S. Hanessian, M. Brassard / Tetrahedron 60 (2004) 7621–7628
7625
(852 mg, 2.2 mmol, 80%); [a]2D0 228.78 (c 3.1, CHCl3),
reported30 [a]D20 þ33.18 (c 0.7, CHCl3); (film) (cm21) 1794
3.1.4. (S)-1-[(R)-2-(tert-Butyldiphenylsilanyloxymethyl)-
tetrahydrofuran-(R)-3-yl]-4-methyl-(S)-2-nitropentan-
1-ol (6). Method A: heterobimetallic catalyst (Shibasaki).18c
The catalyst was prepared as follows: to a solution of
(R)-(þ)-1,10-bi(2-naphthol) (100 mg, 0.35 mmol) in THF
(10 ml) was added a solution of La(Oi-Pr)3 (37 mg,
116 mmol) in THF (1.5 ml) at 0 8C. To this mixture was
added BuLi (2.5 M/hexanes) (140 ml). The ice bath was
removed and mixture was stirred for 12 h. Water (1 M/THF)
(116 ml) and BuLi (2.5 M/hexanes) (42 ml) were added and
the catalyst was used as such. To a solution of catalyst
(3.7 ml) at 240 8C was added 3-methyl-1-nitrobutane31
(1.3 ml, 11 mmol) and the mixture was stirred 30 min.
A solution of 5 (400 mg, 1.1 mmol) in THF (3.3 ml) was
added and the reaction mixture was stirred for 80 h. The
mixture was quenched with HCl 1.2 M (2 ml), the aqueous
phase was extracted with ether (3£10 ml) and the organic
phase was washed with brine. Drying with Na2SO4,
concentration under vacuum, and purification by flash
chromatography (1% AcOEt/CH2Cl2 to isolate 9 and 10
and a gradient to 5% AcOEt/CH2Cl2 to isolate 11 and 6)
gave the four isomers 9 (17 mg, 35 mmol, 3%), 10 (69 mg,
142 mmol, 13%), 11 (14 mg, 29 mmol, 3%) and 6 (246 mg,
507 mmol, 46%), by order of elution, respectively.
1
(CvO); NMR H (CDCl3, 400 MHz) d (ppm) 7.70–7.67
(m, 4H), 7.48–7.39 (m, 6H), 5.81–5.72 (ddd, J¼8.0, 10.6,
16.7 Hz, 1H), 5.15 (s, 1H), 5.13–5.11 (d, J¼7.1 Hz, 1H),
4.28–4.25 (td, J¼3.3, 6.8 Hz, 1H), 3.97–3.93 (dd, J¼2.8,
11.7 Hz, 1H), 3.76–3.72 (dd, J¼3.4, 11.7 Hz, 1H), 3.26–
3.18 (qu, J¼8.0 Hz, 1H), 2.88–2.81 (dd, J¼9.0, 17.6 Hz,
1H), 2.50–2.43 (dd, J¼8.5, 17.6 Hz, 1H), 1.08 (s, 9H);
NMR 13C (CDCl3, 100 MHz) d (ppm) 176.5, 136.8, 136.1,
136.0, 133.3, 133.0, 130.4, 128.3, 117.9, 85.0, 63.7,
41.2, 35.5, 27.2, 19.7; HRMS: calcd 380.1808; found,
380.1751.
3.1.2. (R)-2-(tert-Butyldiphenylsilanyloxymethyl)-(S)-3-
vinyltetrahydrofuran (4). To a solution of 3 (1.0 g,
2.6 mmol) in CH2Cl2 (10 ml) at 278 8C was added
DIBAL (1.5 M/toluene) (2.1 ml, 31.5 mmol) dropwise.
After stirring for 3 h, few drops of water were added and
stirring was continued for another hour. Temperature was
raised to 0 8C, ether (10 ml) and water (0.5 ml) were added
and the resulting mixture was stirred 20 min at room
temperature. The resulting gel was filtered through Celite
and washed with hot AcOEt. After evaporation of the
solvents under vacuum, the residue was dissolved in CH2Cl2
(10 ml) and Et3SiH (648 mg, 3.9 mmol) was added. The
resulting solution was cooled to 245 8C and BF3·Et2O
(412 mg, 2.9 mmol) was added dropwise. After stirring for
3 h, the reaction mixture was quenched with saturated
aqueous NaHCO3 and phases were separated. Drying with
Na2SO4, concentration under vacuum, and purification
by flash chromatography (5% AcOEt/hexanes) gave 4
(809 mg, 2.2 mmol, 85%);. [a]2D0 28.78 (c 0.9, CHCl3); IR
For isomer 9, mp 84–86 8C; [a]2D0 219.48 (c 0.82, CHCl3);
IR (film) (cm21) 3392 (OH), 1551 (NO2); NMR 1H (CDCl3,
400 MHz) d (ppm) 7.70–7.67 (m, 4H), 7.46–7.41 (m, 6H),
4.58–4.55 (m, 1H), 4.08–4.03 (m, 2H), 3.93–3.89 (m, 1H),
3.83–3.73 (m, 2H), 3.64–3.60 (m, 2H), 2.33–2.23 (m, 2H),
2.00–1.97 (m, 1H), 1.75–1.50 (m, 3H), 1.08 (s, 9H), 1.00–
0.99 (d, J¼6.5 Hz, 3H), 0.96–0.95 (d, J¼6.4 Hz, 3H); NMR
13C (CDCl3, 100 MHz) d (ppm) 135.5, 133.5, 132.4, 132.3,
129.8, 127.7, 89.4, 82.3, 75.5, 67.6, 66.2, 45.9, 35.5, 30.1,
26.6, 24.9, 23.2, 21.1, 19.0; MS (m/z) 486 (Mþ1); HRMS:
calcd 485.2598; found, 485.2592.
1
(film) (cm21) 2932; NMR H (CDCl3, 400 MHz) d (ppm)
7.78–7.75 (m, 4H), 7.49–7.40 (m, 6H), 5.83–5.74 (ddd,
J¼8.1, 10.2, 17.1 Hz, 1H), 5.10–5.05 (ddd, J¼1.0,
1.6, 17.1 Hz, 1H), 5.05–5.02 (ddd, J¼0.7, 1.7, 10.2 Hz,
1H), 4.01–3.71 (m, 5H), 2.88–2.80 (qu, J¼8.0 Hz, 1H),
2.19–2.12 (m, 1H), 1.90–1.80 (m, 1H), 1.12 (s, 9H);
NMR 13C (CDCl3, 100 MHz) d (ppm) 138.9, 135.6,
133.5, 129.5, 127.5, 115.3, 84.0, 67.9, 64.7, 45.0, 33.2,
26.7, 19.1.
For isomer 10, mp 145–147 8C; [a]2D0 210.48 (c 0.68,
CHCl3); IR (film) (cm21) 3392 (OH), 1551 (NO2); NMR 1H
(CDCl3, 400 MHz) d (ppm) 7.71–7.65 (m,4H), 7.48–7.39
(m, 6H), 4.68–4.64 (dt, J¼3.4, 9.9 Hz, 1H), 4.10–4.02
(m,1H), 3.93–3.88 (m,H), 3.80–3.72 (m,2H), 3.68–3.62
(m,1H), 3.55–3.51 (m, 2H), 2.34–2.22 (m, 3H), 1.71–1.61
(m, 3H), 1.07 (s, 9H), 0.98 (d, J¼2.8 Hz, 3H), 0.96 (d, J¼
2.7 Hz, 3H); NMR 13C (CDCl3, 100 MHz) d (ppm) 136.1,
136.0, 132.8, 130.4, 128.3, 89.1, 82.2, 75.6, 68.3, 66.5, 46.6,
39.3, 31.3, 27.2, 25.5, 23.1, 22.1, 19.5; MS (m/z) 486
(Mþ1); HRMS: calcd. 485.2598; found, 485.2589.
For isomer 11, mp 104–107 8C; [a]2D0 210.88 (c 0.98,
CHCl3); IR (film) (cm21) 3401 (OH), 1549 (NO2); NMR 1H
(CDCl3, 400 MHz) d (ppm) 7.69–7.65 (m, 4H), 7.47–7.39
(m, 6H), 4.55–4.50 (ddd, J¼2.6, 5.9, 11.5 Hz, 1H), 4.04–
4.01 (m, 1H), 3.91–3.81 (m, 3H), 3.71–3.67 (dd, J¼4.5,
10.8 Hz, 1H), 3.66–3.62 (dd, J¼5.1, 10.8 Hz, 1H), 2.37 (m,
1H), 2.28–2.22 (m, 1H), 2.14–1.94 (m, 3H), 1.67–1.48 (m,
2H), 1.07 (s, 9H), 0.95–0.93 (d, J¼6.5 Hz, 3H), 0.92–0.90
(d, J¼6.4 Hz, 3H); NMR 13C (CDCl3, 100 MHz) d (ppm)
136.1, 136.0, 133.6, 130.2, 130.2, 128.2, 89.9, 81.6, 73.1,
68.6, 65.9, 44.0, 38.4, 27.2, 26.6, 25.5, 23.6, 21.5, 19.6; MS
(m/z) 486 (Mþ1); HRMS: calcd 485.2598; found, 485.2594.
3.1.3. (R)-2-(tert-Butyldiphenylsilanyloxymethyl)-tetra-
hydrofuran-(R)-3-carbaldehyde (5). Through a solution
of 4 (591 mg, 1.6 mmol) in CH2Cl2 (16 ml) at 278 8C was
passed a stream of ozone during 30 min until a blue color
persisted. The solution was stirred under argon for another
30 min and the ozonide was reduced with PPh3 (420 mg,
1.6 mmol). The mixture was stirred for 4 h at room
temperature. Evaporation under vacuum and purification
by flash chromatography (5% AcOEt/hexanes) gave 5
(531 mg, 1.4 mmol, 90%); [a]2D0 221.08 (c 1.25; CHCl3);
IR (film) (cm21) 1727.3 (CvO); NMR 1H (CDCl3,
400 MHz) d (ppm) 9.72–9.71 (d, J¼2.3 Hz, 1H), 7.74–
7.66 (m, 4H), 7.47–7.38 (m, 6H), 4.27–4.21 (m, 1H), 3.98–
3.82 (m, 2H), 3.80–3.75 (dd, J¼4.3, 10.6 Hz, 1H), 3.74–
3.69 (dd, J¼5.5, 10.6 Hz, 1H), 3.15–3.07 (m, 1H), 2.31–
2.08 (m, 2H), 1.06 (s, 9H); NMR 13C (CDCl3, 100 MHz) d
(ppm) 201.3, 136.0, 136.0, 133.5, 133.5, 130.3, 130.2,
128.2, 128.2, 79.7, 68.8, 65.5, 54.5, 27.6, 27.2, 19.6; MS
(m/z) 291.2 (M2C6H5); HRMS: calcd 368.1808; found,
368.l801.
For isomer 6, mp 128–131 8C; [a]2D0 230.68 (c 1.73,