424
Russ.Chem.Bull., Int.Ed., Vol. 63, No. 2, February, 2014
Veselovsky and Stepanov
4,6ꢀDibromoꢀ2ꢀ({(2S)ꢀ2ꢀ[hydroxy(diphenyl)methyl]pyrrolꢀ
(S)ꢀ1ꢀNitrohexꢀ5ꢀenꢀ2ꢀol (9b). A mixture of ligand 1a
(39.0 mg, 0.096 mmol), Cu(OAc)2•2H2O (20.0 mg, 0.11 mmol),
and anhydrous PriOH (1.5 mL) was sonicated for 10 min, then
aldehyde 8b (84 mg, 1.0 mmol) and MeNO2 (610 mg, 10 mmol)
were added. The reaction mixture was kept for 30 h at 20 C until
complete consumption of the starting aldehyde (TLC monitorꢀ
ing), and concentrated in vacuo. Purification of the residue by
column chromatography (SiO2, elution with CHCl3) afforded
nitro alcohol 9b in the yield of 120 mg (83%), oil, Rf 0.26
idinꢀ1ꢀyl}methyl)phenol (1b) was synthesized similarly from alꢀ
dehyde 2b (0.59 g, 2.1 mmol) and amino alcohol 3 (0.5 g,
1.97 mmol) in the yield of 0.71 g (70%), light yellow amorphous
28
powder, Rf 0.37 (AcOEt—petroleum ether, 1 : 5), []D + 78.2
(c 1.00, CH2Cl2). High resolution MS (ESI), m/z: found 516.0164;
calculated for C24H23Br2NO2, m/z: 516.0168 [M + H]+.
IR (CHCl3), /cm–1: 672, 726, 752, 767, 864, 1001, 1033,
1083, 1153, 1208, 1224, 1262, 1352, 1381, 1451, 1458, 1599,
2832—3063, 3113, 3603, 3683. 1H NMR (CDCl3), : 1.63—2.24
(m, 4 H, C(3)H2, C(4)H2); 2.42 (dd, 1 H, C(5)H, J = 17.4 Hz,
J = 8.1 Hz); 3.03 (m, 1 H, C(5)H´); 3.27, 3.49 (both d, 1 H each,
CH2N, J = 15.1 Hz); 4.02 (dd, 1 H, C(2)H, J = 9.1 Hz,
J = 4.9 Hz); 4.74 (br.s, 2 H, 2 OH); 6.84—7.71 (m, 12 H, HCAr).
(S)ꢀ1ꢀ(4ꢀNitrophenyl)ꢀ2ꢀnitroethanꢀ1ꢀol (7). A. A mixture
of ligand 1a (38.2 mg, 0.094 mmol), Cu(OAc)2•2H2O (21.7 mg,
0.011 mmol), and anhydrous PriOH (1.5 mL) was sonicated for
10 min, then 4ꢀnitrobenzaldehyde 6 (151 mg, 1 mmol) and
MeNO2 (610 mg, 10 mmol) were added. The reaction mixture
was kept for 20 h at 20 C until complete consumption of the
starting aldehyde (TLC monitoring) and concentrated in vacuo.
Purification of the residue by column chromatography (SiO2,
elution with CHCl3) afforded nitro alcohol 7 in the yield of
210 mg (99%), []D28 + 37.8 (c 1.00, CH2Cl2) (~94% ee, HPLC
28
(CHCl3), []D +8.3 (c 1.00, CH2Cl2; ~93% ee, HPLC data).
Retention times: 9.6 min for (R)ꢀ7 and 10.4 min for (S)ꢀ7.
1H NMR (CDCl3), : 1.63 (m, 2 H, C(3)H2); 2.22 (m, 2 H, C(4)H2);
2.54 (br.s, 1 H, OH); 4.27—4.52 (m, 3 H, CHO, CH2N);
4.98—5.17 (m, 2 H, H2C=); 5.81 (ddt, 1 H, —HC=, J = 16.7 Hz,
J = 10.3 Hz, J = 6.4 Hz) (cf. for ( )ꢀ9b)14
.
(S)ꢀ1ꢀNitroheptꢀ6ꢀenꢀ2ꢀol (9c). A mixture of ligand 1a
(40.1 mg, 0.10 mmol), Cu(OAc)2•2H2O (21.3 mg, 0.11 mmol),
and anhydrous PriOH (1.5 mL) was sonicated for 10 min, then
aldehyde 8c (100 mg, 1.0 mmol) and MeNO2 (610 mg, 10 mmol)
were added. The reaction mixture was kept for 45 h at 20 C
until complete consumption of the starting alcohol (TLC moniꢀ
toring) and concentrated in vacuo. Purification of the residue
by column chromatography (SiO2, elution with CHCl3) afꢀ
forded nitro alcohol 9c in the yield of 130 mg (82%), oil, Rf 0.15
(CHCl3), []D28 +8.4 (c 1.00, CH2Cl2) (~94% ee, HPLC data).
Retention time: 9.1 min for (R)ꢀ9c and 9.8 min for (S)ꢀ9c.
1H NMR (CDCl3), : 1.38—1.76 (m, 4 H, C(3)H2, C(4)H2);
2.12 (m, 2 H, C(5)H2); 2.45 (br.s, 1 H, OH); 4.23—4.55
(m, 3 H, CHO, CH2N); 4.93—5.14 (m, 2 H, H2C=); 5.80
(ddt, 1 H, —HC=, J = 16.9 Hz, J = 10.1 Hz, J = 6.6 Hz) (cf.
for ( )ꢀ9c).15
25
data; cf. Ref. 13: []D + 39.7 (c 1.0, CH2Cl2) for 7 with ee
98%). Retention times: 12.2 min for (R)ꢀ7 and 15.3 min for
1
(S)ꢀ7. M.p. 83—85 C (cf. Ref. 13). H NMR (CDCl3), : 3.47
(br.s, 1 H, OH); 4.58—4.62 (m, 2 H, CH2N); 5.61 (dd, 1 H,
CHO, J = 7.4 Hz, J = 5.0 Hz); 7.62 (d, 2 H, 2 HAr, J = 8.7 Hz);
8.23 (d, 2 H, 2 HAr, J = 8.7 Hz) (cf. Ref. 13).
B. Nitro alcohol 7 was synthesized from aldehyde 6 (151 mg,
1 mmol), MeNO2 (610 mg, 10 mmol), PriOH (1.5 mL), and the
catalyst obtained from ligand 1b (52.2 mg, 0.101 mmol) and
Cu(OAc)2•2H2O (20.9 mg, 0.105 mmol) following the proceꢀ
dure described above. Yield 198 mg (93%), []D28 +33.5 (c 1.00,
CH2Cl2; ~81% ee, HPLC data).
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 13ꢀ03ꢀ00197).
References
(S)ꢀ1ꢀNitrohexanꢀ2ꢀol (9a). A. A mixture of ligand 1a (40.1 mg,
0.10 mmol), Cu(OAc)2•2H2O (20.0 mg, 0.11 mmol), and anꢀ
hydrous PriOH (1.5 mL) was sonicated for 10 min, then pentaꢀ
nal (8a) (100 mg, 1.02 mmol) and MeNO2 (610 mg, 10 mmol)
were added. The reaction mixture was kept for 44 h at 20 C until
complete consumption of the starting aldehyde (TLC monitorꢀ
ing) and concentrated in vacuo. Purification of the residue by
column chromatography (SiO2, elution with CHCl3) afforded
nitro alcohol 9a in the yield of 130 mg (82%), oil, Rf 0.52
(CHCl3—EtOAc, 4 : 1), []D28 +9.6 (c 1.00, CH2Cl2; ~94% ee,
HPLC data; cf. Ref. 13: []D25 + 5.0 (c 2.5, CH2Cl2) for 9a with
ee 70%). Retention times: 9.1 min for (R)ꢀ9a and 10.3 min for
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1
(S)ꢀ9a. H NMR (CDCl3), : 0.92 (br.t, 3 H, Me, J = 6.9 Hz);
1.18—1.67 (m, 6 H, 3 CH2); 3.48 (br.s, 1 H, OH); 4.21—4.53
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B. To a suspension of 10% Pd/C (10 mg) in EtOH (0.5 mL)
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added over 20 min and the reaction mixture was stirred for 30 min
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was concentrated in vacuo. Purification of the residue by column
chromatography (SiO2, elution with CHCl3 afforded compound 2
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