M. Luo, B. Yan / Tetrahedron Letters 50 (2009) 5208–5209
5209
Reaction condition III:
Ph
Ph
O
Si
O
Ph
Ph
Ph
Ph
OH
Ph
H2O
HO
Ph
Si
Et3N
Si
Ph
Cl
Ph
Si
Si
O
O
Cl
Si
Toluene
Toluene
Ph Ph
5
1
In another approach, a solution of diphenyl-dichlorosilane
(4.76 mmol) in 20 mL of water and 20 mL of toluene was added
slowly into a flask. After 3 h, the product was extracted with
dichloromethane and dried by rotary evaporation. Dihydroxy-di-
phenyl-silane (compound 5) was obtained (0.83 g, yield, 80.7%).9
Compound 5 (3.84 mmol) was dissolved in 20 mL of toluene,
and a 10 mL of triethylamine was added. After recrystallization
in dichloromethane, a large amount of white crystals (compound
1) was obtained (0.70 g, yield: 92.1%).
Figure 2. The crystal structure of compound 1.
Acknowledgments
Regarding the mechanism, we proposed two possibilities. First,
compound 4 maybe transiently formed and converted to 1. This
conversion might happen during the refluxing or after the addition
of aq NaOH in reaction condition I or during the purification in con-
dition II. The existence of compound 4 was indicated by its NMR
data in moisture free reactions. Under the condition III, we also
propose that the starting material is highly unstable in the pres-
ence of H2O, and it may be quickly converted to compound 5 which
is polymerized to form compound 1 in the presence of amine.
The structure of compound 1 was confirmed by X-ray diffrac-
tion (Fig. 2).
This work was supported by Hefei University of Technology,
American Lebanese Syrian Associated Charities (ALSAC), and St.
Jude Children’s Research Hospital.
Supplementary data
Supplementary data (X-ray and NMR) associated with this arti-
A
colorless crystal of compound 1 with a dimension of
0.42 ꢀ 0.40 ꢀ 0.36 mm was selected for the data collection on a
References and notes
BRUKER SMART diffractometer with graphite monochromated
0
MoK
a
radiation (k = 0.7103 ÅA). A total of 7088 reflections were col-
1. Yang, M. H.; Chou, C.; Lin, C. H. J. Chin. Chem. Soc. 1995, 42, 923–928.
2. Brandt, P. J. A.; Elsbernd, C. L. S.; Patel, N.; York, G.; Mcgrath, J. E. Polymer 1990,
31, 180–190.
3. Burrows, R.; Cooke, M.; Gillespie, D. G. J. Chromatogr. 1983, 2, 168–172.
4. Burkhard, C. A.; Decker, B. F.; David, H. J. Am. Chem. Soc. 1945, 67, 2173–2174.
5. Deka, K.; Jyoti Sarma, R.; Baruah, J. B. Inorg. Chem. Commun. 2005, 8, 1082–
1084.
lected in the range of 2.76° < h < 27.50° by using ‘phi and omega’
scan techniques at 293(2) K. C48H40O4Si4, M =0 793.16, triclinic, P1,
a = 10.7251(3) ÅA,
ꢀ
0
a = 83.757°, b = 10.7595(4) ÅA, b = 83.066(3)°, c =
0
0
19.1332(8) ÅA,
c
= 76.077°, V = 2120.08(14) ÅA3, Z = 2, Dcalc = 1.243 g/
cm3, the final R factor was R1 = 0.0398, 5180 for reflections with
6. Zuev, V. V.; Kalinin, A. V. Phosphorus, Sulfur Silicon Relat. Elem. 2003, 178, 1289–
1294.
I0 > 2r(I0), Rx = 0.0831 for all data. The structure was solved by
full-matrix least-squares on F2 using the SHELXTL Program.10 The
7. Yang, M. H.; Chou, C. Y.; Lin, C.-H. Dep. Chem., Natl. Taiwan Univ., Taipei, Taiwan.
J. the Chin. Chem. Soc. (Taipei) 1995, 42, 923–928.
eight-membered ring is almost planar, the average of eight Si–O
bond lengths was 1.6159 ÅA, and two types of Si–O–Si angles were
found with mean values of 152.77° and 164.87°.
In summary, using simple procedures, we obtained the octaphe-
nylcyclotetra (siloxane) in high yields. By comparing our results
with those of the previous methods, this synthetic method was
found to be simple and easy to operate. This enables the synthesis
of octaphenylcyclotetra (siloxane) with much less cost for various
applications.
8. 1H NMR (500 MHz, CDCl3) 7.19 (t, 4H, Ar–H), 7.35 (t, J = 2.5 Hz, 2H, Ar–H), 7.48–
7.49 (d, J = 6.5 Hz, 4H, Ar–H). 13C NMR (125 MHz, CDCl3) 127.70(ꢀ4),
130.11(ꢀ4), 134.46(ꢀ4). IR (KBr): 3440, 3070, 3049, 3024, 1591, 1487, 1429,
1187, 1119, 1103, 1028, 997, 741, 717, 698, 528, 510, 493 1/cm; HRMS(EI): m/z
(%): calcd for C48H40Si4O4: 792.2004; found: 792.1998. Elemental Anal. Calcd:
C, 72.77; H, 5.08. Found: C, 72.37; H, 5.10.
0
9. 1H NMR (500 MHz, CDCl3) 7.19 (d, J = 7 Hz, 4H, Ar–H), 7.33–7.39 (m, 6H, Ar–H),
4.91(s, 2H).
10. Sheldrick, G. M. SHELXS-97, Program for X-ray Crystal Structure Solution; Göttingen
University: Germany, 1997; Sheldrick, G. M. SHELXL-97, Program for X-ray Crystal
Structure Refinement; Göttingen University: Germany, 1997.