E. I. León, A. Martín, I. Peréz-Martín, L. M. Quintanal, E. Suárez
Compound 17: 1H NMR (500 MHz, C6D6): δ = 1.77 (s, 3 H, OAc), 459.2203. C20H36O10 (436.50): calcd. C 55.03, H 8.31; found C
FULL PAPER
3.06 (dd, J = 3.4, 9.3 Hz, 1 H, 2-H), 3.087 (s, 3 H, OMe), 3.090 (s,
3 H, OMe), 3.28 (s, 3 H, OMe), 3.33 (s, 3 H, OMe), 3.35 (s, 3 H,
OMe), 3.48 (s, 3 H, OMe), 3.51 (s, 3 H, OMe), 3.70–3.82 (m, 7 H),
3.894 (d, J = 9.0 Hz, 4Ј-H-D), 3.897 (dd, J = 9.3, 9.3 Hz, 1 H, 4Ј-
H), 4.01 (ddd, J = 1.7, 5.1, 9.9 Hz, 1 H, 5Ј-H), 4.40 (dd, J = 5.1,
12.1 Hz, 1 H, 6-Ha), 4.57 (d, J = 3.7 Hz, 1 H, 1-H), 4.67 (dd, J =
2.2, 11.9 Hz, 1 H, 6-Hb), 5.55 (d, J = 2.0 Hz, 1 H, 1Ј-H) ppm. 13C
NMR (125.7 MHz, C6D6): δ = 20.5 (CH3, OAc), 54.8 (CH3, OMe),
57.3 (CH3, OMe), 57.6 (CH3, OMe), 58.6 (CH3, OMe), 59.1 (CH3,
OMe), 60.4 (CH3, OMe), 60.8 (CH3, OMe), 63.9 (CH2, C-6), 68.8
(CH, C-5), 72.312 (CH2, C-6Ј-D), 72.376 (CH2, C-6Ј-H), 73.9 (CH,
C-5Ј-H), 76.894 (CH, C-4Ј-D), 76.947 (CH, C-4Ј-H), 77.3 (CH, C-
4), 78.3 (CH, C-2Ј), 81.9 (CH, C-3Ј), 82.6 (CH, C-2), 83.8 (CH, C-
3), 97.4 (CH, C-1), 100.2 (CH, C-1Ј), 170.0 (C, OAc) ppm. MS
(70 eV, EI): m/z (%) = 451 (Ͻ1) [M – CH3OH]+, 450 (Ͻ1), 307
(19), 247 (26), 88 (100). HRMS (EI): m/z: calcd. for C20H342HO11:
451.2164 [M – CH3OH]+; found 451.2179.
55.33, H 7.99.
Compound 19: [α]D = +174.8 (c = 0.076, in CHCl3). 1H NMR
(500 MHz, C6D6): δ = 1.11 (dd, J = 12.3, 12.3 Hz, 1 H, 4a-Ha),
2.25 (dddd, J = 3.7, 10.5, 10.5, 12.1 Hz, 1 H, 4-H), 2.78 (dd, J =
3.7, 13.3 Hz, 1 H, 4a-Hb), 3.14 (dd, J = 3.4, 9.2 Hz, 1 H, 2-H), 3.17
(s, 6 H, 2ϫOMe), 3.22 (s, 3 H, OMe), 3.33 (s, 3 H, OMe), 3.33 (d,
J = 3.1 Hz, 1 H, 2Ј-H), 3.37 (dd, J = 9.3, 10.7 Hz, 1 H, 3-H), 3.40
(s, 3 H, OMe), 3.42 (s, 3 H, OMe), 3.49 (s, 3 H, OMe), 3.59 (dd, J
= 1.8, 10.7 Hz, 1 H, 6-Ha), 3.65 (dd, J = 5.4, 10.5 Hz, 1 H, 6-Hb),
3.70 (m, 1 H, 5-H), 3.75–3.82 (m, 4 H, 6Ј-H2, 5Ј-H, 4Ј-H), 3.88
(dd, J = 2.9, 9.0 Hz, 1 H, 3Ј-H), 4.72 (d, J = 3.5 Hz, 1 H, 1-H)
ppm. 13C NMR (125.7 MHz, C6D6): δ = 33.7 (CH2, C-4a), 40.7
(CH, C-4), 54.9 (CH3, OMe), 57.7 (CH3, OMe), 57.8 (CH3, OMe),
59.2 (CH3, OMe), 60.2 (CH3, OMe), 60.5 (CH3, OMe), 61.3 (CH3,
OMe), 62.6 (CH2, C-6Ј), 67.1 (CH, C-5), 72.4 (CH2, C-6), 73.1
(CH, C-5Ј), 77.2 (CH, C-4Ј), 80.6 (CH, C-3), 81.2 (CH, C-2Ј), 83.9
(CH, C-3Ј), 84.0 (CH, C-2), 99.1 (CH, C-1), 99.2 (C, C-1Ј) ppm.
IR (film): ν = 2916, 2828, 1195, 1096, 960 cm–1. MS (70 eV, EI):
Oxidative HAT of Methyl 2,3,4,6-Tetra-O-methyl-α-
D-manno-
˜
m/z (%) = 436 (Ͻ1) [M]+, 391 (Ͻ1), 261 (25), 88 (100). HRMS
(EI): m/z: calcd. for C20H36O10: 436.2308 [M]+; found 436.2323.
C20H36O10 (436.50): calcd. C 55.03, H 8.31; found C 55.21, H 8.13.
pyranosyl-(1Ǟ4a)-2,3-di-O-methyl-4a-carba-α- -glucopyranoside
D
(2): A solution of the alcohol 2 (64 mg, 0.146 mmol) in dry CH2Cl2
(7 mL) containing DIB (80 mg, 0.248 mmol) and iodine (29 mg,
0.146 mmol) under nitrogen was irradiated with two 80 W tung-
sten-filament lamps at room temperature for 1.5 h. The mixture
was then poured into 10% aqueous Na2S2O3 and extracted with
CH2Cl2, dried with Na2SO4 and concentrated under reduced pres-
sure. Chromatography of the residue (hexanes/EtOAc, 2:8 Ǟ 0:1)
afforded in order of elution: a mixture of methyl (4aS)-1Ј,6-anhy-
dro-(2Ј,3Ј,4Ј,6Ј-tetra-O-methyl-α--manno-hex-1Ј-ulopyranosyl)-
(1Ǟ4a)-2,3-di-O-methyl-4a-iodo-4a-carba-α--glucopyranoside
(20) and methyl (2S,4aS)-2Ј,6-anhydro-(2Ј,3Ј,4Ј,6Ј-tetra-O-methyl-
α--arabino-hex-2Ј-ulopyranosyl)-(1Ǟ4a)-2,3-di-O-methyl-4a-
iodo-4a-carba-α--glucopyranoside (21) (9 mg, 0.016 mmol, 9%),
methyl 1Ј-6-anhydro-(2Ј,3Ј,4Ј,6Ј-tetra-O-methyl-α--manno-hex-1Ј-
ulopyranosyl)-(1Ǟ4a)-2,3-di-O-methyl-4a-carba-α--glucopyrano-
side (19) (26.1 mg, 0.06 mmol, 41%), and methyl (5ЈR)-5Ј-6-anhy-
dro-(2Ј,3Ј,4Ј,6Ј-tetra-O-methyl-α--lyxo-hexos-5Ј-ulopyranosyl)-
(1Ǟ4a)-2,3-di-O-methyl-4a-carba-α--glucopyranoside (18)
(20 mg, 0.046 mmol, 32%). Careful purification by chromatotron
chromatography of the mixture of iodo compounds 20 and 21 al-
lowed isolation of small amounts of pure 20 together with enriched
fractions of 21.
Compound 18: [α]D = +38.7 (c = 0.390, in CHCl3). 1H NMR
(500 MHz, C6D6): δ = 1.70 (ddd, J = 7.3, 13.6, 13.6 Hz, 1 H, 4a-
Ha), 1.72 (ddd, J = 1.9, 7.3, 13.6 Hz, 1 H, 4a-Hb), 1.97 (dddd, J =
1.9, 6.6, 10.4, 10.4 Hz, 1 H, 4-H), 3.13 (s, 3 H, OMe), 3.15 (s, 3 H,
OMe), 3.17 (s, 3 H, OMe), 3.21 (s, 3 H, OMe), 3.25 (dd, J = 3.5,
9.5 Hz, 1 H, 2-H), 3.31 (dd, J = 1.6, 3.0 Hz, 1 H, 2Ј-H), 3.37 (dd,
J = 9.5, 10.7 Hz, 1 H, 3-H), 3.38 (s, 3 H, OMe), 3.45 (d, J =
10.4 Hz, 1 H, 6Ј-Ha), 3.57 (s, 3 H, OMe), 3.65 (ddd, J = 3.8, 10.4,
10.4 Hz, 1 H, 5-H), 3.67 (s, 3 H, OMe), 3.72 (d, J = 10.4 Hz, 1 H,
6Ј-Hb), 3.89 (dd, J = 4.1, 11.3 Hz, 1 H, 6-Hb), 3.94 (dd, J = 2.8,
10.1 Hz, 1 H, 3Ј-H), 4.05 (dd, J = 10.7, 10.7 Hz, 1 H, 6-Ha), 4.22
(ddd, J = 1.6, 7.3, 12.0 Hz, 1 H, 1Ј-H), 4.36 (d, J = 10.4 Hz, 1 H,
4Ј-H), 4.73 (d, J = 3.2 Hz, 1 H, 1-H) ppm. 13C NMR (125.7 MHz,
C6D6): δ = 31.9 (CH2, C-4a), 43.9 (CH, C-4), 54.8 (CH3, OMe),
57.2 (CH3, OMe), 57.5 (CH3, OMe), 58.1 (CH3, OMe), 59.1 (CH3,
1
Compound 20: H NMR (500 MHz, C6D6): δ = 1.87 (ddd, J = 2.8,
10.1, 10.1 Hz, 1 H, 4-H), 3.09 (s, 3 H, OMe), 3.10 (s, 3 H, OMe),
3.17 (s, 3 H, OMe), 3.23 (s, 3 H, OMe), 3.25 (dd, J = 3.5, 9.1 Hz,
1 H, 2-H), 3.45 (s, 3 H, OMe), 3.53 (dd, J = 1.6, 10.7 Hz, 1 H, 6Ј-
Ha), 3.59 (dd, J = 5.7, 10.7 Hz, 1 H, 6Ј-Hb), 3.64 (s, 3 H, OMe),
3.72 (dd, J = 9.8, 9.8 Hz, 1 H, 4Ј-H), 3.76 (s, 3 H, OMe), 3.77 (ddd,
J = 1.3, 5.7, 9.8 Hz, 1 H, 5Ј-H), 3.80–3.87 (m, 3 H, 6-H2, 3Ј-H),
3.98 (dd, J = 9.8, 9.8 Hz, 1 H, 3-H), 4.27 (ddd, J = 6.3, 9.8, 9.8 Hz,
1 H, 5-H), 4.30 (d, J = 2.8 Hz, 1 H, 2Ј-H), 4.64 (d, J = 3.5 Hz, 1
H, 1-H), 5.26 (d, J = 2.8 Hz, 1 H, 4a-H) ppm. 13C NMR
(125.7 MHz, C6D6): δ = 36.7 (CH, C-4a), 44.8 (CH, C-4), 55.2
(CH3, OMe), 57.6 (CH3, OMe), 57.8 (CH3, OMe), 59.1 (CH3,
OMe), 60.5 (CH3, OMe), 60.9 (CH3, OMe), 61.5 (CH3, OMe), 63.2
(CH2, C-6), 64.3 (CH, C-5), 72.2 (CH2, C-6Ј), 73.8 (CH, C-5Ј), 76.9
(CH, C-4Ј), 80.1 (CH, C-3), 80.3 (CH, C-2Ј), 84.4 (CH, C-3Ј), 85.2
(CH, C-2), 99.0 (CH, C-1), 99.9 (C, C-1Ј) ppm. MS (ESI+):
m/z (%) = 585 (100) [M + Na]+. HRMS (ESI+): m/z: calcd. for
C20H35INaO10: 585.1186 [M + Na]+; found 585.1188.
Compound 21: From spectroscopic data obtained from an enriched
mixture of 20 and 21, only clearly distinguished signals are re-
1
ported: H NMR (500 MHz, C6D6): δ = 1.76 (ddd, J = 4.1, 10.1,
10.1 Hz, 1 H, 4-H), 3.10 (s, 3 H, OMe), 3.12 (s, 3 H, OMe), 3.25
(s, 3 H, OMe), 3.38 (dd, J = 3.2, 8.8 Hz, 1 H, 2-H), 3.45 (s, 3 H,
OMe), 3.50 (s, 3 H, OMe), 3.52 (s, 3 H, OMe), 3.68 (dd, J = 8.8,
8.8 Hz, 1 H), 3.73 (s, 3 H, OMe), 3.98 (m, 1 H, 5-H), 4.15 (dd, J
= 9.5, 9.5 Hz, 1 H, 3-H), 4.59 (d, J = 9.5 Hz, 1 H, 1Ј-H), 4.65 (d,
J = 4.1 Hz, 1 H, 1-H), 5.29 (dd, J = 4.4, 9.5 Hz, 1 H, 4a-H) ppm.
13C NMR (125.7 MHz, C6D6): δ = 31.6 (CH, C-4a), 44.2 (CH, C-
4), 51.4 (CH3, OMe), 55.1 (CH3, OMe), 57.4 (CH3, OMe), 59.3
(CH3, OMe), 60.5 (CH3, OMe), 61.1 (CH3, OMe), 61.5 (CH3,
OMe), 64.1 (CH2, C-6), 69.5 (CH, C-5), 72.0 (CH2, C-6Ј), 75.0
(CH), 78.4 (CH), 82.2 (CH, C-3), 84.3 (CH, C-2), 84.9 (CH, C-1Ј),
87.3 (CH), 98.7 (CH, C-1), 101.1 (C, C-2Ј) ppm.
Reductive HAT of Methyl 2,3,4,6-Tetra-O-methyl-α-D-manno-
OMe), 61.0 (CH3, OMe), 61.1 (CH3, OMe), 65.5 (CH2, C-6), 70.7 pyranosyl-(1Ǟ4a)-2,3-di-O-methyl-6-O-phthalimido-4a-carba-α-D-
(CH, C-5), 73.2 (CH2, C-6Ј), 74.4 (CH, C-1Ј), 77.8 (CH, C-4Ј), 78.7 glucopyranoside (22). Method A (nBu3SnH/AIBN): A solution of
(CH, C-3Ј), 79.2 (CH, C-2Ј), 80.3 (CH, C-3), 84.4 (CH, C-2), 98.0 the phthalimide 22 (29 mg, 0.05 mmol) in dry benzene (3.57 mL)
(CH, C-1), 103.4 (C, C-5Ј) ppm. IR (film): ν = 2944, 2836, 1191, containing nBu3SnH (13.4 µL, 0.05 mmol) and AIBN (0.8 mg,
˜
1141 cm–1. MS (ESI+): m/z (%) = 459 (100) [M + Na]+. HRMS
(ESI+): m/z: calcd. for C20H36O10: 459.2206 [M + Na]+; found
0.005 mmol) was heated at reflux for 1 h under N2. After this time
another portion of nBu3SnH (13.4 µL, 0.05 mmol) and AIBN
5256
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Eur. J. Org. Chem. 2010, 5248–5262