Feldman et al.
trated. Flash column chromatography (5% Et2O in hexanes
43.5, 35.3, 21.7, 18.1, 12.8; APCIMS m/z (relative intensity)
608 (MH+, 95); HRMS calcd for C34H46NO5SSi 608.2866 (M +
H), found 608.2878.
as eluent) of the residue yielded the alkyne 50 (2.90 g, 95%)
1
as a clear, yellow oil: IR (CDCl3) 3295, 2238 cm-1; H NMR
(CDCl3, 300 MHz) δ 7.25 (d, J ) 6.7 Hz, 2H), 6.92 (d, J ) 6.7
Hz, 2H), 6.80 (s, 1H), 3.89 (t, J ) 6.8 Hz, 2H), 3.89 (s, 3H),
3.41 (s, 3H), 3.03 (t, J ) 6.8 Hz, 2H), 2.98 (s, 1H), 1.26 (m,
N-{2-[5,6-Dim eth oxy-2-(tr ibu tylsta n n a n yleth yn yl)-4′-
(t r iisop r op ylsila n yloxy)b ip h en yl-3-yl]et h yl}-4-m et h yl-
ben zen esu lfon a m id e (52). To a solution of alkyne 51 (542
mg, 0.89 mmol) in THF (9 mL) at -78 °C was added n-BuLi
(1.88 mmol, 0.75 mL from a 2.5 M hexanes solution). After 30
min, Bu3SnCl (580 mg, 1.79 mmol) was added, and after 45
min further, the solution was diluted with Et2O and poured
into cold brine. The layers were separated, the aqueous phase
was further extracted with Et2O, and the combined organic
layers were dried over Na2SO4, filtered, and concentrated.
Flash column chromatography (20% ethyl acetate and 3%
triethylamine in hexanes as eluent) of the residue yielded the
product alkynylstannane 52 (613 mg, 77%) as a clear, yellow
3H), 1.11 (d, J ) 6.9 Hz, 18H), 0.87 (s, 9H), -0.01 (s, 6H); 13
C
NMR (CDCl3, 75 MHz) δ 155.5, 153.2, 145.2, 139.7, 139.0,
131.4, 129.5, 119.5, 114.5, 113.3, 82.8, 81.4, 63.5, 60.5, 56.0,
39.0, 26.2, 18.6, 18.1, 12.9, -5.1; APCIMS m/z (relative
intensity) 570 (MH+, 94); HRMS calcd for C33H53O4Si2 569.3482
(M + H), found 569.3500.
N-{2-[2-Eth yn yl-5,6-d im eth oxy-4′-(tr iisop r op ylsila n y-
lo x y )b ip h e n y l-3-y l]e t h y l}-4-m e t h y lb e n ze n e s u lfo n a -
m id e (51). The alkynyl silyl ether 50 (1.36 g, 2.39 mmol) was
dissolved in acetonitrile (48 mL) in a Nalgene bottle, and a
solution of 25% HF in acetonitrile was added dropwise until
consumption of the starting material was observed by TLC
(50% Et2O in hexanes as eluent). At completion of the reaction,
the solution was carefully poured into an ice cold aqueous
solution of NaHCO3. After the resulting solution was stirred
for 20 min, the aqueous phase was extracted with Et2O, and
the combined organic extracts were washed with brine, dried
over Na2SO4, filtered, and concentrated. Flash column chro-
matography (50% Et2O in hexanes as eluent) of the residue
yielded the product alcohol (1.05 g, 97%) as a clear, yellow oil:
oil: IR (CCl4) 3295, 2120, 1719 cm-1 1H NMR (CDCl3, 300
;
MHz) δ 7.64 (d, J ) 8.2 Hz, 2H), 7.3-7.2 (m, 4H), 6.87 (d, J )
8.4 Hz, 2H), 6.56 (s, 1H), 4.61 (t, J ) 5.9 Hz, 1H), 3.82 (s, 3H),
3.38 (s, 3H), 3.30 (apparent q, J ) 6.0 Hz, 2H), 2.99 (t, J ) 6.5
Hz, 2H), 2.40 (s, 3H), 1.44 (m, 6H), 1.3-1.2 (m, 9H), 1.12 (d,
J ) 7.2 Hz, 18H), 1.0-0.8 (m, 15H); 13C NMR (CDCl3, 90 MHz)
δ 155.5, 153.0, 145.7, 143.3, 139.1, 137.3, 136.9, 131.6, 129.7,
129.2, 127.2, 116.6, 107.4, 100.5, 60.4, 56.1, 43.8, 35.2, 29.1
(J C-Sn ) 11.6 Hz), 27.1 (J C-Sn ) 29.4 Hz), 21.7, 18.2, 13.9, 12.9,
13
117
11.2 (J
) 190.7 Hz); APCIMS m/z (relative intensity)
C- Sn
1
IR (CCl4) 3624, 3307, 2097 cm-1; H NMR (CDCl3, 300 MHz)
920 (MNa+, 100), 898 (M + 2, Sn isotope); HRMS calcd for
46H71NO5SSiSnNa 920.3744 (M + Na), found 920.3741.
δ 7.25 (d, J ) 8.6 Hz, 2H), 6.92 (d, J ) 8.6 Hz, 2H), 6.79 (s,
1H), 3.93 (t, J ) 6.2 Hz, 2H), 3.90 (s, 3H), 3.42 (s, 3H), 3.08 (t,
J ) 6.6 Hz, 2H), 3.01 (s, 1H), 1.29 (m, 3H), 1.12 (d, J ) 7.0
Hz, 18H); 13C NMR (CDCl3, 90 MHz) δ 155.6, 153.4, 145.4,
139.9, 138.3, 131.3, 129.3, 119.5, 114.7, 112.7, 83.1, 81.4, 63.1,
60.5, 56.1, 38.6, 18.1, 12.8; APCIMS m/z (relative intensity)
455 (MH, 100); HRMS calcd for C27H39O4Si 455.2617 (M + H),
found 455.2576.
C
5,6-Dim et h oxy-1-(t olu en e-4-su lfon yl)-9-(t r iisop r op yl-
sila n yloxy)-2,3-d ih yd r o-1H-1-a za cycloh ep ta [a ]a cen a p h -
th ylen e (54). A solution of PhI(CN)OTf23 (32 mg, 0.083 mmol)
in CH2Cl2 (0.83 mL) was cooled to -40 °C, followed by dropwise
addition of a solution of stannylalkyne 52 (62 mg, 0.069 mmol)
in CH2Cl2 (0.83 mL) via cannula. After 30 min, the solvent
was removed in vacuo while the flask was maintained in a
-40 °C bath. The residue was taken up in DME (3.45 mL)
followed by treatment with LiHMDS (0.09 mmol, 0.09 mL of
a 1 M THF solution), all at -40 °C. Upon addition of LiHMDS,
the color of the solution changed immediately from yellow to
dark green. After being stirred for an additional 75 min while
gradually being warmed to room temperature, the mixture was
poured into Et2O and washed with water. The aqueous phase
was further extracted with Et2O, and the combined organic
layers were washed with brine, dried over Na2SO4, filtered,
and concentrated. Flash column chromatography (25% Et2O
in hexanes as eluent) of the residue yielded the product
cycloheptatrienylidene 54 (26.8 mg, 64%) as a dark blue-green
Diethylazodicarboxylate (271 mg, 1.56 mmol) was added
dropwise to a 0 °C solution of triphenylphosphine (409 mg,
1.56 mmol), FmocNHTs (566 mg, 1.44 mmol), and the alcohol
from above (544 mg, 1.20 mmol) in THF (17 mL). After the
solution was stirred for 20 h, the residue was concentrated,
followed by purification of the residue via flash column
chromatography (20% ethyl acetate in hexanes as eluent) to
yield the product sulfonimide (799 mg, 80%) as a clear, yellow
oil: IR (CCl4) 3307, 1731, 1607 cm-1 1H NMR (CDCl3, 300
;
MHz) δ 7.79 (d, J ) 6.6 Hz, 2H), 7.73 (d, J ) 7.3 Hz, 2H), 7.48
(d, J ) 6.9 Hz, 2H), 7.38 (t, J ) 7.3 Hz, 2H), 7.3-7.2 (m, 6H),
6.87 (d, J ) 6.9 Hz, 2H), 6.75 (s, 1H), 4.29 (d, J ) 6.8 Hz, 2H),
4.21 (t, J ) 7.3 Hz, 2H), 4.08 (t, 6.8 Hz, 1H), 3.83 (s, 3H), 3.38
(s, 3H), 3.21 (t, J ) 7.3 Hz, 2H), 2.99 (s, 1H), 2.49 (s, 3H), 1.26
(m, 3H), 1.09 (d, J ) 6.9 Hz, 18H); 13C NMR (CDCl3, 75 MHz)
δ 155.6, 153.5, 152.6, 145.6, 144.8, 143.4, 141.5, 139.8, 137.7,
136.9, 131.4, 129.6, 129.2, 128.6, 128.1, 127.4, 125.2, 120.2,
119.5, 115.0, 112.8, 83.5, 81.0, 69.3, 60.5, 56.2, 47.7, 46.9, 35.7,
21.9, 18.1, 12.8; APCIMS m/z (relative intensity) 830 (MH+,
100); HRMS calcd for C49H56NO7SSi 830.3547 (M + H), found
830.3584.
1
film: IR (CCl4) 1725, 1584 cm-1; H NMR (CDCl3, 300 MHz)
δ 8.56 (d, J ) 9.7 Hz, 1H), 8.32 (d, J ) 12.1 Hz, 1H), 7.36 (d,
J ) 8.0 Hz, 2H), 7.00 (d, J ) 8.0 Hz, 2H), 6.81 (s, 1H), 6.64
(dd, J ) 12.1, 2.5 Hz 1H), 6.45 (dd, J ) 9.7, 2.5 Hz 1H), 4.06
(s, 3H), 4.03 (t, J ) 5.7 Hz, 2H), 3.90 (s, 3H), 2.46 (t, J ) 5.7
Hz, 2H), 2.28 (s, 3H), 1.34 (m, 3H), 1.17 (d, J ) 7.1 Hz, 18H);
13C NMR (CDCl3, 75 MHz) δ 163.2, 148.8, 144.2, 143.7, 137.0,
134.6, 133.1, 132.3, 129.6, 128.2, 127.5, 127.1, 122.7, 122.0,
121.1, 120.2, 112.7, 112.1, 60.4, 57.7, 48.5, 24.5, 21.7, 18.2, 13.0;
APCIMS m/z (relative intensity) 606 (MH+, 10); HRMS calcd
for C34H44NO5SSi 606.2709 (M + H), found 606.2741.
The imide from above (799 mg, 0.964 mmol) was dissolved
in DMF and cooled to 0 °C under argon. Piperidine (82.1 mg,
0.964 mmol) was added dropwise. After 20 min, the solvent
was removed in vacuo, the residue was washed with water,
and the aqueous phase was extracted with Et2O. The combined
organic extracts were washed with brine, dried over Na2SO4,
filtered, and concentrated. Flash column chromatography (50%
Et2O in hexanes as eluent) of the residue yielded the tosyl-
amide product 51 (542 mg, 93%) as a clear yellow oil: IR (CCl4)
P a r eitr op on e (1). Cycloheptatrienylidene 54 (19 mg, 0.03
mmol), which was precooled to -78 °C in THF (5.5 mL), was
added to Al2O3-supported KF (40% by wt, 3.6 mg, 0.063 mmol)
at -78 °C. The mixture was then slowly allowed to warm to
room temperature. After the mixture was stirred for 3 days,
the starting material was no longer visible by TLC (5% MeOH
in CH2Cl2 as eluent), and the reaction mixture was concen-
trated. Flash column chromatography (2.5% MeOH in CH2-
Cl2 as eluent) yielded pareitropone (1) (5 mg, 57%) as a brown
3307, 2097, 1719, 1596 cm-1 1H NMR (CDCl3, 300 MHz) δ
;
7.69 (d, J ) 8.2 Hz, 2H), 7.26 (d, J ) 8.6 Hz, 2H), 7.21 (d, J )
8.7 Hz, 2H), 6.91 (d, J ) 8.7 Hz, 2H), 6.65 (s, 1H), 4.63 (t, J )
6.0 Hz, 1H), 3.86 (s, 3H), 3.42 (s, 3H), 3.30 (apparent q, J )
6.7 Hz, 2H), 2.98 (t, J ) 6.7 Hz, 2H), 2.95 (s, 1H), 2.41 (s, 3H),
1.26 (m, 3H), 1.11 (d, J ) 6.9 Hz, 18H); 13C NMR (CDCl3, 75
MHz) δ 155.7, 153.6, 145.6, 143.5, 139.9, 137.5, 137.2, 131.3,
129.8, 129.0, 127.2, 119.5, 114.5, 112.5, 83.5, 81.1, 60.5, 56.1,
1
film: IR (CCl4) 1602, 1578 cm-1; H NMR (CDCl3, 300 MHz),
8.73 (d, J ) 5.7 Hz, 1H), 8.29 (d, J ) 12.0 Hz, 1H), 8.20 (d, J
) 12.0 Hz, 1H), 7.55 (d, J ) 5.7 Hz, 1H), 7.25 (dd, J ) 12.0,
2.8 Hz, 1H), 7.20 (dd, J ) 12.0, 2.8 Hz, 1H), 7.16 (s,1H), 4.20
(s, 3H), 4.08 (s, 3H); 13C NMR (CDCl3, 75 MHz), 188.3, 159.1,
157.8, 151.8, 147.0, 142.5, 141.7, 141.6, 141.0, 133.4, 130.5,
8536 J . Org. Chem., Vol. 67, No. 24, 2002