Organometallics 1995, 14, 2361-2365
2361
Aluminum Chloride Catalyzed Regioselective Allylsilylation of Alkenes: Convenient Route to 5-Silyl-1-alkenes Seung Ho Yeon, Bong Woo Lee, Bok Ryul Yoo, Mi-Yeon Suk, and I1 Nam Jung" Organometallic Chemistry Laboratory, Korea Institute of Science & Technology, P.O. Box 131, Cheongryang, Seoul 130-650, Korea Received September 27, 1994@
Allyltriorganosilanes react regioselectively with terminal or cyclic alkenes in the presence of aluminum chloride catalyst under mild conditions to afford 5-silyl-1-alkenes in good yield. In the allylsilylation of terminal alkenes the silyl group adds to the terminal carbon and the allyl group to the inner carbon of the double bond and the reaction with cyclic olefins gives allylsilylated products having the silyl and allyl groups in the trans position. This allylsilylation is a convenient route to 5-silyl-1-alkenes. In the allylsilylations with the stereohomogeneous (2)-crotyltrimethylsilane, an allylic inversion is observed indicating a stepwise process of allylsilylation.
Introduction The allylation of carbonyl compounds using allyltrimethylsilane is an important carbon-carbon bond forming meth0d.l In particular, the Lewis acid-promoted allylation, which proceeds in high regioselectivities, is versatile and broadly applicable to many organic reactions.2 In the allylation reaction, the allyl group adds to the carbon atom and the silyl group to the oxygen atom of the carbonyl group. Subsequent hydrolysis of the allylsilylated products then gives the correspondinghomoallyl alcohol. The allylation reaction also can be applied to a$-enones to give 13,eenones.~ The [3 21 cycloaddition of a,p-enones with allylsilanes to give silylcyclopentaneshas been reported recently (eq
+
-1 A 11.-
not been reported. We previously studied the direct synthesis5 of allylchlorosilanes and the Friedel-Crafts alkylation6 of substituted benzenes with allylsilanes in the presence of a Lewis acid catalyst. Considering the allylation, cycloaddition, and alkylation reactions of allylsilanes to unsaturated compounds, we attempted the addition of allylsilanes to olefins. In this paper, we wish to report the allylsilylation reactions of linear or cyclic alkenes and the probable reaction mechanism.
Results and Discussion Allylsilylationof Linear Alkenes. The addition of allyltrimethylsilane, la, t o 1-hexene, 2a, in n-hexane solution in the presence of anhydrous aluminum chloride as a catalyst at room temperature gave the allylsilylated 4-((trimethylsilyl)methyl)-l-octene,3a, as the major product in 78% yield based on la used. The compound 3a was presumably produced by addition of the silyl group t o the terminal carbon atom and of the allyl group to the inner carbon atom of the double bond of 2a as shown in eq 2. The other regio-isomer of 3a R1 &di-R2
&+
Me
+ ARy AIC13
I
Me &.%(1)
allylation product
[3+2] cycloadduct
l a : R'=H, RZ=Me b : R', R2=Me C : R1=H, R2=Ph d : R1=H, R2=CH2Ph
2a : R=C4Hg b : R=C6H13 c : R=CH2Ph
To our knowledge, however, allylsilane addition reactions to alkenes having no other functional groups have Abstract published in Advance ACS Abstracts, April 15,1995. (1)For general review, see: (a) Colvin, E. W. Silicon in Organic Synthesis; Butterworths: London, 1981. (b) Weber, W. P. Silicon Reagents for Organic Synthesis; Springer: Berlin, 1983.(c) Fleming, I.; Dunogubs, J.; Smithers, R. Organic Reactions; Wiley: New York, 1989;Vol. 37. (2)(a) Hosomi, A.; Sakurai, H. Tetrahedron Lett. 1976,17,1295. (b) Seyferth, D.; Pomet, J.;Weinstein, R. M. Organometallics 1982,1, 1651. (3)Hosomi, A.; Sakurai, H. J.Am. Chem. SOC.1977,99,1675. (4)(a)Knolker, H.-J.; Graf, R. Tetrahedron Lett. 1993,34,4765.(b) Knolker, H.-J.; Foitzik, N.; Goesmann, H.; Graf, R. Angew. Chem., Int. Ed. Engl. 1993,32, 1081. (c) Knolker, H.-J.; Foitzik, N.; Graf, R.; Pannek, J.-B. Jones, P. G. Tetrahedron 1993,49,9955.
I R2-$iM
@
Me
e
1 R1 + others(2)
-
3a g
was not detected indicating that the allylsilylation is regioselective. In addition to 3a, 4,6,6-trimethyl-6~~
(5)Yeon, S.H.; Lee, B. W.; Kim, %-I.; Jung, I. N. Organometallics 1993.12.4887. (6jLee, B. W.; Yoo, B. R.; Kim, S.-I.; Jung, I. N. Organometallics 1994,13,1312.
0276-733319512314-236l$O9.OOlO 0 1995 American Chemical Society
Yeon et al.
2362 Organometallics, Vol. 14, No. 5, 1995
Table 1. Results on Allylsilylation of Linear Alkenes with Allylsilanes entry ream conditionsa no. allvlsilane alkene solvent
1 2
la la
2a la
3 4 5 6 7
la la
2b 2c 2a 2a 2a
lb lo Id
n-hexane n-hexane benzene n-hexane n-hexane none benzene n-hexane
yieldb time (h) oroduct
1.5 12 6 3 6 8.5 6
1.5
3a 3b 3b 3c 3d 3e 3f 3g
(%)
78 48 44 60
20 79 42 47
Reactions were carried out at room temperature. Based on allylsilane used.
silahept-1-ene (3%), 4a, was obtained as a minor product. Several other minor byproducts also were obtained and identified as 4-((trimethylsilyl)methyl)-6silahept-1-ene, 3b (2%),hexamethyldisiloxane (7%),and unidentified high boilers and polymeric materials (10%). Lewis acids such as titanium tetrachloride, stannic chloride, aluminum trichloride, boron trifluoride, etc., have been used as catalysts for the allylation of carbonyl However, this compounds with allyltrimethy1~ilane.l~~~~~ allylsilylation of alkenes did not occur with Lewis acid catalysts other than aluminum chloride. About 10 mol % of aluminum chloride was sufficient to catalyze the allylsilylation, and the reaction proceeded at room temperature or below. In benzene solution, the reaction was observed to be more exothermic and generally proceeded faster than in n-hexane. This reactivity difference may be attributed to the higher solubility of aluminum chloride in benzene. The allylsilylation of 2a with 2-methyl-2-propenyltrimethylsilane, lb, instead of l a gave 2-methyl-4((trimethylsily1)methyl)-1-octene, 3e, as expected, in 79%yield. This reaction proceeded at a slightly slower rate than that of la. The allylsilylations of various linear alkenes with allylsilanes were carried out in the presence of aluminum chloride catalyst as represented in eq 2, and the results are summarized in Table 1. As shown in Table 1, the isolated yields were good, ranging from 20% to 79% depending upon the nature of two reactants. Advantageously, the present allylsilylation can be carried out under mild conditions affording 5-silyl-1-alkenes in good yield and high regioselectivities also are attained in all the experiments. The allylsilylation of allylbenzene gave the lowest yield and a large amount of polymeric material. The hexamethyldisiloxane byproduct, apparently produced by hydrolysis of trimethylchlorosilane, was obtained in the every allylsilylation reaction, indicating that the cleavage of allyl group from allyltrimethylsilane was involved. Protodesilylation of allyltrimethylsilane by acids has been r e p ~ r t e d .In ~ the Friedel-Crafts alkylation with alkenes in the presence of aluminum chloride, a small amount of hydrogen chloride resulting from the reaction of anhydrous aluminum chloride with adventitious water in the reaction mixture is responsible for this well-known8 and well-understood9J0 cleavage reaction. The stabilized carbocation intermediate I generated by the protonation of l a either undergoes (7) (a) Jenkins P. R.; Gut, R.; Wetter, H.; Eschenmoser, A. Helu. Chim. Acta 1979, 62, 1922. (b)Fleming, I.; Marchi, D.; Patel, K. J. Chem. SOC.,Perkin Trans. 1 , 1981, 2518. (8)Thomas, C. A. Anhydrous Aluminum Chloride in Organic Chemistry; Reinhold Publishing Co.: New York, 1941.
desilylation to give propylene and the trimethylsilyl cation7J1or reacts with l a t o give the cation adduct I1 which gives the byproduct 4a by donating a trimethylsilyl cation to la. Electrophilic attack on electron-rich systems by trialkylsilyl cations has been reported for other systems.12 GC-MS analysis of the off-gas indeed showed the presence of propylene indicating the occurence of the desilylation of la. This type of intermediate i.e., 11, was proposed to be formed by protonation of 1,3-bis(trimethylsilyl)propene,which resulted in the desilylation to give allylsilane.ll At the final stage of the allylsilylation, the cation intermediate I1 would interact with AlC14- to give trimethylchlorosilane which is hydrolyzed to hexamethyldisiloxane during the workup. These results are consistent with the initial formation of trimethylsilyl cation intermediates by protodesilylation. The reaction pathways for the byproducts are proposed in Scheme 1. Allylic Inversion. The stereohomogeneous (2)-crotyltrimethylsilane, le, was prepared13and reacted with 2a. This allylsilylation gave 3-methyl-4-((trimethylsi1yl)methyl)-1-octene,3h, as a mixture of two diastereomers in 25% yield (eq 3). The structural assignment
le
3h, 25 96 yield
of diastereomers by 13C NMR was reported for other ~ y s t e m .13C ~ NMR studies of 3h showed indeed the presence of two diastereomers. The products have a methyl group at the carbon a to the double bond which was moved from the terminal carbon of the starting allylsilane, indicating that an allylic inversion occured during the allylsilylation. This type of allylic inversion has been reported in the allylation of carbonyl comp o u n d ~ This . ~ ~allylic ~ inversion is consistent with the interaction of the cation intermediate I1 with the electron-rich double bond of the allylsilane and then elimination of a silyl cation from the incoming allylsilane to give the allylsilylated products. Allylsilylation of Cycloalkenes. We extended the allylsilylation to cyclohexene, 2d, and trans-1-(trimethylsilyl)-2-allylcyclohexane,3i, was obtained in 22% yield (eq 4). The NMR studies of 3i show that the coupling
3i
\
J b = 11.9 Hz, Jr = 10.5 Hz. .Iw* = 3.3 Hz
constant between the protons Ha and Hb a t the carbons, to which the silyl and allyl groups are attached, respec-
Regioselective Allylsilation of Alkenes
Organometallics, Vol. 14, No. 5, 1995 2363
Scheme 1
-la Scheme 2. Catalytic Cycle of Allylsilylation
la
M e a S i d
3 tively, is 11.9 Hz. Since the cis coupling constant is smaller than the trans coupling constant in general and usually smaller than 6 Hz,14 it can be concluded that the two bulky groups are positioned trans. The allylsilylation of cyclopentene, 2e, also gave trans-1-(trimethylsilyl)-2-allylcyclopentane,3j, in 39% yield. The stereochemistry of 3j has been assigned analogously to be trans. The trans configurtion for the two bulky groups is consistent with a stepwise process of allylsilylation. Reaction Mechanism. We propose a mechanism for the allylsilylation in which a cation intermediate, 11, is formed at the begining stages of the reaction as illustrated in Scheme l. The sterically hindered intermediate 11is stabilized by the /3 stabilization effect from two silyl groups. This may be the reason for the slower self-allylsilylation reaction compared with the allylsilylation of alkenes. When intermediate 11interacts with 2, the trimethylsilyl cation would be transferred to the terminal carbon of 2 to generate a new intermediate 111. The more stable secondary carbocation formation and the /3 stabilization effect in the intermediate I11 would be responsible for the regiochemistry of the products. When intermediate I11 interacts with the double bond of l a to form a new carbon-carbon bond, the carbenium (9) Wierschke, S. G.; Chandrasekhar, J.; Jorgensen, W. L. J. Am. Chem. SOC.1986,107,1496. (10) Eabom, C.; Bott, R. W. Organometallic Compounds of the Group N Elements; MacDiarmid, A. G., Ed.; Dekker: New York, 1968; Vol. 1, Part 1, pp 359-437. (11)Fleming, I.; Langley, J. A. J. Chem. SOC.,Perkin Trans. 1,1981, 1421.
R
ion center at the carbon /3 to silicon, IV, would be generated. When intermediate IV interacts with 2, the allylsilylated products, 3,would be obtained by transferring the trimethylsilyl cation to 2 t o regenerate the intermediate, 111. The allylic inversion could be best explained by forming a new double bond between the carbons a and /3 t o silicon of the incoming allylsilane and eliminating trimethylsilyl cation as illustrated in Scheme 2. The trans allylsilylation of l a t o cyclic olefins could be explained by the approach of l a to the intermediate I11 type cation from the other side of trimethylsilyl group in order to minimize the steric repulsion between the bulky trimethylsilyl group and the incoming allyltrimethylsilane. All the results are consistent with a stepwise process of allylsilylation in the proposed mechanism above.
Experimental Section The solventsn-hexane and benzene were dried over sodium benzophenone ketyl and distilled before use. Allyltrimethylsilane w8s purchased from Hiils America Inc. and used without further purification. 2-Methyl-2-propenyltrimethylsilane and (12) (a) Olah, G. A.; Bach, T.; Surya Prakash, G. K. J. Org. Chem. 1999,54, 3770. (b) Frick, U.; Simchen, G. Synthesis 1984,929. (c) Eaborn, C.; Jones, K. L.; Lickiss, P. D. J . Chem. SOC.,Perkin Trans. 2 1992, 489. (d) Fornarini, S. J. Org. Chem. 1988, 53, 1314. (13) (a) Tsuji, J.; Hara,M.; Ohno, K. Tetrahedron 1974, 30, 2143. (b) Kira, M.; Hino, T Sakurai, H. Tetrahedron Lett. 1989,30, 1099. (14) Pretsch, E.; Clerc, T.; Siebl, J.; Simon, W. Spectral Data for Structure Determination of Organic Compounds; Springer-Verlag: New York, 1983; p H185.
2364 Organometallics, Vol. 14,No. 5, 1995
(2)-crotyltrimethylsilane were prepared from literature methods.12 Anhydrous aluminum chloride was obtained from Aldrich Chemical Co. Other simple chemicals were purchased and used without further purification. Products obtained from the allylsilylation of various alkenes were analyzed by GLC using a capillary column (SE-54, 30m) or a packed column (10% OV-101 on 80-100 mesh Chromosorb WlAW, 1.5 m x l l g in.) on a Varian 3300 gas chromatograph equipped with a flame ionization detector or a thermal conductivity detector, respectively. The samples for characterization were purified by a preparative GLC using a Varian Aerograph Series 1400 gas chromatograph with a thermal conductivity detector and a 2 m by '18 in. stainless steel column packed with 20% OV-101 on 80-100 mesh Chromosorb PlAW. NMR spectra were recorded using CDC13 (CHC13taken as 6 7.26) on a Varian Gemini 300 spectrometer. Mass spectra were obtained using a Hewlett Packard 5890 Series I1 gas chromatograph equipped with a Model 5972 mass selective detector. Elemental analyses were performed by the Advanced Analysis Center of the Korea Institute of Science and Technology, Seoul, Korea. HRMS (high resolution mass (70 eV, EI) spectra) were performed by the Analytical Chemistry Laboratory of the Korea Research Institute of Chemical Technology, Daejon, Korea. Typical Procedure for Allylsilylation Reaction. To a stirred solution of 0.52 g (4.0 mmol) of anhydrous aluminum chloride and 10.0 mL of dried n-hexane in a 50 mL threenecked round-bottomed flask equipped with an addition funnel, a reflux condenser, and a gas inlet tube at room temperature was added dropwise mixture of 4.6 g (40 mmol) of l a and 10.1 g (120 mmol) of 2a under dry nitrogen. The mixture was stirred for 1.5 h at room temperature, and the solution was quenched with 5 mL of water. The upper layer was separated and dried over anhydrous magnesium sulfate. The solvent and low boilers were distilled, and the product mixture was distilled under vacuum to give 4-((trimethylsilyl)methyl)1-octene, 3a (6.2 g, bp 28-30 "ClO.6 Torr) in 78% yield based on la. Several other byproducts also were obtained by vacuum distillation and identified as 4,6,6-trimethyl-6-silahept-l-ene (3%),4a, 6,6-dimethyl-4-((trimethylsilyl)methyl)-6-sil~ept-lene, 3b (2%),hexamethyldisiloxane (7%),and unidentified high boilers and polymeric material (10%). Data for 3a: 'H-NMR 6 0.01 (s, 9H, SiCH3), 0.51-0.60 (m, 2H, SiCHd, 0.90 (t, J = 6.8 Hz, 3H, CH3), 1.26 (br s, 6H, CHz), 1.50-1.60 (br m, lH, CH),1.98-2.10(m, 2H,CH~),4.99(d,J = 12.3Hz,2H,CHz=), 5.70-5.85 (m, lH, -CH=); 13C-NMR 6 0.54 (SiCH3), 14.16 ( C H 3 ) , 21.63, 23.01, 28.91, 34.14, 36.10, 41.01 (CH, CHz), 115.64 ( C H 2 = ) , 137.64 (-CH=); mass spectra: mle (relative intensity) 157 (11, M+ - CHzCH=CHz), 99 (121, 74 (9), 73 (loo), 59 (8). HRMS ( m l e ) : calcd for CllH23Si (M+ - CHd, 183.1569; found, 183.1570. Anal. Calcd (found) for C12H26Si: C, 72.64 (72.71); H, 13.21 (13.42). Data for 4a: 'H-NMR 6 0.02 (s, 9H, Sic&), 0.40 (dd, J = 8.9, 14.7 Hz, lH, SiCHaH), 0.67 (dd, J = 4.9, 14.7 Hz, l H , SiCHHh), 0.92 (d, J = 6.6 Hz, 3H, CH3), 1.61-1.74 (m, l H , CH), 1.89-2.09 (m, 2H, CHZ), 4.96-5.03 (m, 2H, =CHz), 5.72-5.87 (m, lH, -CH=); W-NMR 6 -0.60 (SiCH3),22.59 ( C H 3 ) , 24.75, 45.04 (CHZ),29.78 (CHI, 115.52 (CH2=), 137.85 (-CH=); mass spectra mle (relative intensity) 115 (14, M+ - CHzCH=CH2), 99 (13), 73 (1001, 59
Yeon et al. (-CH-); mass spectra m l e (relative intensity) 187 (39, M+ CH&H=CHz), 100 (14), 74 (17),73 (100),59(18). HRMS ( m l e ) : calcd for C9H23Siz (M+ - CHzCH=CHz), 187.1338; found, 187.1337. Anal. Calcd (found) for ClzHzsSiz: C, 63.07 (62.83); H, 12.35 (12.81). Allylsilylation of 2b with la. Using the typical reaction 312, 3.5 procedure above, 4-((trimethylsilyl)methyl)-l-decene, g (bp 46-48 "ClO.6 Torr, 60% yield), was obtained from the reaction of 3.0 g (26 mmol) of l a and 8.8 g (78 mmol) of 1-octene, 2b, using 0.35 g (2.6 mmol) of anhydrous aluminum chloride. Data for 3c: 'H-NMR 6 0.12 (s, 9H, SiCH3), 0.480.62 (m, 2H, SiCHZ), 0.89 (t,J = 6.9 Hz, 3H, CH3), 1.27 (br s, 10H, CHz), 1.51-1.62 (br m, lH, CH), 2.01-2.06 (m, 2H, CHd, 4.99 (d, J = 12.4 Hz, 2H, CH2=), 5.70-5.85 (m, l H , -CH=); T - N M R 6 0.54 (SiCHs), 14.11 (CH3), 21.63, 22.74, 26.62, 29.67, 31.98, 34.43, 36.43, 41.10 (CH, CHd, 115.62 (CH2=), 137.64 (-CH=); mass spectra m l e (relative intensity) 185 (4, M+ - CHiCH=CHz), 99 (8), 73 (loo), 59 (8). HRMS ( m l e ) : calcd for C14H30Si (M+), 226.2116; found, 226.2115. Anal. Calcd (found) for C14H30Si : C, 74.25 (74.11); H, 13.35 (13.89).
Allylsilylation of 2c with la. 4-Benzyl-6,6-dimethy1-6silahept-1-ene, 3d, 1.2 g (bp 51-52 "ClO.6 Torr, 20% yield), was obtained from the reaction of 3.0 g (26 mmol) of la and 9.3 g (79 mmol) of allylbenzene, 2c, using 0.35 g (2.6 mmol) of anhydrous aluminum chloride. Data for 3d: IH-NMR 6 0.04 (s, 9H, SiCH3), 0.57 (dd, J = 6.6, 15.0 Hz, l H , SiCHaH), 0.67
(dd,J=6.3,15.0Hz,1H,SiCHHh),1.91(hep,J=6.5Hz,1H,
CH), 1.98-2.10 (m, 2H, CH2), 2.58 (d, 2H, CHd, 5.00-5.12 (m, 2H, CHz=), 5.74-5.88 (m, l H , -CH=), 7.13-7.32 (Arm; 13C-NMR 6 -0.57 (SiCH3), 21.22, 36.36, 40.40, 43.28 ( C H , CHz), 116.37 ( C H z = ) , 125.74, 128.17, 129.31, 141.49 (Ar), 137.13 (-CH=); mass spectra mle (relative intensity) 217 (0.8, M+ - CH3), 191 (3, M+ - CH2CH=CHz), 141 (181, 99 (111,91 (12), 73 (loo), 59 (9). HRMS ( m l e ) :calcd for CMHZIS~ (M+ CH3), 217.1413; found, 217.1416. Anal. Calcd (found) for C15H24Si: C, 77.51 (77.28); H, 10.44 (10.63). Allylsilylation of 2a with lb. 2-Methyl-4-((trimethylsi1yl)methyl)-1-octene, 3e, 2.3 g (bp 35-37 "ClO.6 Torr, 79% yield), was obtained from the reaction of 1.8 g (14 mmol) of l b and 3.4 g (40 mmol) of 2a using 0.19 g (1.4 mmol) of anhydrous aluminum chloride in the absence of solvent at room temperature for 8.5 h. Other byproducts were identified as hexamethyldisiloxane (6%) and 2,4,4,6,6-pentamethy1-6silahept-1-ene, 4b (12%). Data for 3b: 'H-NMR 6 0.02 (s,9H, SiCHs), 0 3 2 (d, J = 6.5 Hz, 2H, SiCHZ), 0.90 (t, J = 6.3 Hz, 3H, CH3),1.18-1.34 (br m, 6H, CHZ),1.58-1.66 (m, l H , CH), 1.68 (9, 3H, CH3), 1.88 (dd, J = 6.9, 13.4 Hz, l H , CHaH), 2.02 (dd, J = 7.3, 13.4 Hz, lH, CHHh), 4.65 (s, lH, =CHaH), 4.74 (s, lH, =CHHb); W-NMR 6 0.52 (SiCH31, 14.19, 22.21 (CH3), 21.53, 23.05, 28.72, 36.08, 46.17, 31.94 (CH, C H z ) , 111.56 (CH2=), 144.94 (-CH=); mass spectra mle (relative intensity) 157 (14, M+ - CHZC(Me)=CHz), 113 (8),85 (4), 75 (41, 74 (9), 73 (loo), 59 (9), 43 (3). HRMS ( m l e ) : calcd for C13HzgSi (M+), 212.1960; found, 212.1943. Anal. Calcd (found) for C13H~gSi: C, 73.50 (74.32); H, 13.28 (13.46). Data for 4b: 'H-NMR 6 0.05 (s, 9H, Sic&), 0.72 (s, 2H, SiCHz),0.98 (s,6H, CH3),1.79 (s, 3H, CH3),1.99 (s, 2H, CH2), 4.62-4.65 (m, lH, =CHaH), 4.83-4.87 (m, l H , =CHIP); W-NMR 6 1.03 (SiCHs), 25.49, 55.69 ( C H z ) , 30.38, 33.02 (CH3), 34.45 (C), 113.96 (CHz=), 144.12 (=C-);mass spectra m l e (relative intensity) 169 (1, (10). M+ - CHs), 129 (19, M+ - CHzC(Me)=CHz), 113 (11),74 (101, Self-Allylsilylation of la. Using the reaction procedure described above, 6,6-dimethyl-4-((trimethylsilyl)methyl)-6-si- 73 (loo), 59 (12), 45 (16). HRMS ( m l e ) : calcd for C7H17Si (M+ - CHzC(Me)=CHz),129.1099; found, 129.1099. lahept-1-ene, 3b, 1.4 g (bp 30-32 "C/0.6 Torr, 48% yield), was Allylsilylation of 2a with IC. 4-((Dimethylphenylsilyl)obtained from the reaction of 3.0 g (26 mmol) of la only using methyl)-1-octene, 3f, 2.1 g (bp 72-74 "ClO.6 Torr, 47% yield), 0.35 g (2.6 mmol) of anhydrous aluminum chloride in n-hexane. was obtained from the reaction of 3.0 g (7.0 mmol) of allyldiOther byproducts were identified as hexamethyldisiloxane methylphenylsilane, IC,and 4.3 g (51 mmol) of 2a using 0.10 (13%) and 4a (1%).Data for 3b: 'H-NMR 6 0.01 (8, 18H, g (0.7 mmol) of anhydrous aluminum chloride. Data for 3f: SiCHz), 0.68 (dd, J = 6.9 Hz, 14.7 Hz, 2H, SiCHaH), 0.53 (dd, 'H-NMR 6 0.31 (s,6H, SiCHs), 0.73-0.87 (m, 2H, SiCHZ), 0.85 J = 6.4 Hz, 14.7 Hz, 2H, SiCHHb), 1.77 (hep, J = 6.5 Hz, lH, (t, J = 6.7 Hz, 3H, CH3), 1.12-1.30 (br m, 6H, CHd, 1.53CH), 2.03 (t, J = 6.4 Hz, 2H, CHz), 4.96-5.02 (m, 2H, CHz=), 1.64 (m, lH, CH), 1.92-2.08 (m, 2H, CH2), 4.90-5.00 (m, 2H, 5.70-5.81 (m, l H , -CH=); W-NMR 6 0.40 (SiCH3), 25.30 CHz=), 5.64-5.79 (m, l H , -CH=), 7.30-7.55 (m, 5H, Arm; (SiCH2), 31.02 (CHI, 44.87 (CHz), 117.15 (CH2=), 137.65
Regioselectiue Allylsilation of Alkenes l3C-NMR 6 -1.98 (SiCH3), 14.13, 20.75, 22.94, 28.80, 34.02, 36.00,41.00 (CH,C H 2 ) , 115.80 (CHz=), 127.72,128.74,133.57, 140.11 (Ar),137.46 (-CH=); mass spectra mle (relative intensity) 219 (4, M+ - CHzCH=CHz), 161 (4), 136 (141, 135 (loo), 121 (6), 119 (3), 107 (6), 105 (5). HRMS (mle): calcd for C14H~3Si(M+ - CHzCH=CHz), 219.1569; found, 219.1603. Anal. Calcd (found) for Cl7H2&i: C, 78.38 (78.62); H, 10.83 (11.23). Allylsilylation of 2a with Id. 4-((Benzyldimethylsilyl)methyl)-1-octene, 3g, 1.2 g (bp 78-80 "Cl0.6 Torr, 42% yield), was obtained from the reaction of 2.0 g (10 mmol) of allylbenzyldimethylsilane, Id, and 2.6 g (31 mmol) of 2a using 0.13 g (1.0 mmol) of anhydrous aluminum chloride. Data for 3g: 'HNMR 6 0.00 (s, 6H, SiCH3), 0.51-0.65 (m, 2H, SiCHZ), 0.91 (t, J = 6.7 Hz, 3H, CH3), 1.20-1.33 (br m, 6H, CHz), 1.53-1.62 (m, lH, CH), 1.95-2.09 (m, 2H, CHd, 2.10 (s,2H, CHz), 4.975.03 (m, 2H, CHz=), 5.69-5.83 (m, lH, -CH=), 7.00-7.28 (m, 5H, Arm;13C-NMFt6 -2.43 (SiCH3), 14.17,20.00,23.01,26.50, 28.93, 34.00, 36.16, 41.08 (CH, C H z ) , 115.84 (CHz=), 123.91, 137.44 (-CH=); mass spectra mle 128.13,128.19, 140.43 (Ar), (relative intensity) 259 (0.2, M+ - CH3), 233 (0.2, M+ - CHzCHxCHz), 183 (32), 155 (7), 149 (291, 121 (271, 99 (loo), 91 (9), 59 (15). HRMS (mle): calcd for C15Hz5Si (M+ - CHZCH=CHz), 233.1726; found, 233.1719. Anal. Calcd (found) for Cp,HjoSi: C, 78.76 (78.93); H, 11.01 (11.35). Allylsilylation of 2a with le. 3-Methyl-4-((trimethylsilyl)methyl)-1-octene, 3h, 0.3 g (bp 32-34 "ClO.6 Torr, 25% yield), was obtained from the reaction of 0.7 g (5.5 mmol) of le and 1.4 g (17 mmol) of 2a using 0.08 g (0.6 mmol) of anhydrous aluminum chloride at room temperature for 4 h. Other byproducts were identified as hexamethyldisiloxane (7%)and 4-ethyl-3,6,6-trimethyl-6-silahept-l-ene, 4c (5%). Data for 3h (mixed diastereomers): lH-NMR 6 0.01 (s,9H, Sic&), 0.300.39 (m, l H , SiCHaH), 0.51-0.63 (m, l H , SiCHHb), 0.86-0.95 (m, 6H, CH3), 1.14-1.35 (m, 6H, CHz), 1.39-1.53 (br m, lH, CH), 2.28-2.60 (br m, lH, CH), 4.93-4.99 (m, 2H, CHz=), 5.70-5.81 (m, 1H, -CH=); 13C-NMR 6 (chemical shifts for the diastereomers are given in parentheses) -0.69 (SiCH3),14.15 (14.63), 16.49, 18.04 (17.77), 23.04,29.51(29.68), 33.31, 39.18 (38.96) (CH,C H z ) , 40.78 (40.48) (CHz), 113.51 (113.14) (CHz=), 142.75 (143.65) (-CH=); mass spectra mle (relative intensity) 157 (8, M+ - CH(Me)CH=CHz), 113 (5), 73 (loo), 59 (8), 45 (8), 29 ( 5 ) . HRMS (mle): calcd for CgHzlSi (M+ - CH(Me)CH=CH2), 157.1413; found, 157.1425. Anal. Calcd (found) for C13H28Si : C, 73.50 (73.06); H, 13.28 (13.45). Data for 4c (mixed diastereomers): 'H-NMR 6 0.01 (s, 9H, SiCH3), 0.300.63 (m, 2H, SiCHZ), 0.84-0.96 (m, 6H, CH3), 1.21-1.43 (br m, 3H, CH, CHz), 2.21-2.32 (br m, lH, CH), 4.93-4.99 (m, 2H, CH2=), 5.68-5.82 (m, l H , -CH=); I3C-NMR 6 (chemical shifts for the diastereomers are given in parentheses) -0.70
Organometallics, Vol. 14, No. 5, 1995 2365 (SiCH3),16.63 (14.72), 17.32 (17.62) (CH3), 11.75 (11.61), 26.11 (CHz), 40.26 (40.56), 40.48 (40.89) (CH), 113.10 (113.49) (CH2=), 142.77 (143.70) (-CH=). Allylsilylation of 2d with la. truns-l-(Trimethylsilyl)-2allylcyclohexane, 3i, 2.3 g (bp 38-41 "ClO.6 Torr, 31% yield), was obtained from the reaction of 4.2 g (37 mmol) of l a and 13.2 g (160 mmol) of 2d using 0.49 g (3.7 mmol) of anhydrous aluminum chloride in benzene solution at room temperature for 1.5 h. Other byproducts were identified as hexamethyldisiloxane (8%), 3b (29%), 3-(cyclohex-2-enyl)-l-(trimethylsi1yl)propane (4%) and 4a (5%). Data for 3i: 'H-NMR 6 0.02 (s, 9H, Sic&), 0.45-0.54 (ddd, J(HaHb)= 11.9 Hz, J(HaHCax) = 10.5 Hz, J(HaHC;,) = 3 .3 Hz, lH, ring-CHSi), 0.85-0.98, 1.78-1.84 (m, 2H, ring-CHz), 1.08-1.19, 1.67-1.69 (m, 2H, ring-CHz), 1.20-1.25 (m, 2H, ring-CHz), 1.31-1.42 (m, lH, ring-CH), 1.70-1.77 (m, 2H, ring-CHz), 1.85-1.92, 2.23-2.35 (m, 2H, CHz), 4.96-5.01 (m, 2H, CHz=), 5.74-5.83 (m, lH, -CH=); 13C-NMR 6 1.12 (SiCH3), 26.27, 27.72, 28.02, 30.64, 33.17,38.83,40.98 (CH,C H z ) , 115.45 (CHz=), 137.69 (-(XI=); mas8 spectra mle (relative intensity) 155 (13, M+ - CHzCH=CHz), 99 (3),81(5),74 (9),73 (loo), 59 (9),45(7). HRMS (mle): calcd for CllHzlSi (M+ - CH3), 181.1412; found, 181.1387. Anal. Calcd (found) for C12H24Si: C, 73.38 (73.12); H, 12.32 (12.67). Allylsilylation of 2e with la. truns-l-(Trimethylsilyl)-2allylcyclopentane, 3j, 1.9 g (bp 23-25 "ClO.6 Torr, 39% yield), was obtained from the reaction of 3.0 g (26 mmol) of l a and 5.3 g (78 mmol) of 2e using 0.35 g (2.6 mmol) of anhydrous aluminum chloride in benzene solution at room temperature for 5 h. Data for 3j: lH-NMR 6 0.00 (s, 9H, SiCH3), 0.64 (dt, J = 8.0,9.2 Hz, lH, SiCH), 1.25-1.43 (m, 2H, ring-CHz), 1.471.56 (m, 2H, ring-CHz), 1.60-1.70 (m, l H , ring-CHI, 1.721.85 (m, 2H, ring-CHz), 1.78-1.95, 2.17-2.32 (m, 2H, CHZ), 4.94-5.03 (m, 2H, CHz=), 5.73-5.88 (m, lH, -CH=); I3C-NMR 6 -2.52 (SiCH3), 26.39, 28.68, 31.35, 33.50, 41.10, 41.65 (CH, CH2), 114.94 ( C H 2 = ) , 138.40 (-CH=); mass spectra mle (relative intensity) 167 (1, M+ - CH3), 141 (16, M+ - CHzCH=CH2), 99 (2), 79 (3),73 (loo), 67 (6),59 (10). HRMS (ml e ) : calcd for CloH&i (M+ - CH3), 167.1256; found, 167.1243. Anal. Calcd (found) for C11HZzSi: C, 72.44 (73.57); H, 12.16 (1254).
Acknowledgment. This research was supported financially by the Ministry of Science and Technology of Korea (Project 2N11700). We thank Prof. H. Sakurai of Tohoku University for many valuable discussions on the mechanism of allylsilylation. OM940749G
