M. Arun et al. / Tetrahedron 59 (2003) 2309–2316
2313
70%; [found: C, 66.92; H, 6.37; N, 3.13; C26H29NO7
requires C: 66.78, H: 6.25, N: 2.99]; [a]2D5¼2216.1 (c 1,
CHCl3); nmax (CHCl3) 1751 cm21; dH (200 MHz, CDCl3)
1.36 (3H, s, CH3), 1.51 (3H, s, CH3), 1.97 (3H, s, OCOCH3),
4.02 (1H, dd, J¼4.9, 3.4 Hz, AcOCHCH), 4.21 (1H, d,
J¼14.6 Hz, NCHaHbPh), 4.30 (1H, d, J¼11.8 Hz,
OCHaHbPh), 4.31 (1H, d, J¼3.5 Hz, BzOCHCH), 4.53
(1H, d, J¼11.8 Hz, NCHaHb), 4.56 (1H, dd, J¼3.4, 3.5 Hz,
CHCHOBz), 4.62 (1H, d, J¼3.9 Hz, BzOCHCH), 4.74
(1H, d, J¼14.6 Hz, OCHaHbPh), 5.85 (1H, d, J¼4.9 Hz,
AcOCH), 5.98 (1H, d, J¼3.9 Hz, anomeric CH), 7.19 (10H,
m, Ar); dC (50.3 MHz, CDCl3) 20.2, 26.0, 26.6, 45.2, 55.3,
71.3, 74.0, 80.6, 81.2, 81.5, 104.8, 111.7, 127.4, 127.8,
128.0, 128.3, 135.4, 136.4, 164.1, 168.5; MS (m/z):467
(Mþz).
CHvCH2), 6.02 (1H d, J¼3.9 Hz, anomeric CH), 7.25 (2H,
d, J¼9 Hz, Ar), 7.45 (2H, d, J¼9 Hz, Ar); dC (50.3 MHz,
CDCl3) 26.1, 26.7, 55.3, 58.6, 59.0, 70.8, 8.3, 82.0, 82.2,
82.7, 104.8, 111.5, 113.9, 117.2, 119.5, 131.3, 133.9, 156.3,
164.9; MS (m/z): 405 (Mþ).
4.2.10. (3S,4R,3a0R,50R,60S,6a0R)-1-Allyl-4-(60-allyloxy-
20,20-dimethyltetrahydrofuro [20,30-d][10,30] dioxol-50yl)-
3-phenoxy azetidin-2-one (6j). Oil; yield 69%; [found: C,
66.02; H, 6.57; N, 3.19; C22H27NO6 requires C, 65.90; H,
6.42; N, 3.07]; [a]2D7¼2206.8 (c 1, CHCl3); nmax (CHCl3)
1759 cm21; dH (200 MHz, CDCl3) 1.29 (3H, s, CH3), 1.50
(3H, s, CH3), 3.70 (2H, m, NCH2CHvCH2), 4.00 (2H, m,
OCH2CHvCH2), 4.11 (1H, d, J¼3.4 Hz, allyl–OCHCH),
4.47 (1H, dd, J¼3.4, 3.9 Hz, CHCHO–allyl), 4.57 (1H, d,
J¼3.9 Hz, allyl–OCHCH), 4.80 (1H, dd, J¼4.8, 3.9 Hz,
PhOCHCH) 5.05 (4H, m, N–CH2CHvCH2 and O–CH2-
CHvCH2), 5.32 (1H, d, J¼4.9 Hz, PhOCH), 5.65 (2H, m,
N–CH2CHvCH2 and O–CH2CHvCH2), 5.96 (1H, d,
J¼3.9 Hz, anomeric CH), 6.80–7.35 (5H, m, Ar); dC
(50.3 MHz, CDCl3) 26.1, 26.7, 43.9, 56.6, 70.6, 79.9, 81.3,
82.2, 104.8, 111.6, 115.5, 117.3, 118.3, 122.2, 129.4, 131.3,
133.7, 157.4, 165.4; MS (m/z): 401 (Mþz).
4.2.7. (3S,4R,3a0R,50R,60S,6a0R)-4-(60-Allyloxy-20, 20-di-
methyl-tetrahydrofuro[20,30-d][10,30] dioxol-50yl)-1-(-4-
methoxyphenyl)-3-phenoxy azetidin-2-one (6g). White
solid; yield 79%; mp 144–145 8C; [found: C, 66.89; H,
6.39; N, 3.15; C26H29NO7 requires C, 66.78; H, 6.25; N,
2.99]; [a]2D9¼2242.0 (c 1, CHCl3); nmax (CHCl3)
1751 cm21; dH (200 MHz, CDCl3) 1.30 (3H, s, CH3), 1.50
(3H, s, CH3), 3.80 (3H, s, OCH3), 3.90 (2H, m, OCH2), 4.10
(1H, dd, J¼3, 3.4 Hz, CHCHO–allyl), 4.32 (1H, d, J¼3 Hz,
allyl–OCHCH), 4.58 (1H, d, J¼3.4 Hz, allyl–OCHCH),
4.69 (1H, dd, J¼5.4, 3.4 Hz, PhOCHCH), 5.10 (2H, m,
CHvCH2), 5.46 (1H, d, J¼5.4 Hz, PhOCH), 5.75 (1H, m,
CHvCH2), 6.06 (1H, d, J¼3.9 Hz, anomeric CH), 6.80–7.8
(9H, m, Ar); dC (50.3 MHz, CDCl3) 26.2, 26.7, 55.3, 58.6,
70.7, 79.2, 81.3, 81.8, 82.8, 104.8, 111.6, 113.9, 115.6,
117.4, 119.7, 122.4, 129.5, 131.1, 133.7, 156.5, 157.4,
163.3; MS (m/z): 467 (Mþ).
4.2.11. (2R,3S,3a0R,50R,60S,6a0R)-Acetic acid, 1-allyl-4-
(60-allyloxy-20,20-dimethyltetrahydrofuro[20,30-d][10,30]
dioxol-50yl) azetidin-2-one (6k). Oil; yield 68%; [found: C,
66.02; H, 6.57; N, 3.19; C22H27NO6 requires C, 65.90; H,
6.42; N, 3.07]; [a]2D4¼2238.9 (c 1, CHCl3); nmax (CHCl3)
1758 cm21; dH (200 MHz, CDCl3) 1.32 (3H, s, CH3), 1.50
(3H, s, CH3), 2.10 (3H, s, OCOCH3), 3.75 (4H, m, NCH2
and OCH2), 4.00 (1H, dd, J¼3.5, 3.7 Hz, CHCHO–allyl),
4.27 (1H, dd, J¼4.8, 3.5 Hz, AcOCHCH), 4.33 (1H, d, J¼
3.7 Hz, allyl–OCHCH), 4.53 (1H, d, J¼4.0 Hz, allyl–
OCHCH), 5.15–5.30 (4H m, NCH2CHvCH2 and
OCH2CHvCH2), 5.69–5.90 (2H, m, NCH2CHvCH2 and
OCH2CHvCH2), 5.29 (1H, d, J¼4.0 Hz, AcOCH), 5.99 (1H,
d, J¼4.8 Hz, anomeric CH); dC (50.3 MHz, CDCl3) 19.8,
25.5, 26.1, 43.3, 55.4, 59.3, 70.0, 73.2, 79.9, 81.0, 81.2, 104.3,
110.9, 117.3, 130.9, 133.1, 163.4, 168.0; MS (m/z): 368
(Mþz).
4.2.8. (2R,3S,3a0R,50R,60S,6a0R)-Acetic acid-2-(60-allyl-
oxy-2, 2-dimethyl-tetrahydrofuro [20,30-d][10,30] dioxol-
50yl)-1-(4-methoxyphenyl)-4-oxo-azetidin-3yl ester (6h).
Oil; yield 70%; [Found: C, 67.12; H, 6.47; N, 3.35;
C22H27NO8 requires C, 60.94; H, 6.28; N, 3.23]; [a]2D5¼
2225.9 (c 1, CHCl3); nmax (CHCl3) 1751 cm21; dH
(200 MHz, CDCl3) 1.32 (3H, s, CH3), 1.47 (3H, s, CH3),
2.21 (3H, s, OCOCH3), 3.78 (3H, s, OCH3), 3.80–3.89 (2H,
m, OCH2CHvCH2), 3.92 (1H, d, J¼3.4 Hz, allyl–
OCHCH), 4.41 (1H, dd, J¼3.4, 3.8 Hz, CHCHO–allyl),
4.59 (1H, d, J¼3.8 Hz, allyl–OCHCH), 4.63 (1H, dd, J¼
5.6, 3.4 Hz, AcOCHCH), 5.10 (2H, m, CHvCH2), 5.77
(1H, m, CHvCH2), 6.01 (1H, d, J¼3.9 Hz, anomeric CH),
6.15 (1H, d, J¼5.6 Hz, AcOCH), 6.83–7.63 (4H, m, Ar); dC
(50.3 MHz, CDCl3) 20.6, 26.1, 26.6, 55.3, 57.9, 70.8, 72.9,
80.7, 81.5, 81.8, 82.2, 104.7, 111.7, 113.8, 118.2, 119.7,
130.9, 133.4, 156.5, 162.0, 168.5; MS (m/z): 433 (Mþ).
4.2.12. (3S,4R,3a0R,50R,60S,6a0R)-Acetic acid 50-{1-(4-
methoxyphenyl)-4-oxo-3-phenoxy azetidin-2yl}-20,20-
dimethyl tetrahydrofuro[20,30-d][10,30]dioxol-60-yl-ester
(6l). White solid; yield 75%; mp 171 8C; [found: C, 64.06;
H, 5.97; N, 3.12; C25H27NO8 requires C, 63.94; H, 5.80;
N, 2.98]; [a]2D5¼2235.6 (c 1, CHCl3); nmax (CHCl3)
1747 cm21; dH (200 MHz, CDCl3) 1.35 (3H, s, CH3), 1.50
(3H, s, CH3), 2.05 (3H, s, OCOCH3) 3.80 (3H, s, OCH3),
4.57 (1H, d, J¼3.9 Hz, AcOCHCH), 4.62 (1H, dd, J¼3.0,
3.5 Hz, CHCHOAc), 4.68 (1H, dd, J¼4.9, 3.5 Hz,
PhOCHCH), 5.33 (1H, d, J¼4.9 Hz, PhOCH), 5.64 (1H,
d, J¼3.0 Hz, AcOCHCH), 6.02 (1H d, J¼3.9 Hz, anomeric
CH), 6.89–7.25 (9H, m, Ar); dC (50.3 MHz, CDCl3) 20.0,
25.7, 26.1, 54.8, 57.9, 77, 79.1, 79.6, 82.9, 104.0, 111.6,
113.5, 115.7, 119.2, 122.3, 129.1, 130.5, 156.2, 157.0,
162.9, 168.8; MS (m/z): 469 (Mþz).
4.2.9. (2R,3S,3a0R,50R,60S,6a0R)-4-(60-Allyloxy-20,20-di-
methyltetrahydrofuro [20,30-d][10,30] dioxol-50yl)-3-meth-
oxy-1-(4-methoxyphenyl) azetidin-2-one (6i). Oil; yield
72%; [found: C, 62.32; H, 6.87; N, 3.62; C21H27 NO7
requires C, 62.19; H, 6.71; N, 3.45]; [a]2D9¼2209.1 (c 1,
CHCl3); nmax (CHCl3) 1747 cm21; dH (200 MHz, CDCl3)
1.31 (3H, s, CH3), 1.44 (3H, s, CH3), 3.66 (3H, s, OCH3),
3.78 (3H, s, ArOCH3), 3.92 (1H, dd, J¼5.8, 3.4 Hz,
MeOCHCH), 4.11 (2H, m, OCH2CHvCH2), 4.36 (2H, m,
allyl–OCHCH and MeOCH), 4.52 (2H, m, allyl–OCHCH
and CHCHO–allyl), 5.21 (2H, m, CHvCH2), 5.81 (1H, m,
4.3. General procedure for the preparation of
N-unsubstituted b-lactams (7a–c)
To a solution of the b-lactam (6b, g, l) (0.38 mmol) in