328
S. Vuong et al. / Carbohydrate Research 345 (2010) 324–329
d6, 300 MHz) d 6.43 (dd, 1H, J = 12 Hz, J = 18 Hz, H-10), 5.92 (s, 1H,
H-5), 5.81 (s, 1H, H-3), 5.33 (d, 1H, J = 18 Hz, H-20), 5.23 (d, 1H,
J = 12 Hz, H-20), 4.92 (m, 1H, H-2), 3.75 (m, 4H, OCH2CH3, CH2OH),
1.28 (t, 3H, J = 8 Hz, CH3). 13C (CDCl3, 75 MHz) d 139.9 (C-4), 128.7
(C-3, C-10), 118.2 (C-20), 107.1 (C-5), 85.4 (C-2), 64.6 (CH2OH), 63.8
(OCH2CH3), 15.8 (CH3). HRMS (ESI) [M+Na]+ 193.0841, found
m/z = 193.0851. 12 trans. Rf = 0.2 (EtOAc/hexane 20:80). 1H NMR
(acetone-d6, 300 MHz) d 6.46 (dd, 1H, J = 12 Hz, J = 18 Hz, H-10),
6.00 (d, 1H, J = 4 Hz, H-5), 5.95 (s, 1 H, H-3), 5.43 (d, 1H,
J = 18 Hz, H-20), 5.27 (d, 1H, J = 12 Hz, H-20), 5.04 (m, 1H, J = 4 Hz,
H-2), 3.65 (m, 4H, OCH2CH3, CH2OH), 1.25 (t, 3H, CH3). 13C (CDCl3,
75 MHz) d 139.8 (C-4), 128.9 (C-3), 128.7 (C-10), 118.5 (C-20), 107.1
(C-5), 85.8 (C-2), 65.1 (CH2OH), 62.4 (OCH2CH3), 15.7 (CH3). HRMS
(ESI) [M+Na]+ 193.0841, found m/z = 193.0858.
(OCH2Bz), 62.1 (OCH2CH3), 15.3 (CH3). HRMS (ESI) [M+Na]+ calcd
297.1103, found m/z = 297.1103.
1.8.5. (2S,5R)- and (2R,5S)-(5-Ethoxy-4-vinyl-2,5-dihydrofuran-
2-ylmethyl)-acetate (24 cis) and (2R,5S)- and (2S,5R)-(5-ethoxy-
4-vinyl-2,5-dihydrofuran-2-ylmethyl)-acetate (24 trans)
Starting from enyne mixture of 19 and 20 (100 mg, 0.47 mmol),
the flash chromatography (CH2Cl2/hexane 30:70) gave 24 cis
(16 mg, 16%) and 24 trans (32 mg, 32%) in the order of fractions
eluted. 24 cis. Rf = 0.2 (CH2Cl2/hexane 60:40). 1H NMR (acetone-
d6, 300 MHz) d 6.43 (dd, 1H, J = 12 Hz, J = 18 Hz, H-10), 6.11 (s,
1H, H-3), 5.86 (s, 1H, H-5), 5.47 (d, 1H, J = 18 Hz, H-20), 5.23 (d,
1H, J = 12 Hz, H-20), 4.88 (s, 1H, H-2), 4.10 (m, 2H, CH2OAc), 3.63
(m, 2H, OCH2CH3), 2.04 (s, 3H, CH3), 1.25 (t, 3H, J = 8 Hz, CH3).
13C (CDCl3, 75 MHz) d 170.9 (CO), 139.7 (C-4), 128.4 (C-3), 127.7
(C-10), 118.4 (C-2), 107.3 (C-5), 82.6 (C-2), 66.5 (C-1), 62.6
(OCH2CH3), 20.9 (CH3CO), 15.4 (CH3). HRMS (ESI) [M+Na]+ calcd
235.0946, found m/z = 235.0935. 24 trans. Rf = 0.1 (CH2Cl2/hexane
60:40). 1H NMR (acetone-d6, 300 MHz) d 6.50 (dd, 1H, J = 12 Hz,
J = 18 Hz, H-10), 6.10 (s, 1H, H-3), 5.97 (d, 1H, J = 4 Hz, H-5), 5.44
(d, 1H, J = 18 Hz, H-20), 5.25 (d, 1H, J = 12 Hz, H-20), 5.05 (m, 1H,
H-2), 4.08 (m, 2H, CH2OAc), 3.56 (m, 2H, OCH2CH3), 2.05 (s, 3H,
CH3), 1.24 (t, 3H, J = 8 Hz, CH3), 13C (CDCl3, 75 MHz) d 170.9 (CO),
139.7 (C-4), 128.4 (C-3), 127.7 (C-10), 118.4 (C-20), 107.2 (C-5),
82.3 (C-2), 66.2 (C-1), 62.4 (OCH2CH3), 20.9 (CH3CO), 15.4 (CH3).
HRMS (ESI) [M+Na]+ calcd 235.0946, found m/z = 235.0938.
1.8.3. (2S,5R)- and (2R,5S)-(5-Ethoxy-4-vinyl-2,5-dihydrofuran-
2-ylmethoxy)-triphenylmethane (22 cis) and (2R,5S)- and
(2S,5R)-(5-ethoxy-4-vinyl-2,5-dihydrofuran-2-ylmethoxy)-
triphenylmethane (22 trans)
Starting from enyne mixture of 15 and 16 (100 mg, 0.24 mmol),
the flash chromatography (CH2Cl2/hexane 40:60) gave 22 cis
(30 mg, 30%) and 22 trans (20 mg, 20%) in the order of fractions
eluted. 22 cis. Rf = 0.6 (EtOAc/hexane 5:95). 1H NMR (acetone-d6,
300 MHz) d 7.50 (m, 6H, Ph), 7.28 (m, 9H, Ph), 6.46 (dd, 1H,
J = 12 Hz, J = 18 Hz, H-30), 6.10 (s, 1H, H-3), 5.90 (s, 1H, H-5), 5.43
(d, 1H, J = 18 Hz, H-20), 5.22 (d, 1H, J = 12 Hz, H-20), 4.90 (m, 1H,
H-2), 3.65 (m, 2H, CH2OTr), 3.16 (m, 2H, OCH2CH3), 1.21 (t, 3H,
J = 8 Hz, CH3). 13C (CDCl3, 75 MHz) d 144.4 (Ph), 139.0 (C-4),
129.8 (C-3), 129.2 (Ph), 128.9 (C-10), 128.1 (Ph), 127.3 (Ph), 118.1
(C-20), 107.7 (C-5), 87.0 (CPh3), 84.6 (C-2), 67.5 (CH2OTr), 62.8
(OCH2CH3), 15.7 (CH3). HRMS (ESI) [M+Na]+ 435.1936, found
m/z = 435.1951. 22 trans. Rf = 0.5 (EtOAc/hexane 5:95). 1H NMR
(acetone-d6, 300 MHz) d 7.43 (m, 6H, Ph), 7.25 (m, 9H, Ph), 6.36
(dd, 1H, J = 12 Hz, J = 18 Hz, H-10), 6.13 (s, 1H, H-3), 5.90 (d, 1H,
J = 4 Hz, H-5), 5.41 (d, 1H, J = 18 Hz, H-20), 5.22 (d, 1H, J = 12 Hz,
H-20), 5.10 (m, 1H, H-2), 3.61 (m, 2H, CH2OTr), 3.13 (m, 2H,
OCH2CH3), 1.21 (t, 3H, J = 8 Hz, CH3). 13C (CDCl3, 75 MHz) d 144.4
(Ph), 138.6 (C-4), 130.7 (C-3), 129.1 (Ph), 128.9 (C-10), 128.2 (Ph),
127.4 (Ph), 118.1 (C-20), 107.5 (C-5), 86.9 (CPh3), 84.3 (C-2), 66.8
(CH2OTr), 61.9 (OCH2CH3), 15.7 (CH3). HRMS (ESI) [M+Na]+ calcd
435.1936, found m/z = 435.1938.
1.9. 1-(tert-Butyldiphenylsilanyloxy)but-3-en-2-ol ((2S)-8)
The (2S)-but-3-en-1,2-diol ((2S)-7) was converted to the silylat-
ed compound by the procedure employed above for the racemate
to give the alcohol (2S)-8; enantiomer (2S)-8 had NMR data iden-
tical to those for the racemic compound 8, ½a D22
¼ þ0:6 (c 1.0 in
ꢀ
CHCl3); HRMS (ESI) [M+Na]+ calcd 349.1600, found m/z = 349.1604.
1.10. (1R,2S)-(2-(1-Ethoxyprop-2-ynyloxy)but-3-enyloxy)-tert-
butyldiphenylsilane ((1R,2S)-10) and (1S,2S)-(2-(1-ethoxyprop-
2-ynyloxy)but-3-enyloxy)-tert-butyldiphenylsilane ((1S,2S)-11)
Compound (2S)-8 was converted to the acyclic enynes by the
procedure employed above for the racemate to give the acyclic
enynes (1R,2S)-10 and (1S,2S)-11; enantiomers (1R,2S)-10 and
(1S,2S)-11 have NMR data identical to those for the racemic
compounds 10 and 11. HRMS (ESI) [M+Na]+ calcd 431.2018, found
m/z = 431.2016.
1.8.4. (2S,5R)- and (2R,5S)-(5-Ethoxy-4-vinyl-2,5-dihydrofuran-
2-ylmethyl)-benzoate (23 cis) and (2R,5S)- and (2S,5R)-(5-
Ethoxy-4-vinyl-2,5-dihydrofuran-2-ylmethyl)-benzoate (23
trans)
Starting from enyne mixture of 17 and 18 (100 mg, 0.36 mmol),
the flash chromatography (EtOAc/hexane 5:95) gave 23 cis (20 mg,
20%) and 23 trans (15 mg, 15%) in the order of fractions eluted. 23
cis. Rf = 0.3 (EtOAc/hexane 5:95). 1H NMR (acetone-d6, 300 MHz) d
8.06 (m, 2H, Ph), 7.50 (m, 3H, Ph), 6.46 (dd, 1H, J = 12 Hz, J = 18 Hz,
H-10), 6.21 (s, 1H, H-3), 5.90 (s, 1H, H-5), 5.46 (d, 1H, J = 18 Hz, H-
20), 5.23 (d, 1H, J = 12 Hz, H20), 5.03 (s 1H, H-2), 4.42 (m, 2H,
OCH2Bz), 3.60 (m, 2H, OCH2CH3), 1.14 (t, 3H, J = 8 Hz, CH3), 13C
(CDCl3, 75 MHz) d 166.4 (CO), 139.8 (C-4), 133.0 (Ph), 130.0 (C-
3), 129.9 (Ph), 129.8 (Ph), 128.3 (Ph), 127.8 (C-10), 118.4 (C-2),
107.4 (C-5), 82.6 (C-2), 66.8 (OCH2Bz), 62.7 (OCH2CH3), 15.4
(CH3). HRMS (ESI) (M+Na+) calcd 297.1103, found m/z = 297.1100.
23 trans. Rf = 0.2 (EtOAc/hexane 5:95). 1H NMR (acetone-d6,
300 MHz) d 8.01 (m, 2H, Ph), 7.58 (m, 3H, Ph), 6.46 (dd, 1H,
J = 12 Hz, J = 18 Hz, H-10), 6.21 (s, 1H, H-3), 6.02 (d, 1H, J = 4 Hz,
H-5), 5.49 (d, 1H, J = 18 Hz, H-20), 5.24 (d, 1H, J = 12 Hz, H-20),
5.21 (m, 1H, H-2), 4.39 (m, 2H, OCH2Bz), 3.60 (m, 2H, OCH2CH3),
1.14 (t, 3H, J = 8 Hz, CH3), 13C (CDCl3, 75 MHz) d 166.4 (CO),
139.6 (C-4), 133.1 (Ph), 129.9 (C-3), 129.8 (Ph), 129.7 (Ph), 128.4
(Ph), 128.1 (C-10), 118.6 (C-4), 107.3 (C-5), 82.7 (C-2), 66.2
1.11. (2S,5R)-tert-Butyl-(5-ethoxy-4-vinyl-2,5-dihydrofuran-2-
ylmethoxy)-diphenylsilane ((2S,5R)-12) and (2S,5S)-tert-butyl-
(2-(1-ethoxyprop-2-ynyloxy)but-3-enyloxy)-diphenylsilane
((2S,5S)-12)
A mixture of compounds (1R,2S)-10 and (1S,2S)-11 was con-
verted to the cyclic enynes by the procedure employed above for
the racemate to give the cyclic enynes (2S,5R)-12 and (2S,5S)-12;
enantiomer (2S,5R)-12 had NMR data identical to those for the
racemic compound 12 cis, ½a D20
¼ ꢁ70:6 (c 0.3 in CHCl3); HRMS
ꢀ
(ESI) [M+Na]+ calcd 431.2018, found m/z = 431.2034; enantiomer
(2S,5S)-12 had NMR data identical to those for the racemic com-
pound 12
trans, ½a 2D0
¼ ꢁ30:9 (c 0.3 in CHCl3); HRMS (ESI)
ꢀ
[M+Na]+ calcd 431.2018, found m/z = 431.2005.
Acknowledgment
This work was supported by regional program for invited
researcher from the Région Poitou-Charentes, France.