Synthesis of fused-ring indenes by ruthenium-catalyzed ring-closing metathesis

DOI: 10.1002/ejoc.200500761

Source and publish data:

European Journal of Organic Chemistry p. 1965 - 1977 (2006)

Update date:2022-08-02

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Authors:

Silver, Satu

Leino, Reko

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Article abstract of DOI:10.1002/ejoc.200500761

The preparation of new 1,2-unsymmetrically substituted fused-ring indenes from dialkenyl precursors by utilization of the ruthenium-catalyzed ring-closing metathesis is described. By analogous strategy, 1,3-substituted fused-ring indenes with medium-ring

Full text of DOI:10.1002/ejoc.200500761

FULL PAPER

DOI: 10.1002/ejoc.200500761

Synthesis of Fused-Ring Indenes by Ruthenium-Catalyzed Ring-Closing

Metathesis

Satu Silver^[a]and Reko Leino*^[a]

Keywords: Indene / Cyclopentadienyl / Metathesis / Ruthenium / Metallocenes

The preparation of new 1,2-unsymmetrically substituted

fused-ring indenes from dialkenyl precursors by utilization

of the ruthenium-catalyzed ring-closing metathesis is de-

scribed. By analogous strategy, 1,3-substituted fused-ring in-

denes with medium-ring sizes have also been synthesized.

For bis(allylsilyl)indene, the formation of a 1,3-fused ring

pound is obtained instead due to rearrangement of the sub-

stituents. The rearrangement is enabled by the [1,5]-sila-

tropic shifts operating in silyl-substituted cyclopentadienyl

compounds.

appears to be prevented by ring strain and a 1,1-spiro com- Germany, 2006)

and ammonia at low temperature, a method which is not

Introduction

necessarily of general use.^[29,30]Towards tetrahydrofluo-

renes^[30]similar and related synthetic routes have been ex-

plored.^[12,31]

Synthetic pathways to substituted indenes continue to at-

tract attention due to the versatility of multiply substituted

indenes as building blocks for functional materials,^[1,2]

pharmaceuticals,^[3–5]small organic molecules^[6,7]and as li-

gand precursors for transition-metal complexes.^[8–11]Re-

cently, e.g., Halterman,^[12,13]Takahashi et al.,^[14]and Takai

and co-workers^[15]have reported efficient metal-mediated or

metal-catalyzed methods for preparation of new indenyl

frameworks.

Specifically, in transition-metal chemistry, group IV

metallocenes incorporating substituted indenyl ligands are

widely employed catalysts for stereospecific propylene poly-

merization providing access to polypropylene materials with

a range of tacticities and material properties.^[16]The micro-

structure and thus the properties of the polymer produced

can be tailored by variations in the ligand substitution

pattern. Here, unsymmetrically substituted C₁-symmetric

mixed-ligand indenyl complexes with diastereotopic coordi-

nation sites often form efficient catalysts for the preparation

of elastomeric polypropylenes due to alternation of isotac-

tic and atactic stereosequences in the polymer chain pro-

duced.^[17–21]In such catalysts, however, fused-ring substitu-

ents attached to the five-membered ring of the indenyl moi-

ety have been reported in few cases only,^{[12,22,23,24]}whereas

in a number of cases beneficial effects have been related to

the presence of one or two fluorenyl ligands.^[25–28]In earlier

work, Rabideau and co-workers have described the prepara-

tion of 1,4-dihydrofluorene by the use of metallic lithium

Recently, we described the simple synthesis of several al-

lyl-substituted indenes by Zn-mediated allylation of 1- and

2-indanones in aqueous media.^[32]Derivatization of the al-

lylindenes obtained by Pt-catalyzed hydrosilylation reac-

tions was briefly explored in the previous paper. Here, we

describe the utilization of such allyl-substituted indenes in

the simple preparation of new substituted fused-ring in-

denes by ring-closing alkene metathesis using the 2^nd-gener-

ation Grubbs ruthenium catalyst 1,3-bis(2,4,6-trimeth-

ylphenyl)-2-(imidazolidinylidene)(dichlorophenylmeth-

ylene)(tricyclohexylphosphane)ruthenium [(NHC)(PCy₃)-

Cl₂Ru=CHR].^[33–35]The indenes prepared should prove

useful as modified fluorenyl mimic ligand precursors for

unsymmetric metallocene complexes enabling further tun-

ing of the steric and electronic surroundings of the central

metal in such systems. Additionally, we wished to explore

the applicability of the approach for the synthesis of substi-

tuted indenes containing fused large-ring substituents, the

preparation of which is likewise briefly illustrated.

Results and Discussion

Ring-Closing Metathesis of 1,2-Disubstituted Indenes

Indenes with terminally unsaturated alkyl or silyl substit-

uents in both 1- and 2-positions were prepared in good

yields by standard lithiation/alkylation or lithiation/

silylation reactions of 2-allylindenes and obtained as mix-

tures of the expected regio- and/or stereoisomers (for de-

tails, see Exp. Sect. and Scheme 1, 2, 3, 4, and 5). Alkene

isomerization towards more conjugated and thus more

[a] Laboratory of Organic Chemistry Åbo Akademi University,

20500 Åbo, Finland

Fax: + 358-2-215-4866

E-mail: reko.leino@abo.fi

Supporting information for this article is available on the

WWW under http://ww w .eurjoc.org or from the author.

Eur. J. Org. Chem. 2006, 1965–1977

1965

S. Silver, R. Leino

FULL PAPER

stable olefin structures were observed in some cases (2, rac-

3, rac-7 and rac-11). Because such isomerization is poten-

tially carried further in the subsequent metathesis reactions,

resulting in decreased ring sizes and in undesired side-prod-

uct formation, it proved essential to carry out the alky-

lation/silylation sequences at low temperature in order to

minimize the isomerization pathways. Unsymmetrically

substituted fused-ring indenes were then prepared in mod-

erate to good yields by treating the 1,2-disubstituted unsat-

urated precursors with the 2^ndgeneration Grubbs ruthe-

nium catalyst in dichloromethane (Scheme 1–5).

Scheme 3. (i) nBuLi, then allyl(chloro)dimethylsilane, THF, –72 °C.

(ii) Grubbs 2^ndgeneration cat., DCM.

Scheme 4. (i) nBuLi, then allyl bromide, THF, –72 °C. (ii) Grubbs

2^ndgeneration cat., DCM. (iii) TEA, reflux.

Scheme 1. (i) nBuLi, then allyl bromide, THF, –72 °C. (ii) Grubbs

2^ndgeneration cat., DCM. (iii) TEA, reflux.

Scheme 5. (i) nBuLi, then allyl bromide, THF, –72 °C. (ii) Grubbs

2^ndgeneration cat., DCM. (iii) TEA, reflux.

Scheme 2. (i) nBuLi, then 4-bromo-1-butene, THF, –72 °C. (ii)

Grubbs 2^ndgeneration cat., DCM. (iii) TEA, reflux.

in 49–73% yields as displayed in Scheme 1, 2 and 3, and

Thus, when the mixtures of rac-1/2/rac-3, rac-6/rac-7 and conveniently isolated by flash chromatography. In the case

rac-10/rac-11 were exposed to the metathesis conditions, the of the diallylindene rac-1/2/rac-3 the ring-closing metathesis

fused-ring indenes rac-4/5, rac-8 and rac-12 were obtained yielded a 4:1 mixture of the kinetic and thermodynamic

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Synthesis of Fused-Ring Indenes by Ruthenium-Catalyzed Ring-Closing Metathesis

FULL PAPER

products rac-4 and 5 which upon refluxing in triethylamine arrangements may occur after the silylation reaction by the

gave the thermodynamically more stable 2,3-disubstituted [1,5]-silatropic shifts operating in silyl-substituted in-

indene 5 as the sole product in excellent yield (Scheme 1). denes.^[36–41]Rigby and co-workers have investigated [1,5]-

The ring-closing reaction of the rac-6/rac-7 mixture yielded silatropic shifts in disubstituted silylindenes and benzind-

the kinetically favored 1,2-substituted indene rac-8 as the enes showing that the initially formed, sterically crowded,

only product (Scheme 2). Also this compound was con- 1,1-disubstituted product commonly undergoes a [1,5]-sila-

verted quantitatively to the more stable thermodynamic tropic shift forming the less congested 1,3-disubstituted

product 9 by refluxing in triethylamine. In the case of the compound.^[37]Thus, for compounds rac-20 and 21, the

allylsilyl-substituted compounds rac-10/rac-11, the expected geminally substituted product 21 is likely to be formed first,

1,2-substituted indene rac-12 was obtained in good yield which then, due to steric crowding, undergoes migration via

after purification by flash chromatography.

isoindene to form the 1,3-substituted product (Scheme 7).

Analogously, when the dialkenyl indene mixtures rac-

13a/rac-13b/rac-14 and rac-17a/rac-17b, prepared by stan-

dard alkylations of racemic 2-(1-methylallyl)-1H-indene^[32]

and racemic 2-(1-phenylallyl)-1H-indene,^[32]were treated

with the 2^ndgeneration Grubbs catalyst in dichlorometh-

ane, the metathesis products rac-15a/rac-15b and rac-18a/

rac-18b were obtained as 1:0.9 and 1:0.8 diastereomeric

mixtures, respectively, in 69 and 90% yields (Scheme 4 and

Scheme 5). In both cases only the kinetic products were ob-

tained, which again could be converted in excellent yields

to the thermodynamic indenyl products rac-16 and rac-19

by refluxing in triethylamine.

Scheme 7. [1,5]-Silatropic shifts in compounds rac-20 and 21.

Unexpectedly, when the 1:0.04 mixture of rac-20 and 21

was treated with the 2^ndgeneration Grubbs catalyst, the

only metathesis product isolated was the spirocyclic com-

pound 22, instead of the expected 1,3-ring-bridged product,

obtained in 17% isolated yield (Scheme 6). Most likely, the

spiro compound 22 has been formed via [1,5]-silatropic

shifts of one of the silyl groups. The ring-closing metathesis

probably operates only in compound 21; however it is pre-

vented in the case of rac-20 due to the much larger ring

strain in the corresponding 1,3-bridged ring-closure prod-

uct. The presumable reason for the low yield of the spirocy-

cle 22 is that the rate of the [1,5]-silatropic shift, and thus

the amount of 21 formed from rac-20 at ambient tempera-

ture, is much lower than the rate of polymerization of rac-

20.^[42]

Ring-Closing Metathesis of 1,3-Disubstituted Indenes

The successful preparation of the 1,2-substituted fused-

ring indenes by ring-closing metathesis motivated us to in-

vestigate a similar strategy for the preparation of analogous

1,3-substituted compounds. The 1,3-diallylsilyl-substituted

indene rac-20 was prepared in moderate overall yield from

indene by two subsequent standard lithiation/silylation re-

actions and obtained, after purification by flash column

chromatography, in admixture (1:0.04) with the correspond-

ing 1,1-disubstituted product (Scheme 6).

We investigated the factor that might govern the forma-

tion of the spirocyclic product: lowering of the activation

energy by ruthenium catalyst or ring strain in the metathesis

product. We prepared the analogous bis(alkenylsilyl)indene

rac-23/24 with a longer aliphatic chain that carries two hex-

enyl(dimethyl)silyl substituents (Scheme 8). The attempted

ring-closing metathesis of this mixture produced, albeit in

poor yield (10%), exclusively 1,3-bridged ring structures.

Here, the rate of the [1,5]-silatropic shift is much lower at

ambient temperature than the rate for ring-closing metathe-

sis. The low yield again probably results from the polymeri-

zation of the precursor rac-23.^[42]

Interestingly, the ring closure of the rac-23/24 mixture

gave, in poor yield, three different products rac-(E)-25, rac-

(Z)-25 and rac-(Z)-26 in a 1:0.16:0.15 ratio. Of these, only

the last mentioned have the expected 15-membered ring

Scheme 6. (i) nBuLi, THF, 0 °C, allyl(chloro)dimethylsilane. (ii) As

in (i). (iii) Grubbs 2^ndgeneration cat., DCM.

That both of these compounds are formed may be ex- size. In the other two, a ring size of 14 was observed. Pre-

plained by reaction kinetics/thermodynamics in the lithi- viously, Kinderman and co-workers have reported Ru-cata-

ation/silylation sequence, where competing silylation of the lyzed isomerization reactions of terminal alkenes to more

indenyl 1- and 3-positions takes place. Alternatively, re- stable ones, prior to ring closing, resulting in a decreased

Eur. J. Org. Chem. 2006, 1965–1977

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S. Silver, R. Leino

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Scheme 9. (i) nBuLi, THF, 0 °C, 5-bromo-1-pentene. (ii) As in (i).

(iii) Grubbs 2^ndgeneration cat., DCM.

ture to yield, upon exposure to Grubbs catalyst, at least

some amount of the ring-closed product, either a spirocycle

or a 1,3-bridged compound. However, after the reaction at

room temperature, only traces of the metathesis product

were detected by MS. It can thus be concluded, that the

1,3-bridged product is too strained to be formed and only

rac-31 reacts under the ring-closing metathesis conditions.

In this case it is likely that the activation energy for the

required [1,5]-silatropic shift is too high to be overcome at

ambient temperature resulting in an extremely low rate for

such migration and consequently in the predominance of

polymerization of rac-29/rac-30.^[42]

Scheme 8. (i) nBuLi, THF, 0 °C, 5-hexenyl(dimethyl)chlorosilane.

(ii) As in (i). (iii) Grubbs 2^ndgeneration cat., DCM.

ring size.^[43]Here, the precursor rac-23 must first be iso-

merized to form a more stable compound containing only

one terminal alkene group. The isomerized compound then,

upon exposure to the Grubbs catalyst and subsequent ring

closure, produces a 14-membered ring instead of the ex-

pected 15-membered ring.

In the preceding examples reported here, for obvious ste-

ric reasons, the ring structures formed have exhibited Z–

geometry of the double bond inside the ring system. How-

ever, when larger rings are produced, such as in the case of

rac-(E/Z)-25, also (E)-alkenes may form as indicated by a

1:0.31 E/Z-ration for rac-25 as confirmed by NMR spec-

troscopy.

Additionally, possibilities to prepare indenes with me-

dium-size 1,3-ring structures containing carbon chains only

were investigated. The disubstituted indene rac-27 was pre-

pared from indene in good yield by two subsequent lithi-

ation/alkylation sequences yielding the 1,1-disubstituted an-

alogue 28 as a side-product (Scheme 9). Exposure of the

rac-27/28 mixture to the 2^ndgeneration Grubbs catalyst in

dichloromethane gave, after 2 hours, polymerization prod-

ucts only, without traces of starting material or ring-closed

products. Again, the ring-closing metathesis is probably

prevented due to ring-strain factors.

Scheme 10. (i) nBuLi, THF, 0 °C, allyl(chloro)dimethylsilane. (ii)

nBuLi, THF, 0 °C, 5-bromo-1-pentene. (iii) Grubbs 2^ndgeneration

cat., DCM, ambient temperature/reflux.

Scale-Up Experiments with 1^stGeneration Grubbs Catalyst

For further insights, one of the alkenyl substituents was

The ring-closing reactions performed here on a fairly

replaced with a silyl substituent in order to introduce a po- small scale were first investigated by using the 2^ndgenera-

tentially migrating group to the molecule (Scheme 10). In tion Grubbs catalyst which, while more expensive than the

the light of the earlier results on the ring-closing metathesis earlier reported commercially available variants, exhibits a

of 21 and rac-23 we expected the rac-29/rac-30/rac-31 mix- superior performance in terms of catalyst activity and selec-

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Eur. J. Org. Chem. 2006, 1965–1977

Synthesis of Fused-Ring Indenes by Ruthenium-Catalyzed Ring-Closing Metathesis

tivity. However, in terms of cost and efficiency, the scale-up

FULL PAPER

Experimental Section

of the cyclopentadienyl ligand synthesis for practical use in

metallocene chemistry necessitates the preparation of these

compounds in multi-gram amounts. Thus we also briefly

investigated the possibilities to use the Grubbs 1^stgenera-

tion Ru catalyst (PCy₃)₂Cl₂Ru=CHR, bis(tricyclohexylpho-

sphane) benzylidene, instead of the 2^ndgeneration variant

for these reactions. Accordingly, on a small scale, by anal-

ogy to Scheme 1, the ring-closing metathesis of the rac-1/

2/rac-3 mixture in refluxing dichloromethane, catalyzed by

10 mol-% of Grubbs 1^stgeneration catalyst, yielded a mix-

ture of rac-4 and 5 in a yield comparable to that obtained

from the same reaction catalyzed by the 2^ndgeneration cata-

lyst (see experimental section). Furthermore, our prelimi-

nary results from the scale-up experiments using the 1^stgen-

eration catalyst show that the isolated yield of the ring-clos-

ing reaction can be improved from 69% to 82% when pro-

ducing multigram amounts of dihydrofluorene in a single

reaction. Thus, the approach described does indeed provide

a practical route to new cyclopentadienyl ligand precursors.

General Remarks: All air- and moisture-sensitive reactions were

conducted under argon using standard techniques. Commercially

available solvents and reagents were used without further purifica-

tion. 2-Allyl-1H-indene, 2-(1-methylallyl)-1H-indene and 2-(1-

phenylallyl)-1H-indene were prepared as described earlier.^[32]Tetra-

hydrofuran was distilled from sodium/benzophenone ketyl prior to

use. Dichloromethane was distilled from calcium hydride prior to

use. Flash chromatography was performed on silica gel 60 (40–

63 µm). NMR spectra were recorded at 298 K with a Bruker Av-

ance 600 (¹H NMR 600 MHz, ¹³C NMR 150.9 MHz, ²⁹Si

119.3 MHz) or Bruker Avance 500 (¹H NMR 500 MHz, ¹³C NMR

125.8 MHz). ¹H NMR were referenced against residual ¹H impuri-

ties in the solvent and ¹³C NMR to the solvent signals. In the ²⁹Si

experiments TMS was used as external reference. The NMR spec-

tra were recorded in δ values with CDCl₃as the solvent. Mass

spectra were recorded with a high-resolution mass spectrometer

(Fison’s ZapSpec).

General Procedure 1: To a solution of monosubstituted indene in

dry tetrahydrofuran (5–15 mL) at –72 °C was added nBuLi (2.5 

in n-hexane) in drops. The resulting reaction mixture was stirred

at –72 °C for 4 h. To this solution was added the halide in drops

at –72 °C. The reaction mixture was gradually warmed to room

temperature and after a period of 1–19 h, 50 mL of water and di-

ethyl ether were added and the formed layers were separated. The

aqueous layer was further extracted with 50 mL of diethyl ether

and the combined organic layers were dried with Na₂SO₄, filtered

and the solvents evaporated to dryness. The crude product was

purified by silica gel column chromatography (hexane as eluent) to

yield the desired product/products.

Summary and Conclusions

To summarize, we have prepared several new 1,2-unsym-

metrically substituted fused-ring indenes in moderate to ex-

cellent yields by utilizing the well-known and straightfor-

ward ring-closing metathesis reaction catalyzed by the

Grubbs 2^ndgeneration catalyst. The same method can be

applied to the preparation of 1,3-substituted fused-ring in-

denes with medium ring sizes as well where the ring strain

effects are negligible. In smaller 1,3-fused rings, however,

the ring strain becomes an important factor. In the case of

the 1,3-diallylsilyl-substituted indene rac-20 the 1,3-substi-

tuted disilylindene rearranges to the geminal disubstituted

analogue 21 via [1,5]-silatropic shifts forming the spirocyclic

compound 22.

General Procedure 2. Ring-Closing Metathesis (RCM) Reaction: To

a solution of disubstituted indene in dry dichloromethane (2–5 mL)

was added the 2^ndgeneration (NHC)(PCy₃)Cl₂Ru=CHR Grubbs

catalyst in portions. The resulting reaction mixture was stirred at

ambient temperature for a period of 30 min–24 h before the solvent

was removed under reduced pressure. The residue was directly chro-

matographed on silica gel (hexane as eluent) and the desired prod-

uct/products were obtained. The concentrations of disubstituted in-

denes in dichloromethane (0.18–0.25 mmol/mL, in scale-up experi-

ment 0.36 mmol/mL) were not optimized.

The method described provides an attractive route to

new unsymmetrically substituted cyclopentadienyl ligand

precursors for transition metal complexes, the preparation

of which is currently under investigation. Importantly, as

demonstrated here, the ring-closing reaction has also

proven amenable for scale-up by using the more economical

1^stgeneration Grubbs catalyst without decrease in efficiency

and reaction yield.

General Procedure 3: The tricyclic compound/compounds were dis-

solved in triethylamine (4 mL) and this reaction mixture was heated

to reflux for 4 h. Solvent was removed under reduced pressure and

the desired compound was obtained.

General Procedure 4: To a solution of indene in dry tetrahydrofuran

(15 mL) at 0 °C was added nBuLi (2.5  in n-hexane) in drops. The

resulting reaction mixture was stirred at ambient temperature for

4 h and to this solution at 0 °C was added the chlorosilane in drops.

The reaction mixture was taken into room temperature and after a

Some saturated and partially saturated fused-ring com-

pounds, such as decahydronaphthalene, tetrahydronaphtha- period of 1 h 50 mL of water and diethyl ether were added and

the formed layers were separated. The aqueous layer was further

extracted with 50 mL of diethyl ether and the combined organic

layers were dried with Na₂SO₄, filtered and the solvents evapo-

rated. This product was used without further purification. It was

dissolved in dry tetrahydrofuran (15 mL) and to this solution was

added nBuLi (2.5  in n-hexane) in drops at 0 °C. The resulting

reaction mixture was stirred at ambient temperature for 4 h and to

this solution at 0 °C was added the chlorosilane in drops. The reac-

tion mixture was taken into room temperature and after a period

of 1.5 h, 50 mL of water and diethyl ether were added and the

formed layers were separated. The aqueous layer was further ex-

lene and perhydrofluorene, have earlier been found to be

relatively stable at high temperatures (at 648 K), required

for example in the synthesis of higher alcohols.^[44]These

compounds could, therefore, be utilized as liquids in which

the solid catalyst is suspended. Completely or partially hy-

droganeted 1,2-unsymmetrically substituted fused-ring in-

denes described here might also be stable at high tempera-

tures and be used as suspending liquids in similar high-tem-

perature reactors. Potential practical uses for these com-

pounds could be found in other areas as well.

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1969

S. Silver, R. Leino

FULL PAPER

tracted with 50 mL of diethyl ether and the combined organic lay-

ers were dried with Na₂SO₄, filtered and the solvents evaporated

to dryness. The crude product was purified by silica gel column

chromatography (hexane as eluent) to yield the desired product/

products.

dene (2) and 1-allyl-2-prop-2-en-(E/Z)-ylidene-indane (rac-3)

(0.2329 g, 1.2 mmol) and Grubbs 2^ndgeneration catalyst (0.0523 g,

0.1 mmol) gave, after a 19-h reaction time, 0.1469 g (73%) of a 4:1

mixture of the title compounds as a very pale yellow oil. ¹H NMR

(600 MHz, 25 °C, CDCl₃): δ = 7.43 (d, J = 7.5 Hz, 1 H, 1 arom.

CH in 5), 7.41 (d, J = 7.5 Hz, 2 H, 2 arom. CH in rac-4), 7.33 (d,

J = 7.5 Hz, 2 H, 2 arom. CH in rac-4), 7.28 (m, 1 H, arom. CH in

5), 7.25 (t, J = 7.5 Hz, 2 H, 2 arom. CH in rac-4), 7.23 (m, 1 H,

arom. CH in 5), 7.16 (m, 1 H, arom. CH in 5), 7.14 (td, J = 7.5 Hz,

1.1 Hz, 2 H, 2 arom. CH in rac-4), 6.54 (s, 2 H, 2 olefin. CH in

five-ring in rac-4), 5.96 (dm, J = 9.5 Hz, 1 H, olefin. CH in six-

ring in 5), 5.90 (dm, J = 9.5 Hz, 1 H, olefin. CH in six-ring in 5),

5.85 (m, 4 H, 4 olefin. CH in six-ring in rac-4), 3.30 (m, 4 H, 2

aliph. CH in five-ring in rac-4 and alophatic CH₂in five-ring in 5),

3.23 (m, 4 H, 2 aliph. CH₂in six-ring in rac-4), 3.14 (m, 4 H, 2

aliph. CH₂in six-ring in 5), 2.92 (m, 2 H, 2 aliph. CH in six-ring

in rac-4), 1.81 (m, 2 H, 2 aliph. CH in six-ring in rac-4) ppm. ¹³C

NMR (150.9 MHz, 25 °C, CDCl₃): δ = 149.12 (2 C_qin rac-4),

147.65 (2 C_qin rac-4), 145.68 (C_qin 5), 144.97 (2 C_qin rac-4),

142.74 (C_qin 5), 138.09 (C_qin 5), 133.50 (C_qin 5), 126.68 (2 arom.

CH in rac-4), 126.31 (1 arom. or olefin. CH in 5), 125.88 (2 olefin.

CH in rac-4), 125.51 (2 olefin. CH in rac-4), 124.63 (1 arom. or

olefin. CH in 5), 124.33 (1 arom. or olefin. CH in 5), 124.13 (1

arom. or olefin. CH in 5), 123.80 (2 arom. CH in rac-4), 123.51 (1

arom. or olefin. CH in 5), 123.23 (2 olefin. CH in five-ring in rac-

4), 122.83 (2 arom. CH in rac-4), 120.45 (2 arom. CH in rac-4),

117.93 (arom. CH in 5), 46.20 (2 aliph. CH in five-ring in rac-4),

40.44 (aliph. CH₂in five-ring in 5), 30.46 (2 aliph. CH₂in six-ring

in rac-4), 28.66 (2 aliph. CH₂in six-ring in rac-4), 27.47 (aliph.

CH₂in six-ring in 5), 24.12 (aliph. CH₂in six-ring in 5) ppm. EIMS

(70eV): calcd. C₁₃H₁₂168.0939; found 168.0944.

A Mixture of 1,2-Diallyl-1H-indene (rac-1), [(1E,4E)-2-Hexa-1,4-di-

enyl]-1H-indene (2) and 1-Allyl-2-prop-2-en-(E/Z)-ylidene-indane

(rac-3): By applying the general procedure 1,2-allyl-1H-indene

(1.0232 g, 6.5 mmol), nBuLi (2.6 mL, 6.5 mmol, 2.5  in n-hexane)

and allyl bromide (860 µL, 9.8 mmol) gave, after a 17-h reaction

time, 1.0099 g (79%) of a mixture of the title compounds as a pale

yellow oil. The ratio between the obtained compounds was

1:0.25:0.25. ¹H NMR (600 MHz, 25 °C, CDCl₃): δ = 7.45–7.12 (m,

20 H, all arom. CH in rac-1, 2 and rac-3), 6.62 (s, 1 H, olefin. CH

in five-ring in 2), 6.54 (s, 2 H, 2 olefin. CH in five-ring in rac-1),

6.43 (d, J = 16.3 Hz, 1 H, olefin. CH in chain in 2), 5.95 (m, 8 H,

2 olefin. CH in chain in rac-1, 2 olefin. CH in chain in 2 and 4

olefin. CH in chain in rac-3), 5.51 (m, 4 H, 2 olefin. CH in chain

in rac-1 and 2 olefin. CH in chain in rac-3), 5.07 (m, 17 H, 4 olefin.

CH₂in chain in rac-1, olefin. CH in chain in 2 and 4 olefin. CH₂

in chain in rac-3), 3.66 (dd, J = 7.1 Hz, 4.7 Hz, 2 H, 2 aliph. CH

in five-ring in rac-3), 3.46 (t, J = 6.0 Hz, 2 H, 2 aliph. CH in five-

ring in rac-1), 3.36 (s, 2 H, aliph. CH₂in five-ring in 2), 3.35 (m, 2

H, aliph. CH₂in chain in 2), 3.35 (m, 2 H, 2 aliph. CH in five-ring

in rac-3), 3.28–3.23 (A-part of an ABX system, dd, J_AB= –16.7 Hz,

J_AAX= 6.3 Hz, 2 H, 2 aliph. CH in chain in rac-1), (The spin-

system is an ABX system and the values of chemical shifts and

coupling constants are approximations.), 3.26 (m, 2 H, 2 aliph. CH

in five-ring in rac-3), 3.16–3.10 (a B part of an ABX system, dd,

J_AB= –16.7 Hz, J_AAX= 7.3 Hz, 2 H, 2 aliph. CH in chain in rac-

1)^*, 2.87 (dtm, J = –14.1 Hz, 4.7 Hz, 2 H, 2 aliph. CH in chain in

rac-3), 2.79 (dtm, J = –14.3 Hz, 6.0 Hz, 2 H, 2 aliph. CH in chain

in rac-1), 2.50 (dtm, J = –14.3 Hz, 6.0 Hz, 2 H, 2 aliph. CH in

chain in rac-1), 2.45 (dtm, J = –14.1 Hz, 7.1 Hz, 2 H, 2 aliph. CH

in chain in rac-3), 1.92 (d, J = 6.7 Hz, 3 H, CH₃in 2) ppm. ¹³C

4,9-Dihydro-1H-fluorene (5): By applying the General Procedure 3,

a mixture of 4,4a-dihydro-1H-fluorene (rac-4) and 4,9-dihydro-1H-

fluorene (5) (0.058 g, 0.3 mmol) gave 0.0533 g (92%) of the title

compound as a pale brown oil, which solidified when cooled down.

NMR (150.9 MHz, 25 °C, CDCl₃): δ = 151.32 (2 C_qin rac-1), ¹H NMR (600 MHz, 25 °C, CDCl₃): δ = 7.42 (m, 1 H, arom. CH),

149.25 (C_qin 2), 147.47 (C_qin 2), 146.94 (2 C_qin rac-1), 146.41 (2 7.27 (m, 1 H, arom. CH), 7.22 (m, 1 H, arom. CH), 7.15 (m, 1 H,

C_qin rac-3), 144.75 (2 C_qin rac-1), 144.51 (C_qin 2), 142.91 (2 C_q

in rac-3), 141.26 (2 C_qin rac-3), 136.58 (olefin. CH in chain in 2),

136.11 (2 olefin. CH in chain in rac-1), 135.69 (2 olefin. CH in

chain in rac-3), 135.34 (2 olefin. CH in chain in rac-3), 135.03 (2

olefin. CH in chain in rac-1), 134.88 (2 olefin. CH in chain in rac-

3), 127.95 (olefin. CH in five-ring in 2), 127.74 (olefin. CH in chain

in 2), 127.13 (2 olefin. CH in five-ring in rac-1), 127.00 (olefin. CH

in chain in 2), 126.83, 126.18, 124.46, 124.08, 123.45, 123.38,120.78,

119.05 (12 arom. CH in 2 and rac-3), 126.73 (2 arom. CH in rac-

1), 123.99 (2 arom. CH in rac-1), 123.19 (2 arom. CH in rac-1),

120.26 (2 arom. CH in rac-1), 116.68 (2 olefin. CH₂in chain in rac-

1), 116.58 (2 olefin. CH₂in chain in rac-3), 116.42 (2 olefin. CH₂

in chain in rac-1), 115.70 (olefin. CH in chain in 2 or 2 olefin. CH₂

in rac-3), 115.67 (olefin. CH in chain in 2 or 2 olefin. CH₂in rac-

3), 50.34 (2 aliph. CH in five-ring in rac-1), 48.09 (2 aliph. CH in

five-ring in rac-3), 40.68 (aliph. CH₂in five-ring in 2), 36.29 (2

aliph. CH₂in chain in rac-3), 34.36 (2 aliph. CH₂in chain in rac-

1), 34.25 (2 aliph. CH₂in chain in rac-1), 33.19 (2 aliph. CH₂in

five-ring in rac-3), 29.85 (aliph. CH₂in chain in 2), 18.94 (CH₃in

2) ppm. EIMS (70eV): calcd. C₁₅H₁₆196.1252; found 196.1248.

The configuration of the diene part of the compound rac-3 could

arom. CH), 5.95 (dm, J = 9.5 Hz, 1 H, olefin. CH in six-ring), 5.89

(dm, J = 9.5 Hz, 1 H, olefin. CH in six-ring), 3.29 (s, 2 H, aliph.

CH₂in five-ring), 3.13 (s, 4 H, 2 aliph. CH₂in six-ring) ppm. ¹³C

NMR (150.9 MHz, 25 °C, CDCl₃): δ = 145.59 (C_q), 142.77 (C_q),

138.05 (C_q), 133.53 (C_q), 126.25 (arom. CH), 124.59 (olefin. CH in

six-ring), 124.29 (arom. CH), 124.13 (olefin. CH in six-ring), 123.47

(arom. CH), 117.90 (arom. CH), 40.42 (aliph. CH₂in five-ring),

27.43 (aliph. CH₂in six-ring), 24.13 (aliph. CH₂in six-ring) ppm.

EIMS (70eV): calcd. C₁₃H₁₂168.0939; found 168.0942.

A Mixture of 2-Allyl-1-but-3-enyl-1H-indene (rac-6) and 1-But-3-

enyl-2-[(E)-propenyl]-1H-indene (rac-7): By applying the General

Procedure 1, 2-allyl-1H-indene (0.7708 g, 4.9 mmol), nBuLi

(2.0 mL, 5.0 mmol, 2.5  in n-hexane) and 4-bromo-1-butene

(530 µL, 5.2 mmol) gave, after a 1-h reaction time, 0.9259 g (89%)

of a 1:0.15 mixture of the title compounds as a colorless oil. ¹H

NMR (500 MHz, 25 °C, CDCl₃): δ = 7.44 (m, 2 H, 2 arom. CH in

rac-7), 7.42 (d, J = 7.3 Hz, 2 H, 2 arom. CH in rac-6), 7.33 (m, 2

H, 2 arom. CH in rac-7), 7.31 (d, J = 7.3 Hz, 2 H, 2 arom. CH in

rac-6), 7.28 (m, 2 H, 2 arom. CH in rac-7), 7.27 (t, J = 7.3 Hz, 2

H, 2 arom. CH in rac-6), 7.20 (m, 2 H, 2 arom. CH in rac-7), 7.18

(t, J = 7.3 Hz, 2 H, 2 arom. CH in rac-6), 6.64 (s, 2 H, 2 olefin.

CH in five-ring in rac-7), 6.57 (s, 2 H, 2 olefin. CH in five-ring in

rac-6), 6.44 (d, J = 16.2 Hz, 2 H, 2 olefin. CH in chain in rac-7),

not be determined due to the heavily overlapping signals in the H

NMR spectrum.

A Mixture of 4,4a-Dihydro-1H-fluorene (rac-4) and 4,9-Dihydro- 6.02 [a X-part of an ABX – system, dddd, J = 17.1 Hz, 10.2 Hz,

1H-fluorene (5): By applying the General Procedure 2, a mixture

of 1,2-diallyl-1H-indene (rac-1), [(1E,4E)-2-hexa-1,4-dienyl]-1H-in-

7.2 Hz (J_AAX)^*, 6.5 Hz (J_AAX)^*, 2 H, 2 olefin. CH in chain in rac-

6], 5.96 (m, 2 H, 2 olefin. CH in chain in rac-7), 5.81 (ddt, J =

1970

www.eurjoc.org

Eur. J. Org. Chem. 2006, 1965–1977

Synthesis of Fused-Ring Indenes by Ruthenium-Catalyzed Ring-Closing Metathesis

FULL PAPER

17.1 Hz, 10.2 Hz, 7.2 Hz, 2 H, 2 olefin. CH in chain in rac-6), 5.78

(m, 2 H, 2 olefin. CH in chain in rac-7), 5.23 (dm, J = 17.1 Hz, 2

H, 2 olefin. CH in the chain in rac-6), 5.17 (dm, J = 10.2 Hz, 2 H,

2 olefin. CH in the chain in rac-6), 5.02 (dm, J = 17.1 Hz, 2 H, 2

olefin. CH in the chain in rac-6), 4.98 (m, 4 H, 2 olefin. CH₂in

chain in rac-7), 4.97 (dm, J = 10.2 Hz, 2 H, 2 olefin. CH in the

chain in rac-6), 3.72 (t, J = 5.2 Hz, 2 H, 2 aliph. CH in five-ring in

rac-7), 3.50 (t, J = 5.2 Hz, 2 H, 2 aliph. CH in five-ring in rac-6),

3.30–3.23 (A-part of an ABX – system, dd, J_AB= –16.3 Hz, J_AAX

= 6.5 Hz, 2 H, 2 aliph. CH in chain in rac-6)^*, 3.17–3.10 (a B-part

of an ABX – system, dd, J_AB= –16.3 Hz, J_AAX= 7.2 Hz, 2 H, 2

aliph. CH in chain in rac-6)^*, 2.16 (m, 4 H, 2 aliph. CH in chain

in rac-6 and 2 aliph. CH in chain in rac-7), 1.91 (m, 14 H, 2 CH₃

in rac-7, 4 aliph. CH in chain in rac-6 and 4 aliph. CH in chain in

rac-7), 1.75 (m, 4 H, 2 aliph. CH in chain in rac-6 and 2 aliph. CH

in chain in rac-7). ¹³C NMR (125.8 MHz, 25 °C, CDCl₃): δ =

151.35 (2 C_qin rac-6), 149.58 (2 C_qin rac-7), 147.83 (2 C_qin rac-

7), 147.09 (2 C_qin rac-6), 144.91 (2 C_qin rac-6), 144.68 (2 C_qin

rac-7), 138.98 (2 olefin. CH in chain in rac-7), 138.85 (2 olefin. CH

in chain in rac-6), 136.10 (2 olefin. CH in chain in rac-6), 127.98

(2 olefin. CH in five-ring in rac-7), 127.74 (2 arom. CH in rac-7),

127.06 (2 olefin. CH in five-ring in rac-6), 127.02 (2 olefin. CH in

chain in rac-7), 126.81 (2 olefin. CH in chain in rac-7), 126.62 (2

arom. CH in rac-6), 124.52 (2 arom. CH in rac-7), 124.03 (2 arom.

CH in rac-6), 123.01 (2 arom. CH in rac-7), 122.93 (2 arom. CH

in rac-6), 120.77 (2 arom. CH in rac-7), 120.27 (2 arom. CH in rac-

6), 116.47 (2 olefin. CH₂in chain in rac-6), 114.61 (2 olefin. CH₂

in chain in rac-6), 114.40 (2 olefin. CH₂in chain in rac-7), 50.45 (2

aliph. CH in five-ring in rac-6), 48.00 (2 aliph. CH in five-ring in

rac-7), 34.19 (2 aliph. CH₂in chain in rac-6), 31.14 (2 aliph. CH₂

in chain in rac-7), 29.04 (2 aliph. CH₂in chain in rac-6), 28.77 (2

aliph. CH₂in chain in rac-6), 28.58 (2 aliph. CH₂in chain in rac-

7), 19.07 (2 CH₃in rac-7). EIMS (70eV): calcd. C₁₆H₁₈210.1409;

found 210.1413.

(dtm, J = 10.6 Hz, 6.6 Hz, 1 H, olefin. CH in seven-ring), 5.84 (dt,

J = 10.6 Hz, 5.2 Hz, 1 H, olefin. CH in seven-ring), 3.27 (m, 4 H,

aliph. CH₂in five-ring and aliph. CH₂in seven-ring), 2.63 (m, 2

H, aliph. CH₂in seven-ring), 2.45 (td, J = 6.4 Hz, 5.7 Hz, 2 H,

aliph. CH₂in seven-ring). ¹³C NMR (150.9 MHz, 25 °C, CDCl₃):

δ = 147.86 (C_q), 141.93 (C_q), 139.48 (C_q), 137.81 (C_q), 131.70 (ole-

fin. CH in seven-ring), 128.98 (olefin. CH in seven-ring), 126.18

(arom. CH), 123.92 (arom. CH), 123.16 (arom. CH), 117.65

(arom. CH), 43.24 (aliph. CH₂in five-ring), 29.72 (aliph. CH₂

in seven-ring), 26.02 (aliph. CH₂in seven-ring), 24.55 (aliph. CH₂

in seven-ring). EIMS (70eV): calcd. C₁₄H₁₄182.1096; found

182.1101.

A Mixture of Allyl(2-allyl-1H-inden-1-yl)dimethylsilane (rac-10) and

Allyldimethyl[[(E)-2-propenyl]-1H-inden-1-yl]silane (rac-11): By ap-

plying the General Procedure 1, 2-allyl-1H-indene (0.3514 g,

2.3 mmol), nBuLi (910 µL, 2.3 mmol, 2.5  in n-hexane) and allyl(-

chloro)dimethylsilane (350 µL, 2.4 mmol) gave, after a 1-h reaction

time, 0.5177 g (90%) of a 1:0.13 mixture of the title compounds as

a colorless oil. H NMR (600 MHz, 25 °C, CDCl₃): δ = 7.38 (d, J

= 7.3 Hz, 2 H, 2 arom. CH in rac-10), 7.37 (m, 4 H, 4 arom. CH

in rac-11), 7.36 (d, J = 7.3 Hz, 2 H, 2 arom. CH in rac-10), 7.22

(m, 2 H, 2 arom. CH in rac-11), 7.22 (t, J = 7.3 Hz, 2 H, 2 arom.

CH in rac-10), 7.11 (m, 2 H, 2 arom. CH in rac-11), 7.11 (t, J =

7.3 Hz, 2 H, 2 arom. CH in rac-10), 6.73 (s, 2 H, 2 olefin. CH in

five-ring in rac-11), 6.63 (s, 2 H, 2 olefin. CH in five-ring in rac-

10), 6.43 (d, J = 16.1 Hz, 2 H, 2 olefin. CH in chain in rac-11),

5.99 [a X-part of an ABX – system, ddt, J = 17.5 Hz, 10.3 Hz,

6.8 Hz (J_AAX,AAX), 2 H, 2 olefin. CH in chain in rac-10]¹, 5.89 (dq,

J = 16.1 Hz, 6.7 Hz, 2 H, 2 olefin. CH in chain in rac-11), 5.70 (m,

2 H, 2 olefin. CH in chain in rac-11), 5.70 (tt, J = 12.2 Hz, 8.4 Hz,

2 H, 2 olefin. CH in chain in rac-10), 5.16 (d, J = 17.5 Hz, 2 olefin.

CH in the chain in rac-10), 5.13 (d, J = 10.3 Hz, 2 olefin. CH in

the chain in rac-10), 4.87 (m, 4 H, 2 olefin. CH₂in chain in rac-

11), 4.87 (d, J = 12.2 Hz, 4 H, 2 olefin. CH₂in chain in rac-10),

3.79 (s, 2 H, 2 aliph. CH in five-ring in rac-11), 3.53 (s, 2 H, 2

aliph. CH in five-ring in rac-10), 3.40–3.34 (A-part of an ABX –

system, dd, J_AB= –16.4 Hz, J_AAX= 6.8 Hz, 2 H, 2 aliph. CH in

chain in rac-10)^*, 3.27–3.22 (a B-part of an ABX – system, dd, J_AB

= –16.4 Hz, J_AAX= 6.8 Hz, 2 H, 2 aliph. CH in chain in rac-10)^*,

1.89 (d, J = 6.7 Hz, 6 H, 2 C–CH₃in rac-11), 1.51 (m, 8 H, 2 aliph.

CH₂in chain in rac-10 and 2 aliph. CH₂in chain in rac-11), 0.05

(s, 6 H, Si–CH₃in rac-10), –0.0 (s, 6 H, Si–CH₃in rac-10), –0.03

(s, 6 H, Si–CH₃in rac-11), –0.12 (s, 6 H, Si–CH₃in rac-11). ¹³C

NMR (150.9 MHz, 25 °C, CDCl₃): δ = 150.16 (2 C_qin rac-10),

148.85 (2 C_qin rac-11), 145.07 (2 C_qin rac-10), 144.75 (2 C_qin

rac-10), 144.45 (2 C_qin rac-11), 2 C_qin rac-11 are overlapping with

one of these signals, 136.50 (2 olefin. CH in chain in rac-10 and 2

olefin. CH in chain rac-11), 134.70 (2 olefin. CH in chain in rac-

11), 134.36 (2 olefin. CH in chain in rac-10), 127.95 (2 olefin. CH

in chain in rac-11 or 2 olefin. CH in five-ring in rac-11), 127.69 (2

olefin. CH in chain in rac-11 or 2 olefin. CH in five-ring in rac-

11), 125.77 (2 olefin. CH in five-ring rac-10), 125.20 (2 arom. CH

in rac-11), 125.11 (2 arom. CH in rac-10), 123.34 (2 arom. CH in

rac-11), 123.16 (2 arom. CH in rac-10), 123.03 (2 arom. CH in rac-

11), 122.88 (2 arom. CH in rac-10), 120.77 (2 arom. CH in rac-11),

120.33 (2 arom. CH in rac-10), 116.29 (2 olefin. CH₂in chain in

rac-10), 114.00 (2 olefin. CH₂in chain in rac-10), 133.81 (2 olefin.

CH₂in chain in rac-11), 46.71 (2 aliph. CH in five-ring in rac-10),

44.20 (2 aliph. CH in five-ring in rac-11), 36.24 (2 aliph. CH₂in

chain in rac-10), 22.01 (2 aliph. CH₂in chain in rac-10), 21.89 (2

aliph. CH₂in chain in rac-11), 18.69 (2 C–CH₃in rac-11), –3.79 (2

Si–CH₃in rac-10), –3.96 (2 Si–CH₃in rac-11), –4.09 (2 Si–CH₃in

4b,5,6,9-Tetrahydrobenzo[a]azulene (rac-8): By applying the General

Procedure 2, a mixture of 2-allyl-1-but-3-enyl-1H-indene (rac-6)

and 1-but-3-enyl-2-[(E)-propenyl]-1H-indene (rac-7) (0.2539 g,

1.2 mmol) and Grubbs 2^ndgeneration catalyst (0.053 g, 0.1 mmol)

gave, after a 2-h reaction time, 0.1052 g (48%) of the title com-

pound as a colorless oil. H NMR (600 MHz, 25 °C, CDCl₃): δ =

7.30 (d, J = 7.3 Hz, 2 H, 2 arom. CH), 7.22 (d, J = 7.3 Hz, 2 H, 2

arom. CH), 7.18 (t, J = 7.3 Hz, 2 H, 2 arom. CH), 7.10 (td, J =

7.3 Hz, 1.2 Hz, 2 H, 2 arom. CH), 6.39 (s, 2 H, 2 olefin. CH in

five-ring), 5.82 (m, 2 H, 2 olefin. CH in seven-ring), 5.79 (m, 2 H,

2 olefin. CH in seven-ring), 3.37 (dd, J = 10.2 Hz, 5.7 Hz, 2 H, 2

aliph. CH in five-ring), 3.23 (m, 4 H, 2 aliph. CH₂in seven-ring),

2.39 (dddd, J = –13.0 Hz, 7.4 Hz, 5.7 Hz, 2.1 Hz, 2 H, 2 aliph. CH

in seven-ring), 2.22 (m, 2 H, 2 aliph. CH in seven-ring), 2.16 (m, 2

H, 2 aliph. CH in seven-ring), 1.23 (ddt, J = –13.0 Hz, 10.2 Hz,

2.0 Hz, 2 H, 2 aliph. CH in seven-ring). ¹³C NMR (150.9 MHz,

25 °C, CDCl₃): δ = 149.98 (2 C_q), 148.12 (2 C_q), 144.51 (2 C_q),

132.14 (2 olefin. CH in seven-ring), 127.79 (2 olefin. CH in seven-

ring), 126.64 (2 arom. CH), 125.52 (2 olefin. CH in five-ring),

123.98 (2 arom. CH), 122.38 (2 arom. CH), 120.22 (2 arom. CH),

54.59 (2 aliph. CH in five-ring), 30.92 (2 aliph. CH₂in seven-ring),

30.33 (2 aliph. CH₂in seven-ring), 25.83 (2 aliph. CH₂in seven-

ring). EIMS (70eV): calcd. C₁₄H₁₄182.1096; found 182.1099.

5,6,9,10-Tetrahydrobenzo[a]azulene (9): By applying the General

Procedure 3, 4b,5,6,9-tetrahydro-benzo[a]azulene (rac-8) (0.0355 g,

0.2 mmol) gave 0.0343 g (97%) of the title compound as a yellow

oil. H NMR (600 MHz, 25 °C, CDCl₃): δ = 7.34 (d, J = 7.3 Hz,

1 H, arom. CH), 7.24 (t, J = 7.3 Hz, 1 H, arom. CH), 7.18 (d, J =

7.3 Hz, 1 H, arom. CH), 7.10 (t, J = 7.3 Hz, 1 H, arom. CH), 5.96 rac-10), –4.34 (2 Si–CH₃in rac-11) ppm. ²⁹Si NMR (119.3 MHz,

Eur. J. Org. Chem. 2006, 1965–1977

www.eurjoc.org

1971

S. Silver, R. Leino

FULL PAPER

25 °C, CDCl₃): δ = 3.36 (2 Si in rac-11), 3.02 (2 Si in rac-10) ppm.

EIMS (70eV): calcd. C₁₇H₂₂Si 254.1491; found 254.1498.

14), 1.84 (d, J = 6.9 Hz, 6 H, 2 CH₃in the end of the chain rac-

14), 1.35 (d, J = 6.9 Hz, 6 H, 2 CH₃in chain in rac-13a or rac-

13b), 1.27 (d, J = 6.9 Hz, 6 H, 2 CH₃in chain in rac-13a or rac-

13b) ppm. ¹³C NMR (150.9 MHz, 25 °C, CDCl₃): δ = (Cq in rac-

13a/b and rac-14 are partly overlapping with each other and other

signals) 156.74 (C_qin rac-13a/b), 155.93 (C_qin rac-13a/b), 153.75

(C_qin rac-14), 153.11 (C_qin rac-14), 147.53 (C_qin rac-14), 147.10

(C_qin rac-13a/b), 146.71 (C_qin rac-13a/b), 145.50 (C_qin rac-14),

144.55 (C_qin rac-13a/b),143.42 (2 olefin. CH in chain in rac-13a

or rac-13b), 143.31 (C_qin rac-14), 142.69 (2 olefin. CH in chain in

rac-14), 141.69 (2 olefin. CH in chain in rac-13a or rac-13b), 135.04

(2 olefin. CH in chain in rac-14), 134.93 (2 olefin. CH in chain in

rac-13a and 2 olefin. CH in chain in rac-13b), 126.72 (2 arom. CH

in rac-13a or rac-13b), 126.65 (2 arom. CH in rac-13a or rac-13b),

126.41 (2 arom. CH in rac-14), 125.81 (2 olefin. CH in five-ring in

rac-13a or rac-13b), 125.41 (2 olefin. CH in five-ring in rac-14),

125.32 (2 olefin. CH in five-ring in rac-13a or rac-13b), 124.25 (2

arom. CH in rac-14), 124.06 (2 arom. CH in rac-13a or rac-13b),

123.99 (2 arom. CH in rac-13a or rac-13b), 123.34 (2 arom. CH in

rac-14), 123.21 (2 arom. CH in rac-13a and 2 arom. CH in rac-

13b), 120.72 (2 arom. CH in rac-14), 120.40 (2 arom. CH in rac-

13a and 2 arom. CH in rac-13b), 116.79 (2 olefin. CH₂in chain in

rac-13a or rac-13b), 116.64 (2 olefin. CH₂in chain in rac-13a or

rac-13b), 116.43 (2 olefin. CH₂in chain in rac-14), 113.84 (2 olefin.

CH₂in chain in rac-13a or rac-13b), 113.61 (2 olefin. CH₂in chain

in rac-13a or rac-13b), 49.56 (2 aliph. CH in five-ring in rac-13a or

rac-13b), 49.46 (2 aliph. CH in five-ring in rac-13a or rac-13b),

47.86 (2 aliph. CH in five-ring in rac-14), 38.08 (2 aliph. CH in

chain in rac-13a or rac-13b), 37.53 (2 aliph. CH in chain in rac-13a

or rac-13b), 37.10 (2 aliph. CH₂in chain in rac-14), 34.48 (2 aliph.

CH₂in chain in rac-13a or rac-13b), 34.30 (2 aliph. CH₂in chain

in rac-13a or rac-13b), 20.82 (2 CH₃in chain in rac-13a or rac-

13b), 18.94 (2 CH₃in chain in rac-13a or rac-13b), 14.52 (2 CH₃

in chain in rac-14), 14.42 (2 CH₃in chain in rac-14) ppm. EIMS

(70eV): calcd. C₁₆H₁₈210.1409; found 210.1400.

5,5-Dimethyl-4b,5,6,9-tetrahydro-5-silabenzo[a]azulene (rac-12): By

applying the General Procedure 2, a mixture of allyl(2-allyl-1H-

inden-1-yl)dimethylsilane (rac-10) and allyl(dimethyl){[(E)-2-pro-

penyl]-1H-inden-1-yl}silane (rac-11) (0.2118 g, 0.8 mmol) and

Grubbs 2^ndgeneration catalyst (0.0359 g, 0.04 mmol) gave, after a

5-h reaction time, 0.1309 g (70%) of the title compound as a color-

less oil. ¹H NMR (600 MHz, 25 °C, CDCl₃): δ = 7.39 (d, J =

7.7 Hz, 4 H, 4 arom.), 7.22 (t, J = 7.7 Hz, 2 H, 2 arom. CH), 7.13

(t, J = 7.7 Hz, 2 H, 2 arom. CH), 6.55 (s, 2 H, 2 olefin. CH in five-

ring), 5.78 (m, 4 H, 4 olefin. CH in seven-ring), 3.51 (s, 2 H, 2

aliph. CH in five-ring), 3.34–3.30 (A-part of an ABX – system, dd,

J_AB= –14.7 Hz, J_AAX= 7.5 Hz, 2 H, 2 aliph. CH in seven-ring)^*,

3.28–3.24 (a B-part of an ABX – system, dd, J_AB= –14.7 Hz, J_AAX

= 5.2 Hz, 2 H, 2 aliph. CH in seven-ring)^*, 1.94–1.91 (A-part of an

ABX – system, dd, J_AB= –14.0 Hz, J_AAX= 5.3 Hz, 2 H, 2 aliph.

CH in seven-ring)^*, 1.53–1.50 (a B-part of an ABX – system, dd,

J_AB= –14.0 Hz, J_AAX= 7.7 Hz, 2 H, 2 aliph. CH in seven-ring)^*,

0.47 (s, 6 H, 2 CH₃), –0.74 (s, 6 H, 2 CH₃) ppm. ¹³C NMR

(150.9 MHz, 25 °C, CDCl₃): δ = 146.84 (2 C_q), 145.13 (2 C_q),

144.92 (2 C_q), 128.03 (2 olefin. CH in seven-ring), 125.71 (2 olefin.

CH in seven-ring), 124.86 (2 arom. CH), 123.77 (2 olefin. CH in

five-ring), 122.81 (2 arom. CH), 121.75 (2 arom. CH), 120.18 (2

arom. CH), 50.37 (2 aliph. CH in five-ring), 29.07 (2 aliph. CH₂in

seven-ring), 16.72 (2 aliph. CH₂in seven-ring), –1.30 (2 CH₃), –

8.57 (2 CH₃) ppm. ²⁹Si NMR (119.3 MHz, 25 °C, CDCl₃): δ = 3.83

(2 Si) ppm. Denotes: The spin-system is an ABX-system and the

values of chemical shifts and coupling constants are approxi-

mations. EIMS (70eV): calcd. C₁₅H₁₈Si 226.1178; found 226.1185.

A Mixture of a Diastereomeric Mixture of 1-Allyl-2-(1-methylallyl)-

1H-indene (rac-13a and rac-13b) and 1-Allyl-2-[(E/Z)-propenyl]-1H-

indene (rac-14): By applying the General Procedure 1, racemic 2-

(1-methylallyl)-1H-indene (0.6555 g, 3.9 mmol), nBuLi (1.7 mL,

4.2 mmol, 2.5  in n-hexane) and allyl bromide (510 µL, 5.8 mmol)

gave, after a 2-h reaction time, 0.4463 g (55%) of a mixture of the

title compounds as a colorless oil. The ratio between the dia-

Diastereomeric Mixture of 1-Methyl-4,4a-dihydro-1H-fluorene (rac-

15a and rac-15b): By applying the General Procedure 2, a mixture

stereomeric mixture and the racemic mixture was 1:0.06. ¹H NMR of 1-allyl-2-(1-methylallyl)-1H-indene (rac-13a and rac-13b) and 1-

(600 MHz, 25 °C, CDCl₃): δ = 7.39 (d, J = 7.6 Hz, 2 H, 2 arom.

allyl-2-[(E/Z)-propenyl]-1H-indene (rac-14) (0.1837 g, 0.9 mmol)

CH in rac-13a or rac-13b), 7.38 (m, 2 H, 2 arom. CH in rac-14), and Grubbs 2^ndgeneration catalyst (0.0376 g, 0.04 mmol) gave, af-

7.36 (d, J = 7.6 Hz, 2 H, 2 arom. CH in rac-13a or rac-13b), 7.23

(m, 12 H, 4 arom. CH in rac-13a, 4 arom. CH in rac-13b, 4 arom.

ter a 4-h reaction time, 0.1091 g (69%) of a mixture of the title

compounds as a colorless oil. The ratio between the diastereomers

CH in rac-14), 7.11 (t, J = 7.6 Hz, 4 H, 2 arom. CH in rac-13a and rac-15a and rac-15b was 1:0.9. ¹H NMR (600 MHz, 25 °C, CDCl₃):

2 arom. CH in rac-13b), 7.11 (m, 2 H, 2 arom. CH in rac-14), 6.65

(s, 2 H, 2 olefin. CH in rac-14), 6.54 (s, 2 H, 2 olefin. CH in five-

ring in rac-13a or rac-13b), 6.46 (s, 2 H, 2 olefin. CH in five-ring

in rac-13a or rac-13b), 6.05 (ddd, J = 16.8 Hz, 10.1 Hz, 7.2 Hz, 2

H, 2 olefin. CH in chain in rac-13a or rac-13b), 5.90 (ddm, J =

16.8 Hz, 10.1 Hz, 2 H, 2 olefin. CH in chain in rac-14), 5.79 (ddd,

J = 16.8 Hz, 10.1 Hz, 7.2 Hz, 2 H, 2 olefin. CH in chain rac-13a

or rac-13b), 5.43 (m, 4 H, 2 olefin. CH in rac-13a and 2 olefin. CH

in rac-13b), 5.01 (m, 22 H, 4 olefin. CH₂in chain in rac-13a, 4

olefin. CH₂in chain in rac-13b, 2 olefin. CH in chain in rac-14 and

2 olefin. CH₂in chain in rac-14), 3.71 (dd, J = 7.2 Hz, 3.6 Hz, 2

H, 2 aliph. CH in five-ring in rac-14), 3.51 (t, J = 5.5 Hz, 2 H, 2

aliph. CH in five-ring rac-13a or rac-13b), 3.47 (t, J = 5.5 Hz, 2 H,

2 aliph. CH in five-ring rac-13a or rac-13b), 3.22 (m, 4 H, 2 aliph.

CH in chain in rac-13a and 2 aliph. CH in chain in rac-13b), 2.79

(m, 6 H, 2 aliph. CH in chain in rac-13a, 2 aliph. CH in chain in

rac-13b and 2 aliph. CH in chain in rac-14), 2.47 (dtm, J =

–13.5 Hz, 5.5 Hz, 4 H, 2 aliph. CH in chain in rac-13a and 2 aliph.

CH in chain in rac-13b), 2.34 (dtm, J = –14.3 Hz, 7.2 Hz, 2 H, 2

aliph. CH in chain in rac-14), 1.95 (s, 6 H, 2 CH₃in chain in rac-

δ = 7.38 (d, J = 7.3 Hz, 2 H, 2 arom. CH in rac-15a or rac-15b),

7.36 (d, J = 7.3 Hz, 2 H, 2 arom. CH in rac-15a or rac-15b), 7.31

(d, J = 7.3 Hz, 2 H, 2 arom. CH in rac-15a or rac-15b), 7.30 (d, J

= 7.3 Hz, 2 H, 2 arom. CH in rac-15a or rac-15b), 7.22 (t, J =

7.3 Hz, 4 H, 2 arom. CH in rac-15a and 2 arom. CH in rac-15b),

7.11 (t, J = 7.3 Hz, 4 H, 2 arom. CH in rac-15a and 2 arom. CH

in rac-15b), 6.50 (s, 2 H, 2 olefin. CH in five-ring in rac-15a), 6.46

(s, 2 H, 2 olefin. CH in five-ring in rac-15b), 5.71 (m, 8 H, 8 olefin.

CH in six-ring in rac-15a and rac-15b), 3.30 (m, 8 H, 4 aliph. CH

in five-ring in rac-15a and rac-15b and 4 aliph. CH in six-ring in

rac-15a and rac-15b), 2.85 (m, 4 H, 4 aliph. CH in six-ring in rac-

15a and rac-15b), 1.71 (m, 4 H, 4 aliph. CH in six-ring in rac-15a

and rac-15b), 1.32 (d, J = 7.1 Hz, 6 H, 2 CH₃in rac-15a or rac-

15b), 1.24 (d, J = 7.1 Hz, 6 H, 2 CH₃in rac-15a or rac-15b). ¹³C

NMR (150.9 MHz, 25 °C, CDCl₃): δ = 155.04 (2 C_qin rac-15a or

rac-15b), 154.95 (2 C_qin rac-15a or rac-15b), 147.80 (2 C_qin rac-

15a or rac-15b), 147.57 (2 C_qin rac-15a or rac-15b), 144.94 (2 C_q

in rac-15a or rac-15b), 144.85 (2 C_qin rac-15a or rac-15b), 132.57

(2 arom. CH in rac-15a or rac-15b), 132.48 (2 arom. CH in rac-15a

or rac-15b), 126.72 (2 arom. CH in rac-15a or rac-15b), 126.68 (2

1972

www.eurjoc.org

Eur. J. Org. Chem. 2006, 1965–1977

Synthesis of Fused-Ring Indenes by Ruthenium-Catalyzed Ring-Closing Metathesis

FULL PAPER

arom. CH in rac-15a or rac-15b), 124.91 (2 olefin. CH in six-ring

in rac-15a or rac-15b), 124.64 (2 olefin. CH in six-ring in rac-15a

126.76 (2 arom. CH in rac-17b), 124.33 (2 arom. CH in rac-17b),

123.25 (2 arom. CH in rac-17b), 120.67 (2 arom. CH in rac-17b),

or rac-15b), 123.87 (2 arom. CH in rac-15a or rac-15b), 123.81 (2 116.85 (2 olefin. CH₂in chain in rac-17a or rac-17b), 116.79 (2

arom. CH in rac-15a or rac-15b), 122.96 (2 olefin. CH in six-ring

in rac-15a or rac-15b), 122.83 (2 olefin. CH in six-ring in rac-15a

or rac-15b), 122.49 (2 olefin. CH in five-ring in rac-15a or rac-15b),

121.69 (2 olefin. CH in five-ring in rac-15a or rac-15b), 120.57 (2

arom. CH in rac-15a and 2 arom. CH in rac-15b), 46.74 (2 aliph.

CH in five-ring in rac-15a or rac-15b), 43.40 (2 aliph. CH in five-

ring in rac-15a or rac-15b), 33.63 (2 aliph. CH in six-ring in rac-

15a or rac-15b), 33.00 (2 aliph. CH in six-ring in rac-15a or rac-

15b), 30.89 (2 aliph. CH in six-ring in rac-15a or rac-15b), 30.83 (2

aliph. CH in six-ring in rac-15a or rac-15b), 24.28 (2 CH₃in rac-

15a or rac-15b), 18.52 (2 CH₃in rac-15a or rac-15b). EIMS (70eV):

calcd. C₁₄H₁₄182.1096; found 182.1093.

olefin. CH₂in chain in rac-17a or rac-17b), 116.20 (2 olefin. CH₂

in chain in rac-17a or rac-17b), 115.71 (2 olefin. CH₂in chain in

rac-17a or rac-17b), 50.32 (2 aliph. CH in chain in rac-17a), 50.12

(2 aliph. CH in chain in rac-17b), 49.74 (2 aliph. CH in five-ring

in rac-17b), 49.25 (2 aliph. CH in five-ring in rac-17a), 34.40 (2

aliph. CH₂in chain in rac-17b), 34.33 (2 aliph. CH₂in chain in rac-

17a) ppm. EIMS (70eV): calcd. C₂₁H₂₀272.1565; found 272.1562.

Diastereomeric Mixture of 1-Phenyl-4,4a-dihydro-1H-fluorene (rac-

18a and rac-18b): By applying the General Procedure 2, 1-allyl-2-

(1-phenylallyl)-1H-indene (rac-17a and rac-17b) (0.1860 g,

0.7 mmol) and Grubbs 2^ndgeneration catalyst (0.032 g, 0.03 mmol)

gave, after a 4-h reaction time, 0.1493 g (90%) of a mixture of the

title compounds as a pale yellow oil. The ratio between the dia-

stereomers rac-18a and rac-18b was 1:0.8. ¹H NMR (600 MHz,

25 °C, CDCl₃): δ = 7.39 (m, 36 H, arom. CH in rac-18a and rac-

18b), 6.78 (s, 2 H, 2 olefin. CH in five-ring in rac-18b), 6.19 (m, 2

H, 2 olefin. CH in six-ring in rac-18b), 6.12 (m, 2 H, 2 olefin. CH

in six-ring in rac-18a), 6.09 (m, 2 H, 2 olefin. CH in six-ring in rac-

18b), 6.02 (s, 2 H, 2 olefin. CH in five-ring in rac-18a), 5.96 (m, 2

H, 2 olefin. CH in six-ring in rac-18a), 4.69 (m, 2 H, 2 aliph. CH

in six-ring in rac-18b), 4.58 (m, 2 H, 2 aliph. CH in six-ring in rac-

18a), 3.61 (dd, J = 8.2 Hz, 7.8 Hz, 2 H, 2 aliph. CH in five-ring in

rac-18a), 3.50 (dd, J = 8.2 Hz, 7.8 Hz, 2 H, 2 aliph. CH in five-

ring in rac-18b), 3.09 (m, 4 H, 2 aliph. CH in six-ring in rac-18a

and 2 aliph. CH in six-ring in rac-18b), 1.99 (m, 4 H, 2 aliph. CH

in six-ring in rac-18a and 2 aliph. CH in six-ring in rac-18b) ppm.

¹³C NMR (150.9 MHz, 25 °C, CDCl₃): δ = 153.85 (2 C_qin rac-

18a), 152.22 (2 C_qin rac-18a), 147.66 (2 C_qin rac-18b), 147.52 (2

C_qin rac-18a), 144.62 (2 C_qin rac-18b), 144.47 (2 C_qin rac-18b),

143.96 (2 C_qin rac-18b), 142.88 (2 C_qin rac-18a), 130.09 (2 olefin.

CH in six-ring in rac-18a), 128.99 (2 olefin. CH in six-ring in rac-

18b), 128.86, 128.62, 128.57, 127.74, 126.81, 126.73, 126.42, 124.04,

122.89, 122.84, 120.81, 120.74 (36 overlapping arom. CH in rac-18a

and rac-18b), 127.35 (2 olefin. CH in six-ring in rac-18b), 126.13 (2

olefin. CH in six-ring in rac-18a), 124.87 (2 olefin. CH in five-ring

in rac-18a), 123.61 (2 olefin. CH in five-ring in rac-18b), 46.79 (2

aliph. CH in five-ring in rac-18a), 45.64 (2 aliph. CH in six-ring in

rac-18a), 44.45 (2 aliph. CH in six-ring in rac-18b), 43.59 (2 aliph.

CH in five-ring in rac-18b), 30.76 (2 aliph. CH₂in six-ring in rac-

18b), 30.63 (2 aliph. CH₂in six-ring in rac-18a) ppm. EIMS (70eV):

calcd. C₁₉H₁₆244.1252; found 244.1251.

1-Methyl-4,9-dihydro-1H-fluorene (rac-16): By applying the Gene-

ral Procedure 3, the diastereomeric mixture of 1-methyl-4,4a-dihy-

dro-1H-fluorene (rac-15a and rac-15b) (0.043 g, 0.2 mmol) gave

0.0415 g (97%) of a mixture of the title compounds as a yellow oil.

¹H NMR (600 MHz, 25 °C, CDCl₃): δ = 7.50 (d, J = 7.3 Hz, 2 H,

2 arom. CH), 7.35 (t, J = 7.3 Hz, 2 H, 2 arom. CH), 7.29 (d, J =

7.3 Hz, 2 H, 2 arom. CH), 7.23 (t, J = 7.3 Hz, 2 H, 2 arom. CH),

5.97 (m, 2 H, 2 olefin. CH in six-ring), 5.85 (m, 2 H, 2 olefin. CH

in six-ring), 3.52 (d, J_AB= –21.9 Hz, 2 H, 2 aliph. CH in five-ring),

3.31 (m, 2 H, 2 aliph. CH in six-ring), 3.29 (d, J_AB= –21.9 Hz, 2

H, 2 aliph. CH in five-ring), 3.17 (m, 4 H, 2 aliph. CH₂in six-ring),

1.34 (d, J = 7.1 Hz, 6 H, 2 CH₃). ¹³C NMR (150.9 MHz, 25 °C,

CDCl₃): δ = 145.51 (2 C_q), 143.22 (2 C_q), 142.74 (2 C_q), 132.91 (2

C_q), 131.38 (2 olefin. CH in six-ring), 126.31 (2 arom. CH), 124.15

(2 arom. CH), 123.56 (2 arom. CH), 123.02 (2 olefin. CH in six-

ring), 118.14 (2 arom. CH), 38.56 (2 aliph. CH₂in five-ring), 31.98

(2 aliph. CH in six-ring), 24.29 (2 aliph. CH₂in six-ring), 21.89 (2

CH₃). EIMS (70eV): calcd. C₁₄H₁₄182.1096; found 182.1096.

Diastereomeric Mixture of 1-Allyl-2-(1-phenylallyl)-1H-indene (rac-

17a and rac-17b): By applying the General Procedure 1, racemic

2-(1-phenylallyl)-1H-indene (0.6499 g, 2.8 mmol), nBuLi (1.3 mL,

3.1 mmol, 2.5  in n-hexane) and allyl bromide (370 µL, 4.2 mmol)

gave, after a 2-h reaction time, 0.4867 g (64%) of a mixture of the

title compounds as a yellow oil. The ratio between the dia-

stereomers rac-17a and rac-17b was 1:0.7. ¹H NMR (600 MHz,

25 °C, CDCl₃): δ = 7.29 (m, 36 H, arom. CH in rac-17a and rac-

17b), 6.76 (s, 2 H, 2 olefin. CH in five-ring in rac-17a), 6.30 (ddd,

J = 17.6 Hz, 10.1 Hz, 7.2 Hz, 2 H, 2 olefin. CH in chain in rac-

17a), 6.22 (ddd, J = 17.6 Hz, 10.1 Hz, 8.0 Hz, 2 H, 2 olefin. CH in

chain in rac-17b), 6.15 (s, 2 H, 2 olefin. CH in five-ring in rac-17b),

5.41 (m, 4 H, 2 olefin. CH in chain in rac-17a and 2 olefin. CH in

chain in rac-17b), 5.09 (m, 16 H, 2 olefin. CH₂in chain in rac-17a

and 2 olefin. CH₂in chain in rac-17b), 4.48 (d, J = 8.0 Hz, 2 H, 2

aliph. CH in chain in rac-17b), 4.43 (d, J = 7.2 Hz, 2 H, 2 aliph.

CH in chain in rac-17a), 3.64 (t, J = 5.2 Hz, 2 H, 2 aliph. CH in

five-ring in rac-17a), 3.28 (t, J = 5.2 Hz, 2 H, 2 aliph. CH in five-

ring in rac-17b), 2.88 (ddm, J = –14.5 Hz, 5.2 Hz, 2 H, 2 aliph. CH

in chain in rac-17b), 2.75 (ddm, J = –14.5 Hz, 5.2 Hz, 2 H, 2 aliph.

CH in chain in rac-17a), 2.57 (ddm, J = –14.5 Hz, 5.2 Hz, 2 H, 2

aliph. CH in chain in rac-17b), 2.50 (ddm, J = –14.5 Hz, 5.2 Hz, 2

H, 2 aliph. CH in chain in rac-17a) ppm. ¹³C NMR (150.9 MHz,

25 °C, CDCl₃): δ = 154.58 (2 C_q), 154.18 (2 C_q), 147.03 (4 C_q),

144.30 (4 C_q), 142.61 (2 C_q), 142.06 (2 C_q), 140.32 (2 olefin. CH in

chain in rac-17a), 140.09 (2 olefin. CH in chain in rac-17b), 134.93

(2 olefin. CH in chain in rac-17b), 134.72 (2 olefin. CH in chain in

rac-17a), 129.19 (2 olefin. CH in five-ring in rac-17b), 128.78 (2

arom. CH in rac-17a), 128.66 (4 arom. CH in rac-17a), 128.56 (2

1-Phenyl-4,9-dihydro-1H-fluorene (rac-19): By applying the General

Procedure 3, the diastereomeric mixture of 1-phenyl-4,4a-dihydro-

1H-fluorene (rac-18a and rac-18b) (0.0927 g, 0.4 mmol) gave

0.0776 g (84%) of a mixture of the title compounds as a very thick,

white oil. H NMR (600 MHz, 25 °C, CDCl₃): δ = 7.23 (m, 18 H,

18 arom. CH), 5.99 (m, 2 H, 2 olefin. CH in six-ring), 5.86 (m, 2

H, 2 olefin. CH in six-ring), 4.33 (m, 2 H, 2 aliph. CH in six-ring),

3.22 (m, 4 H, 2 aliph. CH₂in six-ring), 3.14 (d, J_AB= –22.0 Hz, 2

H, 2 aliph. CH in five-ring), 3.01 (d, J_AB= –22.0 Hz, 2 H, 2 aliph.

CH in five-ring) ppm. ¹³C NMR (150.9 MHz, 25 °C, CDCl₃): δ =

145.18 (2 C_q), 144.52 (2 C_q), 143.03 (2 C_q), 141.11 (2 C_q), 133.67

(2 C_q), 129.22 (2 olefin. CH in six-ring), 128.66 (4 arom. CH),

128.30 (4 arom. CH), 126.63 (2 arom. CH), 126.28 (2 arom. CH),

124.45 (2 arom. CH), 123.61 (2 arom. CH), 123.40 (2 olefin. CH

in six-ring), 118.39 (2 arom. CH), 44.31 (2 aliph. CH in six-ring),

39.05 (2 aliph. CH₂in five-ring), 24.27 (2 aliph. CH₂in six-ring)

ppm. EIMS (70eV): calcd. C₁₉H₁₆244.1252; found 244.1247.

A Mixture of 1,3-Bis[allyl(dimethyl)silanyl]-1H-indene (rac-20) and

arom. CH in rac-17a), 127.87 (2 olefin. CH in five-ring in rac-17a), 1,1-Bis[allyl(dimethyl)silanyl]-1H-indene (21): By applying the Ge-

Eur. J. Org. Chem. 2006, 1965–1977

www.eurjoc.org

1973

S. Silver, R. Leino

FULL PAPER

neral Procedure 4, indene (500 µL, 4.3 mmol), nBuLi (2 × 1.8 mL,

2×4.3 mmol, 2.5  in n-hexane) and allyl(chloro)dimethylsilane

(2×700 µL, 2×4.6 mmol) gave 0.6357 g (48%) of a mixture of the

title compounds as a pale yellow oil. The ratio between the ob-

J_AB= –14.2 Hz, J_AAX= 6.0 Hz, 2 H, 2 aliph. CH in seven-

ring)^*, –0.27 (s, 6 H, 2 CH₃), –0.30 (s, 6 H, 2 CH₃) ppm. ¹³C NMR

(150.9 MHz, 25 °C, CDCl₃): δ = 146.88 (C_q), 144.47 (C_q), 137.34

(olefin. CH in five-ring), 128.15 (olefin. CH in five-ring), 124.76 (2

tained compounds was 1:0.04. ¹H NMR (600 MHz, 25 °C, CDCl₃): olefin. CH in seven-ring), 124.15 (arom. CH), 123.39 (arom. CH),

7.56 (d, J = 7,4 Hz, 2 H, 2 arom. CH in rac-20), 7.53 (d, J = 7.4 Hz,

1 H, arom. CH in 21), 7.49 (d, J = 7.4 Hz, 1 H, arom. CH in 21),

7.47 (d, J = 7.4 Hz, 2 H, 2 arom. CH in rac-20), 7.26 (t, J = 7.4 Hz,

2 H, 2 arom. CH in rac-20), 7.26 (m, 1 H, arom. CH in 21), 7.18

(t, J = 7.4 Hz, 2 H, 2 arom. CH in rac-20), 7.18 (m, 1 H, arom.

CH in 21), 7.05 (d, J = 5.2 Hz, 1 H, olefin. CH in five-ring in 21),

6.88 (d, J = 1.6 Hz, 2 H, 2 olefin. CH in five-ring in rac-20), 6.69

(d, J = 5.2 Hz, 1 H, olefin. CH in five-ring in 21), 5.81 (ddt, J =

18.1 Hz, 10.1 Hz, 8.2 Hz, 2 H, 2 olefin. CH in chain rac-20), 5.70

(ddt, J = 18.1 Hz, 10.1 Hz, 8.2 Hz, 2 H, 2 olefin. CH in chain rac-

20), 5.45 [a X-part of an ABX – system, ddt, J = 18.1 Hz, 10.1 Hz,

8.2 Hz (J_AAX,AAX), 2 H, 2 olefin. CH in chain 21]¹, 4.87 (m, 8 H,

4 olefin. CH₂in chain in rac-20), 4.72 (d, J = 10.1 Hz, 2 H, olefin.

CH₂in chain in 21), 4.69 (d, J = 18.1 Hz, 2 H, olefin. CH₂in chain

in 21), 3.67 (d, J = 1.6 Hz, 2 H, 2 aliph. CH in five-ring in rac-20),

1.80 (d, J = 8.2 Hz, 4 H, 2 aliph. CH₂in chain in rac-20), 1.50 (d,

J = 8.2 Hz, 4 H, 2 aliph. CH₂in chain in rac-20), 1.29–1.24 (A-

part of an ABX – system, dd, J_AB= –13.5 Hz, J_AAX= 8.2 Hz, 2

H, 2 aliph. CH in chain in 21)^*, 1.19–1.14 (a B-part of an ABX –

system, dd, J_AB= –13.5 Hz, J_AAX= 8.2 Hz, 2 H, 2 aliph. CH in

chain in 21)^*, 0.324 (s, 6 H, 2 CH₃in rac-20), 0.321 (s, 6 H, 2 CH₃

in rac-20), 0.04 (s, 6 H, 2 CH₃in 21), –0.01 (s, 6 H, 2 CH₃in 20),

–0.05 (s, 6 H, 2 CH₃in rac-20), –0.13 (s, 6 H, 2 CH₃in rac-20)

ppm. ¹³C NMR (150.9 MHz, 25 °C, CDCl₃): δ = 147.52 (2 C_qin

rac-20), 146.19 (2 C_qin rac-20), 146.05 (2 olefin. CH in five-ring

in rac-20), 140.27 (2 C_qin rac-20), 3 C_qin 21 could not be detected

due to the very small amount of the compound 21, 2 olefin. CH

in five-ring in 21 are overlapping with other signals, 137.19 (olefin.

CH in chain in 21), 135.07 (2 olefin. CH in chain in rac-20), 134.77

(olefin. CH in chain in 21), 134.41 (2 olefin. CH in chain in rac-

20), 124.84 (2 arom. CH in rac-20), 124.42 (arom. CH in 21), 123.63

(2 arom. CH in rac-20), 123.40 (arom. CH in 21), 122.95 (2 arom.

CH in rac-20), 122.33 (2 arom. CH in rac-20), 121.53 (arom. CH

in 21), one arom. CH in 21 is overlapping with other signals, 113.86

(2 olefin. CH₂in chain in rac-20), 113.54 (olefin. CH₂in chain in

21), 133.43 (2 olefin. CH₂in chain in rac-20), olefin. CH₂in chain

in 21 in overlapping with other signals, 47.57 (2 aliph. CH in five-

ring in rac-20), 23.89 (2 aliph. CH₂in chain in rac-20), 22.52 (2

aliph. CH₂in chain in rac-20 and aliph. CH₂in chain in 21), 22.14

(aliph. CH₂in chain in 21), –2.54 (2 CH₃in 21), –2.84 (2 CH₃in

rac-20), –2.95 (2 CH₃in rac-20), –3.14 (2 CH₃in 21), –4.41 (2 CH₃

in rac-20), –4.81 (2 CH₃in rac-20) ppm. ²⁹Si NMR (119.3 MHz,

25 °C, CDCl₃): δ = 3.38 (2 Si in rac-20), 0.45 (2 Si in 21), –9.98 (2

Si in rac-20) ppm. EIMS (70eV): calcd. C₁₉H₂₈Si₂312.1730; found

312.1728.

123.08 (arom. CH), 121.25 (arom. CH), 50.96 (C_q), 17.69 (2 aliph.

CH₂in seven-ring), –3.47 (2 CH₃), –3.81 (2 CH₃) ppm. ²⁹Si NMR

(119.3 MHz, 25 °C, CDCl₃): δ = –5.27 ppm. EIMS (70eV): calcd.

C₁₇H₂₄Si₂284.1417; found 284.1415.

A Mixture of 1,3-Bis[(hex-5-enyl)dimethylsilanyl]-1H-indene (rac-

23) and 1,1-Bis[(hex-5-enyl)dimethylsilanyl]-1H-indene (24): By ap-

plying the General Procedure 4, indene (810 µL, 6.9 mmol), nBuLi

(2 × 2.8 mL, 2×7.0 mmol, 2.5  in n-hexane) and chloro(5-hex-

enyl)dimethylsilane (2 × 1.5 mL, 2×7.6 mmol) gave 2.1314 g (78%)

of a mixture of the title compounds as a yellow oil. The ratio be-

tween the obtained compounds was 1:0.07. ¹H NMR (600 MHz,

25 °C, CDCl₃): δ = 7.66 (d, J = 7.5 Hz, 1 H, arom. CH in 24), 7.62

(d, J = 7.5 Hz, 2 H, 2 arom. CH in rac-23), 7.59 (d, J = 7.5 Hz, 1

H, arom. CH in 24), 7.53 (d, J = 7.5 Hz, 2 H, 2 arom. CH in rac-

23), 7.32 (t, J = 7.5 Hz, 2 H, 2 arom. CH in rac-23), 7.32 (m, 1 H,

arom. CH in 24), 7.24 (d, J = 7.5 Hz, 2 H, 2 arom. CH in rac-23),

7.24 (m, 1 H, arom. CH in 24), 7.09 (d, J = 5.1 Hz, 1 H, olefin.

CH in five-ring in 24), 6.91 (m, 2 H, 2 olefin. CH in five-ring in

rac-23), 6.76 (d, J = 5.1 Hz, 1 H, olefin. CH in five-ring in 24),

5.85 (ddt, J = 16.9 Hz, 10.3 Hz, 6.8 Hz, 4 H, 4 olefin. CH in chain

in rac-23), 5.47 (m, 6 H, 2 olefin. CH and 2 olefin. CH₂in chain

in 24), 5.07 (dm, J = 10.3 Hz, 2 H, 2 olefin. CH in chain in rac-

23), 5.03 (dm, J = 16.9 Hz, 2 H, 2 olefin. CH in chain in rac-23),

5.02 (dm, J = 16.9 Hz, 2 H, 2 olefin. CH in chain in rac-23), 4.99

(dm, J = 10.3 Hz, 2 H, 2 olefin. CH in chain in rac-23), 3.71 (m, 2

H, 2 aliph. CH in five-ring in rac-23), 2.11 (m, 8 H, 4 aliph. CH₂

in chain in rac-23), 2.02 (m, 8 H, 2 aliph. CH₂in chain in 24), 1.70

(m, 4 H, 2 aliph. CH₂in chain in 24), 1.41 (m, 8 H, 4 aliph. CH₂

in chain in rac-23), 0.97 (t, J = 6.6 Hz, 4 H, 2 aliph. CH₂in chain

in 24), 0.91 (dd, J = 6.9 Hz, 6.6 Hz, 4 H, 2 aliph. CH₂in chain in

rac-23), 0.56 (t, J = 8.3 Hz, 4 H, 2 aliph. CH₂in chain in rac-23),

0.38 (s, 12 H, 4 CH₃in rac-23), 0.12 (s, 6 H, 2 CH₃in 24), 0.05 (s,

6 H, 2 CH₃24), –0.00 (s, 6 H, 2 CH₃in rac-23), –0.05 (s, 6 H, 2

CH₃in rac-23) ppm. ¹³C NMR (150.9 MHz, 25 °C, CDCl₃): δ =

Intensity of the C_q– signals in 24 are so low that they could not

be observed, 147.80 (2 C_qin rac-23), 146.48 (2 C_qin rac-23), 145.92

(2 olefin. CH in five-ring in rac-23), 140.64 (2 C_qin rac-23), 139.26

(2 olefin. CH in chain in 24), 139.21 (2 olefin. CH in chain in rac-

23), 139.05 (2 olefin. CH in chain in rac-23), 124.86 (arom. CH in

24), 124.64 (2 arom. CH in rac-23), 123.99 (arom. CH in 24), 123.39

(2 arom. CH in rac-23), 123.10 (arom. CH in 24), 122.85 (2 arom.

CH in rac-23), 122.22 (arom. CH in 24), 122.15 (2 arom. CH in

rac-23), 144.42 (2 aliph. CH₂in chain in rac-23), 114.25 (2 aliph.

CH₂in chain in rac-23), 2 aliph. CH₂in chain in 24 are overlapping

with other signals, 47.94 (2 aliph. CH in five-ring in rac-23), 33.68

(2 aliph. CH₂in chain in 24), 33.64 (2 aliph. CH₂in chain in rac-

23), 33.56 (2 aliph. CH₂in chain in rac-23), 32.94 (2 aliph. CH₂in

chain in rac-23), 32.81 (2 aliph. CH₂in chain in rac-23), 32.72 (2

Spiro Compound 22: By applying General Procedure 2, a mixture

of 1,3-bis[allyl(dimethyl)silanyl]-1H-indene (rac-20) and 1,1-bis[al-

lyl(dimethyl)silanyl]-1H-indene (21) (0.1497 g, 0.5 mmol) and

Grubbs 2^ndgeneration catalyst (0.0222 g, 0.03 mmol) gave, after a aliph. CH₂in chain in 24), 23.80 (2 aliph. CH₂in chain in rac-23),

24-h reaction time, 0.023 g (17%) of the title compound as a color-

less oil. ¹H NMR (600 MHz, 25 °C, CDCl₃): δ = 7.66 (d, J = in 24), 18.38 (2 aliph. CH₂in chain in 24), 15.81 (2 aliph. CH₂in

7.7 Hz, 1 H, arom. CH), 7.51 (d, J = 7.7 Hz, 1 H, arom. CH), 7.24 chain in rac-23), 14.51 (2 aliph. CH₂in chain in rac-23), 0.51 (2

23.35 (2 aliph. CH₂in chain in rac-23), 22.93 (2 aliph. CH₂in chain

(t, J = 7.7 Hz, 1 H, arom. CH), 7.21 (t, J = 7.7 Hz, 1 H, arom. CH₃in 24), –2.27 (2 CH₃in 24 and 2 CH₃in rac-23), –2.52 (2 CH₃

CH), 7.03 (d, J = 5.0 Hz, 1 H, olefin. CH in five-ring), 6.82 (d, J in rac-23), –4.00 (2 CH₃in rac-23), –4.26 (2 CH₃in rac-23)

= 5.0 Hz, 1 H, olefin. CH in five-ring), 5.68 (a X-part of an ABX – ppm. ²⁹Si NMR (119.3 MHz, 25 °C, CDCl₃): δ = 4.81 (2 Si

system, m, 2 H, 2 olefin. CH in seven-ring)^*, 1.92–1.87 (A-part of

an ABX – system, dd, J_AB= –14.2 Hz, J_AAX= 5.8 Hz, 2 H, 2 aliph.

CH in seven-ring)^*, 1.83–1.79 (a B-part of an ABX – system, dd,

in rac-23), 2.09 (Si in 24), 1.65 (Si in 24), –8.44 (2 Si in

rac-23) ppm. EIMS (70eV): calcd. C₂₅H₄₀Si₂396.2669; found

396.2680.

1974

www.eurjoc.org

Eur. J. Org. Chem. 2006, 1965–1977

Synthesis of Fused-Ring Indenes by Ruthenium-Catalyzed Ring-Closing Metathesis

FULL PAPER

A Mixture of (E)-2,2,12,12-Tetramethyl-2,12-disilatricyclo-

[11.6.1.0*14,19*]icosa-1(20),7,14,16,18-pentaene [rac-(E)-25], (Z)-

2,2,12,12-Tetramethyl-2,12-disilatricyclo[11.6.1.0*14,19*]icosa-

1(20),7,14,16,18-pentaene [rac-(Z)-25] and (Z)-2,2,13,13-Tetra-

methyl-2,13-disilatricyclo[12. 6.1. 0*15,20*]henicosa-

1(21),7,15,17,19-pentaene [rac-(Z)-26]: By applying the General

Procedure 2, a mixture of 1,3-bis[(hex-5-enyl)dimethylsilanyl]-1H-

indene (rac-23) and 1,1-bis[(hex-5-enyl)dimethylsilanyl]-1H-indene

(24) (0.2422 g, 0.6 mmol) and Grubbs 2^ndgeneration catalyst

(0.0322 g, 0.04 mmol) gave, after a 22-h reaction time, 0.0226 g

(10%) of a mixture of the title compounds as a colorless oil. The

ratio between the obtained compounds was 0.8:0.16:0.15. ¹H NMR

(600 MHz, 25 °C, CDCl₃): δ = 7.54 [d, J = 7.5 Hz, 2 H, 2 arom.

CH in rac-(E)-25], 7.54 [m, 4 H, 2 arom. CH in rac-(Z)-25 and 2

arom. CH in rac-(Z)-26], 7.46 [d, J = 7.5 Hz, 2 H, 2 arom. CH in

rac-(E)-25], 7.46 [m, 4 H, 2 arom. CH in rac-(Z)-25 and 2 arom.

CH in rac-(Z)-26], 7.25 [t, J = 7.5 Hz, 2 H, 2 arom. CH in rac-(E)-

25], 7.25 [m, 4 H, 2 arom. CH in rac-(Z)-25 and 2 arom. CH in

rac-(Z)-26], 7.16 [t, J = 7.5 Hz, 2 H, 2 arom. CH in rac-(E)-25],

7.16 [m, 4 H, 2 arom. CH in rac-(Z)-25 and 2 arom. CH in rac-

(Z)-26], 6.91 [m, 2 H, 2 olefin. CH in five-ring in rac-(Z)-26], 6.84

[m, 4 H, 2 olefin. CH in five-ring in rac-(E)-25 and 2 olefin. CH in

five-ring in rac-(Z)-25], 5.39 [m, 4 H, 4 olefin. CH in large ring in

rac-(Z)-25], 5.25 [m, 4 H, 4 olefin. CH in large ring in rac-(Z)-26],

4.98 [ddd, J = 14.3 Hz, 7.4 Hz, 7.0 Hz, 2 H, 2 olefin. CH in large

ring in rac-(E)-25], 4.88 [ddd, J = 14.3 Hz, 7.4 Hz, 7.0 Hz, 2 H, 2

olefin. CH in large ring in rac-(E)-25], 3.63 [m, 2 H, 2 aliph. CH

in five-ring in rac-(Z)-25], 3.60 [m, 2 H, 2 aliph. CH in five-ring in

rac-(E)-25], 3.57 [m, 2 H, 2 aliph. CH in five-ring in rac-(Z)-26],

14 CH₂in large ring in rac-(Z)-25 and 8 CH₃in rac-(Z)-25 are

overlapping with other signals, 2.08 [m, 4 H, 2 aliph. CH in large

ring in rac-(E)-25 and 2 aliph. CH in large ring in rac-(Z)-26], 2.01

[m, 4 H, 4 aliph. CH in large ring in rac-(Z)-26], 1.92 [m, 10 H, 4

aliph. CH in large ring in rac-(E)-25 and 6 aliph. CH in large ring

in rac-(Z)-26], 1.63 [m, 2 H, 2 aliph. CH in large ring in rac-(E)-

25], 1.44 [m, 6 H, 2 aliph. CH in large ring in rac-(E)-25 and 4

aliph. CH in large ring in rac-(Z)-26], 1.32 [m, 6 H, 2 aliph. CH in

large ring in rac-(E)-25 and 4 aliph. CH in large ring in rac-(Z)-

26], 1.25 [m, 6 H, 2 aliph. CH in large ring in rac-(E)-25 and 4

aliph. CH in large ring in rac-(Z)-26], 1.16 [m, 2 H, 2 aliph. CH in

large ring in rac-(E)-25], 1.03 [m, 2 H, 2 aliph. CH in large ring in

rac-(E)-25], 0.88 [m, 2 H, 2 aliph. CH in large ring in rac-(E)-25],

0.82 [m, 2 H, 2 aliph. CH in large ring in rac-(Z)-26], 0.72 [m, 2

H, 2 aliph. CH in large ring in rac-(E)-25], 0.67 [m, 2 H, 2 aliph.

CH in large ring in rac-(E)-25], 0.48 [m, 2 H, 2 aliph. CH in large

ring in rac-(Z)-26], 0.29 [m, 36 H, 6 CH₃in rac-(E)-25 and 6 CH₃

in rac-(Z)-26], 0.18 [s, 6 H, 2 CH₃in rac-(E)-25], –0.11 [m, 6 H, 2

aliph. CH in large ring in rac-(E)-25 and 4 aliph. CH in large ring

in rac-(Z)-26], –0.38 [s, 6 H, 2 CH₃in rac-(Z)-26], –0.48 [m, 2 H,

2 aliph. CH in large ring in rac-(E)-25] ppm. ¹³C NMR

(150.9 MHz, 25 °C, CDCl₃): δ = 147.89 [2 C_qin rac-(Z)-26], 147.71

[2 C_qin rac-(Z)-25], 147.62 [2 C_qin rac-(E)-25], 146.71 [2 C_qin

rac-(E)-25], 146.59 [2 olefin. CH in five-ring in rac-(E)-25 and 2

olefin. CH in five-ring in rac-(Z)-25 and 2 C_qin rac-(Z)-26], 146.29

[2 C_qin rac-(Z)-25], 146.09 [2 olefin. CH in five-ring in rac-(Z)-26],

140.53 [2 C_qin rac-(Z)-25], 140.32 [2 C_qin rac-(E)-25], 140.05 [2

C_qin rac-(Z)-26], 131.98 [2 olefin. CH in large ring in rac-(E)-25],

131.68 [2 olefin. CH in large ring in rac-(Z)-25], 131.53 [2 olefin.

CH in large ring in rac-(Z)-25], 131.14 [2 olefin. CH in large ring

in rac-(Z)-26], 130.98 [2 olefin. CH in large ring in rac-(Z)-26],

130.86 [2 olefin. CH in large ring in rac-(E)-25], 8 arom. CH in rac-

(Z)-25 are overlapping with other signals, 124.63 [2 arom. CH in

rac-(E)-25], 124.60 [2 arom. CH in rac-(Z)-26], 123.30 [2 arom. CH

in rac-(E)-25], 123.29 [2 arom. CH in rac-(Z)-26], 122.87 [2 arom.

CH in rac-(Z)-26], 122.75 [2 arom. CH in rac-(E)-25], 122.16 [2

arom. CH in rac-(E)-25 and 2 arom. CH in rac-(Z)-26], 49.07 [2

aliph. CH in five-ring in rac-(Z)-25], 48.79 [2 aliph. CH in five-ring

in rac-(Z)-26], 48.52 [2 aliph. CH in five-ring in rac-(E)-25], 35.45

[2 aliph. CH₂in large ring in rac-(E)-25], 35.12 [2 aliph. CH₂in

large ring in rac-(Z)-25], 33.55 [2 aliph. CH₂in large ring in rac-

(Z)-26], 32.74 [2 aliph. CH₂in large ring in rac-(Z)-26], 32.54 [2

aliph. CH₂in large ring in rac-(Z)-26], 32.37 [2 aliph. CH₂in large

ring in rac-(Z)-25], 32.25 [2 aliph. CH₂in large ring in rac-(E)-25],

31.63 [2 aliph. CH₂in large ring in rac-(E)-25], 31.22 [2 aliph. CH₂

in large ring in rac-(Z)-26], 30.60 [2 aliph. CH₂in large ring in rac-

(Z)-25], 22.72 [2 aliph. CH₂in large ring in rac-(Z)-25], 22.47 [2

aliph. CH₂in large ring in rac-(Z)-26], 22.44 [2 aliph. CH₂in large

ring in rac-(E)-25], 22.32 [2 aliph. CH₂in large ring in rac-(Z)-26],

22.15 [2 aliph. CH₂in large ring in rac-(Z)-25], 22.10 [2 aliph. CH₂

in large ring in rac-(E)-25], 15.90 [2 aliph. CH₂in large ring in rac-

(E)-25], 15.88 [2 aliph. CH₂in large ring in rac-(Z)-25], 14.95 [2

aliph. CH₂in large ring in rac-(Z)-26], 9.17 [2 aliph. CH₂in large

ring in rac-(E)-25, 2 aliph. CH₂in large ring in rac-(Z)-25 and 2

aliph. CH₂in large ring in rac-(Z)-26], –1.19 [2 CH₃in rac-(Z)-

26], –1.32 [2 CH₃in rac-(E)-25 and 2 CH₃in rac-(Z)-25], –1.72 [2

CH₃in rac-(E)-25 and 2 CH₃in rac-(Z)-25], –1.84 [2 CH₃in rac-

(Z)-26], –1.92 [2 CH₃in rac-(Z)-26], –3.45 [2 CH₃in rac-(E)-25 and

2 CH₃in rac-(Z)-25], –3.47 [2 CH₃in rac-(E)-25 and 2 CH₃in rac-

(Z)-25], –5.71 [2 CH₃in rac-(Z)-26] ppm. ²⁹Si NMR (119.3 MHz,

25 °C, CDCl₃): δ = 5.48 [2 Si in rac-(Z)-25 or rac-(Z)-26], 4.92 [2

Si in rac-(Z)-25 or rac-(Z)-26], 4.83 [2 Si in rac-(E)-25], –7.98 [2 Si

in rac-(E)-25], –8.46 [2 Si in rac-(Z)-25 or rac-(Z)-26], –8.63 [2 Si

in rac-(Z)-25 or rac-(Z)-26] ppm. EIMS (70eV): calcd. C₂₂H₃₄Si₂

354.2199; found 354.2204 [rac-(E)-25 and rac-(Z)-25], calcd.

C₂₃H₃₆Si₂368.2356; found 368.2365 [rac-(Z)-26].

A Mixture of 1,3-Di(pent-4-enyl)-1H-indene (rac-27) and 1,1-Di-

(pent-4-enyl)-1H-indene (28): By applying the General Procedure 4,

indene (500 µL, 4.3 mmol), nBuLi (2 × 1.9 mL, 2×4.7 mmol, 2.5 

in n-hexane) and 5-bromo-1-pentene (2 × 560 µL, 2 × 4.7 mmol)

gave 0.8044 g (75%) of a mixture of the title compounds as a color-

less oil. The ratio between the obtained compounds was 1:0.23. ¹H

NMR (600 MHz, 25 °C, CDCl₃): δ = 7.41 (m, 2 H, 2 arom. CH in

rac-27), 7.30 (m, 5 H, 4 arom. CH in rac-27 and arom. CH in 28),

7.21 (m, 5 H, 2 arom. CH in rac-27 and 3 arom. CH in 28), 6.72

(d, J = 6.0 Hz, 1 H, olefin. CH in five-ring in 28), 6.29 (d, J =

6.0 Hz, 1 H, olefin. CH in five-ring in 28), 6.23 (m, 2 olefin. CH

in five-ring in rac-27), 5.89 (ddt, J = 16.8 Hz, 10.1 Hz, 6.7 Hz, 2

H, 2 olefin. CH in chain in rac-27), 5.82 (ddt, J = 16.8 Hz, 10.1 Hz,

6.7 Hz, 2 H, 2 olefin. CH in chain in rac-27), 5.69 (ddt, J = 16.8 Hz,

10.1 Hz, 6.7 Hz, 2 H, 2 olefin. CH in chain in 28), 5.08 (dm, J =

16.8 Hz, 2 H, 2 olefin. CH in chain in rac-27), 5.03 (dm, J =

16.8 Hz, 2 H, 2 olefin. CH in chain in rac-27), 5.02 (dm, J =

10.1 Hz, 2 H, 2 olefin. CH in chain in rac-27), 4.97 (dm, J =

10.1 Hz, 2 H, 2 olefin. CH in chain in rac-27), 4.93 (dm, J =

16.8 Hz, 2 H, 2 olefin. CH in chain in 28), 4.89 (dm, J = 16.8 Hz,

2 H, 2 olefin. CH in chain in 28), 3.42 (m, 2 H, 2 aliph. CH in

five-ring in rac-27), 2.56 (m, 4 H, 2 aliph. CH₂in chain in rac-27),

2.15 (m, 8 H, 4 aliph. CH₂in chain in rac-27), 1.92 (m, 4 H, 2

aliph. CH₂in chain in rac-27), 1.77 (m, 8 H, 2 aliph. CH₂in chain

in rac-27 and 2 aliph. CH₂in chain in 28), 1.51 (m, 8 H, 2 aliph.

CH₂in chain in rac-27 and 2 aliph. CH₂in chain in 28), 1.19 (m,

2 H, 2 aliph. CH in chain in 28), 0.93 (m, 2 H, 2 aliph. CH in chain

in 28) ppm. ¹³C NMR (150.9 MHz, 25 °C, CDCl₃): δ = 150.99 (C_q

in 28), 148.83 (2 C_qin rac-27), 145.17 (2 C_qin rac-27), 144.49 (C_q

in 28), 144.13 (olefin. CH in five-ring in 28), 143.27 (2 C_qin rac-

27), 138.93 (2 olefin. CH in chain in 28), 138.85 (2 olefin. CH in

Eur. J. Org. Chem. 2006, 1965–1977

www.eurjoc.org

1975

S. Silver, R. Leino

FULL PAPER

chain in rac-27), 138.80 (2 olefin. CH in chain in rac-27), 133.18 (2

olefin. CH in five-ring in rac-27), 129.98 (olefin. CH in five-ring in

28), 126.47 (arom. CH in 28), 126.32 (2 arom. CH in rac-27), 124.94

rac-31), 131.00 (2 olefin. CH in five-ring in rac-31), 129.56 (2 olefin.

CH in five-ring in rac-30), 126.54 (2 arom. CH in rac-31), 126.43

(2 arom. CH in rac-29 or rac-30), 124.75 (2 arom. CH in rac-29 or

(arom. CH in 28), 124.72 (2 arom. CH in rac-27), 122.94 (2 arom. rac-30), 124.53 (2 arom. CH in rac-29 or rac-30), 124.08 (2 arom.

CH in rac-27), 121.59 (arom. CH in 28), 121.12 (arom. CH in 28),

119.10 (2 arom. CH in rac-27), 114.86 (2 olefin. CH₂in chain in

rac-27), 114.67 (2 olefin. CH₂in chain in rac-27), 114.50 (2 olefin.

CH in rac-31), 123.79 (2 arom. CH in rac-29 or rac-30), 123.10 (2

arom. CH in rac-29 or rac-30), 123.00 (2 arom. CH in rac-29 or

rac-30), 122.96 (2 arom. CH in rac-31), 122.19 (2 arom. CH in rac-

CH₂in chain in 28), 57.53 (C_qin 28), 48.93 (2 aliph. CH in five- 29 or rac-30), 121.11 (2 arom. CH in rac-31), 119.21 (2 arom. CH

ring in rac-27), 37.07 (2 aliph. CH₂in chain in 28), 34.43 (2 aliph.

CH₂in chain in 28), 34.19 (2 aliph. CH₂in chain in rac-27), 33.76

(2 aliph. CH₂in chain in rac-27), 31.41 (2 aliph. CH₂in chain in

rac-27), 27.32 (2 aliph. CH₂in chain in rac-27), 27.14 (2 aliph. CH₂

in chain in rac-27), 26.99 (2 aliph. CH₂in chain in rac-27), 23.76

(2 aliph. CH₂in chain in 28) ppm. EIMS (70eV): calcd. C₁₉H₂₄

252.1878; found 252.1881.

in rac-29 or rac-30), 144.85 (2 olefin. CH₂in chain in rac-29 or rac-

30), 144.75 (2 olefin. CH₂in chain in rac-29 or rac-30), 144.45 (2

olefin. CH₂in chain in rac-31), 113.64 (2 olefin. CH₂in chain in

rac-29 or rac-30), 113.48 (2 olefin. CH₂in chain in rac-29 or rac-

30), 113.27 (2 olefin. CH₂in chain in rac-31), 58.62 (2 C_qin rac-

31), 51.92 (2 aliph. CH in five-ring in rac-29), 43.24 (2 aliph. CH

in five-ring in rac-30), 37.08 (2 aliph. CH₂in chain in rac-31), 34.17

(2 aliph. CH₂in chain in rac-29), 33.88 (2 aliph. CH₂in chain in

rac-30), 31.05 (2 aliph. CH₂in chain in rac-29), 30.33 (2 aliph. CH₂

in chain in rac-31), 28.61 (2 aliph. CH₂in chain in rac-31), 28.11

(2 aliph. CH₂in chain in rac-30), 27.21 (2 aliph. CH₂in chain in

rac-30), 26.81 (2 aliph. CH₂in chain in rac-29), 23.56 (2 aliph. CH₂

in chain in rac-29), 22.57 (2 aliph. CH₂in chain in rac-30), 22.25

(2 aliph. CH₂in chain in rac-31), –2.48 (2 CH₃in rac-31), –2.99 (2

CH₃in rac-31), –3.13 (2 CH₃in rac-29), –3.18 (2 CH₃in rac-29),

–4.34 (2 CH₃in rac-30), –4.73 (2 CH₃in rac-30) ppm. ²⁹Si NMR

(119.3 MHz, 25 °C, CDCl₃): δ = 3.39 (2 Si in rac-30), 0.78 (2 Si in

rac-31), –9.68 (2 Si in rac-29) ppm. EIMS (70eV): calcd. C₁₉H₂₆Si

282.1804; found 282.1811.

A Mixture of Allyl(dimethyl)(3-pent-4-enyl-3H-inden-1-yl)silane

(rac-29), Allyl(dimethyl)(3-pent-4-enyl-1H-inden-1-yl)silane (rac-30)

and Allyl(dimethyl)(1-pent-4-enyl-1H-inden-1-yl)silane (rac-31): By

applying the General Procedure 4, indene (420 µL, 3.6 mmol),

nBuLi (2 × 1.5 mL, 2×4.7 mmol, 2.5  in n-hexane), allyl(chloro)

dimethylsilane (600 µL, 4.0 mmol) and 5-bromo-1-pentene

(473 µL, 4.0 mmol) gave 0.7592 g (74%) of a mixture of the title

compounds as a yellow oil. The ratio between the obtained com-

pounds was 1:0.8:0.08. ¹H NMR (600 MHz, 25 °C, CDCl₃): δ =

7.51 (m, 2 H, 2 arom. CH in rac-31), 7.46 (m, 8 H, 4 arom. CH in

rac-29 and 4 arom. CH in rac-30), 7.38 (m, 2 H, 2 arom. CH in

rac-31), 7.30 (m, 6 H, 2 arom. CH in rac-29, 2 arom. CH in rac-30

and 2 arom. CH in rac-31), 7.22 (m, 6 H, 2 arom. CH in rac-29, 2

arom. CH in rac-30 and 2 arom. CH in rac-31), 6.84 (d, J = 5.4 Hz,

2 H, 2 olefin. CH in five-ring in rac-31), 6.80 (m, 2 H, 2 olefin. CH

in five-ring in rac-29), 6.58 (d, J = 5.4 Hz, 2 H, 2 olefin. CH in

five-ring in rac-31), 6.35 (m, 2 H, 2 olefin. CH in five-ring in rac-

30), 5.93 (m, 2 H, 2 olefin. CH in chain in rac-30), 5.84 (m, 4 H, 4

olefin. CH in chain in rac-29), 5.74 (m, 2 H, 2 olefin. CH in chain

in rac-30), 5.35 (a X-part of an ABX – system, m, 4 H, 4 olefin.

CH in chain in rac-31)^*, 4.95 (m, 20 H, 4 olefin. CH₂in chain in

rac-29, 4 olefin. CH₂in chain in rac-30 and 2 olefin. CH₂in chain

in rac-31), 4.75 (m, 4 H, 2 olefin. CH₂in chain in rac-31), 3.49 (m,

4 H, 2 aliph. CH in five-ring in rac-29 and 2 aliph. CH in five-ring

in rac-30), 2.75 (t, J = 7.7 Hz, 4 H, 2 aliph. CH₂in chain in rac-

31), 2.67 (t, J = 7.5 Hz, 4 H, 2 aliph. CH₂in chain in rac-30), 2.22

(m, 4 H, 2 aliph. CH₂in chain in rac-30), 2.12 (m, 4 H, 2 aliph.

CH₂in chain in rac-29), 1.93 (m, 2 H, 2 aliph. CH in chain in rac-

29), 1.84 (m, 12 H, 2 aliph. CH₂in chain in rac-29, 2 aliph. CH₂

in chain in rac-30 and 2 aliph. CH₂in chain in rac-31), 1.56 (m, 8

H, 2 aliph. CH₂in chain in rac-29 and 2 aliph. CH₂in chain in

rac-30), 1.49 (m, 2 H, 2 aliph. CH in chain in rac-29), 1.35 (m, 2

H, 2 aliph. CH in chain in rac-31), 1.31–1.26 (A-part of an ABX –

system, dd, J_AB= –13.5 Hz, J_AAX= 8.2 Hz, 2 H, 2 aliph. CH in

chain in rac-31)^*, 1.22–1.17 (a B-part of an ABX – system, dd, J_AB

= –13.5 Hz, J_AAX= 8.2 Hz, 2 H, 2 aliph. CH in chain in rac-31)^*,

1.16 (m, 2 H, 2 aliph. CH in chain in rac-31), 0.35 (s, 12 H, 4 CH₃

in rac-29), 0.07 (s, 6 H, 2 CH₃in rac-31), 0.02 (s, 6 H, 2 CH₃in

rac-31), –0.01 (s, 6 H, 2 CH₃in rac-30), –0.08 (s, 6 H, 2 CH₃in

rac-30) ppm. ¹³C NMR (150.9 MHz, 25 °C, CDCl₃): δ = 150.35 (2

olefin. CH in five-ring in rac-29), 148.77 (2 C_qin rac-29), 147.93

(2 C_qin rac-31), 147.54 (2 C_qin rac-29), 146.04 (2 C_qin rac-30),

144.71 (2 C_qin rac-30), 144.44 (2 C_qin rac-31), 142.20 (2 C_qin

rac-29), 141.99 (2 C_qin rac-30), 139.39 (2 olefin. CH in chain in

rac-31), 138.84 (2 olefin. CH in chain in rac-29 or rac-30), 138.74

(2 olefin. CH in chain in rac-29 or rac-30), 135.01 (2 olefin. CH in

chain in rac-31), 134.83 (2 olefin. CH in chain in rac-29), 134.53 (2

olefin. CH in chain in rac-30), 131.63 (2 olefin. CH in five-ring in

A Mixture of 4,4a-Dihydro-1H-fluorene (rac-4) and 4,9-Dihydro-

1H-fluorene (5). Ring-Closing Metathesis with Grubbs 1^stGenera-

tion Catalyst: To a solution of 1,2-diallyl-1H-indene (rac-1),

[(1E,4E)-2-hexa-1,4-dienyl]-1H-indene (2) and (E/Z)-1-allyl-2-

(prop-2-enylidene)indane (rac-3) (0.3465 g, 1.8 mmol) in dry

dichloromethane (5 mL) was added Grubbs 1^stgeneration catalyst

(0.1534 g, 0.2 mmol) in portions. The resulting reaction mixture

was refluxed for 3.5 h before the solvent was removed under re-

duced pressure. The residue was directly chromatographed on silica

gel (hexane as eluent) and 0.2049 g (69%) of a 8:1 mixture of the

title compounds as a colorless oil. EIMS (70eV): calcd. C₁₃H₁₂

168.0939; found 168.0931. The ¹H NMR spectroscopic data

(600 MHz, 25 °C, CDCl₃) and the ¹³C NMR spectroscopic data

(150.9 MHz, 25 °C, CDCl₃) are analogous to those reported in the

context of the experiment with the 2^ndgeneration catalyst (vide

supra).

Supporting Information (for details see the footnote on the first

page of this article): Copies of ¹³C NMR spectra of the compounds

reported are provided.

Acknowledgments

Financial support from the Swedish Academy of Engineering Sci-

ences in Finland is gratefully acknowledged. We also thank Mr.

Markku Reunanen for his assistance with the EIMS analyses.

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