Synthesis of C3 Symmetric, Optically Active Triamidoamine and Protetraazaphosphatrane

Full text of DOI:10.1021/jo9804689

5692
J . Org. Chem. 1998, 63, 5692-5695
Sch em e 1
Syn th esis of C3 Sym m etr ic, Op tica lly Active
Tr ia m id oa m in e a n d
P r otetr a a za p h osp h a tr a n e
Kazuaki Ishihara,† Yoshinori Karumi,‡
Shoichi Kondo,‡ and Hisashi Yamamoto*,‡
Research Center for Advanced and Waste Emission
Management (ResCWE), Nagoya University, Chikusa,
Nagoya 464-8603, J apan, and School of Engineering,
Nagoya University, CREST, J apan Science and Technology
Corporation (J ST), Chikusa, Nagoya 464-8603, J apan
Received March 11, 1998
Triamidoamine ligands [(RNCH2CH2)3N]3- can bind to
a variety of transition metals and phosphorus in oxida-
tion states 3+ or higher in a tetradentate manner like
1.1,2 Because of an interest in the C3 symmetric structure
of 1, a number of novel transition tetraazametallatranes
have been synthesized along with the study of their
structural chemistry and chemical and redox reactivity.1,3
Verkade and co-workers, pioneers of phosphatrane chem-
istry, have demonstrated that the bicyclic protetraaza-
phosphatrane 2 is a remarkably strong base, reacting
with a proton to give the stable tetraazaphosphatrane
3.2,4 Cation 3 features a transannular PrN covalent
bond that forms via inversion of the bridgehead nitrogen.
Unusual basicity and reactivity of 2 can be explained by
the delocalization of the bridgehead nitrogen lone pair
into the three-center, four-electron bond systems along
the molecular axes. Very recently, further important
findings by the same group have shown that 2 is a
nonionic superbase catalyst for the conversion of isocy-
anates to isocyanurates,4b acylation,4d and silylation of
hindered alcohols,4f,h and dehydrohalogenation.4g This
has stimulated interest in the asymmetric version of their
reactions. Here, we report the first synthesis of chiral
C3 symmetric, optically active triamidoamine 4 and
protetraazaphosphatrane 5.
used as a chiral amine fragment. The route to chiral
triamidoamine 4 based on (S)-proline is shown in Scheme
1. In the first step, (S)-N-benzyl-2-aminomethylpyrroli-
dine (6)5 and N-benzyl-(S)-proline (7)6 were condensed
using 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide
hydrochloride (EDC) and N-hydroxybenzotriazole (HOBt)
in the presence of triethylamine in anhydrous dichloro-
methane to give (S,S)-amide 8 in 86% yield. Subsequent
reduction by lithium aluminum hydride gave (S,S)-bis-
(N′-benzyl-2-pyrrolidinylmethyl)amine (9) in 90% yield.
The next step, introduction of the third proline fragment,
was conducted in a similar manner. Thus, tris(N′-benzyl-
(3) For some leading articles on transition tetraazametallatranes,
see: (a) Cummins, C. C.; Lee, J .; Schrock, R. R.; Davis, W. D. Angew.
Chem., Int. Ed. Engl. 1992, 31, 1501. (b) Friedrich, S.; Gade, L. H.;
Edwards, A. J .; McPartlin, M. Chem. Ber. 1993, 126, 1797. (c) Blake,
A. J .; Collier, P. E.; Gade, L. H.; McPartlin, M.; Mountford, P.;
Schubart, M.; Scowen, I. J . Chem. Commun. 1997, 1555.
(4) For recent articles on protetraazaphosphatranes, see: (a) Tang,
J . S.; Verkade, J . G. Tetrahedron Lett. 1993, 34, 2903. (b) Tang, J . S.;
Verkade, J . G. Angew. Chem., Int. Ed. Engl. 1993, 32, 896. (c) Tang,
J . S.; Verkade, J . G. J . Org. Chem. 1994, 59, 7793. (d) D’Sa, B. A.;
Verkade, J . G. J . Org. Chem. 1996, 61, 2963. (e) Tang, J . S.; Verkade,
J . J . Org. Chem. 1996, 61, 8750. (f) D’Sa, B. A.; Verkade, J . G. J . Am.
Chem. Soc. 1996, 118, 12832. (g) Arumugam, S.; Verkade, J . G. J . Org.
Chem. 1997, 62, 4827. (h) D’Sa, B. A.; McLeod, D.; Verkade, J . G. J .
Org. Chem. 1997, 62, 5057.
(5) For preparation of 6, see: Rispens, M. T.; Gelling, O. J .; de Vries,
A. H. M.; Meetsma, A.; van Bolhuis, F.; Feringa, B. L. Tetrahedron
1996, 52, 3521.
(6) For preparation of 7, see: Belokon’, Yu. N.; Zel’tzer, I. E.;
Bakhmutov, V. I.; Saporovakaya, M. B.; Ryzhov, M. G.; Yanovsky, A.
I.; Struchkov, Yu. T.; Belikov, V. M. J . Am. Chem. Soc. 1983, 105, 2010.
To synthesize a chiral triamidoamine concisely, (S)-
proline, a readily available and inexpensive material, was
† ResCWE.
‡ Graduate Scool of Engineering.
(1) For a review, see: Schrock, R. R. Acc. Chem. Res. 1997, 30, 9.
(2) For a review, see: Verkade, J . G. Acc. Chem. Res. 1993, 26, 483.
S0022-3263(98)00468-X CCC: $15.00 © 1998 American Chemical Society
Published on Web 07/10/1998

Notes
J . Org. Chem., Vol. 63, No. 16, 1998 5693
Sch em e 2
2-pyrrolidinylmethyl)amine (11) was synthesized from 6
in 65% overall yield. Deprotection of N-benzylated
triamidoamine 11 was easily achieved using Pd/C under
a hydrogen atmosphere to give the desired optically pure
triamidoamine 4 quantitatively. J udging from the fact
that only one diastereomer has been observed for each
of products 8-11, little or no racemization has occurred
in the amide-coupling and the subsequent reduction
steps.
Chiral protetraazaphosphatrane 5 was synthesized in
a one-pot two-step procedure according to the literature4a
with a slight modification, as shown in Scheme 2. In the
first step the reaction of one molar equiv of 4 and bis-
(diethylamino)chlorophosphane gave the stable cation 12
prepared as the chloride quantitatively. Subsequently,
the treatment of 12 with potassium tert-butoxide gave 5
in 72% isolated yield.
F igu r e 1. ORTEP drawing and atomic numbering scheme
for 13. (BF4- is excluded from the figure. Although the H-P
bond distance shown here is not positive, its direction could
be detected.) Pertinent bond distances are P(1)-N(1), 1.652(1);
P(1)-N(2), 1.660(1); P(1)-N(3),1.664(1); and P(1)-N(4), 2.039(1)
Å; important bond angles are N(1)P(1)N(2), 120.3(1); N(2)P-
(1)N(3), 118.1(1); N(3)P(1)N(1), 119.5(1); N(1)P(1)N(4), 84.9(1);
N(2)P(1)N(4), 85.5(1); N(3)P(1)N(4), 85.3(1); N(1)P(1)H(1),
94.6(5); N(2)P(1)H(1), 92.6(5); and N(3)P(1)H(1), 97.1(5)°.
of racemic 1-phenylethanol with sterically hindered tri-
alkylsilyl chlorides such as tert-butyldimethylsilyl chlo-
ride, triisopropylsilyl chloride, and triphenylsilyl chloride.
Next, 5 was examined as a chiral catalyst for ethylation
of benzaldehyde with diethylzinc (eq 2). Certain catalytic
activity and asymmetric induction were observed, al-
though they were entirely insufficient.
Treatment of 12 with AgBF4 in CH2Cl2 gave HBF4 salt
1
13 in quantitative yield. The H NMR chemical shift of
5.88 ppm for the H-P hydrogen in 13 is indicative of four-
or five-coordinative phosphorus, as is its one-bond H-P
coupling constant of 477 Hz.7,8 The structure of 13 was
confirmed by X-ray crystallography (Figure 1). Although
the H-P hydrogen in 13 could not be located exactly, the
high electron density of this hydrogen was certainly
distributed in the direction of the H-P-Nax angle
(177.4°). Also, the sum of the NPN angles in the
equatorial plane (357.9°), the nearly right-angle relation-
ship of the Nax-P bond with the Neq-P linkages (average
1
85.2°), the detection of the H-31P coupling in solution,
and the directionality of the Nax lone pair toward the
phosphorus are consistent with the H-P proton occupy-
ing the vacant axial position. The P-Nax bond distance
In conclusion, the first chiral C3 symmetric protetra-
azaphosphatrane 5 has been developed. Exploratory
studies indicate that this area of research will produce
other chiral protetraazaphosphatrane and tetraaza-
metallatrane structures and various useful enantio-
selective reactions. Applications of 5 and its derivatives
in asymmetric synthesis as a potent chiral ligand or
catalyst are currently being investigated in our labora-
tories.
-
in 13 (2.039 Å) is similar to that in 3-BF4 (R ) Me,
1.967 Å) reported previously.7 The considerably shorter
P-Neq distances (average 1.659 Å) compared with the
P-Nax bond distance in 13 may reflect a combination of
the diminished σ bond order in the axial three-center four
electron system9 and the lack of Nax-P π bonding.
Protetraazaphosphatrane 5 was examined for silylation
of benzyl alcohol (eq 1). As expected, 5 behaved as a base
catalyst as strong as 2 (R ) Me).7 However, no asym-
metric induction was observed in incomplete silylation
Exp er im en ta l Section
Gen er a l. All experiments were carried out under an atmo-
sphere of dry argon. For thin-layer chromatography (TLC)
analysis throughout this work, Merck precoated TLC plates
(silica gel 60 GF,254 0.25 mm) were used. The products were
purified by preparative column chromatography on silica gel E.
Merck 9385. Microanalyses were accomplished at the School of
Agriculture, Nagoya University. The high-resolution mass
spectra (HRMS) were conducted at Daikin Industries, Ltd.
(7) Lensink, C.; Xi, S. K.; Daniels, L. M.; Verkade, J . G. J . Am. Chem.
Soc. 1989, 111, 3478.
(8) Phosphorus-hydrogen coupling constants: R2P-H, J ) 150-
225 Hz; R2P(O)-H, J ) 450-725 Hz; R3P+-H, J ) 450-600 Hz. See,
Smith, D. J . H. In Comprehensive Organic Chemistry; Sutherland, I.
O., Ed.; Pergamon Press: New York, 1979; Vol. 2, Part 10.1.
(9) Carpenter, L. E.; Verkade, J . G. J . Am. Chem. Soc. 1985, 107,
7084.

5694 J . Org. Chem., Vol. 63, No. 16, 1998
Notes
N-Benzyl-(S)-proline derivatives 65 and 76 were prepared
according to the literature procedures. Silylation of alcohols
catalyzed by 5 was carried out according to the reported
procedures.4f,h
3.14 (m, 2H), 3.18 (t, J ) 6.9 Hz, 1H), 3.31 (d, J ) 13.4 Hz, 1H),
3.33 (d, J ) 13.4 Hz, 1H), 3.38-3.53 (m, 3H), 3.78 (d, J ) 12.9
Hz, 1H), 3.98 (d, J ) 12.9 Hz, 2H), 4.16 (d, J ) 13.5 Hz, 1H),
7.20-7.40 (m, 15H); 13C NMR (CDCl3, 75 MHz) δ 22.4, 22.5, 22.6,
29.0 (3C), 50.4, 52.2, 52.4, 53.6, 54.2, 57.2, 59.0, 59.6, 61.9, 62.0,
62.8, 126.3, 126.5, 126.6, 127.7 (4C), 127.9 (2C), 128.2 (2C), 128.3
(2C), 128.8 (2C), 138.8, 139.1, 139.5, 173.4; HREIMS calcd for
C36H46N4O [M+] 550.3657, found 550.3672.
(S,S)-N-Ben zyl-2-[N-(N′-ben zylp r olyl)a m in om eth yl]p yr -
r olid in e (8). To a solution of EDC (21.3 g, 111.0 mmol) and
HOBt (14.0 g, 103.6 mmol) in dichloromethane (200 mL) was
added a solution of 7 (16.7 g, 81.4 mmol) and 6 (14.1 g, 74.0
mmol) in dichloromethane (200 mL) at 0 °C. To the mixture
was added dropwise triethylamine (15.5 mL, 111.0 mmol) at the
same temperature. After being stirred for 2 h, the reaction
mixture was allowed to warm to ambient temperature. The
reaction was left to stir at room temperature overnight (ca. 12
h). Subsequently, water was added to the reaction mixture and
the resulting aqueous solution was extracted with dichloro-
methane. The combined organic extracts were washed with
aqueous NaHCO3 and dried over Na2SO4. Filtration followed
by solvent evaporation afforded a crude product. The residue
was purified using flash chromatography on silica gel [hexane/
ethyl acetate mixtures (1:1f1:0) as eluents] to give 8 (24.0 g,
63.6 mmol, 86%) as a colorless oil: TLC (ethyl acetate) Rf ) 0.77;
(S,S,S)-Tr is(N′-ben zyl-2-p yr r olid in ylm eth yl)a m in e (11).
A solution of 10 (34.1 g, 62.0 mmol) in THF (125 mL) was added,
under an argon atmosphere, to a suspension of lithium alumi-
num hydride (7.06 g, 186 mmol) in THF (125 mL). This mixture
was heated under reflux for 20 h and subsequently cooled to 0
°C. Next 10% aqueous pottasium hydroxide (11 mL) was
carefully added and the resulting mixture was heated under
reflux for 1 h until the salts were white. After cooling to room
temperature the salts were removed by filtration. These salts
were again heated under reflux for 1 h with THF (100 mL) and
water (2 mL). After removal of the salts by filtration, the THF
layers were combined and dried over Na2SO4. After filtration
and evaporation of the solvent, the residue was purified by flash
chromatography on silica gel [hexane/CH2Cl2 mixtures (1:1f1:
2) as eluents] to give 11 (30.0 g, 55.8 mmol, 90%) as a coloress
[R]24.5 ) -131.1 (c ) 2.1, CHCl3); IR (film) 2967, 2801, 1674,
D
1500, 1455, 1372, 1129, 741, 700 cm-1
;
1H NMR (CDCl3, 300
MHz) δ 1.40-1.52 (m, 1H), 1.52-1.65 (m, 2H), 1.65-1.82 (m,
2H), 1.82-1.96 (m, 2H), 2.12-2.34 (m, 3H), 2.68-2.75 (m, 1H),
2.92-3.02 (m, 2H), 3.17-3.28 (m, 2H), 3.25 (d, J ) 12.7 Hz, 1H),
3.38 (d, J ) 12.8 Hz, 1H), 3.67 (ddd, J ) 2.0, 8.4, 13.9 Hz, 1H),
4.03 (d, J ) 12.8 Hz, 1H), 4.04 (d, J ) 12.9 Hz, 1H), 7.10-7.20
(m, 3H), 7.20-7.32 (m, 3H), 7.32-7.37 (m, 4H), 8.17 (d, J ) 6.0
Hz, 1H); HREIMS calcd for C24H31N3O [M+] 377.2467, found
377.2460.
oil: TLC (CH2Cl2/MeOH ) 8:1) Rf ) 0.43; [R]28 ) -212.8 (c )
D
1.40, CHCl3); IR (film) 2975, 2797, 1495, 1453, 1370, 1117, 1075,
737, 698 cm-1; 1H NMR (CDCl3, 300 MHz) δ 1.58-1.80 (m, 9H),
1.93-2.05 (m, 3H), 2.11-2.21 (m, 3H), 2.34 (dd, J ) 10.2, 12.3
Hz, 3H), 2.45 (dd, J ) 3.2, 12.3 Hz, 3H), 2.53-2.65 (m, 3H),
2.89-2.97 (m, 3H), 3.25 (d, J ) 12.8 Hz, 3H), 4.02 (d, J ) 12.8
Hz, 3H), 7.20-7.40 (m, 15H); 13C NMR (CDCl3, 75 MHz) δ 23.2,
31.0, 55.4, 60.3, 61.2, 62.6, 127.3, 128.7 (2C), 129.5 (2C), 140.2.
Anal. Calcd for C36H48N4: C, 80.51; H, 9.01; N, 10.43. Found:
C, 80.26; H, 9.20; N, 10.59.
(S,S)-Bis(N′-ben zyl-2-p yr r olid in ylm eth yl)a m in e (9).
A
solution of 8 (24.2 g, 64.0 mmol) in THF (100 mL) was added,
under an argon atmosphere, to a suspension of lithium alumi-
num hydride (7.29 g, 192 mmol) in THF (100 mL). This mixture
was heated under reflux for 20 h and subsequently cooled to 0
°C. Next 10% aqueous potassium hydroxide (11 mL) was
carefully added and the resulting mixture was heated under
reflux for 1 h until the salts were white. After cooling to room
temperature the salts were removed by filtration. These salts
were again heated under reflux for 1 h with THF (100 mL) and
water (2 mL). After removal of the salts by filtration, the THF
layers were combined and dried over Na2SO4. After filtration
and evaporation of the solvent, the residue was purified by flash
chromatography on silica gel [CH2Cl2/methanol mixtures (20:
1f10:1f7:1) as eluents] to give 9 (20.9 g, 57.6 mmol, 90%) as a
(S,S,S)-Tr is(2-p yr r olid in ylm eth yl)a m in e (4). N-Benzy-
lated amine 11 (24.2 g, 45.0 mmol) and 10% palladium on
activated carbon (3 g) were mixed in dry methanol (100 mL) and
stirred at room temperature under atmospheric pressure of H2
for 3 days. The catalyst was removed by filtration through a
Celite pad under an argon atmosphere, and the filtrate was
concentrated. The crude product was purified by distillation
with a Kugelrohr aparatus (0.02 Torr, 110-120 °C) to give 4
(11.4 g, 42.7 mmol, 95%) as a colorless liquid: [R]28D ) 55.1 (c )
1.23, CHCl3); IR (film) 3300 (br, NH), 2955, 1541, 1453, 1404,
1069, 814, 750 cm-1 1H NMR (CDCl3, 300 MHz) δ 1.20-1.38
;
(m, 3H), 1.66-1.90 (m, 9H), 2.1-3.6 (br, 3H), 2.25-2.48 (m, 6H),
2.77-3.05 (m, 6H), 3.12-3.27 (m, 3H); 13C NMR (CDCl3, 75
MHz) δ 24.9 (3C), 29.4 (3C), 45.8 (3C), 56.2 (3C), 60.5 (3C). Anal.
Calcd for C15H30N4: C, 67.62; H, 11.35; N, 21.03. Found: C,
67.61; H, 11.13; N, 21.11.
colorless oil: TLC (CH2Cl2/methanol ) 8:1) Rf ) 0.32; [R]24.9
)
D
-96.4 (c ) 1.4, CHCl3); IR (film) 2961, 2874, 2789, 1495, 1453,
1372, 1352, 1210, 1119, 1075, 1028, 787, 698 cm-1 1H NMR
;
(CDCl3, 300 MHz) δ 1.62-1.76 (m, 7H), 1.86-2.02 (m, 2H), 2.20
(q, J ) 8.5 Hz, 2H), 2.55-2.76 (m, 6H), 2.88-2.96 (m, 2H), 3.32
(d, J ) 13.1 Hz, 2H), 4.03 (d, J ) 13.1 Hz, 2H), 7.18-7.36 (m,
10H); 13C NMR (CDCl3, 75 MHz) δ 23.0 (3C), 29.2 (3C), 54.1
(3C), 54.4 (3C), 59.7 (3C), 63.6 (3C), 126.6 (3C), 128.0 (6C), 128.7
(6C), 139.9 (3C); HREIMS calcd for C24H33N3 [M+] 363.2666,
found 363.2675.
(S,S,S)-P r otetr a a za p h osp h a tr a n e (5). To a solution of
triamidoamine 4 (2.18 g, 8.16 mmol) in dry acetonitrile (30 mL)
was added bis(diethylamino)chlorophosphane (1.72 mL, 8.16
mmol) via a syringe over 5 min. After stirring of the reaction
mixture at room temperature for 2 h, the solution was trans-
ferred by syringe or cannula to a flask containing t-BuOK (1.83
g, 16.3 mmol) in dry acetonitrile (6 mL). After stirring of the
reaction mixture for 1 h at room temperature, the solvent was
removed under vacuum and the residue was extracted overnight
while being stirred with dry pentane (150 mL) which was
transferred in by cannula. The extract was transferred by
cannula to another flask and evaporated in vauo to give a white
solid which was purified by vacuum sublimation (170 °C at 0.02
Torr), giving pure proazaphosphatrane 5 (1.73 g, 5.87 mmol, 72%
(S,S)-N-(N′-Ben zylp r olyl)-b is(N′-b en zyl-2-p yr r olid in yl-
m eth yl)a m in e (10). To a solution of EDC (20.9 g, 109 mmol)
and HOBt (13.0 g, 96.0 mmol) in dichloromethane (125 mL) was
added a solution of 7 (15.4 g, 70.4 mmol) and 9 (23.3 g, 64.0
mmol) in dichloromethane (125 mL) at 0 °C. To the mixture
was added dropwise triethylamine (15.2 mL, 109 mmol) at the
same temperature. After being stirred for 2 h, the reaction
mixture was allowed to warm to ambient temperature. The
reaction was left to stir at room temperature overnight (ca. 12
h). Subsequently, water was added to the reaction mixture and
the resulting aqueous solution was extracted with dichloro-
methane. The combined organic extracts were washed with
aqueous NaHCO3 and dried over Na2SO4. Filtration followed
by solvent evaporation afforded a crude product. The residue
was purified using flash chromatography on silica gel [CH2Cl2/
methanol mixtures (60:1f30:1f15:1f10:1) as eluents] to give
10 (33.1 g, 60.2 mmol, 94%) as a coloress oil: TLC (CH2Cl2/
methanol ) 8:1) Rf ) 0.50; IR (film) 2965, 2793, 1646, 1455,
1215, 1121, 749, 700 cm-1; 1H NMR (CDCl3, 300 MHz) δ 1.58-
2.07 (m, 12H), 2.14 (q, J ) 6.9 Hz, 1H), 2.24 (q, J ) 8.4 Hz, 1H),
2.38-2.56 (m, 2H), 2.76-2.85 (m, 1H), 2.85-2.98 (m, 2H), 3.03-
1
yield): IR (Nujol) 1457, 1443, 1379, 1360, 1065 cm-1; H NMR
(C6D6, 300 MHz) δ 1.10-1.22 (m, 3H), 1.52-1.68 (m, 6H), 1.68-
1.80 (m, 3H), 2.32 (dd, J ) 11.4, 13.8 Hz, 3H), 2.88-3.02 (m,
6H), 3.38-3.52 (m, 3H); 13C NMR (CD3CN) δ 27.8 (d, J ) 9.5
Hz, 3C), 30.4 (3C), 50.2 (d, J ) 42.5 Hz, 3C), 57.6 (d, J ) 6.3 Hz,
3C), 60.3 (3C); HREIMS calcd for C15H27N4P [M+] 294.1973,
found 294.1969.
(S,S,S)-Tetr a a za p h osp h a tr a n e Tetr a flu or obor a te (13).
To a solution of 5 (118 mg, 0.4 mmol) in acetonitrile (5 mL) was
added 1 M HCl in ether (1 mL, 1 mmol) at room temperature.
After 10 min, the solvents were pumped off. The residual solid
was dissolved in dichloromethane (5 mL) and then silver
tetrafluoroborate (78 mg, 0.4 mmol) was added. Silver chloride
precipitated was filtered off and the filtrate was concentrated

Notes
J . Org. Chem., Vol. 63, No. 16, 1998 5695
in vacuo. The residual solid was recrystallized with acetonitrile
°C. After being stirred for 0.5 h at -20 °C, the reaction mixture
was warmed to room temperature. After 3.5 h, 1 N aqueous
HCl was added to the reaction mixture and the resulting
aqueous solution was extracted with diethyl ether. The com-
bined organic extracts were dried over MgSO4. Filtration
followed by solvent evaporation afforded a crude product. The
residue was purified using flash chromatography on silica gel
[hexane/ethyl acetate mixtures (5:1) as eluents] to give (R)-1-
phenylpropanol (33.4 mg, 0.25 mmol, 49%) in 15% ee. The ee
was determined by HPLC analysis [OD-H column, hexane-i-
PrOH ) 20:1, flow rate ) 0.5 mL/min; tR ) 15.8 min for (R)-
enantiomer, tR ) 17.6 min for (S)-enantiomer]. The absolute
configuration was determined by comparison of optical rotation
values with data in the literature.10
(ca. 2 mL): IR (KBr) 2930, 2972, 1460, 1088, 1084, 575, 532 cm-1
1H NMR (CDCl3, 300 MHz) δ 1.54-1.65 (m, 3H), 1.88-2.06 (m,
6H), 2.06-2.19 (m, 3H), 3.06-3.31 (m, 6H), 3.38-3.49 (m, 3H),
3.52-3.65 (m, 3H), 5.88 (d, J PH ) 477 Hz, 3H); 13C NMR (CDCl3,
75 MHz) δ 26.3 (d, J ) 8.4 Hz, 3C), 30.7 (d, J ) 3.3 Hz, 3C),
46.8 (d, J ) 9.0 Hz, 3C), 51.6 (d, J ) 2.9 Hz, 3C), 54.6 (d, J )
10.8 Hz, 3C); Anal. Calcd for C15H28N4PBF4: C, 47.14; H, 7.38;
N, 14.66. Found: C, 47.21; H, 7.39; N, 14.52.
;
Cr ysta l Da ta for 13. X-ray diffraction analysis on 13 was
carried out on a DIP2030-NW CEF diffractometer (MacScience)
at 298 K. All diagrams and calculations were performed using
maXus (MacScience). The structure of 13 (C15H28N4PBF4, Mw
382.19 amu) was determined from an orthorhombic crystal of
dimensions 0.35 × 0.2 × 0.15 mm3 (space group P212121), with
unit cell a ) 8.3890 (3) Å, b ) 9.2860 (4) Å, c ) 24.2570 (8) Å,
V ) 1889.5(4) Å3. It has four molecules per cell, dcalcd ) 1.530
Su p p or tin g In for m a tion Ava ila ble: 1H NMR spectra for
compounds 5, 8, 9, and 10 and tables of crystal data, positional
and anisotropic thermal parameters, and bond lengths and
bond angles (15 pages). This material is contained in libraries
on microfiche, immediately follows this article in the microfilm
version of the journal, and can be ordered from ACS; see any
current masthead page for ordering information.
g/cm3, µ ) 1.894 cm-1
. Mo KR radiation (λ ) 0.71073 Å) was
used, and 2473 unique reflections for 1 < θ < 28° were collected
2368 being observed (I > 3σ(I)). The occupancies of the two
-
orientations of the BF4 ion refined to 50% for one orientation.
Refinement of 365 parameters converged with agreement factors
of the following: R ) 0.052 and Rw ) 0.060.
En a n tioselective Eth yla tion of Ben za ld eh yd e w ith Di-
eth ylzin c Ca ta lyzed by (S,S,S)-5. To a mixture of benzalde-
hyde (51 µL, 0.50 mmol) and a 0.1 M solution of (S,S,S)-5 in
toluene (0.5 mL, 0.05 mmol) in toluene (2 mL) was added a 1.0
M solution of diethylzinc in hexane (1.0 mL, 1.0 mmol) at -20
J O9804689
(10) (a) Kitamura, M.; Suga, D.; Kawai, K.; Noyori, R. J . Am. Chem.
Soc. 1986, 108, 6071. (b) Takahashi, H.; Kawakita, T.; Ohno, M.;
Yoshioka, M.; Kobayashi, S. Tetrahedron 1992, 48, 5691.