Enantioselective Allylation of Aromatic Aldehydes with Allyltrichlorosilane
layer was separated and the aqueous layer was extracted
with CH2Cl2 (10 mL×3). The combined organic layers
were washed with water (15 mL×3) and then with brine
(15 mL×3) and dried over anhydrous Na2SO4. The
crude product was purified with flash column chroma-
tography on silica gel (eluent: CH2Cl2/MeOH=20:1) to
afford chiral 2,2'-bipyridine N,N-dioxides (−)-5a (153.8
mg, 29 % yield) and (+)-5a (47.7 mg, 9% yield) as
slightly yellow oil. (−)-5a: [α]D23 −311.2 (c 2.8, CHCl3);
1H NMR (400 MHz, CDCl3) δ: 9.24 (br, 1H), 8.22 (s,
1H), 8.13 (d, J=6.4 Hz, 1H), 7.89 (s, 1H), 7.63 (d, J=
8.0 Hz, 1H), 7.00-7.50 (m, 7H), 5.95 (s, 1H), 5.65 (d,
J=6.4 Hz, 1H), 5.00 (dd, J=35.2, 12 Hz, 2H), 4.10-
4.40 (m, 1H), 3.50-3.95 (m, 4H), 1.31 (d, J=7.2 Hz,
3H); 13C NMR (100 MHz, CDCl3) δ: 171.9, 155.9,
140.7, 139.6, 137.6, 136.0, 135.8, 135.6, 134.3, 132.7,
130.0, 129.6, 128.6, 128.3, 128.0, 126.1, 125.9, 125.7,
121.6, 99.6, 66.8, 65.0, 64.7, 53.4, 51.4, 50.5, 29.6, 17.9;
(d, J=8.0 Hz, 1H), 6.90-7.49 (m, 12H), 5.98 (s, 1H),
5.34 (d, J=7.6 Hz, 1H), 4.90-5.00 (m, 2H), 4.41 (dd,
J=13.6, 6.4 Hz, 1H), 3.40-4.00 (m, 4H), 2.90-3.20
(m, 2H); 13C NMR (100 MHz, CDCl3) δ: 170.2, 155.7,
141.1, 139.7, 139.8, 138.1, 136.0, 135.9, 135.8, 135.7,
129.3, 129.1, 128.7, 128.6, 128.3, 128.0, 127.1, 126.2,
125.9, 125.3, 121.2, 99.8, 66.9, 64.8, 64.7, 56.3, 53.5,
+
37.5; HRMS (ESI) calculated for C30H29N4O7 (M+H ):
557.2031, found 557.2022.
3-Nitro-2-(3-nitropyridin-2-yl)pyridine
(16)[12]
Under N2 to a well stirred suspension of freshly acti-
vated copper powder (2.0 g, 31.6 mmol) in anhydrous
DMF (40 mL) was added 2-chloro-3-nitropyridine (2.0
g, 12.7 mmol) in one portion. The resulted mixture was
stirred at 150 ℃ for 45 min. After cooling to room
temperature, the excessive copper powder was removed
by filtration under reduced pressure. The filtrate was
treated with 20.0 mL of con. ammonia(aq), and the re-
sulted blue suspension was extracted with EtOAc (50.0
mL×3). The organic extracts were dried over anhy-
drous Na2SO4, and concentrated under reduce pressure.
The crude product was purified by flash chromatogra-
phy on silica gel (eluent: EtOAc/petroleum ether=1:1.5)
to afford compound 16 (1.0 g, 65% yield) as colorless
+
HRMS (ESI) calculated for C24H25N4O7 (M+H ):
23
481.1718, found 481.1716. (+)-5a: [α]D +322.9 (c
3.0, CHCl3); 1H NMR (400 MHz, CDCl3) δ: 9.29 (s, 1H),
8.35 (d, J=6.0 Hz, 1H), 8.13 (d, J=6.4 Hz, 1H), 7.91
(d, J=8.0 Hz, 1H), 7.68 (d, J=8.0 Hz, 1H), 7.20-7.50
(m, 7H), 5.96 (s, 1H), 5.26 (d, J=4.2 Hz, 1H), 4.99 (s,
2H), 4.10-4.20 (m, 1H), 3.50-3.90 (m, 4H), 1.39 (d,
J=6.8 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ: 171.3,
155.7, 141.1, 140.0, 139.9, 138.2, 136.0, 135.8, 135.6,
128.5, 128.2, 128.0, 126.2, 125.9, 125.1, 120.8, 99.8,
66.9, 64.9, 64.8, 51.0, 29.7, 18.0; HRMS (ESI)
1
oil. H NMR (400 MHz, CDCl3) δ: 8.88 (dd, J=4.8, 1.2
Hz, 2H), 8.59 (dd, J=8.4, 1.6 Hz, 2H), 7.65 (dd, J=8.4,
4.8 Hz, 2H).
2-(3-Aminopyridin-2-yl)pyridin-3-amine (17)[13]
A suspension of compound 16 (1.1 g, 4.5 mmol) and
10% Pd-C in absolute EtOH (30.0 mL) was hydrogen-
ated under 1.0 atm for 8 h. The reaction mixture was
diluted with EtOH (60.0 mL), and filtered through a
Celite pad under reduced pressure. The filtrate was
concentrated under reduced pressure, and the resulted
residue was purified by flash chromatography on silica
gel (eluent: EtOAc/petroleum ether=1:2) to afford
compound 17 (790.0 mg, 95% yield) as a yellow solid.
1H NMR (400 MHz, CDCl3) δ: 7.98 (d, J=1.6 Hz, 2H),
7.06-7.01 (m, 4H), 6.28 (br. s, 4H).
+
calculated for C24H25N4O7 (M+H ): 481.1718, found
481.1717.
Axially chiral 2,2'-bipyridine N,N'-dioxides (−)-5b
and (+)-5b (−)-5b and (+)-5b were prepared by
following the same procedure as that of (−)-5a and
(+)-5a: 14b (230.0 mg, 0.439 mmol, 1.0 equiv.) in dried
CHCl3 (2.0 mL), m-CPBA (605.7 mg, 3.511 mmol, 8.0
equiv.) in dried CHCl3 (3.0 mL). The reaction mixture
was stirred at room temperature for 3 h. Purification with
flash column chromatography on silica gel (eluent:
CH2Cl2/MeOH=20:1) provided chiral 2,2'-bipyridine
N,N-dioxides (−)-5b (140.2 mg, 58 % yield) and (+)-5b
(53.0 mg, 22% yield) as slightly yellow oil. (−)-5b:
Dibenzyl((2R,2'S)-([2,2'-bipyridine]-3,3'-diyl-bis-
(azanediyl))bis(1-oxopropane-2,1-diyl))dicarbamate
(18) Under N2 to a well stirred solution of compound
17 (790.0 mg, 4.2 mmol) in anhydrous dichloromethane
(10.0 mL) was added N-Cbz-(S)-Ala (2.8 g, 12.6 mmol)
and EDCI (2.4 g, 12.6 mmol) successively. The result-
ing mixture was stirred at room temperature for 2 h. The
reaction mixture was filtered under reduced pressure
and the collected yellow solid was recrystallized from
chloroform to provide compound 18 (2.0 g, 80% yield)
23
1
[α]D −126.4 (c 3.4, CHCl3); H NMR (400 MHz,
CDCl3) δ: 9.40 (br, 1H), 8.17 (d, J=6.4 Hz, 1H), 7.90 (t,
J=8.6 Hz, 1H), 7.64 (d, J=7.6 Hz, 1H), 7.00-7.60 (m,
12H), 5.96 (s, 1H), 5.61 (d, J=7.6 Hz, 1H), 4.80-5.10
(m, 2H), 4.51 (d, J=5.2 Hz, 1H), 4.50 (d, J=5.2 Hz,
1H), 3.90-4.00 (m, 2H), 3.60-3.80 (m, 2H), 3.17 (dd,
J=14.0, 4.8 Hz, 1H), 2.93 (dd, J=14.0, 8.0 Hz, 1H);
13C NMR (100 MHz, CDCl3) δ: 170.6, 155.9, 141.2,
139.9, 139.6, 137.9, 136.0, 135.9, 135.7, 134.4, 132,9,
130.0, 129.6, 129.1, 129.0, 128.7, 128.6, 128.2, 128.1,
127.8, 127.1, 126.1, 126.0, 125.3, 121.0, 99.7, 66.9,
65.0, 64.8, 56.7, 53.4, 37.8; HRMS (ESI) calculated for
15
as a white solid. [α]D −93.3 (c 0.03, CHCl3); 1H NMR
(400 MHz, DMSO-d6) δ: 13.46-13.61 (m, 2H), 9.03 (d,
J=8.4 Hz, 2H), 8.44-8.30 (m, 2H), 8.14-7.80 (m,
2H), 7.49-7.32 (m, 10H), 7.96 (d, J=17.2 Hz, 4H),
5.04-4.96 (m, 4H), 4.17-4.13 (m, 2H), 1.35 (d, J=
7.2 Hz, 4H); 13C NMR (100 MHz, DMSO-d6) δ: 173.1,
156.5, 141.8, 137.0, 136.0, 129.4, 128.8, 128.5, 124.4,
66.4, 52.7, 17.9; HRMS (ESI) calculated for C32H32-
N6O6 (M+H+): 597.2456, found 597.2444.
+
C30H29N4O7 (M +H ): 557.2031, found 557.2023.
23
1
(+)-5b: [α]D +187.5 (c 3.5, CHCl3); H NMR (400
MHz, CDCl3) δ: 9.46 (br, 1H), 8.26 (d, J=6.4 Hz, 1H),
8.09 (d, J=6.4 Hz, 1H), 7.75 (d, J=8.4 Hz, 1H), 7.63
Chin. J. Chem. 2013, 31, 485—493
© 2013 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
491