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127.7, 127.6, 119.1, 115.5, 85.2, 82.5, 71.9, 71.6, 71.0, 57.5, 53.3; and the diol 17b was obtained as a colourless oil: Rf ¼ 0.4
HRMS calcd for C22H25NNaO2[M + Na]+ 358.1783, found: 358.1786. (hexane–EtOAc ¼ 2 : 1); IR (neat) nmax: 3402, 3060, 3030, 2925,
(2R,3R,4R)-tert-Butyl-3,4-bis(benzyloxy)-2-(hydroxymethyl)- 1491, 1448, 1077 cmꢀ1 1H NMR (500 MHz, CDCl3, 1.4 : 1
;
pyrrolidine-1-carboxylate (30b). The procedure used for con- mixture of diols): d 7.40–7.36 (m, 6H, both isomers), 7.33–7.19
verting 22a to 30a was followed to obtain 30b (215 mg, 70% over (m, 17H, both isomers), 7.13–7.08 (m, 2H, both isomers), 5.28
2 steps) from 28a (300 mg, 0.74 mmol) as a colourless oil: (d, J ¼ 3.7 Hz, 1H, major isomer), 4.73–4.63 (m, 2H major
Rf ¼ 0.4 (hexane–EtOAc ¼ 3 : 1); [a]2D8 ¼ ꢀ16.5 (c 2.85, CH2Cl2); isomer, 4H minor isomer), 4.48–4.40 (m, 1H major isomer, 2H
IR (neat) nmax: 3419, 2928, 1691, 1454, 1400, 1366, 1170, 1098 minor isomer), 4.13 (t, J ¼ 6.7 Hz, 1H, major isomer), 4.09 (dd,
1
cmꢀ1; H NMR (500 MHz, CDCl3): d 7.36–7.24 (m, 10H), 4.62– J ¼ 3.6, 10.2 Hz, 1H, minor isomer), 4.04 (br s, 1H, major
4.45 (m, 4H), 4.04–3.97 (m, 2H), 3.84–3.75 (m, 3H), 3.67–3.64 isomer), 3.97 (d, J ¼ 2.7 Hz, 1H, major isomer), 3.78 (dd, J ¼ 7.9,
(m, 1H), 3.49–3.47 (m, 1H), 1.46 (s, 9H); 13C NMR (125 MHz, 9.5 Hz, 1H, minor isomer), 3.75 (dd, J ¼ 2.7, 10.0 Hz, 1H, major
CDCl3): d 156.8, 137.4, 128.6, 128.0, 127.8, 82.9, 80.6, 80.3, 71.7, isomer), 3.49–3.47 (m, 2H, minor isomer), 3.42–3.38 (m, 2H,
71.6, 65.3, 65.2, 51.3, 28.5; HRMS calcd for C24H31NNaO5[M + major isomer), 3.29 (t, J ¼ 10.2 Hz, 1H, minor isomer) 3.24–3.21
Na]+ 436.2100, found: 436.2100.
(m, 1H, major isomer), 2.97 (br s, 1H, major isomer), 2.55 (br s,
(2R,3R,4R)-tert-Butyl-3,4-bis(benzyloxy)-2-vinylpyrrolidine-1- 1H minor isomer), 2.33 (br s, 1H, major isomer); 1.88 (br s, 1H,
carboxylate (31b). The same procedure used for obtaining 31a minor isomer) 13C NMR (125 MHz, CDCl3): d 143.8, 138.5, 138.4,
from 30a was followed to obtain 31b (145 mg, 70% over 2 steps) 128.7, 128.6, 128.2, 128.1, 127.9, 127.8, 127.5, 127.2, 97.3, 92.8,
from 30b (210 mg, 0.51 mmol) as a colourless oil: Rf ¼ 0.7 87.3, 87.2, 82.1, 79.0, 74.6, 74.1, 73.1, 72.9, 72.4, 70.2, 68.9, 62.5,
(hexane–EtOAc ¼ 4 : 1); [a]2D8 ¼ ꢀ2.85 (c 1.40, CH2Cl2); IR (neat) 62.2; HRMS calcd for C39H38NaO6 [M + Na]+ 625.2566, found:
nmax: 2976, 2928, 1695, 1496, 1454, 1393, 1365, 1171, 1098 cmꢀ1
;
625.2563.
(2R,3S,4S)-3,4-Bis(benzyloxy)-5-oxo-1-(trityloxy)pentan-2-yl
1H NMR (500 MHz, CDCl3): d 7.36–7.25 (m, 10H), 5.85 (br s, 1H),
5.29–5.09 (m, 2H), 4.61–4.41 (m, 4H), 4.21 (br s, 1H), 4.06–4.01 formate (18b). Following the procedure for oxidative cleavage of
(m, 1H), 3.89 (br s, 1H), 3.78–3.63 (m, 1H), 3.52–3.50 (m, 1H), diol 17a, crude diol 17b was converted to 18b (2.20 g, 70% over 2
1.42 (s, 9H); 13C NMR (125 MHz, CDCl3): d 154.7, 137.7, 137.1, steps) as a colourless oil: Rf ¼ 0.5 (hexane–EtOAc ¼ 3 : 1); [a]2D8
¼
128.5, 127.9, 127.7, 115.7, 86.7, 85.4, 81.2, 80.1, 79.8, 79.7, 71.8, ꢀ7.8 (c 0.90, CH2Cl2); IR (neat) nmax: 3060, 3031, 2928, 1728,
71.7, 71.6, 71.4, 65.3, 51.0, 49.9, 29.7, 28.5; HRMS calcd for 1491, 1449, 1170, 1070 cmꢀ1; 1H NMR (500 MHz, CDCl3): d 9.55
C
25H31NNaO4 [M + Na]+ 432.2151, found: 432.2152.
(s, 1H), 8.00 (s, 1H), 7.39–7.37 (m, 6H), 7.31–7.22 (m, 17H), 7.14–
(2R,3R,4R)-3,4-Bis(benzyloxy)-1-(but-3-enyl)-2-vinylpyrrolidine 7.12 (m, 2H), 5.40 (dd, J ¼ 5.1, 10.0 Hz, 1H), 4.60–4.55 (m, 2H),
(32b). The procedure used for converting 31a to 32a was used to 4.40–4.46 (m, 2H), 4.15 (t, J ¼ 4.9 Hz, 1H), 3.85 (dd, J ¼ 5.1, 2.0
obtain 32b (90 mg) from 31b (140 mg, 0.34 mmol) in 73% yield as Hz, 1H), 3.38 (dd, J ¼ 5.1, 10.3 Hz, 1H), 3.32 (dd, J ¼ 5.1, 10.0 Hz,
a colourless oil: Rf ¼ 0.4 (hexane–EtOAc ¼ 9 : 1); [a]D28 ¼ +11.0 1H); 13C NMR (125 MHz, CDCl3): d 201.6, 160.3, 143.4, 137.1,
(c 1.00, CH2Cl2); IR (neat) nmax: 2922, 1695, 1638, 1496, 1454, 136.7, 129.0, 128.6, 128.4, 128.3, 128.2, 128.1, 128.0, 127.8,
1
1363, 1206, 1096 cmꢀ1; H NMR (500 MHz, CDCl3): d 7.35–7.24 127.3, 87.2, 82.2, 77.7, 74.4, 72.9, 72.1, 61.7; HRMS calcd for
(m, 10H), 5.86–5.70 (m, 2H), 5.12–5.00 (m, 4H), 4.64–4.51 (m, 4H),
3.76 (dd, J ¼ 4.6, 6.8 Hz, 1H), 3.70–3.61 (m, 3H), 3.57 (dd, J ¼ 2.9,
C
39H36NaO6 [M + Na]+ 623.2410, found: 623.2416.
(2R,3S,4R)-2,3-Bis(benzyloxy)-5-(trityloxy)pentane-1,4-diol (19b).
4.6 Hz, 1H), 2.99 (br s, 1H), 2.69 (br s, 1H), 2.34–2.17 (m, 2H); 13
C
In the same way as 18a was reduced using NaBH4, the aldehyde
NMR (125 MHz, CDCl3): d 135.6, 135.4, 132.7, 132.8, 128.0, 127.6, 18b (2.45 g, 4.08 mmol) was reduced to furnish 1.92 g (82%) of 19b
127.5, 84.5, 79.8, 76.4, 67.8, 63.9, 60.7, 32.7; HRMS calcd for as a colourless oil: Rf ¼ 0.3 (hexane–EtOAc ¼ 4 : 1); [a]2D8 ¼ ꢀ5.40
C24H30NO2[M + H]+ 364.2277, found: 364.2272.
(c 2.05, CH2Cl2); IR (neat) nmax: 3437, 3060, 3030, 2936, 2876, 1491,
(1R,2R,8aR)-1,2-Bis(benzyloxy)-1,2,3,5,6,8a-hexahydroindolizine 1449, 1074 cmꢀ1; 1H NMR (500 MHz, CDCl3): d 7.51–7.43 (m, 6H),
(33b). The diene 32b was subjected to ring closing metathesis 7.36–7.23 (m, 17H), 7.12–7.10 (m, 2H), 4.68–4.61 (m, 3H), 4.37 (d,
using the same procedure as described for diene 32a (80 mg, 0.22 J ¼ 10.6 Hz, 1H), 4.01 (t, J ¼ 5.8 Hz, 1H), 3.90 (dd, J ¼ 1.4, 6.4 Hz,
mmol) to obtain 33b (58 mg, 79%) as a colorless oil: Rf ¼ 0.7 1H), 3.85 (dd, J ¼ 3.9, 11.9 Hz, 1H), 3.72 (dd, J ¼ 3.3, 11.9 Hz, 1H),
(hexane–EtOAc ¼ 4 : 1); [a]2D8 ¼ + 11.0 (c 1.00, CH2Cl2); IR (neat) 3.67–3.65 (m, 1H), 3.37 (dd, J ¼ 6.1, 9.2 Hz, 1H) 3.12 (dd, J ¼ 7.0, 9.2
nmax: 2922, 1695, 1638, 1496, 1454, 1363, 1206, 1096 cmꢀ1; 1H NMR Hz, 1H); 2.43 (br s, 1H), 2.30 (br s, 1H); 13C NMR (125 MHz, CDCl3):
(500 MHz, CDCl3): d 7.34–7.25 (m, 10H), 5.91–5.88 (m, 1H), 5.82– d 143.8, 138.0, 137.7, 128.7, 128.6, 128.4, 128.3, 128.0, 127.9, 127.2,
5.78 (m, 1H), 4.71–4.68 (m, 2H), 4.63–4.52 (m, 2H), 4.35 (dd, J ¼ 2.4, 86.9, 79.5, 77.2, 74.6, 72.5, 70.0, 64.7, 60.8; HRMS calcd for
6.5 Hz, 1H), 4.26 (dd, J ¼ 3.1, 8.2 Hz, 1H), 3.92 (br s, 1H), 3.50 (dd, C38H38NaO5 [M + Na]+ 597.2617, found: 597.2615.
J ¼ 6.7, 9.8 Hz, 1H), 3.39 (d, J ¼ 11.2 Hz, 1H), 3.14 (d, J ¼ 11.2 Hz,
(2R,3R,4R)-2,3-Bis(benzyloxy)-5-(trityloxy)pentane-1,4-diyl
1H), 2.97 (m, 1H), 2.50 (dd, J ¼ 5.5, 8.2 Hz, 1H), 2.25 (J ¼ 5.5, 8.2 dimethanesulfonate (20b). The diol 19b (1.20 g, 2.08 mmol) was
Hz, 1H); 13C NMR (125 MHz, CDCl3): d 138.3, 138.2, 136.5, 135.8, converted to its mesylate in the same manner as diol 19a, to
128.5, 128.3, 127.9, 127.8, 127.7, 127.6, 121.2, 119.6, 82.3, 81.3, yield 1.42 g (95%) of 20b as a colourless viscous liquid: Rf ¼ 0.4
71.9, 71.6, 71.0, 57.6, 53.5; HRMS calcd for C22H25NNaO2[M + Na]+ (hexane–EtOAc ¼ 3 : 1); [a]2D8 ¼ +16.4 (c 0.65, CH2Cl2); IR (neat)
358.1783, found: 358.1782.
nmax: 3031, 1492, 1450, 1357, 1176 cmꢀ1 1H NMR (500 MHz,
;
(4R,5S,6R)-4,5-Bis(benzyloxy)-6-(trityloxymethyl)tetrahydro- CDCl3): d 7.45–7.14 (m, 25H), 5.10–5.07 (m, 1H), 3.65–3.58 (m,
2H-pyran-2,3-diol (17b). The olen 16b (3.00 g, 5.28 mmol) was 3H), 4.54 (dd, J ¼ 2.8, 11.4 Hz, 1H), 4.44 (d, J ¼ 10.9 Hz, 1H), 4.31
subjected to dihydroxylation using the same procedure as 16a, (dd, J ¼ 3.7, 11.4 Hz, 1H), 3.92 (dd, J ¼ 3.7, 8.3 Hz, 1H), 3.79–3.77
12562 | RSC Adv., 2014, 4, 12555–12567
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