(MgSO4) and evaporated to afford the product as either a
viscous oil or a solid.
68.2, 79.1, 111.6, 113.3, 127.4, 130.4, 131.9, 134.7, 156.7 and
168.9.
Dimethyl
(4R,5R)-2-(3-bromo-4-methoxyphenyl)-2-[(S)-1-
Dimethyl (4R,5R)-2-[(S)-1-bromoethyl]-2-(4-methoxyphenyl)-
1,3-dioxolane-4,5-dicarboxylate 5a. Colourless oil (yield 97%,
90% de) (Found Mϩ, 402.0346. C16H1979BrO7 requires
402.0314); νmax(film)/cmϪ1 1766, 1739; δH(250 MHz; CDCl3)
1.60 (3H, d, J 7, CH3), 3.55, 3.80, 3.85 (3 × 3H, 3 × s, ArOCH3
and 2 × CO2CH3), 4.35 (1H, q, J 7, CHBr), 4.85 (1H, d, J 6,
OCH), 4.90 (1H, d, J 6, OCH), 6.85 (2H, d, J 9, ArH), 7.45 (2H,
d, J 9, ArH); δC(62.5 MHz; CDCl3) 20.9, 52.8, 53.2, 55.5, 77.3,
78.2, 113.4, 113.6, 128.8, 129.3, 160.5, 169.2 and 168.9.
bromopentyl]-1,3-dioxolane-4,5-dicarboxylate 5g. 2 Equivalents
of bromine used. Colourless oil (yield 91%, 85% de) (Found
Mϩ, 521.9862. C19H2479Br2O7 requires 521.9889); νmax(film)/
cmϪ1 1762, 1731; δH(250 MHz; CDCl3) 0.85 (3H, t, J 7, CH3),
1.30 (2H, m, CH2CH3), 1.60 (3H, m, CHBrCHHCH2 and
CH2CH2CH3), 1.90 (1H, m, CHBrCHHCH2), 3.65, 3.85, 3.95
(3 × 3H, 3 × s, ArOCH3 and 2 × CO2CH3), 4.20 (1H, dd, J 11,
2, CHBr), 4.85 (1H, d, J 6, OCH), 4.95 (1H, d, J 6, OCH), 6.85
(1H, d, J 8, ArH), 7.50 (1H, dd, J 8, 2, ArH), 7.70 (1H, d, J 2,
ArH); δC(62.5 MHz; CDCl3) 14.2, 22.2, 30.1, 32.6, 53.3, 56.6,
60.1, 79.1, 111.2, 113.0, 128.3, 131.2, 132.6, 156.6 and 168.8.
Dimethyl
(4R,5R)-2-[(S)-1-bromopropyl]-2-(4-methoxy-
phenyl)-1,3-dioxolane-4,5-dicarboxylate 5b. Colourless oil (yield
91%, 90% de) (Found Mϩ, 416.0486. C17H2179BrO7 requires
416.0471); νmax(film)/cmϪ1 1772, 1746; δH(250 MHz; CDCl3)
1.00 (3H, t, J 7, CH3), 1.60 (1H, m, CHHCH3), 1.95 (1H, m,
CHHCH3), 3.55, 3.80, 3.85 (3 × 3H, 3 × s, ArOCH3 and
2 × CO2CH3), 4.15 (1H, dd, J 11, 2, CHBr), 4.85 (1H, d, J 6,
OCH), 4.90 (1H, d, J 6, OCH), 6.85 (2H, d, J 9, ArH), 7.45 (2H,
d, J 9, ArH); δC(62.5 MHz; CDCl3) 12.9, 26.4, 52.8, 53.2, 55.5,
62.7, 77.3, 113.5, 113.6, 128.8, 129.7, 160.4, 168.9 and 169.2.
Dimethyl
(4R,5R)-2-(3-bromo-4-methoxyphenyl)-2-[(S)-1-
bromononyl]-1,3-dioxolane-4,5-dicarboxylate 5h. 2 Equivalents
of bromine used. Colourless oil (yield 98%, 82% de) (Found
Mϩ, 578.0511. C23H3279Br2O7 requires 578.0515); νmax(film)/
cmϪ1 1764, 1736; δH(250 MHz; CDCl3) 0.85 (3H, t, J 7, CH3),
1.25 (10H, m, 5 × CH2), 1.65 (2H, m, CH2CH2CHBr), 1.85
(2H, m, CH2CH2CHBr), 3.65, 3.85, 3.90 (3 × 3H, 3 × s,
ArOCH3 and 2 × CO2CH3), 4.20 (1H, dd, J 11, 2, CHBr), 4.85
(1H, d, J 6, OCH), 4.90 (1H, d, J 6, OCH), 6.85 (1H, d, J 8,
ArH), 7.45 (1H, dd, J 8, 2, ArH), 7.70 (1H, d, J 2, ArH); δC(62.5
MHz; CDCl3) 14.1, 22.7, 24.6, 26.3, 29.4, 29.7, 31.8, 35.3, 53.3,
56.6, 60.1, 79.1, 111.2, 113.0, 128.3, 131.2, 132.6, 156.6 and
168.8.
Dimethyl (4R,5R)-2-[(S)-bromo(phenyl)methyl]-2-(4-meth-
oxyphenyl)-1,3-dioxolane-4,5-dicarboxylate 5c. Colourless oil
(yield 91%, 85% de) (Found Mϩ, 464.0458. C21H2179BrO7
requires 464.0471); νmax(film)/cmϪ1 1767, 1735; δH(250 MHz;
CDCl3) 3.70, 3.80, 3.85 (3 × 3H, 3 × s, ArOCH3 and 2 ×
CO2CH3), 4.65 (1H, d, J 6, OCH), 4.85 (1H, d, J 6, OCH),
6.70 (1H, s, CHBr), 6.80 (2H, d, J 9, ArH), 7.10–7.30 (7H, m,
ArH); δC(62.5 MHz; CDCl3) 52.8, 53.2, 55.5, 77.3, 78.2, 113.6,
116.8, 126.6, 127.0, 127.4, 127.5, 134.1, 139.5, 157.2, 168.9 and
169.2.
Dimethyl
(4R,5R)-2-[(S)-1-bromoethyl]-2-[4-(toluene-p-
sulfonamido)phenyl]-1,3-dioxolane-4,5-dicarboxylate 5i. Off-
white solid (yield 80%, 82% de); mp 121–123 ЊC (methanol)
(Found Mϩ, 541.0422. C22H2479BrNO8 requires 541.0406);
νmax(KBr)/cmϪ1 3292, 1740; δH(250 MHz; CDCl3) 1.55 (3H, t,
J 7, CHBrCH3), 2.35 (3H, s, ArCH3), 3.45 (3H, s, CO2CH3),
3.85 (3H, s, CO2CH3), 4.30 (1H, q, J 7, CHBr), 4.80 (1H, d, J 6,
OCH), 4.90 (1H, d, J 6, OCH), 6.70 (1H, s, NH), 7.05 (2H, d,
J 8, ArH), 7.25 (2H, d, J 8, ArH), 7.40 (2H, d, J 8, ArH), 7.70
(2H, d, J 8, ArH); δC(62.5 MHz; CDCl3) 20.8, 21.8, 52.7, 53.3,
78.2, 113.3, 120.2, 127.6, 128.6, 130.0, 133.8, 136.4, 137.9,
144.4, 168.9 and 169.1.
Dimethyl (4R,5R)-2-[(S)-1-bromoethyl]-2-(3-bromo-4-meth-
oxyphenyl)-1,3-dioxolane-4,5-dicarboxylate 5d. 2 Equivalents of
bromine used. White solid (yield 88%, 90% de); mp 80–82 ЊC
(methanol) (Found Mϩ, 479.9432. C16H1879Br2O7 requires
479.9419); νmax(KBr)/cmϪ1 1769, 1740; δH(250 MHz; CDCl3)
1.75 (3H, d, J 7, CH3), 3.75, 4.00, 4.05 (3 × 3H, 3 × s, ArOCH3
and 2 × CO2CH3), 4.45 (1H, q, J 7, CHBr), 4.95 (1H, d, J 6,
OCH), 5.05 (1H, d, J 6, OCH), 7.00 (1H, d, J 9, ArH), 7.60 (1H,
dd, J 9,2, ArH), 7.85 (1H, d, J 2, ArH); δC(62.5 MHz; CDCl3)
20.8, 52.7, 53.0, 53.3, 56.6, 77.2, 78.4, 111.2, 112.9, 128.2, 130.8,
132.5, 132.6, 156.7, 168.7 and 169.1.
Dimethyl
(4R,5R)-2-[(S)-1-bromopropyl]-2-[4-(toluene-p-
sulfonamido)phenyl]-1,3-dioxolane-4,5-dicarboxylate 5j. Off-
white solid (yield 66%, 82% de); mp 136–138 ЊC (methanol)
(Found Mϩ, 555.0575. C23H2679BrNO8 requires 555.0563);
νmax(KBr)/cmϪ1 3299, 1735; δH(250 MHz; CDCl3) 0.95 (3H,
t, J 7, CH2CH3), 1.55 (1H, m, CHHCHBr), 1.90 (1H, m,
CHHCHBr), 2.35 (3H, s, ArCH3), 3.45 (3H, s, CO2CH3), 3.85
(3H, s, CO2CH3), 4.10 (1H, dd, J 11, 2, CHBr), 4.80 (1H, d, J 6,
OCH), 4.90 (1H, d, J 6, OCH), 7.05 (2H, d, J 8, ArH), 7.25 (2H,
d, J 8, ArH), 7.40 (2H, d, J 8, ArH), 7.55 (1H, s, NH), 7.70 (2H,
d, J 8, ArH); δC(62.5 MHz; CDCl3) 12.9, 21.8, 26.3, 52.7, 53.3,
62.2, 78.2, 113.3, 119.1, 120.2, 127.6, 128.6, 130.0, 130.9, 134.2,
136.4, 137.9, 144.3, 168.9 and 169.1.
Dimethyl
(4R,5R)-2-(3-bromo-4-methoxyphenyl)-2-[(S)-1-
bromopropyl]-1,3-dioxolane-4,5-dicarboxylate 5e. 2 Equivalents
of bromine used. Colourless oil (yield 91%, 90% de) (Found
Mϩ, 493.9598. C17H2079Br2O7 requires 493.9576); νmax(film)/
cmϪ1 1765, 1742; δH(250 MHz; CDCl3) 1.05 (3H, t, J 7, CH3),
1.60 (1H, m, CHHCH3), 2.00 (1H, m, CHHCH3), 3.65, 3.85,
3.95 (3 × 3H, 3 × s, ArOCH3 and 2 × CO2CH3), 4.10 (1H, dd,
J 11, 2, CHBr), 4.80 (1H, d, J 6, OCH), 4.90 (1H, d, J 6, OCH),
6.85 (1H, d, J 8, ArH), 7.45 (1H, dd, J 8, 2, ArH), 7.70 (1H, d,
J 2, ArH); δC(62.5 MHz; CDCl3) 12.9, 26.3, 52.9, 53.3, 56.5,
62.2, 77.3, 111.2, 112.9, 128.1, 131.2, 132.4, 156.6, 168.7 and
169.0.
Dimethyl
(4R,5R)-2-[(S)-1-bromo-2-methylpropyl]-2-[4-
(toluene-p-sulfonamido)phenyl]-1,3-dioxolane-4,5-dicarboxylate
5k. Off-white solid (yield 23%, 78% de); mp 122–124 ЊC
(methanol) (Found Mϩ, 569.0724. C24H2879BrNO8 requires
569.0719); νmax(KBr)/cmϪ1 3290, 1735; δH(250 MHz; CDCl3)
0.90 (6H, m, (CH3)2CH), 1.60 (1H, m, CH(CH3)2), 2.35 (3H, s,
ArCH3), 3.45 (3H, s, CO2CH3), 3.85 (3H, s, CO2CH3), 4.25 (1H,
d, J 2, CHBr), 4.80 (1H, d, J 6, OCH), 4.90 (1H, d, J 6, OCH),
7.05 (2H, d, J 8, ArH), 7.25 (2H, d, J 8, ArH), 7.35 (2H, d, J 8,
ArH), 7.70 (2H, d, J 8, ArH), 7.80 (1H, s, NH); δC(62.5 MHz;
CDCl3) 17.8, 21.8, 23.4, 29.1, 52.7, 53.2, 68.2, 78.2, 113.6,
120.6, 127.6, 127.9, 130.0, 135.2, 136.4, 137.9, 144.4, 168.6 and
169.3.
Dimethyl
(4R,5R)-2-(3-bromo-4-methoxyphenyl)-2-[(S)-1-
bromo-2-methyl-1-propyl]-1,3-dioxolane-4,5-dicarboxylate 5f. 2
Equivalents of bromine used. Colourless oil (yield 95%, 85%
de) (Found Mϩ, 507.9750. C18H2279Br2O7 requires 507.9732);
νmax(film)/cmϪ1 1766, 1737; δH(250 MHz; CDCl3) 0.95 (6H, d,
J 7, (CH3)2CH), 1.80 (1H, m, CH(CH3)2), 3.60, 3.80, 3.90
(3 × 3H, 3 × s, ArOCH3 and 2 × CO2CH3), 4.25 (1H, d, J 2,
CHBr), 4.85 (1H, d, J 6, OCH), 4.95 (1H, d, J 6, OCH), 6.85
(1H, d, J 9, ArH), 7.45 (1H, dd, J 9, 2, ArH), 7.70 (1H, d, J
2, ArH); δC(62.5 MHz; CDCl3) 17.9, 23.5, 29.2, 53.3, 56.6,
J. Chem. Soc., Perkin Trans. 1, 2000, 2759–2765
2763