5712 Organometallics, Vol. 29, No. 21, 2010
Corey et al.
MgSO4 and the volatiles were removed to give a yellow oil.
Kugelrohr distillation provided a forerun, bp up to 100 °C/0.2
mmHg, that contained 4,40-di-tert-butylbiphenyl. Sublimation
through the temperature range 100-250 °C/0.2 mmHg gave
white, well-formed blocks of 2,20,7,70-tetra-tert-butyl-9,90-
spirobi[9H-9-silafluorene] (50): 3.7 g (74% based on the starting
Reaction of PhMgX (X = Cl, Br) with [(teeda) H2SiCl2] in
3
THF. (a) To a slurry of [(teeda) H2SiCl2] (1.00 g, 3.64 mmol) in
3
THF (20 mL) was added, dropwise, a THF solution of PhMgCl
(5 mL, 1.8 M), and the mixture was stirred overnight. After the
usual workup, GC analysis of the crude product showed the
presence of Ph2SiH2 (m/e 184, 60%), Ph3SiH (m/e 260, 14%)
(both verified by doping with an authentic sample), and HPh2-
SiOSiPh2H (m/e 382, 14%). Kugelrohr distillation provided a
fraction, bp 75-97 °C/0.4 mmHg, 0.285 g, that contained,
from GC/GCMS analysis, Ph2SiH2 (76%) and HPh2SiOSiPh2H
(9%). A second fraction, bp 100-190 °C/0.4 mmHg, 0.152 g,
contained the following from GC analysis: Ph2SiH2 (16%), Ph3SiH
(64%), and HPh2SiOSiPh2H (8%). The nondistilled portion, 0.133
g, contained HPh2SiOSiPh2H (60% by GC) and an unidentified
component with a longer retention time (28% by GC).
1
dibromide), mp 243-246 °C. H NMR (CDCl3, 500 MHz): δ
1.28 (s, C(CH3)3, 36H), 7.44 (d, J = 2.0 Hz, Ar-H3, 4H), 7.55
(dd, J = 8.2, 2.0 Hz, Ar-H2, 4H), 7.86 (d, J = 8.2 Hz, Ar-H1,
4H). 13C{1H} NMR (CDCl3, 125.8 MHz): δ 31.6, 35.0, 120.5,
128.4, 131.4, 133.6, 137.7, 150.5. 29Si{1H} NMR (CDCl3, 99.4
MHz): δ -6.52. Mass spectrum: m/e 556 (Mþ). Anal. Calcd for
C40H48Si: C, 86.27; H, 8.69. Found: C, 86.22; H, 8.84.
Reaction of nBuLi with Bis(2-bromo-4-methylphenyl)methyla-
mine (2) Followed by Reaction with [(teeda) H2SiCl2]. (a) A
3
(b) A Grignard reagent was prepared from PhBr (0.80 mL,
1.19 g, 7.6 mmol) in THF (10 mL) that contained EDB (0.2 mL)
and Mg turnings (0.182 g, 7.49 mmol). The PhMgBr was cannu-
solution of 2 (0.496 g, 1.36 mmol) in diethyl ether was cooled in a
dry ice/acetone bath (precipitation occurs), and nBuLi (1.1 mL, 2.5
M) was added. After addition was complete the flask was warmed
to room temperature. An aliquot was withdrawn and hydrolyzed
with D2O (99.96%), and the GC trace showed two major com-
ponents (72% by GC, m/e 211-213, C15H17-nDnN; n = 2 (87%),
1 (7%), 0 (5.7%), and 15% by GC, m/e 227, C15H17NO (suggested
structure, MeN(C6H4Me-p)(C6H3OH-o, Me-p)). The aryllithium
lated into a solution of [(teeda) H2SiCl2] (1.07 g, 3.92 mmol) in a
3
CH2Cl2/THF mixture (5 mL/12 mL), and the flask with the
Grignard reagent was rinsed with additional THF (4 mL), added
to the reaction mixture, and the resultant mixture was stirred over-
night. After aqueous workup with dilute HCl (0.2 M) and extraction
with ether, the ether layer was dried over MgSO4. The volatiles were
removed, and distillation (Kugelrohr) of the remainder provided a
fraction, 0.307 g, bp up to 85 °C/0.4 mmHg (nondistilled portion
weighed 116 mg). Analysis of the distilled fraction by GC indicated
the presence of teeda (12%), biphenyl (12%), and Ph2SiH2 (67%).
Redistillation of this fraction gave a sample that contained biphenyl
(10%), Ph2SiH2 (82%), and HPh2SiOSiPh2H (2.9%).
solution was cannulated into a solution of [(teeda) H2SiCl2] (0.39 g,
3
1.5 mmol) in CH2Cl2/Et2O (8 mL/9 mL), whereupon a precipitate
formed. The mixture was stirred overnight before removing the
solvents and adding diethyl ether (30 mL) and HCl (50 mL, 0.2 M).
The ether layer was separated and dried over MgSO4. After removal
of the ether, the crude product was vacuum-distilled (Kugelrohr
distillation). The first fraction, bp up to 175 °C/0.01 mmHg, 0.154 g,
contained three components >∼6% by GC: MeN(C6H4Me-p)2
(6.4%, m/e 211), phenazasiline 4 (69%, m/e 239), and a component
with m/e 295 (5.5%) assigned to 2,5,8-trimethyl-10-butyl-5,10-
dihydrophenazasiline. The sample was recrystallized from absolute
ethanol to give 4 (97% by GC): 0.051 g, mp 103-103.5 °C (lit.5 mp
(c) A similar reaction on half the scale described in (b) but
with Et2O as solvent gave after workup a fraction, bp up to
85 °C/0.01 mmHg, 0.240 g, that contained the following by GC
and GCMS: teeda (26%), biphenyl (9%), Ph2SiH2 (35%),
Ph2Si(OEt)H (13%), and HPh2SiOSiPh2H (14%) with 0.128 g
nondistilled material.
1
X-ray Structure Determination for 2,20,7,70-tetra-tert-butyl-
9,90-spirobi[9H-9-silafluorene] (50) and Its Ethanol Solvate (5).
Crystals of X-ray diffraction quality were obtained by recrystalliza-
tion (2ꢀ) of5from absolute ethanol, and crystals of 50 were obtained
by sublimation. Crystals of appropriate dimension were used for the
single-crystal X-ray structure determinations using Bruker Kappa
ApexII and Bruker Smart 1K charge coupled device (CCD) detector
systems. All data were collected using graphite-monochromated Mo
103-104.5 °C). H NMR (C6D6, 300 MHz): δ 2.16 (s, C-CH3,
3H), 2.97 (s, N-CH3, 3H), 5.16 (s, SiH2, 2H), 6.71 (d, J = 8.4 Hz,
Ar-H1, 2H), 7.06 (dd, J = 9.0, 2.0 Hz, Ar-H2, 2H), 7.33 (d, J = 2.0
Hz, Ar-H3, 2H) (chemical shift values and multiplicities correspond
to the literature report5).
(b) A solution of 2 (0.700 g, 1.90 mmol) in Et2O (10 mL) was
cooled to -78 °C, at which point 2 begins to precipitate, and
nBuLi (1.5 mL, 2.5 M) was added. The slurry was stirred for 1/2 h
before it was slowly warmed to 0 °C, and the dry ice/acetone
bath was replaced with an ice/water bath. An aliquot hydro-
lyzed with D2O (99.96%) showed two major components:
C15H17-nDnN (m/e 211-213, n = 2 (69%), 1 (12%), 0 (18%);
71% by GC) and 2 (m/e 367, 369, 371; 17% by GC). After an
additional 1/2 h, the lithium reagent was cannulated into a slurry
˚
KR radiation (λ = 0.710 73 A) from a fine-focus sealed-tube X-ray
source. Preliminary unit cell constants were determined with a set of
36 narrow frame scans. Typical data sets consist of combinations of
φ and φ scan frames with typical scan width of 0.5° and a counting
time of 15-30 s/frame at a crystal to detector distance of 4.0-
5.0 cm. The collected frames were integrated using an orientation
matrix determined from the narrow frame scans. Apex II, SMART,
and SAINT software packages9 were used for data collection and
data integration. Analysis of the integrated data did not show any
decay. Final cell constants were determined by global refinement of
reflections from the complete data set. Collected data were corrected
for systematic errors using SADABS10 on the basis of the Laue
symmetry using equivalent reflections.
of [(teeda) H2SiCl2] (0.523 g, 1.92 mmol) in Et2O (20 mL) and
3
the resultant mixture stirred overnight. The solvents were
removed, and diethyl ether (30 mL) and HCl (50 mL, 0.2 M)
were added. The ether layer was separated and dried over
MgSO4. After removal of the ether from the crude product,
distillation (Kugelrohr) provided a fraction, bp up to 130 °C/0.4
mmHg, 0.145 g, which solidified. A GC trace indicated that the
only major component (84%) in the fraction was the starting
dibromide 2. The nondistilled portion, 0.263 g, was dissolved in
CH2Cl2; the CH2Cl2 was then replaced with boiling cyclohexane
and the solution filtered while hot. The filtrate deposited a solid,
2,20,5,50,8,80-hexamethyl-5,10-dihydro-10,10-spirobiphenazasi-
line (6): 0.104 g, mp 227-230 °C (lit.6 mp 230-233 °C after four
recrystallizations). 1H NMR (C6D6, 300 MHz): δ 1.95 (s, CCH3,
12H), 3.23 (s, NCH3, 6H), 6.91 (d, J = 8.5 Hz, Ar-H1, 4H), 7.11
(dd, J = 8.5, 2.2 Hz, Ar-H2, 4H), 7.45 (d, J = 2.2 Hz, Ar-H3,
4H). 1H NMR (CDCl3, 300 MHz): δ 2.19 (s, CCH3, 12H), 3.65
(s, NCH3, 6H), 7.07 (d, Ar-H1, 4H), 7.11(d, Ar-H3, 4H), 7.22
(dd, Ar-H2, 4H). MS (EI, 70 eV): m/e found 446.2168, calcd
446.2178.
Crystal data and intensity data collection parameters are
given in Table 1.
Structure solution and refinement were carried out using the
SHELXTL-PLUS software package.11 The structures were
solved by direct methods in monoclinic space groups C2/c and
P21/n, respectively. The models were refined with full-matrix
P
2 2
least-squares refinement by minimizing w(Fo2 - Fc ) . All non-
hydrogen atoms were refined anisotropically to convergence.
(9) SMART and SAINT; Bruker Analytical X-Ray, Madison, WI.
(10) SADABS; Bruker Analytical X-Ray, Madison, WI, 2008.
(11) Sheldrick, G. M. Bruker-SHELXTL. Acta Crystallogr. 2008,
A64, 112.