17-H), 3.81 (1 H, d, J 10, 7-H), 4.64 (1 H, m, 3-H), 5.16 (1 H,
ddd, J 15, 10, 5, 14-H), 5.88 (1 H, dd, J 15, 10, 13-H) and 7.03–
7.70 (10 H, m, ArH); m/z (EI) 669 (Mϩ, 23%) and 105 (100).
1052 and 974; δH 0.96 (3 H, d, J 7.5, 5-Me), 1.10 (3 H, d, J 7.5,
16-Me), 1.25, 1.30, 1.34, 1.36, 1.49 and 1.54 (each 3 H, s, Me),
1.67 (1 H, m, 16-H), 1.97 (1 H, m, 15-H), 2.15 (2 H, m, 5-H,
15-H), 2.40 (1 H, t, J 9, 8-H), 2.52 (1 H, dd, J 13, 8.5, 10-H),
2.65 (1 H, dd, J 13, 6, 10-H), 3.20 (1 H, dd, J 8, 2.5, 4-H), 3.59
(1 H, m, 3-H), 3.84 (2 H, overlapping s, d, 7-H, 17-H), 5.03
(1 H, ddd, J 16, 11, 4, 14-H), 5.70 (1 H, s, NH), 5.95 (1 H, dd,
J 16, 9, 13-H), 6.29 (1 H, d, J 16, 19- or 20-H) and 7.10–7.38
(6 H, m); m/z (CI) 581 (Mϩ ϩ 18, 2%), 564 (Mϩ ϩ 1, 17), 523
(23) and 506 (100).
(6R,7S,13E,16S,17R,18R,20R)-2-Benzoyl-6,7:17,18-bis-
(isopropylidenedioxy)-16,18-dimethyl-10-phenyl-20-phenyl-
seleno[11]cytochalas-13-ene-1,21-dione 47
Lithium diisopropylamide in THF–hexanes (0.36 M; 3.2 cm3,
1.15 mmol) was added to a solution of the ketone 46 (706 mg,
1.06 mmol) at Ϫ35 ЊC. After 45 min at this temperature, a
cooled solution of benzeneselenenyl chloride (414 mg, 2.16
mmol) in THF (5 cm3) was added via a cannula and the stirring
continued at Ϫ35 ЊC for 45 min. Saturated aqueous ammonium
chloride (30 cm3) was added and the mixture allowed to warm
to ambient temperature when water (25 cm3) was added and the
mixture extracted with dichloromethane (1 × 50 cm3, 2 × 30
cm3). The organic extracts were dried (MgSO4) and con-
centrated under reduced pressure. Chromatography of the resi-
due using gradient elution with ether–light petroleum (1:6) to
(1:4) gave the title compound 47 (450 mg, 52%) (Found: Mϩ,
825.3132. C47H55NO780Se requires M, 825.3144); [α]D20 ϩ34 (c 1
in CHCl3); νmax/cmϪ1 (CDCl3) 1720, 1715, 1686, 1602, 1454,
1380, 1265, 1223, 1111, 1072, 1005 and 995; δH 0.38 (3 H, d,
J 7.5, 5-Me), 1.04 (3 H, d, J 7.5, 16-Me), 1.08, 1.18, 1.27, 1.35
and 1.40 (each 3 H, s, Me), 1.4 (1 H, m, 16-H), 1.50 (3 H, s, Me),
1.90 (2 H, m, 19-H, 15-H), 2.09 (3 H, m, 5-H, 15-H, 19-H), 2.60
(1 H, t, J 10, 8-H), 2.97 (1 H, dd, J 5, 2.5, 4-H), 3.05 (1 H, dd,
J 12.5, 10, 10-H), 3.28 (1 H, dd, J 12.5, 4, 10-H), 3.67 (1 H, d,
J 10, 7-H), 4.00 (1 H, s, 17-H ), 4.65 (1 H, m, 3-H), 4.75 (1 H,
d, J 9, 20-H), 5.21 (1 H, ddd, J 16, 13, 6, 14-H), 5.92 (1 H, dd,
J 16, 10, 13-H) and 7.08–7.82 (15 H, m, ArH); m/z (EI) 825
(Mϩ, 14%), 768 (3), 668 (19) and 610 (11).
(6R,7S,13E,16S,17R,18R,19E,21R)-21-Hydroxy-6,7:17,18-
bis(isopropylidenedioxy)-16,18-dimethyl-10-phenyl[11]cyto-
chalasa-13,19-dien-1-one 50
Following the procedure outlined above for the synthesis of
the alcohol 37, the enone 49 (171 mg, 0.3 mmol), cerium()
chloride heptahydrate in methanol (0.42 M; 14 cm3) and
sodium borohydride (25 mg, 0.66 mmol) gave, after chroma-
tography using ether–light petroleum (2:1) as eluant, the title
compound 50 (165 mg, 96%), as a white powder (Found: Mϩ,
565.3408. C34H47NO6 requires M, 565.3403); [α]D20 Ϫ102 (c 0.77
in CHCl3); νmax/cmϪ1 (CHCl3) 3415, 3020, 1694, 1455, 1430,
1381, 1231, 1181, 1116, 1070, 969 and 886; δH 1.08 and 1.10
(each 3 H, d, J 7, 5-Me, 16-Me), 1.27 and 1.38 (each 6 H, s,
2 × Me), 1.45 and 1.49 (each 3 H, s, Me), 1.68 (1 H, m, 16-H),
1.94 (1 H, q, J 11, 15-H), 2.12–2.36 (3 H, m, 5-H, 15-H, OH),
2.59 (2 H, m, 4-H, 10-H), 2.88 (2 H, m, 8-H, 10-H), 3.60 (1 H,
d, J 10, 7-H), 3.65 (1 H, m, 3-H), 3.88 (1 H, d, J 5, 17-H ), 4.20
(1 H, t, J 2.5, 21-H), 4.99 (1 H, ddd, J 15, 11, 4, 14-H), 5.44
(1 H, dd, J 16, 2.5, 19- or 20-H), 5.63 (1 H, s, NH), 5.77 (1 H,
dd, J 15, 10, 13-H), 6.47 (1 H, dd, J 16, 3, 19- or 20-H) and
7.12–7.36 (5 H, m, ArH); m/z (EI) 565 (Mϩ, 7%), 550 (Mϩ Ϫ 15,
9), 547 (Mϩ Ϫ 18, 21), 490 (28) and 474 (15).
(6R,7S,13E,16S,17R,18R,20R)-6,7:17,18-Bis(isopropyl-
idenedioxy)-16,18-dimethyl-10-phenyl-20-phenylseleno[11]-
cytochalas-13-ene-1,21-dione 48
(6R,7S,13E,16S,17R,18R,19E,21R)-21-Acetoxy-6,7:17,18-
bis(isopropylidenedioxy)-16,18-dimethyl-10-phenyl[11]cyto-
chalasa-13,19-dien-1-one 51
Following the procedure outlined above for the preparation
of the NH-lactam 34, the N-benzoyl cytochalasan 47 (414 mg,
0.5 mmol) in benzene–methanol (3:4; 35 cm3) gave the lactam
48 (415 mg). Chromatography of a sample using ether–light
petroleum (1:1) as eluant gave title compound 48 (Found: Mϩ,
721.2878. C40H51NO680Se requires M, 721.2881); [α]D20 Ϫ39.8
(c 0.8 in CHCl3); νmax/cmϪ1 (CHCl3) 3414, 3020, 1689, 1460,
1438, 1381, 1305, 1246, 1164, 1115, 1073, 1001 and 980; δH 1.06
and 1.15 (each 3 H, d, J 7.5, 5-Me, 16-Me), 1.27 (3 H, s, Me),
1.3 (1 H, m, 16-H), 1.32, 1.40 and 1.43 (each 3 H, s, Me), 1.49
(6 H, s, 2 × Me), 1.79 (1 H, dd, J 17, 1.4, 19-H), 1.96 (2 H, m,
15-H, 19-H), 2.12 (1 H, m, 15-H), 2.40 (1 H, m, 5-H), 2.62 (1 H,
dd, J 11, 10, 8-H), 2.84 (1 H, dd, J 13, 4, 10-H), 2.89 (1 H, dd,
J 6, 2.8, 4-H), 3.28 (1 H, dd, J 13, 10, 10-H), 3.65 (1 H, m, 3-H),
3.79 (1 H, d, J 11, 7-H), 4.08 (1 H, s, 17-H), 5.09 (1 H, dd, J 6, 1,
20-H), 5.19 (1 H, ddd, J 16, 11, 5, 14-H), 5.67 (1 H, s, NH), 5.99
(1 H, dd, J 16, 10, 13-H) and 7.17–7.56 (10 H, m, ArH); m/z
(EI) 721 (Mϩ, 28%), 706 (Mϩ Ϫ 15, 4), 685 (1) and 663 (3).
Following the procedure outlined for the synthesis of the
acetate 38, triethylamine (0.5 cm3, 3.6 mmol), 4-(N,N-di-
methylamino)pyridine (4.5 mg, 0.037 mmol), acetic anhydride
(0.2 cm3, 2.12 mmol) and the alcohol 50 (185 mg, 0.33 mmol),
after 3 h at room temperature and chromatography using ether–
light petroleum (2:1) as eluant, gave the title compound 51 (161
mg, 81%) as an amorphous powder (Found: Mϩ, 607.3512.
C36H49NO7 requires M, 607.3509); [α]D20 Ϫ87 (c 0.8 in CHCl3);
νmax/cmϪ1 (CDCl3) 3414, 2247, 1742, 1698, 1455, 1427, 1375,
1233, 1195, 1117, 1071 and 967; δH 0.93 and 1.09 (each 3 H, d,
J 7, 5-Me, 16-Me), 1.22 and 1.26 (each 3 H, s, Me), 1.39 (6 H, s,
2 × Me), 1.45 and 1.50 (each 3 H, s, Me), 1.68 (1 H, m, 16-H),
1.96 (1 H, q, J 11, 15-H), 2.13 (3 H, m, 4-H, 5-H, 15-H), 2.25
(3 H, s, OAc), 2.63–2.94 (3 H, m, 8-H, 10-H2), 3.59 (1 H, m,
3-H), 3.63 (1 H, d, J 11, 7-H), 3.87 (1 H, d, J 4.5, 17-H ), 5.06
(1 H, ddd, J 16, 11, 4, 14-H), 5.17 (1 H, dd, J 16, 2, 19- or 20-H),
5.68 (2 H, m, NH, 21-H), 5.80 (1 H, dd, J 16, 9, 13-H), 6.35
(1 H, dd, J 16, 3.5, 19- or 20-H) and 7.12–7.36 (5 H, m, ArH);
m/z (EI) 607 (Mϩ, 1%), 592 (Mϩ Ϫ 15, 7), 565 (3), 547 (46), 519
(15), 490 (42), 438 (100) and 425 (65).
(6R,7S,13E,16S,17R,18R,19E)-6,7:17,18-Bis(isopropyl-
idenedioxy)-16,18-dimethyl-10-phenyl[11]cytochalasa-13,19-
diene-1,21-dione 49
(6R,7S,13E,16S,17R,18R,19E,21R)-21-Acetoxy-17,18-
dihydroxy-6,7-isopropylidenedioxy-16,18-dimethyl-10-phenyl-
[11]cytochalasa-13,19-dien-1-one 52
Following the procedure outlined above for the preparation
of the enone 36, the selenide 48 (415 mg, 0.5 mmol), pyridine
(0.5 cm3) and hydrogen peroxide–water (30%; 1:1; 4.5 cm3) in
dichloromethane (20 cm3) were stirred at room temperature for
4 h to give, after chromatography using ether–light petroleum
(3:2) as eluant, the title compound 49 (248 mg, 88% from
selenide 47) (Found: Mϩ, 563.3257. C34H45NO6 requires M,
563.3247); [α]D20 Ϫ49 (c 0.7 in CHCl3); νmax/cmϪ1 (CDCl3) 3416,
2251, 1698, 1625, 1455, 1380, 1298, 1253, 1215, 1116, 1077,
Toluene-p-sulfonic acid monohydrate (22 mg, 0.12 mmol)
was added to a solution of the acetate 51 (170 mg, 0.28 mmol)
in methanol (16 cm3) at room temperature. After 8 h at
this temperature, water (5 cm3) was added and the mixture
extracted with chloroform (3 × 10 cm3). The organic extracts
were dried (MgSO4), filtered and concentrated under reduced
J. Chem. Soc., Perkin Trans. 1, 1999, 3269–3283
3281