PAPER
Norpandamarilactonines, Pandamarilactonines, and Pandanamine
1457
4-(Tetrahydro-2H-pyran-2-yloxy)butanal (8)
(E,Z)-3-Methyl-5-[4-(4-methylsulfonyloxy)butylidene]furan-
2(5H)-one (11)
To a stirred suspension of PCC (17.95 g, 83.27 mmol) and NaOAc
(2.04 g, 24.87 mmol) in CH2Cl2 (50 mL) was added rapidly a soln
of alcohol 7 (14.50 g, 83.22 mmol) in CH2Cl2 (50 mL). The mixture
immediately turned black and after 1 h of stirring, the mixture was
diluted with Et2O. The supernatant soln was filtered through basic
alumina and the filtrate was concentrated in vacuo. Column chro-
matography of the residue (silica gel, EtOAc–PE, 1:9) gave 8 (11.32
g, 79%) as a thick oil.
To a stirred soln of diol 10 (4.00 g, 21.48 mmol) in CH2Cl2 (25 mL)
was added Et3N (14.99 mL, 107.52 mmol) and MsCl (3.49 mL,
45.13 mmol) at 0 °C. The mixture was further stirred at r.t. for 24 h
and then diluted with CH2Cl2 (50 mL), washed with H2O and brine,
and dried (Na2SO4). Concentration of the organic layer in vacuo fol-
lowed by column chromatography (silica gel, EtOAc–PE, 2:3) gave
11 (4.07 g, 77%) as a thick oil; ratio E/Z = 57:43).
IR (CHCl3): 2945, 1726, 1468, 1441 cm–1.
IR (CHCl3): 1757 cm–1.
1H NMR (200 MHz, CDCl3): d = 1.40–1.83 (m, 6 H), 1.92 (quintet,
J = 6 Hz, 2 H), 2.52 (t, J = 6 Hz, 2 H), 3.32–3.55 (m, 2 H), 3.67–
3.90 (m, 2 H), 4.54 (t, J = 2 Hz, 1 H), 9.76 (t, J = 2 Hz, 1 H).
13C NMR (50 MHz, CDCl3): d = 19.3, 22.5, 25.3, 30.4, 41.0, 62.1,
66.3, 98.7, 202.3.
1H NMR (200 MHz, CDCl3): d = 1.80–2.10 (m, 5 H), 2.30–2.60 (m,
2 H), 3.02 (s, 1.71 H), 3.03 (s, 1.29 H), 4.15–4.30 (m, 2 H), 5.14 (t,
J = 8 Hz, 0.43 H), 5.57 (t, J = 8 Hz, 0.57 H), 7.01 (d, J = 2 Hz, 0.43
H), 7.32 (d, J = 2 Hz, 0.57 H).
13C NMR (50 MHz, CDCl3): d = 10.5, 10.8, 22.1, 22.3, 28.4, 29.1,
37.4, 68.6, 68.8, 110.8, 111.5, 129.7, 131.0, 133.5, 137.5, 149.2,
149.5, 170.7, 170.8 (except one, all other carbons showed E/Z split-
ting).
Anal. Calcd for C9H16O3: C, 62.76; H, 9.37. Found: C, 62.70; H,
9.42.
5-[1-Hydroxy-4-(tetrahydro-2H-pyran-2-yloxy)butyl]-3-meth-
ylfuran-2(5H)-one (9)
Anal. Calcd for C10H14O5S: C, 48.77; H, 5.73; S, 13.02. Found: C,
48.61; H, 5.69; S, 13.12.
To a stirred soln of 3-methylfuran-2(5H)-one (5.00 g, 50.97 mmol)
in THF (50 mL) at –78 °C was added the soln of freshly prepared
LDA (5.99 g, 55.92 mmol) in THF (15 mL) in a dropwise fashion
under an argon atmosphere. The mixture was stirred at –78 °C for
30 min and a soln of aldehyde 8 (8.78 g, 50.98 mmol) in THF (10
mL) was added. Further stirring was continued for 2 h while the
temperature was allowed to reach r.t. THF was removed in vacuo at
r.t. The residue was then acidified with 2 M HCl and extracted with
EtOAc (4 × 50 mL). The combined organic layers were washed with
brine and dried (Na2SO4). Concentration of the organic layer in vac-
uo followed by column chromatography (silica gel, EtOAc–PE,
2:8) gave 9 (10.47 g, 76%) as a thick oil as a mixture of diastereo-
mers.
(E,Z)-5-(4-Azidobutylidene)-3-methylfuran-2(5H)-one (12)
To a stirred soln of mesylate 11 (3.50 g, 14.21 mmol) in DMF (15
mL) was added NaN3 (4.67 g, 71.84 mmol) and the mixture was
stirred at r.t. for 16 h. The mixture was then diluted with EtOAc (50
mL), washed with H2O and brine, and dried (Na2SO4). Concentra-
tion of the organic layer in vacuo followed by column chromatog-
raphy (silica gel, EtOAc–PE, 1:9) gave 12 (2.39 g, 87%) as a thick
oil; ratio E/Z = 53:47.
IR (CHCl3): 2097, 1769, 1763 cm–1.
1H NMR (200 MHz, CDCl3): d = 1.60–1.85 (m, 2 H), 2.00 (s, 1.41
H), 2.03 (s, 1.59 H), 2.35 (q, J = 8 Hz, 1.06 H), 2.46 (q, J = 8 Hz,
0.94 H), 3.25–3.40 (m, 2 H), 5.13 (t, J = 8 Hz, 0.47 H), 5.57 (t, J = 8
Hz, 0.53 H), 7.00 (br s, 0.47 H), 7.30 (br s, 0.53 H).
13C NMR (50 MHz, CDCl3): d = 10.5, 10.8, 23.3, 23.4, 28.3, 28.6,
50.2, 50.8, 111.4, 112.2, 129.5, 130.8, 133.4, 137.5, 149.0, 149.4,
170.8, 170.9.
IR (CHCl3): 3439, 1759, 1655, 1456 cm–1.
1H NMR (200 MHz, CDCl3): d = 1.40–1.90 (m, 10 H), 1.94 (br s, 3
H), 3.35–3.60 (m, 2 H), 3.60–4.00 (m, 3 H), 4.50–4.65 (br s, 1 H),
4.70–5.00 (m, 1 H), 7.00–7.25 (m, 1 H).
13C NMR (50 MHz, CDCl3): d = 10.6, 19.5, 19.6, 25.1, 25.2, 25.8,
26.0, 28.6, 30.1, 30.4, 30.5, 30.8, 30.9, 62.4, 62.6, 67.3, 67.4, 67.5,
71.6, 71.9, 72.0, 83.6, 83.8, 98.8, 99.0, 99.1, 130.6, 131.0, 145.4,
146.2, 146.8, 146.9, 174.2 (only prominent carbon signals have
been listed here).
Anal. Calcd for C9H11N3O2: C, 55.95; H, 5.74; N, 21.75. Found: C,
55.80; H, 5.70; N, 21.85.
threo- and erythro-1-(tert-Butoxycarbonyl)-2-(4-methyl-5-oxo-
2,5-dihydrofuran-2-yl)pyrrolidines (14 and 15)
Anal. Calcd for C14H22O5: C, 62.20; H, 8.20. Found: C, 62.25; H,
8.34.
To a stirred soln of azide 12 (1.00 g, 5.18 mmol) in THF (5 mL) at
42 °C was added Ph3P (1.36 g, 5.18 mmol). The mixture was stirred
for 30 min and then H2O (0.47 mL, 25.89 mmol) was added and it
was stirred at 42 °C for 12 h. The mixture was concentrated in vac-
uo, CH2Cl2 (10 mL) was added followed by (Boc)2O (1.36 g, 6.23
mmol) and Et3N (2.16 mL, 15.52 mmol). The mixture was stirred at
r.t. for 16 h and diluted with CH2Cl2 (30 mL). The organic layer was
washed with H2O and brine and dried (Na2SO4). Concentration of
the organic layer in vacuo followed by column chromatography (sil-
ica gel, EtOAc–PE, 1:9) gave a mixture of 14 and 15 (1.07 g, 77%)
as a thick oil; ratio 14/15 = 7:3.
erythro- and threo-5-(1,4-Dihydroxybutyl)-3-methylfuran-
2(5H)-one (10)
To a stirred soln of lactone 9 (10.00 g, 36.99 mmol) in EtOH (30
mL) was added PPTS (900 mg, 3.58 mmol) and the mixture heated
at 56 °C for 24 h. It was then concentrated in vacuo and the obtained
residue was purified by column chromatography (silica gel,
EtOAc–PE, 4:1) to obtain 10 (6.27 g, 91%) as a thick oil; ratio
erythro/threo = 64:36.
IR (CHCl3): 3390, 1751, 1655 cm–1.
IR (CHCl3): 1755, 1682 cm–1.
1H NMR (200 MHz, CDCl3): d = 1.50–1.88 (m, 4 H), 1.94 (br s, 3
H), 3.60–3.85 (m, 3 H), 4.70–4.90 (m, 1 H), 7.07 (quintet, J = 2 Hz,
0.36 H), 7.20 (quintet, J = 2 Hz, 0.64 H).
1H NMR (200 MHz, CDCl3): d = 1.42 (s, 2.70 H), 1.47 (s, 6.30 H),
1.60–2.10 (m, 7 H), 3.20–3.50 (m, 2 H), 3.90–4.30 (m, 1 H), 5.00–
5.40 (m, 1 H), 7.03 (br s, 0.70 H), 7.16 (br s, 0.30 H).
13C NMR (50 MHz, CDCl3): d = 10.7, 28.6, 28.7, 30.1, 30.4, 62.39,
62.42, 71.7, 71.8, 83.8, 84.2, 130.9, 131.1, 146.4, 146.7, 173.3,
174.5 (except first signal, all other carbons showed diastereomeric
splitting).
Anal. Calcd for C14H21NO4: C, 62.90; H, 7.92; N, 5.24. Found: C,
62.96; H, 8.01; N, 5.18.
(E,Z)-5-(4-Iodobutylidene)-3-methylfuran-2(5H)-one (16)
To a stirred soln of mesylate 11 (280 mg, 1.14 mmol) in THF (10
mL) was added LiI (380 mg, 2.84 mmol) and the mixture was stirred
Anal. Calcd for C9H14O4: C, 58.05; H, 7.58. Found: C, 57.99; H,
7.63.
Synthesis 2008, No. 9, 1455–1459 © Thieme Stuttgart · New York