June 2007
863
and dried with Na2SO4. The solution was concentarated under reduced pres-
sure, and the residue was chromatographed on silica gel. The product was
further purified by distillation under reduced pressure.
Table 5. BET Surface Area and the Pore Size of FSM-16
Typical Procedure A substrate (100 mg) and MCM-41 (300 mg) in
MeOH (5 ml) was stirred for the indicated period of time at r.t. The reaction
mixture was filtered through glass filter, and the pure products were obtained
by preparative T.L.C.
Yield of 2
SBET
Pore volume
(mm3/g)
Pore size
(nm)
Silica
(%)
(m2/g)
Typical Procedure of Re-use of FSM-16 A suspension of substrate
(50 mg) and FSM-16 (100 mg) in MeOH (5 ml) was stirred for 4 h at r.t.
FSM-16 was then filtered off and washed with acetonitrile. The used FSM-
16 was collected and re-calcined at 400 °C for 2 h by an electric furnace be-
fore being recycled.
Control
1st
2nd
3rd
4th
5th
1046
1111
983
983
934
1404
1389
1217
1172
1074
1118
2.7
2.5
2.5
2.5
2.5
2.5
93
93
90
72
88
1-tert-Butyldimethylsilyloxy-2-triethylsilyloxyethane (3b): 1H-NMR
(CDCl3) d: 0.06 (s, 6H, –Si–(CH3)2), 0.61 (q, Jꢃ7.8 Hz, 6H, –Si–(CH2–
CH3)3), 0.90 (s, 9H, –Si–t-Bu), 0.96 (t, Jꢃ7.8 Hz, 9H, –Si–(CH2–CH3)3),
3.66 (t, Jꢃ5.4 Hz, 2H, CH2–OSi–), 3.68 (t, Jꢃ5.4 Hz, 2H, CH2–OSi–). IR
(neat): 1255, 1145, 1099, 1006 cmꢄ1. Anal. Calcd for C14H34O2Si2: C, 57.87;
H, 11.79. Found: C, 57.82; H, 11.94.
944
face of mesoporous silica with the silyl group eliminated
from the substrate, is thought to reduce all of the values men-
tioned above. On the other hand, since changes in pore size
could not be observed, deprotection of the silyl group is
thought to occur in the pore, not on the surface of the meso-
porous silicas.
1-tert-Butyldimethylsilyloxy-3-triethylsilyloxypropane (3c): 1H-NMR
(CDCl3) d: 0.04 (s, 6H, –Si–(CH3)2), 0.59 (q, Jꢃ7.8 Hz, 6H, –Si–(CH2–
CH3)3), 0.89 (s, 9H, –Si–t-Bu), 0.95 (t, Jꢃ7.8 Hz, 9H, –Si–(CH2–CH3)3),
1.73 (quint, Jꢃ6.4 Hz, 2H, –CH2–CH2–CH2–), 3.69 (t, Jꢃ6.4 Hz, 4H,
–O–CH2–CH2–CH2–O–). IR (neat): 1255, 1095, 1047, 1006 cmꢄ1. Anal.
Calcd for C15H36O2Si2: C, 59.14; H, 11.91. Found: C, 58.64; H, 12.08. HR-
MS (EI). Calcd for C13H31O2Si2 (MꢁꢄEt): 275.1877. Found: 275.1857.
1-tert-Butyldimethylsilyloxy-4-triethylsilyloxybutane (3a): 1H-NMR
(CDCl3) d: 0.04 (s, 6H, –Si–(CH3)2), 0.59 (q, Jꢃ7.8 Hz, 6H, –Si–(CH2–
CH3)3), 0.89 (s, 9H, –Si–t-Bu), 0.96 (t, Jꢃ7.8 Hz, 9H, –Si–(CH2–CH3)3),
Conclusion
In conclusion, we have studied application of mesoporous
silicas to deprotection of silyl groups, and we successfully
found selective deprotection of the TES group in the pres- 1.56 (4H, –O–CH2–(CH2)2–CH2–O–), 3.62 (4H, –O–CH2–(CH2)2–CH2–O–).
IR (neat): 1255, 1201, 1097, 1008 cmꢄ1. HR-MS (FABꢁ). Calcd for
ence of a TBDMS group of mixed silyl ether of diols with re-
usable MCM-41/MeOH. Since this method requires only fil-
tration to work-up, it is very attractive in viewpoint of syn-
thetic organic chemistry and is environmentally benign.
C16H38O2Si2 (Mꢁꢁ1): 319.2527. Found: 319.2471.
1-tert-Butyldimethylsilyloxy-3-triethylsilyloxypentane (3d): 1H-NMR
(CDCl3) d: 0.04 (s, 6H, –Si–(CH3)2), 0.59 (q, Jꢃ7.8 Hz, 6H, –Si–(CH2–
CH3)3), 0.89 (s, 9H, –Si–t-Bu), 0.95 (t, Jꢃ7.8 Hz, 9H, –Si–(CH2–CH3)3),
1.38 (quint, Jꢃ8.3 Hz, 2H, –(CH2)2–CH2–(CH2)2–), 1.53 (4H, –O–CH2–
CH2–CH2–CH2–CH2–O–), 3.60 (t, Jꢃ6.3 Hz, 4H, –O–CH2–(CH2)3–CH2–
O–). IR (neat): 1255, 1100, 1049, 1006 cmꢄ1. Anal. Calcd for C17H40O2Si2:
C, 61.38; H, 12.12. Found: C, 61.20; H, 12.07.
Experimental
General THF was freshly distilled from Na metal/benzophenone ketyl.
All other dry solvents were obtained from Kanto Kagaku Co., Ltd. Other
chemicals used were of reagent grade and were obtained from Aldrich
Chemical Co., Tokyo Kasei Kogyo Co., Ltd. and Wako Pure Chemical In-
dustries, Ltd. H-ZSM-5 (Si/Alꢃ150) was provided by N. E. Chemcat. Co.,
Tokyo, Japan. H-Y, Na-Y were purchased from TOSOH Co. SiO2 (230—400
mesh) was purchased from Merck Co. Amberlite IR-120B and IRC-50 were
purchased from Organo Co. All reactions were carried out under aerobic
conditions. Compounds 4a, 4c, 4d are commercially available, and 4b,19)
7,20) 10,21) 13,22) 1623) are known compounds. 29Si MAS NMR spectra were
measured at 59.6 MHz on a JNM-CMX 300 (JEOL) solid state NMR spec-
trometer equipped with a magic angle spin probe. The quantitative determi-
nation of Q2, Q3 and Q4 sites was accomplished by deconvolution of the
spectra. BET surface area, the pore size and the pore volume were measured
by volumetric N2-gas adsorption method with BELSORP-mini (BEL Japan,
Inc.).
Synthesis of MCM-41 Tetraethylorthosilicate (20.8 g, 0.1 mol) was
added by pipette to a solution of hexadecyltrimetylammonium bromide
(7.3 g, 0.02 mol) and conc. HCl (8.3 ml, 0.1 mol) in H2O (270 ml), and
stirred for 48 h at r.t. The white precipitate was filtered and washed with dist.
H2O. The solid was dried at 120 °C for 12 h, and calcined at 650 °C for 4 h.
Synthesis of HMS A ethanol solution of tetraethylorthosilicate (20.8 g,
0.1 mol) was added to a suspension of dodecylamine (5.0 g, 0.027 mol) in
H2O (38 ml) under vigorous stirring for 1 h, and aged for 18 h at r.t. The
white precipitate was washed with ethanol and H2O, and calcined at 650 °C
for 4 h.
1-tert-Butyldimethylsilyloxy-4-triethylsilyloxy-2-butyne (6): 1H-NMR
(CDCl3) d: 0.11 (s, 6H, –Si–(CH3)2), 0.65 (q, Jꢃ7.8 Hz, 6H, –Si–(CH2–
CH3)3), 0.90 (s, 9H, –Si–t-Bu), 0.97 (t, Jꢃ7.8 Hz, 9H, –Si–(CH2–CH3)3),
4.34 (s, 4H, –O–CH2–CꢀC–CH2–O–). IR (neat): 1255, 1135, 1097, 1071,
1006 cmꢄ1. Anal. Calcd for C16H34O2Si2: C, 61.08; H, 10.89. Found: C,
60.51; H, 11.05. HR-MS (EI). Calcd for C14H29O2Si2 (MꢁꢄEt): 285.1718.
Found: 285.1702.
1-tert-Butyldimethylsilyloxy-4-triethylsilyloxy-2-butene (9): 1H-NMR
(CDCl3) d: 0.07 (s, 6H, –Si–(CH3)2), 0.61 (q, Jꢃ7.8 Hz, 6H, –Si–(CH2–
CH3)3), 0.90 (s, 9H, –Si–t-Bu), 0.96 (t, Jꢃ7.8 Hz, 9H, –Si–(CH2–CH3)3),
4.22 (d, Jꢃ2.0 Hz, 2H, –CH2–O–Si–), 4.23 (d, Jꢃ2.0 Hz, 2H, –CH2–O–Si–),
5.55—5.57 (2H, –H–CꢃC–H–). IR (neat): 1255, 1085, 1006, 745 cmꢄ1
Anal. Calcd for C16H36O2Si2: C, 60.49; H, 11.46. Found: C, 60.43; H, 11.54.
.
1-(tert-Butyldimethylsilyloxymethyl)-4-triethylsilyloxymethylbenzene
(12): 1H-NMR (CDCl3) d: 0.09 (s, 6H, –Si–(CH3)2), 0.64 (q, Jꢃ7.8 Hz, 6H,
–Si–(CH2–CH3)3), 0.93 (s, 9H, –Si–t-Bu), 0.97 (t, Jꢃ7.8 Hz, 9H, –Si–(CH2–
CH3)3), 4.72 (s, 2H, Ph–CH2–O–Si–), 4.73 (s, 2H, Ph–CH2–O–Si–), 7.29—
7.31 (4H, ArH). IR (neat): 1253, 1213, 1087, 1017, 1006, 742, 668 cmꢄ1
.
Anal. Calcd for C20H38O2Si2: C, 65.51; H, 10.44. Found: C, 65.22; H, 10.31.
2-tert-Butyldimethylsilyloxy-3-triethylsilyloxybutane (15): 1H-NMR
(CDCl3) d: 0.05 (s, 6H, –Si–(CH3)2), 0.60 (q, Jꢃ7.8 Hz, 6H, –Si–(CH2–
CH3)3), 0.88 (s, 9H, –Si–t-Bu), 0.96 (t, Jꢃ7.8 Hz, 9H, –Si–(CH2–CH3)3),
1.11 (d, Jꢃ2.4 Hz, 3H, CH3), 1.13 (d, Jꢃ2.4 Hz, 3H, CH3), 3.50—3.55 (2H,
–O–CH–CH–O–). IR (neat): 1253, 1170, 1114, 1084, 1036, 1006 cmꢄ1
.
Synthesis of FSM-16 Kanemite was prepared as paste by filtration of a
suspension of sodium silicate (50 g) and dist. H2O (500 ml), which was
stirred for 3 h at r.t. Kanemite (as paste) was added to an aqueous solution
(1 l) of hexadecyltrimetylammonium chloride (32 g, 0.1 mol), and stirred for
3 h at 70 °C. After adjusting the pH at 8.5 with 2 N dil. HCl, the suspension
was further stirred for 3 h at 70 °C. The white precipitate was filtered,
washed with dist. H2O, dried at 60 °C for 12 h, and calcined at 550 °C for
5 h.
Synthesis of Disilylether To a solution of tert-butyldimethylsilylmo-
noether, triethylsilylchloride (1.1 eq) and imidazole (2.2 eq) in anhydrous di-
methylformamide was added and stirred at r.t. for over night. The residue
was dissolved in ether and the ether solution was washed with H2O, brine
Anal. Calcd for C16H38O2Si2: C, 60.31; H, 12.02. Found: C, 59.94; H, 12.09.
HR-MS (EI). Calcd for C14H33O2Si2 (MꢁꢄEt): 289.2054. Found: 289.2027.
References and Notes
1) Greene T. W., Wuts P. G. M., “Protective Groups in Organic Synthe-
sis,” 2nd ed., Wiley, N. Y., 1991, p. 68.
2) Sheldon R. A., Chemtech, 24, 38—47 (1994).
3) IUPAC recommends classification of pores to micropore (Dꢀ2 nm; D,
pore diameter) and mesopore (2 nmꢀDꢀ50 nm), see: Everett D. H.,
Pure Appl. Chem., 31, 579—638 (1972).
4) Kresge C. T., Leonowicz M. E., Roth W. J., Vartuil J. C., Beck J. S.,
Nature (London), 359, 710—712 (1992).