Tridurylsilylium and Tridurylstannylium Cations
J . Org. Chem., Vol. 66, No. 25, 2001 8539
suspension was transferred under N2 through a wide bore
cannula to an enclosed glass frit and filtered into a 100 mL
flask containing 1.50 g (3.2 mmol) of chlorotridurylsilane. The
resulting dark red solution was stirred at room temperature
for 3 days. The yellow mixture was then quenched with H2O
and extracted twice with hexane. The combined organics were
dried (MgSO4) and concentrated by rotary evaporation. The
residue was chromatographed over neutral alumna with
hexane as eluent to give a white solid: 0.70 g (46%); mp 184-5
desired bromotridurylstannane was isolated as a white powder
by filtration: 3.3 g, 41%; mp 261-3 °C; 1H NMR (CDCl3) δ
2.19 (s, 18H), 2.31 (s, 18H), 6.99 (s, 3H); 13C NMR (CDCl3) δ
20.9, 23.9, 133.3, 134.7, 139.7, 148.3; 119Sn NMR (CDCl3) δ
-124.0. Anal. Calcd for C30H39SnBr: C, 60.23; H, 6.57.
Found: 61.26; H, 6.46.
Allyltr id u r ylsta n n a n e. In a 250 mL three-necked, round-
bottomed flask, allylmagnesium bromide (1.0 M, 3.6 mL, 3.6
mmol) was added to bromotridurylstannane (2.0 g, 3.3 mmol)
in 80 mL of toluene. The solution was refluxed for 24 h and
cooled to room temperature. According to the 1H NMR spec-
trum, some unreacted bromotridurylstannane remained. To
complete the reaction, additional allylmagnesium bromide (1.0
M, 3.6 mL, 3.6 mmol) was added. The mixture was refluxed
overnight and quenched with H2O and 10% aqueous HBr. The
organic portion was separated and washed with H2O, NaHCO3,
and again with H2O. The solution was dried (MgSO4), and the
solvent was removed by rotary evaporation to give a white
powder: 1.8 g, 96%; mp 190-1 °C; 1H NMR (toluene-d8) δ 2.06
(s, 18H), 2.29 (s, 18H), 2.42 (d, 2H), 4.83 (m, 2H), 5.94 (m, 1H),
6.82 (s, 3H); 13C NMR (CDCl3) δ 21.1, 23.6, 28.2, 113.3, 132.1,
133.8, 140.1, 148.9; 119Sn NMR (CDCl3) δ -161.7. Anal. Calcd
for C33H44Sn: C, 70.85; H, 7.95. Found: C, 71.41; H, 7.87.
1
°C; H NMR (C6D6) δ 2.08 (s, 18H), 2.24 (s, 18H), 2.47-2.52
(m, 2H), 4.85-5.00 (m, 2H), 5.76-5.90 (m, 1H), 6.94 (s, 3H);
13C NMR (C6D6) δ 21.2, 23.1, 30.5, 115.6, 133.4, 134.6, 138.9,
141.0, 142.3; 29Si NMR (CDCl3) δ -17.4; MS (EI) m/z 468 (M+,
1), 428 (38), 427 (100), 293 (16), 262 (21). Anal. Calcd for
C
33H44Si: C, 84.55; H, 9.46. Found: C, 84.81; H, 9.33.
Tr id u r ylsilyliu m Tetr a k is(p en ta flu or op h en yl)bor a te
(TP F P B). In a N2-filled glovebox was dissolved trityl TPFPB
(160 mg, 0.17 mmol) in dry C6D6 (0.7 mL) in a valved 5 mm
NMR tube. Addition of triethylsilane (25 mg, 0.22 mmol)
produced two layers. The colorless top phase containing
triphenylmethane was removed with
a syringe. 1,1-Di-
phenylethene (40 mg, 0.22 mmol) was added to the brown oil
residue, which then became deep green. Addition of allyltri-
durylsilane (89.1 mg, 0.19 mmol) in 0.7 mL of C6D6 created
two layers again, the lower, red one containing the ionic
product. The light orange, top phase was removed, and the
lower layer was analyzed by NMR spectroscopy: 1H NMR
(C6D6) 1.86 (s, 18H), 2.01 (s, 18H), 6.92 (s, 3H); 13C NMR 19.3,
22.6, 136.1, 137.1 (d from the anion), 137.8, 138.2 (d from the
anion), 139.7, 140.9, 149.0 (d from the anion); 29Si NMR (C6D6)
δ 226.8. The solvent was removed under high vacuum to
produce a deep red oil, which was washed twice with dry
toluene to remove nonpolar materials. The oil was dissolved
in 2/1 toluene/hexane, and the resulting solution was allowed
to stand in the glovebox, but no crystals formed.
P r od u ct Stu d ies. The concentrated lower layer containing
triduryl TPFPB was washed with 3 × 2 mL of toluene to
remove nonpolar materials. Addition of Bu3SnH (0.14 g, 0.48
mmol) changed the color of the oil from red to brown. Toluene
(1.5 mL) was added, and the new top layer was removed via
syringe and analyzed by GC/MS. The major product was
tridurylsilane: MS (EI) m/z 428 (M+, 1), 294 (21), 279 (7), 160
(100), 133 (8), 119 (7).
Br om otr id u r ylsta n n a n e. Butyllithium (2.5 M, 23.6 mL,
58.9 mmol) in hexane was added at 0 °C under N2 to a solution
of bromodurene (10.4 g, 48.8 mmol) in diethyl ether (80 mL)
in a 250 mL three-necked, round-bottomed flask. The mixture
was warmed slowly to room temperature and then stirred for
3 h. The mixture thickened quickly as duryllithium precipi-
tated out. A solution of tetrabromotin (5.94 g, 13.5 mmol) in
50 mL of toluene was transferred to the flask through a
cannula. The mixture was stirred overnight at room temper-
ature and then refluxed for 6 h. A white solid (LiBr) was
removed by filtration, and the pale yellow solution was
concentrated by rotary evaporation. The brown residue was
washed with 30 mL of acetone to remove colored impurities.
The resulting white powder consisted of about 80% bromotri-
durylstannane and 20% dibromodidurylstannane according to
1H NMR analysis. Stirring the mixture with 100 mL of acetone
dissolved all of the dibromodidurylstannane. The less soluble,
Tr id u r ylst a n n yliu m
bor a te (TP F P B).
Tet r a k is(p en t a flu or op h en yl)-
(a ) F r om t h e Solva t ed Tr iet h ylsilyl Ca t ion . In a N2-
filled glovebox, trityl TPFPB (160 mg, 0.17 mmol) was dis-
solved in dry C6D6 (0.7 mL) in a valved 5 mm NMR tube.
Addition of triethylsilane (25 mg, 0.22 mmol) produced two
layers, the lower of which was a light brown oil. The colorless
top phase containing triphenylmethane was removed via a
syringe. Allyltridurylstannane (106.3 mg, 0.19 mmol) in C6D6
was added, and two phases reformed. The yellow top layer was
removed, and the remaining orange oil was examined by NMR
spectroscopy: 1H NMR (C6D6) δ 1.91 (s, 18H), 1.97 (s, 18H),
6.89 (s, 3H); 13C NMR (C6D6) δ 19.8, 23.7, 137.1 (d from the
anion), 137.4, 137.7, 138.4, 139.4 (d from the anion), 149.1 (d
from the anion), 150.8; 119Sn NMR (C6D6) δ 715 (br).
(b ) F r om t h e F r ee â-Silyl Ca r boca t ion . In a N2-filled
glovebox was dissolved trityl TPFPB (160 mg, 0.17 mmol) in
dry C6D6 (0.7 mL) in a valved 5 mm NMR tube. Addition of
triethylsilane (25 mg, 0.22 mmol) produced two layers, the
lower of which was a light brown oil. The colorless top phase
containing triphenylmethane was removed via a syringe. 1,1-
Diphenylethene (40 mg, 0.22 mmol) was added, and the oil
became deep green. Allyltridurylstannane (106.3 mg, 0.19
mmol) in C6D6 was added. The yellow top phase was removed,
and the remaining orange oil was examined by NMR spec-
troscopy: 1H NMR (C6D6) δ 1.92 (s, 18H), 1.98 (s, 18H), 6.90
(s, 3H); 13C NMR (C6D6) δ 19.8, 23.7, 137.1 (d from the anion),
137.4, 137.7, 138.4, 139.4 (d from the anion), 149.1 (d from
the anion), 150.8; 119Sn NMR (C6D6) δ 725 (br).
Ack n ow led gm en t. This work was supported by the
National Science Foundation (Grant No. CHE-0091162).
We thank Prof. A. Berndt for useful suggestions in the
initiation of this work.
J O010772T