Carbocationic Rearrangements of Silphinane Derivatives
J . Org. Chem., Vol. 63, No. 25, 1998 9175
of solvent under reduced pressure followed by chromatography
(pentane) gave 28 mg (93%) of the chloride as a light yellow
oil. Efforts were made to detect other intermediates by
stopping the reaction when ca. 20% of starting material was
still present. No other compounds were found in detectable
amount. The same chloride was isolated when 0.5, 1, 3, or 10
equiv of 2,6-di-tert-butylpyridine was used as a buffer.
1.39 (d, 1H, J ) 13.5), 1.38-1.46 (m, 1H), 1.51-1.58 (m, 3H),
1.60-1.68 (m, 1H), 1.73 (app quintet, 1H, J ) 7.1), 1.89 (app
septet, 1H, J ) 7.20), 2.11-2.18 (m, 2H), 3.94 (q, 1H, J ) 8.4).
13C NMR: δ 10.96, 16.21, 26.64, 26.83, 28.81, 32.67, 36.48,
38.32, 39.54, 45.34, 46.58, 47.84, 50.81, 57.95, 78.96. Anal.
Calcd for C15H26O: C, 81.02; H, 11.79. Found: C, 80.65; H,
11.60.
For 24, IR (neat): νmax 2930, 1350, 1070, 1010, 980 cm-1
.
2rH-Ter r ecycla n -3-on e (28). The oxidation of alcohol 27
(20 mg, 0.09 mmol), with tetrapropylammonium perruthenate
(2 mg, 0.0045 mmol) and N-methylmorpholine N-oxide (18 mg,
0.135 mmol) in 2.5 mL of CH2Cl2 was carried out at room
temperature for 0.5 h as described above for silphinone.
Filtration over silica gel with CH2Cl2 as eluent and concentra-
tion afforded 19 mg (96%) of ketone 28 as a colorless oil. The
oil crystallized on standing in the freezer: mp 39-41 °C. IR
1H NMR δ 0.79 (s, 3H), 0.88 (d, 3H, J ) 7), 0.94 (m, 1H), 1.03
(s, 3H), 1.14 (s, 3H), 1.48 (m, 2H), 1.64 (m, 2H), 1.78 (m, 1H),
1.95 (m, 2H), 2.19 (m, 1H). 13C NMR δ 17.57, 22.39, 23.54,
25.01, 25.42, 25.55, 26.57, 32.91, 33.94, 37.39, 39.31, 40.42,
44.76, 50.58, 83.64. MS (EI, 70 eV) m/z (relative intensity):
204 (M+, 24), 189 (100), 161 (21), 147 (24), 133 (16), 119 (22),
105 (14), 91 (13).
B. F r om Alcoh ol 25. A solution of 25 was stirred at room
temperature as SOCl2 (8 mg, 0.10 mmol) was added in one
portion. The mixture was allowed to stir at room temperature
for 30 min. The mixture was poured into ice water (15 mL)
and the aqueous solution was extracted with CH2Cl2 (3 × 10
mL) The combined organic layers were washed with 10% Na2-
CO3 (2 × 10 mL) and dried (MgSO4). Evaporation of the
(neat) νmax 1740 cm-1 1H NMR: δ 0.87 (3d, H, J ) 6.8), 1.01
.
(d, 3H, J ) 7.1), 1.06 (s, 3H), 1.11 (s, 3H), 1.23-1.28 (m, 1H),
1.34 and 1.38 (ABdd, 2H, J ) 14.6), 1.53-1.68 (m, 2H), 1.73
(t, 1H, J ) 3.2), 1.86 (app quintet, 1H, J ) 7.1), 2.03 (tt, 1H,
J ) 13.8, 6.7), 2.30-2.50 (m, 4H). 13C NMR: δ 16.97, 18.11,
26.91, 26.96, 28.26, 34.29, 35.62, 39.14, 40.66, 43.83, 47.67,
49.63, 49.97, 56.85, 220.41. Anal. Calcd for C15H24O: C, 81.76;
H, 10.98. Found: C, 81.63; H, 10.99.
1
solvent yielded 10 mg (83%) of a yellow oil. GC and H NMR
spectra showed chloride 24 was the only product.
Ter r ecyclen e-2r,3r-ep oxid e (29). A solution of 5 (245
mg, 0.900 mmol, 75% purity by GC) containing 10% silphinene
in 35 mL of CH2Cl2 was stirred and cooled to 0 °C as m-CPBA
(451 mg, 0.120 mmol, 55% purity) was added. The solution
was stirred at room temperature for 2 h washed with 35 mL
of saturated Na2CO3, dried (MgSO4), and concentrated to afford
a yellow oil. Flash chromatography afforded 170 mg (86%) of
epoxide 29 as a colorless oil (100% purity by GC). IR (neat):
1,4,4,11-Tetr a m eth yl[5.3.1.03,8]u n d eca n -3-ol (25). A so-
lution of 28 mg (0.116 mmol) of chloride 24 (X ) Cl) and 20
µL of pyridine in 4 mL of 3:1 acetone/water was placed in a
10-mL resealable pressure tube (Aldrich Chemical Co.) under
nitrogen. The solution was stirred and heated at 70 °C for 4
h. The pressure tube was cooled to room temperature, and
the solution was concentrated under reduced pressure to
remove most of the acetone. The product was extracted into
pentane (3 × 20 mL). The combined pentane extracts were
washed with 10% HCl (10 mL) and 10% NaHCO3 (10 mL) and
dried (MgSO4). Both TLC and GC indicated that only one
compound was formed. Removal of solvent followed by chro-
matography on silica gel with 9:1 hexanes/ether as an eluant
afforded 17 mg (66%) 25 as white prisms, one of which was
used for X-ray analysis: mp 59-61 °C. IR (neat): νmax 3410,
νmax 2926, 2866, 1373, 1086 cm-1 1H NMR: δ 1.04 (d, 3H, J
.
) 7.1), 1.09 (s, 3H), 1.16 (s, 3H), 1.29 (s, 3H), 1.38 (d, 1H, J )
13.5), 1.36-1.46 (m, 1H), 1.53 (d, 1H, J ) 13.5), 1.55-1.61
(m, 1H), 1.67 (t, 1H, J ) 13.5), 1.81-2.61 (m, 6H), 3.140 (s,
1H). 13C NMR: δ 14.26, 17.80, 27.23, 27.43, 28.69, 30.89,
35.39, 36.23, 39.91, 45.76, 48.99, 50.21, 58.22, 61.26, 69.03.
Anal. Calcd for C15H24O: C, 81.76; H, 10.98. Found: C, 81.82;
H, 10.99.
2910, 1271, 1100, 978 cm-1
.
1H NMR: δ 0.76 (s, 3H), 0.85 (s,
Ter r ecycla n -2r-ol (30). A suspension of LiAlH4 (147 mg,
3.86 mmol) in 5 mL of THF was stirred as terrecyclene epoxide
(29, 85 mg, 0.39 mmol) was added. The reaction mixture was
refluxed for 6 h, cooled to 0 °C, and hydrolyzed with 15% aq
NaOH then water. The white salts were filtered and washed
with Et2O. The combined organic layers were dried (MgSO4)
and evaporated to afford 58 mg (68%) of terrecyclan-2R-ol (30,
3H), 0.86 (s, 3H), 0.94 (s, 3H), 0.99 (m, 1H), 1.11 (m, 5H), 1.38
(m, 6H), 1.92 (m, 1H). 13C NMR: δ 17.60, 20.41, 20.96, 23.21,
25.84, 25.98, 26.80, 32.52, 34.38, 35.28, 38.07, 39.37, 44.02,
48.83, 75.65. Anal. Calcd for C15H26O: C, 81.28; H, 11.71.
Found: C, 80.89; H, 11.73.
Ter r ecycla n -2r,3r-d iol (26). A solution of 5 (46 mg, 0.225
mmol) in 3 mL of pyridine was stirred as a solution of OsO4
in pyridine (1.1 mL, 97 mg/mL, 104 mg) was added. After 5 h
in the dark 5 mL of 0.68 M NaHSO3 was added. The resulting
solution was then stirred overnight, diluted with 20 mL of
ether, and washed with 20 mL of 2 N HCl. The ether layer
was dried (MgSO4) and concentrated to afford a yellow oil.
Flash chromatography using 3:1 (hexanes/ethyl acetate) as
eluant gave 20 mg (37%) of diol 26 as colorless crystals. 1H
NMR: δ 1.05 (s, 3H), 1.11 (s, 3H), 1.15 (s, 3H), 1.23 (d, 3H, J
) 7.1), 1.35 (app q, 2H, J ) 14.5), 1.42-1.70 (m, 4H), 1.80 (s,
1H), 1.94-2.12 (m, 4H), 2.41 (dd, 1H, J ) 3.9, 12.7), 4.10 (q,
1H, J ) 7.1, 4.17 (br q, 1H, J ) 8.3). 13C NMR: δ 19.68, 20.18,
26.47, 28.19, 29.75, 32.60, 36.54, 36.82, 39.64, 45.10, 51.58,
60.91, 77.43, 82.27.
98% purity by GC) as a colorless oil. IR (neat): νmax 3355 cm-1
.
1H NMR: δ 1.04 (s, 3H), 1.08 (s, 3H), 1.21 (m, 3H), 1.22 (s,
3H), 1.33 (d, 2H, J ) 2.4), 1.36-1.49 (m, 3H), 1.53-1.59 (app
dt, 1H, J ) 14.6 and 3.9), 1.61-1.67 (m, 1H), 1.71 (t, 1H, J )
3.2), 1.90-2.02 (m, 4H), 2.34 (dd, 1H, J ) 3.7, 11.0). 13C NMR
δ 20.30, 22.13, 26.52, 26.53, 28.49, 30.29, 32.77, 36.65, 39.75,
40.19, 47.61, 52.05, 52.72, 62.63, 84.71. Anal. Calcd for
C
15H26O: C, 81.02; H, 11.79 Found: C, 80.90; H, 11.69.
Deh yd r a t ion of Ter r ecycla n -2r-ol (30). A solution of
alcohol 30 (29 mg, 0.131 mmol) in 1 mL of benzene and 400
µL of pyridine at 0 °C was stirred as thionyl chloride (19 mg,
0.156 mmol) was added. The solution was stirred for 30 min
and poured into ice-water. Extraction with pentane, drying
(MgSO4), and concentration afforded an 4:1 mixture of R- and
1
2rH-Ter r ecycla n -3r-ol (27). A solution of 75 mg, (0.30
mmol; 83% purity by GC) of 5 in 2 mL of THF was stirred and
cooled at 0 °C as 0.55 mL (0.55 mmol) of 1 M BH3 in THF was
added. The solution was allowed to warm to room temperature
and stirred for 2.5 h after which 0.3 mL of 2 N NaOH (1:1
MeOH, H2O) and 1 mL of 30% H2O2 were added. The mixture
was stirred for an additional 15 min before diluting with 90:
10 hexane/ethyl acetate. The organic layer was washed with
H2O, dried (MgSO4), and concentrated. Flash chromatography
with 70:30 hexanes/ethyl acetate as eluant gave 52 mg (76%)
of a white crystalline solid (95% purity by GC). Several
recrystallizations from hexane (-10 °C) afforded a pure white
â-terrecyclenes (5 and 34) as determined by GC and H NMR
analyses.
â-Ter r ecyclen -3r-ol (31, R ) H). A solution of Et2NH (272
mg, 3.74 mmol) in 5 mL of ether at 0 °C was stirred as n-BuLi
(2.54 mL, 1.47 M in hexane) was added. After warming to
room temperature a mixture containing 274 mg of epoxide 29
(1.02 mmol, 82% pure by GC) and 12% of epoxides 17r and
17â was added. The reaction mixture was then refluxed for 4
h, cooled to room temperature, and washed with 10 mL of 2 N
HCl. The organic layer was dried (MgSO4) and concentrated
to afford a pale yellow oil. Flash chromatography with
(hexane/Et2O 3:1) as eluant afforded 177 mg (78%) of the allylic
alcohol 31 (R ) H) as white crystals: mp 60-61 °C. IR
crystalline solid; mp 92-94 °C. IR: νmax 3285 cm-1
NMR: δ 0.86 (d, 3H, J ) 6.8), 0.93 (d, 3H, J ) 7.1), 1.04 (s,
3H), 1.07 (s, 3Hs), 1.13-1.19 (m, 1H), 1.18 (d, 1H, J ) 13.5),
.
1H
(Nujol): νmax 3316 cm-1
.
1H NMR: δ 0.93 (d, 3H, J ) 7.6),
1.07 (s, 3H), 1.14 (s, 3H), 1.21-1.29 (m, 1H), 1.36 (bs, 1H),