21 (73 mg, 80%), [α]D ϩ 43 (c 0.9 in CHCl3); δH (200 MHz;
CDCl3) 1.31 (s, 6 H), 1.40 (s, 3 H), 1.50 (s, 3 H), 1.79 (m, 1 H),
2.57 (m, 3 H), 3.96 (m, 2 H), 4.10 (m, 2 H), 4.24 (d, 1 H, J 3.7
Hz), 5.69 (m, 3 H); δC (50 MHz; CDCl3) 25.4, 26.4, 26.7, 27.0,
34.9, 36.3, 55.1, 68.3, 74.5, 81.6, 87.2, 103.9, 109.2, 111.7, 127.3,
130.2; MS (EI) m/z 281 (M Ϫ Me) ϩ (Found: C, 64.75; H, 8.23.
C16H24O5 requires C, 64.84; H, 8.16%).
petroleum–EtOAc (3 : 2). The resulting product (0.32 g) was
added to DIBAL-H (2 M solution in toluene, 1.0 mL, 2 mmol)
in CH2Cl2 (8 mL) at Ϫ78 ЊC. After 0.5 h, saturated aq. NH4Cl
was added at Ϫ78 ЊC and the product diluted with CH2Cl2,
washed with brine, dried and evaporated. The residue was
passed through a short bed of silica gel eluting with EtOAc–
light petroleum (1 : 1) to give 25 (0.26 g, overall yield for two
steps 77%); δH (200 MHz; CDCl3) 1.30, 1.32, 1.40, 1.52 (4 s,
12 H), 1.88–2.07 (m, 3 H), 2.29–2.60 (m, 3 H), 3.85–4.17 (m,
7 H), 5.58 (m, 1 H), 5.70 (m, 1 H); δC (50 MHz; CDCl3)
25.2, 25.9, 26.3, 26.6, 26.8, 27.2, 27.5, 30.2, 32.6, 37.4, 55.0,
55.8, 59.9, 60.1, 68.4, 74.2, 81.1, 85.2, 85.4, 103.9, 109.2, 111.5,
121.5, 143.6; MS (EI) m/z 340 (Mϩ) (Found: C, 63.59; H, 8.13.
C18H28O6 requires C, 63.51; H, 8.29%).
3-Deoxy-1,2:5,6-di-O-isopropylidene-ꢀ-D-ribo-hexofuranose-3-
spiro-3-(3-methylcyclopentene) (22)
Following the general procedure for RCM, compound 20 (75
mg, 0.22 mmol) and Grubbs’ catalyst (5 mg) in CH2Cl2 (5 mL)
gave 22 (52 mg, 75%) [α]D ϩ 46 (c 0.45 in CHCl3); δH (200 MHz;
CDCl3) 1.25 (s, 3 H), 1.32 (s, 3 H), 1.41 (s, 3 H), 1.53 (s, 3 H),
1.73 (s, 3 H), 2.57 (m, 4 H), 3.97 (m, 2 H), 4.12 (m, 2 H), 4.26
(d, 1 H, J 3.4 Hz), 5.31 (br s, 1 H), 5.70 (d, 1 H, J 3.4 Hz);
δC (50 MHz; CDCl3) 25.4, 26.4, 26.7, 27.0, 29.7, 34.9, 40.7, 55.8,
68.2, 74.7, 81.8, 87.4, 104.1, 109.3, 111.8, 123.6, 136.9; MS (EI)
m/z 295 (M Ϫ Me)ϩ (Found: C, 65.82; H, 8.63. C17H26O5
requires C, 65.78; H, 8.44%).
(3R)-3-Deoxy-1,2;5,6-di-O-isopropylidene-ꢀ-D-ribo-hexofuran-
ose-3-spiro(3,3-diallylcyclopentane) (26)
Following the general procedure for cyclopropanation, 25
(0.13 g, 0.38 mmol), a 1 M solution of Et2Zn (1.1 mL,
1.14 mmol) and CH2I2 (0.18 mL, 2.28 mmol) in dry CH2Cl2
(5 mL) gave the cyclopropylmethanol derivative (85 mg) which
was converted into the xanthate derivative with NaH (19 mg,
0.48 mmol), CS2 (0.06 mL, 0.96 mmol) and MeI (0.08 mL,
1.2 mmol). By following the general procedure for diallylation,
the xanthate derivate (90 mg, 0.3 mmol), allyltri-n-butyltin
(0.2 mL, 0.6 mmol) and AIBN (5 mg) gave 26 (26 mg, overall
yield 19%), [α]D ϩ22.8 (c 1.1 in CHCl3); δH (200 MHz; CDCl3)
0.97 (d, 1 H, J 14.4 Hz), 1.32, 1.34, 1.40, 1.50 (4 s, 12 H), 1.55–
1.67 (m, 2 H), 1.75 (d, 1 H, J 14.4 Hz), 1.83–2.03 (m, 2 H), 2.15
(d, 4 H, J 6.4 Hz), 3.80–3.93 (m, 2 H), 4.01–4.20 (m, 2 H), 4.26
(d, 1 H, J 3.4 Hz), 4.94–5.10 (m, 4 H), 5.62 (d, 1 H, J 3.4 Hz),
5.66–5.92 (m, 2 H); δC (50 MHz; CDCl3) 25.5, 26.5, 26.8, 27.1,
27.9, 35.5, 39.2, 43.3, 43.9, 45.7, 56.2, 69.1, 74.0, 82.8, 87.8,
104.1, 109.4, 111.9, 117.4, 135.4 (Found: C, 70.03; H, 9.13.
C22H34O5 requires C, 69.81; H, 9.05%).
(3R)-3-Deoxy-1,2:5,6-di-O-isopropylidene-ꢀ-D-ribo-hexofuran-
ose-3-spiro(3-oxocyclopentane) (23) and (3S )-3-deoxy-1,2:5,6-
di-O-isopropylidene-ꢀ-D-ribo-hexofuranose-3-spiro-(3-oxocyclo-
pentane) (24)
To a solution of compound 21 (1.8 g, 6.1 mmol) in THF
(10 mL) under N2, was added BH3ؒSMe2.(0.6 mL, 6.7 mmol) at
0 ЊC. After 2 h, a saturated aq. solution of sodium acetate and
H2O2 (30% solution, 0.8 mL, 7.3 mmol) were added at Ϫ15 ЊC.
Solvent was removed and the residue extracted with EtOAc,
washed with brine, dried (Na2SO4), and concentrated. The
crude product was purified on silica gel using light petroleum–
EtOAc (3 : 2) to give a residue (1.6 g, 5.1 mmol) which was
added to a solution of (COCl)2 (1.0 mL,10.2 mmol) and Me2SO
(1.6 mL, 20.4 mmol) in CH2Cl2 (10 mL) under nitrogen at Ϫ78
ЊC. After 1 h at Ϫ78 ЊC, Et3N (4.4 mL, 30.6 mmol) was added
and allowed to attain rt. The reaction mixture was diluted with
CH2Cl2, washed with water, brine, dried (Na2SO4) and con-
centrated. The crude product was purified on silica gel with
light petroleum–EtOAc (5 : 1) to afford 23 (0.59 g), [α]D ϩ89.11
(c 1.0 in CHCl3); δH (500 MHz; CDCl3) 1.33 (s, 6 H), 1.42,1.55
(2 s, 6 H), 1.95 (d, 1 H, J 17.8 Hz), 2.17–2.32 (m, 2 H), 2.35–2.47
(m, 2 H), 2.50 (d, 1 H, J 17.8 Hz), 3.88 (dt, 1 H, J 8.9,3.2 Hz),
3.95 (m, 2 H), 4.16 (m, 1 H), 4.24 (d, 1 H, J 3.7 Hz), 5.73 (d,
1 H, J 3.7 Hz); δC (50 MHz; CDCl3) 25.1, 26.4, 26.7, 26.9, 36.4,
43.0, 53.1, 68.8, 74.2, 82.2, 86.1, 104.1, 109.7, 112.2, 216.2; MS
(EI) m/z 297 (Mϩ Ϫ CH3) (Found: C, 61.65; H, 7.46. C16H24O6
requires C, 61.52; H, 7.74%). Further elution afforded com-
pound 24 (0.7 g), [α]D ϩ 32.3 (c 1.0 in CHCl3); δH (500 MHz;
CDCl3) 1.31 (s, 6 H), 1.38 (s, 3 H), 1.52 (s, 3 H), 1.65 (m, 1 H),
2.17–2.32 (m, 2 H), 2.46 (m, 1 H), 2.54 (ABq, 2 H, J 17.5 Hz),
3.87 (d, 1 H, J 9.4 Hz), 3.95 (dd, 1 H, J 5.2, 8.6 Hz), 4.07 (ddd,
1 H, J 9.4, 5.2, 6.2 Hz), 4.18 (dd, 1 H, J 6.2, 8.6 Hz), 4.30 (d,
1 H, J 3.2 Hz), 5.79 (d, 1 H, J 3.2 Hz); δC (50 MHz; CDCl3)
24.9, 25.5, 26.1, 26.4, 26.6, 36.7, 41.8, 52.6, 68.6, 73.8, 81.8,
86.6, 103.9, 109.6, 111.9, 215.8; MS (EI) m/z 297 (Mϩ Ϫ CH3)
(Found: C, 61.38; H, 7.54. C16H24O6 requires C, 61.52; H,
7.74%).
(3R)-3-Deoxy-1,2;5,6-di-O-isopropylidene-ꢀ-D-ribo-hexofuran-
ose-3-spirocyclopentane-3-spiro(3-cyclopentene) (27)
Following the general procedure for RCM, compound 26
(22 mg, 0.06 mmol), and Grubbs’ catalyst (3 mg) in CH2Cl2
(5 mL) gave 27 (18 mg, 88%), [α]D ϩ22.7 (c 0.5 in CHCl3);
δH (200 MHz; CDCl3) 1.22 (d, 1 H, J 15.1 Hz), 1.32, 1.35, 1.41,
1.51 (4 s, 12 H), 1.55–1.74 (m, 2 H), 1.82–2.13 (m, 3 H), 2.34
(m, 4 H), 3.88 (m, 2 H), 4.11 (m, 2 H), 4.29 (d, 1 H, J 3.5 Hz),
5.62 (d, 1 H, J 3.5 Hz), 5.65 (s, 2H); δC (50 MHz; CDCl3) 25.6,
26.6, 26.8, 27.2, 28.8, 39.5, 43.7, 47.0, 47.3, 50.3, 55.9, 69.1,
74.2, 83.1, 88.4, 104.3, 109.4, 111.8, 129.5, 130.0 (Found: C,
68.30; H, 8.69. C20H30O5 requires C, 68.55; H, 8.63%).
(3S )-3-Deoxy-1,2;5,6-di-O-isopropylidene-ꢀ-D-ribo-hexofuran-
ose-3-spiro-(3,3-diallylcyclopentane) (29)
Compound 29 was prepared from (24) (overall yield 8%) by
following the same procedure described for 23, [α]D ϩ 47.5
(c 1.0 in CHCl3); δH (200 MHz; CDCl3) 1.31, 1.33, 1.39, 1.49
(4 s, 12 H), 1.57 (m, 3 H), 1.76–1.92 (m, 3 H), 2.11 (d, 4 H, J 7.3
Hz), 3.75–3.93 (m, 2 H), 3.98– 4.17 (m, 3 H), 4.98–5.08 (m,
4 H), 5.63 (d, 1 H, J 3.4 Hz), 5.72–5.93 (m, 2 H); δC (50 MHz;
CDCl3) 25.7, 26.5, 26.8, 27.2, 29.0, 35.9, 38.0, 43.9, 44.1, 44.3,
55.9, 69.1, 74.2, 82.6, 87.7, 104.4, 109.4, 111.6, 117.0, 117.3,
135.7, 135.9 (Found: C, 69.82; H, 9.15. C22H34O5 requires C,
69.81; H, 9.05%).
(3R)-3-Deoxy-1,2:5,6-di-O-isopropylidene-ꢀ-D-ribo-hexofuran-
ose-3-spiro[3-(hydroxyethylidene)cyclopentane] (25)
Compound 23 (0.31 g, 1.0 mmol) in THF (4 mL) was added to
a previously stirred solution of triethyl phosphonoacetate
(0.25 mL, 1.3 mmol) and NaH (0.048 g, 1.2 mmol) in THF
(5 mL) at 0 ЊC under N2. After 0.5 h at rt, saturated aq. NH4Cl
was added and the solvent removed. The residue was extracted
with EtOAc, washed with water, brine, dried and concentrated.
The crude product was purified on silica gel by using light
(3S )-3-Deoxy-1,2;5,6-di-O-isopropylidene-ꢀ-D-ribo-hexofuran-
ose-3-spirocyclopentane-3-spiro(3-cyclopentene) (30)
Following the general procedure for RCM, compound 29
(30 mg, 0.08 mmol) and Grubbs’ catalyst (4 mg) in CH2Cl2
(5 mL) gave 30 (24 mg, 87%), [α]D ϩ 38.9 (c 0.85 in CHCl3);
δH (200 MHz; CDCl3) 1.32, 1.34, 1.40, 1.49 (4 s, 12 H), 1.55–
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 3 6 6 – 1 3 7 3
1371