(dd, 1 H, J 3.4, 10.0), 4.96–4.75 (m, 6 H), 4.64 (d, 1 H, J 8.0),
4.50–4.19 (m, 3 H), 3.95–3.84 (m, 3 H), 3.74 (m, 1 H), 3.52–3.42
(m, 3 H), 2.16, 2.07, 2.05, 2.02, 1.87, 1.86 (6s, 6 × 3 H), 1.21 (d,
3 H, J 6.2), 1.14 (d, 3 H, J 6.3), 0.96–0.79 (m, 12 H); ESIMS m/z
1376 (Mϩ ϩ 2Na ϩ 1, 7.7%), 1353 (Mϩ ϩ Na ϩ 1, 7.3), 647
(22.3), 301 (60.0), 105 (100) (Calc. for C71H92O24ؒ2H2O: C,
62.44; H, 7.08. Found: C, 62.68; H, 7.05%).
40.05, 39.16, 37.68, 37.32, 32.49 (×2), 32.01, 31.87, 30.79, 30.35,
29.45, 21.30, 19.59, 18.83, 18.56, 17.51, 16.52, 15.22; ESIMS
m/z 1071 (Mϩ ϩ K ϩ 1, 12.5%), 1054 (Mϩ ϩ Na, 100).
Diosgenyl ꢀ-L-rhamnopyranosyl-(1→4)-ꢀ-L-rhamnopyrano-
syl-(1→4)-[ꢀ-L-rhamnopyranosyl-(1→2)]-ꢁ-D-glucopyranoside
2. Yield 81%; [α]D24 Ϫ104.4 (c 0.32, MeOH) {lit.,2b [α]D24 Ϫ104.7
1
(c 0.55, MeOH)}; H NMR (400 MHz; C5D5N) 6.35 (s, 1 H),
Diosgenyl
2,3,4-tri-O-acetyl-ꢀ-L-rhamnopyranosyl-(1→3)-
6.23 (s, 1 H), 5.78 (s, 1 H), 5.25 (d, 1 H, J 3.4), 4.93–4.87 (m,
3 H), 4.85 (s, 1 H), 4.80 (s, 1 H), 4.59 (m, 1 H), 4.51–4.42 (m,
4 H), 4.40–4.20 (m, 5 H), 4.20–4.11 (m, 3 H), 3.98 (m, 1 H), 3.81
(m, 1 H), 3.56–3.43 (m, 3 H), 2.75–2.61 (m, 2 H), 1.71 (d, 3 H,
J 6.5), 1.53 (d, 6 H, J 6.1), 1.07 (d, 3 H, J 6.8), 0.98 (s, 3 H), 0.76
(s, 3 H), 0.62 (d, 3 H, J 4.1); 13C NMR (100 MHz; C5D5N)
141.97, 121.97, 109.44, 103.48, 102.39 (×2), 100.53, 81.28,
80.58, 78.24, 78.14, 77.91 (×2), 77.19, 74.32, 74.19, 73.46, 73.04
(×3), 72.82, 72.69, 70.59, 69.73, 68.51, 67.04, 63.07, 61.40,
56.81, 50.47, 42.15, 40.63, 40.03, 39.15, 37.67, 37.32, 32.49,
32.38, 31.99, 31.86, 30.77, 30.34, 29.44, 21.28, 19.58, 19.06,
18.83, 18.61, 17.50, 16.51, 15.21; ESIMS m/z 1055
(Mϩ ϩ K ϩ 1, 61.7%), 1083 (Mϩ ϩ Na, 100).
2,4-di-O-benzoyl-ꢀ-L-rhamnopyranosyl-(1→3)-2-O-acetyl-4-O-
benzoyl-ꢀ-L-rhamnopyranosyl-(1→3)-2-O-acetyl-4-O-benzoyl-ꢀ-
L-rhamnopyranosyl-(1→4)-2,3-di-O-acetyl-6-O-benzoyl-ꢁ-D-
glucopyranoside 41. Yield 66% (recovered 14, 20%); [α]D22 Ϫ27.6
1
(c 1.0, CHCl3); H NMR (300 MHz; CDCl3) 8.10–7.17 (m, 25
H), 5.44–5.21 (m, 9 H), 5.06–5.02 (m, 2 H), 4.94–4.74 (m, 6 H),
4.63 (d, 1 H, J 8.0), 4.60 (d, 1 H, J 1.5), 4.52–4.34 (m, 3 H), 4.22
(dd, 1 H, J 3.3, 9.5), 4.05–3.79 (m, 6 H), 3.49–3.34 (m, 3 H),
2.20, 2.07, 2.04, 1.94, 1.90, 1.89, 1.80 (7s, 7 × 3 H), 1.28–0.95
(m, 18 H), 0.79 (d, 3 H, J 8.2), 0.78 (s, 3 H); ESIMS m/z 2308
(Mϩ ϩ K ϩ Na, 9.6%), 1976 (Mϩ, 17.0), 1008 (100), 479 (45.5),
414 (33.7) (Calc. for C106H126O36ؒ2H2O: C, 63.27; H, 6.51.
Found: C, 63.07; H, 6.50%).
Diosgenyl ꢁ-D-glucopyranosyl-(1→4)-ꢀ-L-rhamnopyranosyl-
(1→4)-ꢁ-D-glucopyranoside 3. Yield 87%; [α]D24 Ϫ69.1 (c 0.41,
Typical procedure for the one-pot synthesis of saponins 36–41
1
MeOH) {lit,.2a [α]D24 Ϫ62.9 (c 0.17, pyridine)}; H NMR (400
A mixture of a trichloroacetimidate 7–9 (≈100 mg, 2.3 equiv.), a
thioglycoside 10–12 (2.0 equiv.), and 4 Å MS (100 mg) in dry
CH2Cl2 (6 mL) was stirred at room temperature under argon
for 0.5 h, and then cooled to Ϫ78 ЊC. At this temperature, a
solution of TMSOTf (0.3 equiv.) in dry CH2Cl2 was added. The
mixture was stirred for an additional 30 min and then warmed
up to Ϫ20 ЊC. To the above mixture was added a solution of a
saponin acceptor 13, 14 (1.0 equiv.) in CH2Cl2 (2 mL) followed
by NIS (2.0 equiv.). After being stirred for 1 h, the reaction
mixture was quenched with Et3N, and then filtered through a
pad of Celite. The filtrate was concentrated. The residue was
purified by silica gel column chromatography (petroleum spirit–
EtOAc, 1:3–1:2) to afford the fully protected saponin 36–41
as a white solid. The amounts of the reactants and the yields
of the products were calculated based on saponin acceptors
13, 14.
MHz; C5D5N) 5.86 (s, 1 H), 5.24 (d, 1 H, J 3.4), 5.21 (d, 1 H,
J 7.8), 5.00 (m, 1 H), 4.90 (d, 1 H, J 7.7), 4.70–4.64 (m, 2 H),
4,49–4.41 (m, 3 H), 4,39–4.16 (m, 7 H), 4.09–4.00 (m, 2 H), 3.93
(t, 1 H, J 8.2), 3.81 (m, 1 H), 3.72 (m, 1 H), 3.63 (m, 1 H), 3.51
(dd, 1 H, J 2.7, 10.3), 3.43 (t, 1 H, J 10.3), 2.63 (dd, 1 H, J 2.7,
12.5), 2.37 (t, 1 H, J 12.0), 1.69 (d, 3 H, J 6.2), 1.07 (d, 3 H,
J 6.9), 0.83 (s, 3 H), 0.76 (s, 3 H), 0.62 (d, 3 H, J 4.9); 13C NMR
(100 MHz; C5D5N) 141.03, 121.89, 109.42, 106.80, 102.64,
102.09, 85.27, 80.25, 78.74, 77.55, 78.40, 77.64, 77.30, 76.80,
76.60, 75.72, 72.80, 72.22, 71.56, 68.66, 67.02, 63.02, 62.70,
61.62, 56.81, 50.42, 42.12, 40.61, 40.03, 39.45, 37.59, 37.20,
32.42, 32.33, 31.96, 31.80, 30.74, 30.35, 29.41, 21.28, 19.55,
18.56, 17.49, 16.53, 15.20; ESIMS m/z 1809 (2Mϩ ϩ K, 18.2%),
1793 (2Mϩ ϩ Na, 9.3), 924 (Mϩ ϩ K, 100), 908 (Mϩ ϩ Na,
45.7).
Diosgenyl ꢀ-L-rhamnopyranosyl-(1→4)-ꢀ-L-rhamnopyrano-
syl-(1→4)-ꢁ-D-glucopyranoside 4. Yield 88%; [α]D24 Ϫ96.5 (c 0.30,
MeOH); H NMR (400 MHz; C5D5N) 6.23 (s, 1 H), 5.79 (s,
Typical procedure for removal of the protecting groups of
saponins 36–39
1
A fully protected saponin 36–39 (≈100 mg) was dissolved in
80% HOAc (5 mL) and the solution was stirred at 80 ЊC for 3 h.
The solvent was then coevaporated with toluene to give a resi-
due, which was then suspended in MeOH–THF–H2O (6 mL;
1:1:1). To the above suspension was added NaOH (40 mg) and
the mixture was stirred at 40 ЊC overnight. The solution was
neutralized with Dowex 50 (Hϩ) resin, and then filtered. The
filtrate was concentrated. The residue was purified by silica gel
column chromatography (MeOH–CH2Cl2, 1:4) to give the
saponin 1–4 as a white solid.
1 H), 5.25 (d, 1 H, J 3.4), 4.96 (m, 1 H), 4.88 (d, 1 H, J 8.2), 4.82
(s, 1 H), 4.52–4.43 (m, 4 H), 4.39 (t, 2 H, J 8.8), 4.30 (m, 1 H),
4.23 (t, 1 H, J 8.9), 4.16 (m, 1 H), 4.14 (t, 1 H, J 8.9), 4.01 (dd,
1 H, J 2.7, 12.3), 3.91 (t, 1 H, J 8.9), 3.80 (m, 1 H), 3.61 (d, 1 H,
J 8.9), 3.50 (dd, 1 H, J 2.7, 11.6), 3.42 (t, 1 H, J 11.0), 2.62 (dd,
1 H, J 2.7, 12.5), 2.37 (t, 1 H, J 12.0), 1.61 (d, 3 H, J 6.1), 1.52
(d, 3 H, J 6.1), 1.06 (d, 3 H, J 6.8), 0.84 (s, 3 H), 0.76 (s, 3 H),
0.62 (d, 3 H, J 4.8); 13C NMR (100 MHz; C5D5N) 141.04,
121.88, 109.42, 103.34, 102.65, 102.29, 81.24, 80.44, 78.37,
77.84, 77.34, 76.68, 75.76, 74.13, 73.55, 73.15, 73.02, 72.78,
70.54, 68.42, 67.01, 63.02, 61.60, 56.80, 50.42, 42.12, 40.60,
40.02, 39.44, 37.59, 37.20, 32.41, 32.34, 31.96, 31.79, 30.74,
30.34, 29.41, 21.27, 19.55, 19.06, 18.60, 17.48, 16.52, 15.19;
ESIMS m/z 1777 (2Mϩ ϩ K, 14.8%), 1761 (2Mϩ ϩ Na, 22.1),
908 (Mϩ ϩ K, 100), 892 (Mϩ ϩ Na, 92.3), 870 (Mϩ ϩ 1, 25.8).
Diosgenyl ꢁ-D-glucopyranosyl-(1→4)-ꢀ-L-rhamnopyranosyl-
(1→4)-[ꢀ-L-rhamnopyranosyl-(1→2)]-ꢁ-D-glucopyranoside
1.
Yield 82%; [α]D24 Ϫ70.5 (c 0.31, MeOH) {lit.,2a [α]D24 Ϫ69.4 (c 0.11,
1
pyridine)}; H NMR (400 MHz; C5D5N) 6.35 (s, 1 H), 5.81 (s,
1 H), 5.24 (d, 1 H, J 4.7), 5.18 (d, 1 H, J 7.5), 4.99 (m, 1 H), 4.94–
4.89 (m, 2 H), 4.82 (d, 1 H, J 2.9), 4.66–4.59 (m, 3 H), 4.48 (m,
1 H), 4.42–4.28 (m, 5 H), 4.25 (t, 1 H, J 9.0), 4.19–4.15 (m, 4 H),
4.07 (t, 1 H, J 8.5), 3.98 (d, 1 H, J 11.6), 3.82 (m, 1 H), 3.72 (m,
1 H), 3.57–3.43 (m, 3 H), 2.74 (dd, 1 H, J 4.1, 12.3), 2.66 (t, 1 H,
J 12.0), 1.70 (d, 3 H, J 5.9), 1.60 (d, 3 H, J 5.9), 1.07 (d, 3 H,
J 7.0), 0.98 (s, 3 H), 0.76 (s, 3 H), 0.63 (d, 3 H, J 5.3); 13C NMR
(100 MHz; C5D5N) 140.99, 121.99, 109.45, 107.02, 102.28,
102.16, 100.56, 85.56, 81.29, 78.75 (×2), 78.24, 78.16 (×2),
77.65, 77.20, 76.82, 74.32, 73.05, 72.74 (×2), 72.14, 71.52, 69.73,
68.79, 67.05, 63.08, 62.64, 61.45, 56.82, 50.48, 42.16, 40.64,
Typical procedure for removal of the protecting groups of
saponins 40–41
To a suspension of the fully protected saponin 40 or 41 (≈100
mg) in dry MeOH (8 mL) was added a catalytic amount of
NaOMe (5 mg). After being stirred at room temperature over-
night, the mixture was neutralized with Dowex 50 (Hϩ) resin,
and then filtered. The filtrate was concentrated. The residue was
purified by silica gel column chromatography (MeOH–CH2Cl2,
1:4) to give the saponin 5 or 6 as a white solid.
1452
J. Chem. Soc., Perkin Trans. 1, 2000, 1445–1453