4304 J . Org. Chem., Vol. 63, No. 13, 1998
Takaki et al.
(C5Me5)2Sm (η3-CH2CHCHMe) (4b)8 fr om 1: 1H NMR
(C6D12) δ -4.61 (3H, br s), 1.14 (30H, s), 6.08 (1H, br s), 9.16
(2H, br s), 14.61 (1H, br s). 4b fr om 2: 1H NMR(C6D6) δ -4.60
(3H, br s), 1.15 (15H, s), 1.24 (15H, s), 6.12 (1H, br s), 7.07
(1H, br s), 10.75 (1H, br s), 14.66 (1H, br s).
using hexanes-ethyl acetate eluent (10/1) gave pure 8 (107
mg, 76% yield) and 9d (18 mg, 13% yield).
Rea ction of Allylic Sa m a r iu m s 4 w ith Cycloh exa n on e.
Cp*2Sm(thf)2 (1) (2.0 equiv) was placed in a Schlenk tube and
dissolved in toluene (ca. 0.2 M). Allylic ether 3 was syringed
to the solution, and stirring was continued for 1 h at room
temperature to generate allylic samarium 4. The ethers 3f,i,j
were treated for 20 h at room temperature. In the case of 3k ,
the reaction was carried out at 80 °C for 5 h. Then cyclohex-
anone (2.0 equiv) was added to the resulting solution of 4 at
room temperature, and the mixture was stirred for 3-20 h.
After addition of water and then 2 M HCl, the mixture was
extracted with ether, washed with brine, dried over MgSO4,
and concentrated in vacuo. GC analyses of the crude reaction
mixture indicated exclusive formation of the homoallylic
alcohol 9, which was isolated by column chromatography on
silica gel using hexanes-ethyl acetate eluent. When 1.0 equiv
of cyclohexanone was used, the yields of 9b and 9d decreased
to 72% and 54% yields, respectively. In the reaction of 4i-k ,
the starting ethers 3i, 3j, (Z-isomer), and 3k were recovered
in 51%, 55%, and 64% yields, respectively.
(C5Me5)2Sm (η3-CH2CHCHP h ) (4d )8 fr om 1: 1H NMR
(C6D12) δ 1.05 (30H, s), 3.72 (2H, d, J ) 7.3 Hz), 5.59 (2H, t, J
) 7.6 Hz), 6.25 (1H, br s), 6.30 (1H, t, J ) 7.3 Hz), 7.96 (2H,
br s), 15.08 (1H, br s). 4d fr om 2: 1H NMR(C6D6) δ 0.76 (15H,
s), 1.26 (15H, s), 3.99 (2H, d, J ) 7.3 Hz), 5.39 (1H, br s), 5.76
(2H, t, J ) 7.6 Hz), 6.48 (1H, t, J ) 7.3 Hz), 6.61 (1H, br s),
10.10 (1H, br s), 15.52 (1H, br s).
(C5Me5)2Sm (η3-CH2CMeCH2) (4e) fr om 1: 1H NMR(C6D6)
δ 1.12 (30H, s), 5.07 (3H, s), 5.19 (4H, br s). 4e fr om 2: 1H
NMR(C6D6) δ 1.13 (15H, s), 1.21 (15H, s), 3.67 (2H, br s), 5.23
(3H, s), 6.75 (2H, br s).
(C5Me5)2Sm (CH2CHCMe2) (4f) fr om 1: 1H NMR(C6D6) δ
0.12 (3H, s), 0.31 (3H, s), 1.50 (30H, s), 8.01 (1H, br s), 9.32
(2H, br s).
(C5Me5)2Sm (η3-MeCHCHCHMe) (4g) fr om 1 a n d 2: 1H
NMR (C6D12) δ -3.10 (6H, br s), 1.12 (15H, s), 1.15 (15H, s),
9.16 (2H, br s), 15.14 (1H, br s).
Rea ction of Allylic Sa m a r iu m s 4 w ith Dim eth ylp h e-
n ylsilyl a n d Tr im eth ylsilyl Ch lor id es. Allylic samarium
4 was generated from 3 and 1 (2.0 equiv) in toluene by a
similar procedure to the above. Then silyl chloride (4.0 equiv)
was added to the solution of 4, and the mixture was stirred at
room temperature for 20 h. The reaction was quenched with
water and 2 M HCl and worked up similarly. Ratios of the
regio- and stereoisomers were determined by GC analyses and
1H and 13C NMR spectra of the crude reaction mixture. Allylic
silanes 11 and 12 were isolated by column chromatography
on silica gel or alumina using hexanes-ethyl acetate eluent.
Rea ction of Allylic Sa m a r iu m s 4 w ith Acetop h en on e
a n d P iva la ld eh yd e. Acetophenone or pivalaldehyde (2.0
equiv) was added to a solution of 4 in toluene, generated from
3 and 1 (2.0 equiv) in situ as above, and the mixture was
stirred at room temperature for 6 or 3 h, respectively. After
usual workup, the crude mixture was chromatographed on
silica gel using hexanes-ethyl acetate eluent to give a mixture
of two diastereomers 13 or 14, whose ratio was determined
by NMR. Stereochemistry of 13g and 14b was determined
by comparison of their 1H and 13C NMR spectra with those of
literature.24,25 The structures of other products 13 and 14 were
assigned by analogy.
(C5Me5)2Sm (η3-MeCHCHCHP h (4h ) fr om 1: 1H NMR
(C6D6) δ -3.54 (3H, br s), 0.79 (15H, s), 1.15 (15H, s), 5.04
(2H, d, J ) 7.3 Hz), 6.14 (2H, t, J ) 7.3 Hz), 6.83 (1H, t, J )
7.3 Hz), 9.00 (1H, br s), 10.05 (1H, br s), 15.42 (1H, br s).
(C5Me5)2Sm (cycloh exen yl) (4i) fr om 1: 1H NMR(C6D6)
δ 1.41 (15H, s), 1.86 (15H, s), 5.73 (2H, br s), 10.51 (1H, br s).
Other methylene protons could not be assigned.
(C5Me5)2Sm (η3-CH2CMeCHMe) (4j) fr om 1: 1H NMR
(C6D6) δ -4.09 (3H, br s), 1.12 (30H, s), 5.26 (3H, s), 7.35 (1H,
br s), 8.95 (2H, br s).
(C5Me5)2Sm (η3-CH2CHCHiP r ) (4k) fr om 1: 1H NMR(C6D6)
δ -3.34 (6H, br s), 0.04 (1H, br s), 1.23 (30H, s), 5.40 (1H, br
s), 9.10 (2H, br s), 15.07 (1H, br s).
Com petitive Reaction of Ben zyl tr a n s-Cin n am yl Eth er
(3d ) a n d Ben zyl 3-P h en yl-2-p r op yn yl Eth er (6) w ith 1.
A mixture of the ethers 3d (200 mg, 0.89 mmol) and 6 (198
mg, 0.89 mmol) in toluene (2 mL) was added to a solution of
1 (983 mg, 1.74 mmol) in toluene (7 mL), and stirring was
continued for 1 h at room temperature. Then cyclohexanone
(177 mg, 1.80 mmol) was added to the mixture. After being
stirred for 3 h at room temperature, the reaction was quenched
with water (2 mL) and 2 M HCl (2 mL), and tetradecane was
added to the mixture as an internal standard. The reaction
mixture was extracted with ether, washed with aqueous
Na2CO3 and brine, dried over MgSO4, and concentrated in
vacuo. 1-(1-Hydroxycyclohexyl)-1-phenylpropadiene (8) and
3-(1-hydoxycyclohexyl)-3-phenyl-1-propene (9d ) were detected
in 43% and 45% yields, respectively, by GC analyses.
Com petitive C-O Clea va ge of tr a n s-Cin n a m yl 3-P h en -
yl-2-p r op yn yl Eth er (7) w ith 1. The ether 7 (164 mg, 0.66
mmol) was treated with 1 (761 mg, 1.35 mmol) in toluene (7
mL) at room temperature for 1 h. Then cyclohexanone (137
mg, 1.40 mmol) was added to the solution, and the mixture
was stirred for 3 h at room temperature. After similar workup
as above, the mixture was analyzed by GC to indicate the
formation of 8 and 9d in 77% and 17% yields, respectively.
Column chromatography of the crude mixture on silica gel
Su p p or tin g In for m a tion Ava ila ble: Complete charac-
terization data (IR, MS, 1H and 13C NMR spectra, and
elemental analyses) for compounds 8, 9b-k , 11d ′-h , 12b-
h , 13b-h ′, and 14b-d (6 pages). This material is contained
in libraries on microfiche, immediately follows this article in
the microfilm version of the journal, and can be ordered from
the ACS; see any current masthead page for ordering
information.
J O9723016
(24) Hoffmann, R. W.; Sander, T. Chem. Ber. 1990, 123, 145-152.
(25) Roush, W. R.; Ando, K.; Powers, D. B.; Palkowitz, A. D.;
Halterman, R. L. J . Am. Chem. Soc. 1990, 112, 6339-6348.