7,7′,8,8′-octahydro-
1,1′-binaphthyl (H8-BINOL-MOM2) (2c): Purification by silica
gel chromatography (hexane/CH2Cl2 ) 1:1); yield 98% (colorless
oil); [R]28D +48.9 (c 1.00, CHCl3; >99.9% ee, R); IR (neat) ν 2931,
2846, 1593, 1475, 1237, 1151, 1023, 923, 803 cm-1; 1H NMR (396
MHz, CDCl3) δ 1.60-1.78 (m, 8H), 2.10 (dt, J ) 17.4, 6.3 Hz,
2H), 2.30 (dt, J ) 17.4, 6.5 Hz, 2H), 2.77 (t, J ) 6.0 Hz, 4H), 3.28
(s, 6H), 4.96 (d, J ) 6.8 Hz, 2H), 5.02 (d, J ) 6.8 Hz, 2H), 6.98
(d, J ) 8.7 Hz, 2H), 7.04 (d, J ) 8.7 Hz, 2H); 13C NMR (99.5
MHz, CDCl3) δ 23.2, 23.3, 27.4, 29.5, 55.7, 94.8, 112.8, 127.2,
128.9, 131.0, 136.9, 152.2; HPLC (hexane/i-PrOH ) 500:1), tR )
15.4 min (S), 16.8 min (R); HRMS (EI) calcd for C24H30O4
382.2144, found 382.2144.
(R)-2-Hydroxy-2′-(pivaloyl)oxy-5,5′,6,6′,7,7′,8,8′-octahydro-
1,1′-binaphthyl (H8-BINOL-Piv) (2e): Purification by silica gel
chromatography (hexane/CH2Cl2 ) 1:1); yield 92% (colorless
solid); mp 107-108 °C; [R]26D +62.6 (c 1.00, CHCl3; >99.9% ee,
R); IR (neat) ν 3479, 2930, 2846, 1749, 1591, 1479, 1227, 1135,
809 cm-1; 1H NMR (396 MHz, CDCl3) δ 0.95 (s, 9H), 1.59-1.81
(m, 8H), 2.02 (dt, J ) 17.4, 5.3 Hz, 1H), 2.14 (dt, J ) 17.4, 6.0
Hz, 1H), 2.32 (dt, J ) 17.4, 6.3 Hz, 1H), 2.42 (dt, J ) 17.4, 6.3
Hz, 1H), 2.63-2.77 (m, 2H), 2.77-2.88 (m, 2H), 4.73 (br s, 1H),
6.76 (d, J ) 8.2 Hz, 1H), 6.87 (d, J ) 8.2 Hz, 1H), 6.96 (d, J )
8.2 Hz, 1H), 7.16 (d, J ) 8.2 Hz, 1H); 13C NMR (99.5 MHz,
CDCl3) δ 22.7, 22.9, 23.2, 23.3, 26.7, 26.9, 27.3, 29.3, 29.7, 38.7,
114.1, 119.3, 122.5, 128.1, 129.4, 129.8, 130.2, 135.85, 135.92,
138.3, 147.2, 150.8, 178.2; HPLC (hexane/i-PrOH ) 500:1), tR )
20.8 min (R), 23.0 min (S); HRMS (EI) calcd for C25H30O3
378.2195, found 378.2194.
(R)-2,2′-Diamino-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphth-
yl (H8-DABN) (2f). Hydrogenation was carried out with (R)-1f
(0.25 mmol) and Ru/CNF-P (S/C ) 150) in EtOH (10 mL) at 100
°C for 24 h under H2 (initial pressure ) 40 atm). Purification by
silica gel chromatography (acetone) gave (R)-H8-DABN 2f in 80%
yield (colorless solid): [R]28 +70.8 (c 0.50, CHCl3; >99.9% ee,
D
R); 1H NMR (396 MHz, CDCl3) δ 1.61-1.76 (m, 8H), 2.17 (dt, J
) 17.4, 6.5 Hz, 2H), 2.28 (dt, J ) 17.4, 6.0 Hz, 2H), 2.71 (t, J )
6.0 Hz, 4H), 3.31 (br s, 4H), 6.62 (d, J ) 8.2 Ht, 2H), 6.92 (d, J
) 8.2 Hz, 2H); 13C NMR (99.5 MHz, CDCl3) δ 23.3, 23.5, 27.1,
29.5, 113.2, 122.1, 127.7, 129.3, 136.3, 141.7; HPLC (CHIRALCEL
OD-H, hexane/i-PrOH ) 20:1), tR ) 24.7 min (R), 28.0 min (S).
This compound was identified by spectral comparison with literature
data.6e
Experimental Section
General Procedure for the Partial Hydrogenation of (R)-1,1′-
Binaphthyls 1a-e. Hydrogenation of (R)-1,1′-binaphthyls 1a-e
(>99.9% ee) was performed in a 100 mL stainless autoclave fitted
with a glass inner tube, in the presence of (R)-1,1′-binaphthyls 1a-e
(0.5 mmol), EtOH (10 mL), and Ru/CNF-P (1.7 wt % Ru, 10
mg; S/C ) 300) at 50-100 °C for 5.5-7 h under H2 (initial pressure
) 40 atm). After the reaction mixture was cooled to ambient
Acknowledgment. This work was partially supported by the
CREST-JST (Japan Science and Technology Corporation) and
by a Grant-in Aid for Scientific Research from the Ministry of
Education, Culture, Sports, Science and Technology, Japan.
Supporting Information Available: Spectroscopic data of 1b-
e, 2a, 2b, and 2d, copies of NMR spectra of 1a-f (1H NMR) and
2a-f (1H and 13C NMR). This material is available free of charge
via the Internet at http://pubs.acs.org.
(14) In the Pd/C-catalyzed reactions, similar results and explanations were
reported; see ref 7d.
(15) DABN 1f is easily soluble in THF, but the hydrogenation of 1f
with Ru/CNF-P in THF at 100 °C did not proceed.
JO702015J
(16) Murdoch reported that chiral BINAP could be synthesized from
optically pure DABN. Brown, K. J.; Berry, M. S.; Waterman, K. C.;
Lingenfelter, D.; Murdoch, J. R. J. Am. Chem. Soc. 1984, 106, 4717.
(17) HPLC analysis was performed on an UV/vis detector (254 nm) using
Daicel CHIRALCEL OD-H (flow rate ) 0.5 mL/min).
J. Org. Chem, Vol. 72, No. 26, 2007 10293