2334
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 11, November, 2011
Lozanova et al.
found 334.1840, calculated for C18H27NO3Si, [M + H]+
334.1833. IR (neat), ν/cm–1: 1072, 1116, 1140, 1252, 1360, 1392,
1472, 1556, 1648, 2124, 2850—3000, 3084. MS (EI), m/z
(Irel (%)): 333 [M]+ (49), 314 (22), 301 (21), 288 (9), 273 (73),
246 (19), 243 (31), 241 (59), 234 (7), 226 (20), 223 (21), 219 (13),
213 (20), 200 (11), 198 (24), 195 (31), 186 (22), 182 (33), 181
(49), 170 (22), 169 (24), 168 (38), 157 (11), 155 (21), 154 (37),
150 (16), 149 (48), 148 (39), 143 (22), 138 (23), 134 (24), 120 (51),
126 (30), 124 (15), 123 (25), 118 (19), 116 (54), 115 (47), 110 (17),
108 (43), 106 (55), 105 (54), 102 (44), 98 (37), 96 (40), 95 (34),
94 (42), 91 (61), 90 (100). 1H NMR (200.13 MHz), δ: 0.23
(s, 9 H, TMSO); 0.99—2.31 (m, 4 H, H2C(4) and H2C(5)); 3.03
(dddd, 1H, HC(3a), J = 2.0 Hz, J = 6.2 Hz, J = 7.9 Hz, J = 9.4 Hz);
3.62 (dd, 1 H, βꢀHC(3), J = 2.0 Hz, J = 8.1 Hz); 3.80 (dd, 1 H,
HC(6), J = 6.3 Hz, J = 11.1 Hz); 4.40 (dd, 1 H, αꢀHC(3),
J = 7.9 Hz, J = 8.1 Hz); 4.63 and 4.80 (both d, 1 H each,
H2CPh, J = 12.1 Hz); 5.16 (dd, 1 H, EꢀHC=C, J = 0.6 Hz,
J = 17.5 Hz); 5.30 (dd, 1 H, ZꢀHC=C, J =0.8 Hz, J = 11.1 Hz);
6.12 (dd, 1 H, HC=C, J = 11.1 Hz, J = 17.5 Hz); 7.27—7.42
(m, 5 H, HCarom).
synꢀ2ꢀ[(2S*,5S*)ꢀ2ꢀBenzyloxyꢀ5ꢀhydroxymethylꢀEꢀcycloꢀ
pentylidene]ethanealdoxime (10a), synꢀ2ꢀ[(2S*,5S*)ꢀ2ꢀbenzylꢀ
oxyꢀ5ꢀhydroxymethylꢀZꢀcyclopentylidene]ethanealdoxime (10b),
antiꢀ2ꢀ[(2S*,5S*)ꢀ2ꢀbenzyloxyꢀ5ꢀhydroxymethylꢀZꢀcyclopentylꢀ
idene]ethanealdoxime (10c) and antiꢀ2ꢀ[(2S*,5S*)ꢀ2ꢀhydroxyꢀ5ꢀ
hydroxymethylꢀEꢀcyclopentylidene]ethanealdoxime (10d). To
stirred suspension of NH4F (0.17 g, 4.62 mmol) in MeOH (7 mL)
cooled to –50 °C, a solution of compound 4 (1.1 g, 3.30 mmol)
in THF (10 mL) was added under argon. The mixture was alꢀ
lowed to warm up to ambient temperature, kept for 1 h, and
concentrated in vacuo. Column chromatography of the residue
(SiO2, gradient elution from petroleum ether to ethyl acetate)
afforded 0.6 g (70%) of a mixture of oximes 10 as viscous oil. HR
MS (ESI), m/z: found 262.1436, calculated for C15H19NO3,
[M + H]+ 262.1438; found 284.1252, calculated for [M + Na]+
284.1257. Subsequent column chromatography gave eluates enꢀ
riched with individual isomers, which with the exception of 10a
(see below) were purified by crystallization.
Oxime 10c. Colorless crystals, m.p. 108—110 °C (MeOBut).
IR (KBr), ν/cm–1: 578, 632, 701, 752, 854, 905, 936, 986, 1033,
1064, 1155, 1228, 1310, 1347, 1391, 1422, 1456, 1474, 1604,
2880—3216. 1H NMR (300.13 MHz), δ: 1.37 and 1.60 (both m,
1 H each, H2C(4´)); 1.84—2.11 (m, 2 H, H2C(3´)); 2.78 (m, 1 H,
CH(5´)); 3.42—3.72 (m, 2 H, CH2O); 4.45 and 4.54 (both d,
1 H each, H2CPh, J = 11.3 Hz); 4.55 (m, 1 H, HC(2´)); 6.20
(br.d, 1 H, HC=C, J = 10.3 Hz); 7.20—7.41 (m, 5 H, HCarom);
8.10 (d, 1 H, HC=N, J = 10.3 Hz). 13C NMR (50.03 MHz), δ:
25.8 (C(3´)); 30.4 (C(4´)); 45.4 (C(5´)); 64.4 (CH2OH); 70.5
(C(2´)); 78.8 (CH2Ph), 119.3 (C=CH), 127.8, 128.1, 128.5, 137.8
(Ph), 148.9 (C=NOH); 152.4 (C(1´)).
Oxime 10d. Colorless crystals, m.p. 123—125 °C (MeOBut).
IR (KBr), ν/cm–1: 594, 626, 699, 744, 857, 882, 912, 999, 1074,
1118, 1211, 1260, 1334, 1359, 1423, 1453, 1651, 2841—3213.
1H NMR (300.13 MHz), δ: 1.45—1.72 (m, 2 H each, H2C(4´));
1.87—2.15 (m, 2 H, H2C(3´)); 3.08 (m, 1 H, CH(5´)); 3.36—3.59
(m, 2 H, CH2O); 4.28 (br.t, 1 H, HC(2´), J = 6.5 Hz); 4.60
(m, 2 H, H2CPh); 6.90 (dt, 1 H, HC=C, J = 1.9 Hz, J = 10.1 Hz);
7.20—7.41 (m, 6 H, HCarom, HC=N). 13C NMR (50.03 MHz),
δ: 24.8 (C(3´)); 30.1 (C(4´)); 42.1 (C(5´)); 65.8 (CH2OH); 71.2
(C(2´)); 81.3 (CH2Ph), 112.3 (C=CH), 127.6, 127.7, 128.4, 138.3
(Ph), 145.7 (C=NOH); 155.3 (C(1´)).
(5S*,7aS*)ꢀ5ꢀBenzyloxyꢀ5,6,7,7aꢀtetrahydrocyclopentaꢀ
[c]pyranꢀ3(1H)ꢀone oxime (12). At 0 °C, to a stirred under argon
solution of a mixture of oximes 10a,d (10a : 10d = 2 : 3, 313 mg,
1.2 mmol) in CHCl3 (40 mL), Nꢀchlorosuccinimide (0.2 g,
1.5 mmol) was added followed by the addition of Et3N (152 mg,
1.5 mmol) 4 h after. The reaction mixture was kept at 20 °C for
12 h and concentrated in vacuo. The residue was dissolved in
MeOBut (20 mL), washed with water, brine, dried with Na2SO4,
and the solvent was removed in vacuo. Column chromatography
of the residue (SiO2, elution with MeOBut) afforded oxime 12 in
a yield of 218 mg (70%) as colorless crystals, m.p. 112—113 °C
(MeOBut—petroleum ether). HR MS (ESI), m/z: found
260.1281, calculated for C15H17NO3, [M + H]+ 260.1281.
IR (KBr), ν/cm–1: 701, 750, 762, 832, 863, 953, 1035, 1068,
1149—1275, 1322, 1385, 1400, 1455, 1470, 1640, 2859—3298.
1H NMR (200.13 MHz), δ: 1.13—1.35 (m, 1 H, HC(7));
1.82—2.27 (m, 3 H, H2C(6), H´C(7)); 3.02 (m, 1 H, HC(7a));
3.64 (dd, 1 H, αꢀHC(1), J = 10.0 Hz, J = 11.7 Hz); 4.38 (m, 1 H,
HC(5)); 4.48 and 4.57 (both d, 1 H each, H2CPh, J = 11.4 Hz);
4.60 (dd, 1 H, βꢀHC(1), J = 6.4 Hz, J = 10.0 Hz); 6.10 (br.d,
1 H, HC(4), J = 2.5 Hz); 7.26—7.41 (m, 5 H, HCarom); 8.42
(br.s, 1 H, OH). 13C NMR (50.03 MHz), δ: 24.7 (C(7)), 31.70
(C(6)), 36.20 (C(7a)), 70.6 (C(1)), 79.6 (C(5)), 113.1 (C(4)),
127.8, 128.5, 137.9 (Ph), 152.0 (C(4a)), 152.4 (C(3)).
Oxime 10a. Rf 0.66 (MeOBut—petroleum ether, 4 : 1). No
crystals were obtained due to ready isomerization into the correꢀ
sponding antiꢀisomer 10d (the transformation halfꢀtime is ~36 h).
1H NMR (300.13 MHz), δ: 1.47—1.69 (m, 2 H, H2C(4´));
1.91—2.12 (m, 2 H, H2C(3´)); 3.04 (m, 1 H, CH(5´)); 3.48
(m, 2 H, CH2O); 4.27 (br.t, 1 H, HC(2´), J = 5.8 Hz); 4.59 (m, 1 H,
H2CPh); 6.30 (br.d, 1 H, HC=C, J = 10.4 Hz); 7.21—7.41 (m, 5 H,
HCarom); 7.99 (d, 1 H, HC=N, J = 10.4 Hz). 13C NMR
(50.03 MHz), δ: 24.9 (C(3´)); 30.1 (C(4´)); 42.1 (C(5´)); 65.8
(CH2OH); 71.2 (C(2´)); 81.1 (CH2Ph), 117.7 (C=CH), 127.6,
128.4, 138.3 (Ph), 148.5 (C=NOH); 153.0 (C(1´)).
(5S*,7aS*)ꢀ5ꢀBenzyloxyꢀ5,6,7,7aꢀtetrahydrocyclopentaꢀ
[c]pyranꢀ3(1H)ꢀone (13). To a stirred solution of oxime 12
(0.27 g, 1.04 mmol) in DMF—THF (4 mL, 1 : 3), 2ꢀiodoxybenꢀ
zoic acid (IBX, 0.33 g, 1.25 mmol) was added at 20 °C. The
resulting suspension was stirred for 1 h, diluted with petroleum
ether (20 mL). The precipitate that formed was filtered off,
washed with petroleum ether—MeOBut, 4 : 1. The combined
filtrates were washed with water, brine, dried with Na2SO4, and
concentrated in vacuo. Column chromatography (SiO2, elution
with MeOBut—petroleum ether, 3 : 2) afforded lactone 13 in
a yield of 224 mg (88%) as colorless oil, Rf 0.50 (petroleum
ether—MeOBut). HR MS (ESI), m/z: found 245.1174, calculatꢀ
ed for C15H16O3, [M + H]+ 245.1172; found 267.0994, calculatꢀ
ed for [M + Na]+ 267.0992. IR (neat), ν/cm–1: 700, 743, 840,
Oxime 10b. Colorless crystals, m.p. 112—114 °C (MeOBut).
IR (KBr), ν/cm–1: 694, 731, 860, 929, 986, 1036, 1069, 1107,
1147, 1170, 1209, 1273, 1319, 1350, 1374, 1395, 1453, 1497,
1
1629, 1655, 2837—3256. H NMR (300.13 NHz), δ: 1.37—1.62
(both m, 1 H each, H2C(4´)); 1.87—2.12 (m, 2 H, H2C(3´));
2.82 (m, 1 H, CH(5´)); 3.44—3.71 (m, 2 H, CH2O); 4.42 and
4.54 (both d, 1 H each, H2CPh, J = 12.1 Hz); 4.58 (m, 1 H,
HC(2´)); 6.76 (br.d, 1 H, HC=C, J = 9.6 Hz); 7.23—7.34 (m, 5 H,
HCarom); 7.42 (d, 1 H, HC=N, J= 9.6 Hz). 13C NMR (50.03 MHz),
δ: 25.6 (C(3´)); 30.3 (C(4´)); 45.6 (C(5´)); 64.3 (CH2OH); 70.4
(C(2´)); 78.8 (CH2Ph), 113.3 (C=CH), 127.8, 127.9, 128.4, 137.7
(Ph), 145.4 (C=NOH); 154.4 (C(1´)).