Substituted lithiumtrimethylsiloxysilanides LiSiRR′(OSiMe3) - Investigations of their synthesis, stability and reactivity

Journal of Organometallic Chemistry 692 (2007) 1421–1441

www.elsevier.com/locate/jorganchem

Substituted lithiumtrimethylsiloxysilanides LiSiRR⁰(OSiMe₃)

– Investigations of their synthesis, stability and reactivity

*

Joerg Harloﬀ, Eckhard Popowski , Helmut Reinke

Institut fu¨r Chemie der Universita¨t Rostock, Albert-Einstein-Straße 3a, D-18051 Rostock, Germany

Received 29 August 2006; received in revised form 16 November 2006; accepted 22 November 2006

Available online 1 December 2006

Abstract

The reactions of the trimethylsiloxychlorosilanes (Me₃SiO)RR⁰SiCl (1a–h: R⁰= Ph, 1a: R = H, 1b: R = Me, 1c: R = Et, 1d: R = ⁱPr,

1e: R = ^tBu, 1f: R = Ph, 1g: R = 2,4,6-Me₃C₆H₂(Mes), 1h: R = 2,4,6-(Me₂CH)₃C₆H₂(Tip); 1i: R = R⁰= Mes) with lithium metal in

tetrahydrofuran (THF) at ꢀ78 ꢀC and in a mixture of THF/diethyl ether/n-pentane in a volume ratio 4:1:1 at ꢀ110 ꢀC lead to mixtures

of numerous compounds. Dependent on the substituents silyllithium derivatives (Me₃SiO)RR⁰SiLi (2b–i), Me₃SiO(RR⁰Si)₂Li (3a–g),

Me₃SiRR⁰SiLi (4a–h), (LiO)RR⁰SiLi (12e, 12g–i), trisiloxanes (Me₃SiO)₂SiRR⁰(5a–i) and trimethylsiloxydisilanes (6f^*, 6h^*, 6i^*) are

formed. All silyllithium compounds were trapped with Me₃SiCl or HMe₂SiCl resulting in the following products:

(Me₃SiO)RR⁰SiSiMe₂R⁰⁰(6b–i: R⁰⁰= Me, 7c–i: R⁰⁰= H), Me₃SiO(RR⁰Si)₂SiMe₂R⁰⁰(8a–g: R⁰⁰= Me, 9a–g: R⁰⁰= H), Me₃SiRR⁰-

SiSiMe₂R⁰⁰(10a–h: R⁰⁰= Me, 11a–h: R⁰⁰= H) and (HMe₂SiO)RR⁰SiSiMe₂H (13e, 13g–i). The stability of trimethylsiloxysilyllithiums

2 depends on the substituents and on the temperature. (Me₃SiO)Mes₂SiLi (2i) is the most stable compound due to the high steric shield-

ing of the silicon centre. The trimethylsiloxysilyllithiums 2a–g undergo partially self-condensation to aﬀord the corresponding trime-

thylsiloxydisilanyllithiums Me₃SiO(RR⁰Si)₂Li (3a–g). (Me₃)Si–O bond cleavage was observed for 2e and 2g–i. The relatively stable

trimethylsiloxysilyllithiums 2f, 2g and 2i react with n-butyllithium under nucleophilic butylation to give the n-butyl-substituted silylli-

n

thiums BuRR⁰SiLi (15g, 15f, 15i), which were trapped with Me₃SiCl. By reaction of 2g and 2i with 2,3-dimethylbuta-1,3-diene the

corresponding 1,1-diarylsilacyclopentenes 17g and 17i are obtained.

˚

X-ray studies of 17g revealed a folded silacyclopentene ring with the silicon atom located 0.5 A above the mean plane formed by the

four carbon ring atoms.

Keywords: Trimethylsiloxysilyllithiums; Self-condensation; Ambiphilic reactivity; Si–O bond cleavage; Disilanes; Trisilanes

1. Introduction

electrophile [5,6,11,12]. They can also be used as sources

of carbenes [1,7,12,15]. Whether a carbenoid reacts as

nucleophile or electrophile, depends mainly on the reaction

temperature [1,7,9,14]. The carbanionic character is

favoured by very low temperatures. Exclusively, organoli-

thium compounds with a nitrogen atom at a-position only

show carbanionic character [9,14,16–18].

Functionalised silyllithium compounds (X)RR⁰SiLi

(X = electronegative leaving group), analogues of the a-

heteroatom-substituted organolithium compounds, have

been the object of increasing interest in recent years

(reviews in [19–22]). Detailed reports are given on syntheses

and chemical properties of aminosilyl- [23–28], alkoxysilyl-

[24,29,30], allyloxysilyl- [25,31], siloxysilyl- [32,33],

a-Heteroatom-substituted organolithium compounds

LiCRR⁰(X) show ambiphilic – carbenoid – behaviour, if

X is a halogen atom or an OR group [1–14]. The reason

for this is the existence of an electropositve metal atom

and an electronegative substituent on the same carbon

atom. Lithiumcarbenoids react with electrophiles as well

as with nucleophiles and in many cases undergo a bimolec-

ular dimerisation (self-condensation), in which one mole-

cule behaves as nucleophile and the other one as

*

Corresponding author. Tel.: +49 381 498 6380; fax: +49 381 498 6382.

E-mail address: eckhard.popowski@uni-rostock.de (E. Popowski).

doi:10.1016/j.jorganchem.2006.11.033

1422

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

halogensilyl- [34–37] and mesitylthiosilyllithium com-

pounds [38], which are stable at least at low temperatures.

Nucleophilic and electrophilic behaviour, i.e. silylenoid

character, were experimentally proved only for the com-

pounds [(Me₃Si)₂N]MePhSiLi [26], (RO)Ph₂SiLi (R =

to give brown, red and green solutions, respectively, con-

taining never only the expected trimethylsiloxysilyllithium

(Me₃SiO)RR⁰SiLi (2). A mixture of several silyllithium

compounds 2–4, 12, trisiloxane 5 as well as siloxydisilane

6^*depending on the substituents R and R⁰is obtained

(Schemes 1 and 2). The typical reaction behaviour of all sil-

oxychlorosilanes is shown in Scheme 1. Beside the summa-

rised compounds in Scheme 1 more ones are given in

Scheme 2, which were additionally formed in the reaction

of the siloxychlorosilanes 1e and 1g–i with lithium.

The silyllithium compounds (Me₃SiO)RR⁰SiLi (2b–i),

(Me₃SiO)RR⁰SiRR⁰SiLi (3a–g), Me₃SiRR⁰SiLi (4a–h) and

(LiO)RR⁰SiLi (12e, 12g–i) were trapped with chloro-

trimethylsilane and chlorodimethylsilane (Schemes 1 and

2) to give the corresponding trimethylsiloxydisilanes

(Me₃SiO)RR⁰Si–SiMe₂R⁰⁰(6b–i: R⁰⁰= Me; 7c–i: R⁰⁰= H),

trimethylsiloxytrisilanes (Me₃SiO)RR⁰SiRR⁰Si–SiMe₂R⁰⁰

(8a–g: R⁰⁰= Me; 9a–g: R⁰⁰= H), trisilanes Me₃SiRR⁰Si–

SiMe₂R⁰⁰(10a–h: R⁰⁰= Me; 11a–h: R⁰⁰= H) and dimethyl-

siloxydisilanes (HMe₂SiO)RR⁰Si–SiMe₂H (13e, 13g–i)

(Schemes 1 and 2, Table 1).

The disilanes (Me₃SiO)HPhSi–SiMe₂R⁰⁰(R⁰⁰= Me, H),

trapping products of hydrido-phenyl-trimethylsiloxy-silylli-

thium (Me₃SiO)HPhSiLi (2a), could not be detected in the

reaction mixtures. Beside chlorotrimethylsilane as trapping

agent chlorodimethylsilane was used to unequivocally

prove the compounds in the reaction mixture. So the forma-

tion of the lithiumoxysilyllithiums 12e and 12g–i (Scheme 2)

was only noticed with HMe₂SiCl as trapping agent. With

Me₃SiCl the lithium derivatives (Me₃SiO)RR⁰SiLi (2) and

(LiO)RR⁰SiLi (12) yielded identical products 6.

As a broad variety of products was observed, a compli-

cated reaction pathway can be assumed, e.g. parallel and

multiple step reactions starting from trimethylsiloxysilylli-

thium 2. The formation of products such as 3–5, 6^*and

12 (Schemes 1 and 2) already began clearly before the tri-

methylsiloxychlorosilane 1 was completely consumed evi-

denced by GC and GC–MS investigations. The samples

for the GC and GC–MS measurements were trapped with

Me₃SiCl and HMe₂SiCl, respectively.

Presumably, the formation of the siloxysilyllithiums

(Me₃SiO)RR⁰SiLi (2) proceeds via a disilane intermediate

(Eq. (2)) as described for the synthesis of silyllithium com-

pounds with at least one aryl group on the silicon atom by

reaction of a chlorosilane Si(aryl)Cl with lithium metal

[19,28,39].

i

^tBu, Pr, Me) [24,29], (Me₃SiO)Me_2ꢀnPh_nSiLi (n = 1, 2)

[32] and X₂[(Me₃Si)₃C]SiLi (X = Cl, Br) [37].

Earlier we reported that the bis(trimethylsilyl)amino-

and trimethylsiloxy-substituted silyllithium compounds

(X)Me_2ꢀnPh_nSiLi (X = (Me₃Si)₂N, Me₃SiO; n = 1, 2) are

available by reaction of the corresponding chlorosilanes

with lithium (used as very thin plates) in tetrahydrofuran

(THF) at low temperatures [26,32]. The formation of the

siloxysilyllithium compounds was accompanied by a Si–O

bond cleavage that aﬀorded the silanides Me₃SiSi-

Me_2ꢀnPh_nLi (n = 1, 2).

Bis(trimethylsilyl)aminosilyllithium [(Me₃Si)₂N]MePh-

SiLi [26] and both trimethylsiloxysilyllithiums (Me₃SiO)-

Me_2ꢀnPh_nSiLi (n = 1, 2) [32] react as alkoxysilyllithiums

i

(RO)Ph₂SiLi (R = ^tBu, Pr, Me) [24,29] under bimolecular

self-condensation, which is a characteristic silylenoid

behaviour (Eq. (1)) [20,21,24,29].

ðXÞMe_2ꢀnPh_nSiLi þ ðXÞMe_2ꢀnPh_nSiLi

! ðXÞMe_2ꢀnPh_nSi–SiMe_2ꢀnPh_nLi þ LiX

X ¼ ðMe₃SiÞ₂N; n ¼ 1; X ¼ Me₃SiO; n ¼ 1; 2

ð1Þ

The extent of self-condensation of diphenyl-trimethylsil-

oxy-silyllithium is considerably smaller than that of

methyl-phenyl-trimethylsiloxy-silyllithium [32].

This result as well as the observed Si–O bond cleavage

during the preparation of both trimethylsiloxysilyllithiums

prompted us to follow the question, how strong substitu-

ents inﬂuence the synthesis, stability and reactivity of

trimethylsiloxysilyllithiums.

In the following, we report the results of our investiga-

tions of the preparation of substituted trimethylsiloxysilylli-

thium compounds (Me₃SiO)RR⁰SiLi by reaction of

siloxychlorosilanes (Me₃SiO)RR⁰SiCl (1a–i) with lithium

metal (preliminary communication in [33]), and on their

reaction behaviour.

a

b

c

d

e

f

g

h

i

R

H

Me Et ⁱPr ^tBu Ph Mes^aTip^bMes

R⁰Ph Ph Ph Ph Ph Ph Ph

Ph

Mes

a

Mes: 2,4,6-Me₃C₆H₂.

Tip: 2,4,6-(Me₂CH)₃C₆H₂.

b

R

R R

+ 2 Li

+ (Me₃SiO)RR'SiCl (1)

- LiCl

Me₃SiO

Si Cl

R'

Si Li

R'

Si Si OSiMe₃

R' R'

- LiCl

2. Results and discussion

1

2

14

+ 2 Li

2.1. Reaction of the siloxychlorosilanes (Me₃SiO)RR⁰SiCl

(1a–i) with lithium metal

R

2Me₃SiO Si Li

R'

The siloxychlorosilanes 1a–i react with very thin lithium

plates in THF at ꢀ78 ꢀC and in a Trapp mixture [1] (THF/

diethyl ether/n-pentane in volume ratio 4:1:1) at ꢀ110 ꢀC

2

ð2Þ

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

1423

R

Me₃SiO Si Cl

R'

1a-i

+Li (4 eq)

A: THF, -7 8 ˚C, 0.5-3 h

-LiCl

-LiOSiMe₃

or

B: TH F / Et ₂O/ n-pentane

(4:1:1), -1 10 ˚C, 1-6 h

1a-i + LiOSiMe₃

R

Me₃SiO Si Li

Me₃SiO Si OSiMe₃

R'

Me₃Si Si Li

R'

2b-i

5a-

4a-h

i

R

1e, 1g-i: further

Me₃SiO Si Si Li

reactions in

Scheme 2.

R' R'

3a-g

+R''Me₂SiCl (R''= Me, H); -LiCl, -R''Me₂SiOSiMe₃

R

H

Me

Et

R'

R

Ph

a

b

c

Me₃SiO Si SiMe₂R''

Me₃Si Si SiMe₂R''

R'

6b-i: R''= Me

7c-i: R''= H

10a-h: R''= Me

11a-h: R''= H

ⁱPr Ph

d

^tBu Ph

Ph Ph

Mes Ph

Tip Ph

Mes Mes

e

f

g

h

i

R

Me₃SiO Si Si SiMe₂R''

R' R'

8a-g: R''= Me

9a-g: R''= H

Scheme 1. Reaction products obtained in the reaction of the siloxychlorosilanes 1a-i with lithium (1b, 1f in [32]) as well as trapping of the formed

lithiumsilanides with Me₃SiCl or HMe₂SiCl.

The initially formed siloxysilyllithium (Me₃SiO)RR⁰SiLi

(2) reacts with the excess chlorosilane (Me₃SiO)RR⁰SiCl

(1) to give a disilane (Me₃SiO)RR⁰Si–SiRR⁰(OSiMe₃)

(14), which is cleft by lithium to form 2. In the reactions

of the siloxychlorosilanes (Me₃SiO)^tBuPhSiCl (1e) or

(Me₃SiO)MesPhSiCl (1g) with lithium the disilanes [(Me_3-

SiO)RPhSi]₂(14e: R = ^tBu, 14g: R = Mes) can only be iso-

lated, if the reaction is stopped at an early stage by

quenching with Me₃SiCl.

According to the data given in Table 2, trimethylsiloxy-

silyllithiums 2b–i are more stable at ꢀ110 ꢀC than at

ꢀ78 ꢀC. With exception of (Me₃SiO)TipPhSiLi (6h) the

trimethylsiloxysilyllithiums (Me₃SiO)RR⁰SiLi (2f: R/

R⁰= Ph/Ph, 2g: R/R⁰= Mes/Ph, 2i: R/R⁰= Mes/Mes)

with two aromatic substituents are considerably more

stable than 2b–e with only one aromatic substituent. The

dimesityl-trimethylsiloxy-silyllithium 2i has the highest

stability at both temperatures (ꢀ78 ꢀC and ꢀ110 ꢀC)

because the Si–Li moiety of 2i is highly shielded. From

the proportions of the trimethylsiloxysilyllithiums 2b–i in

the reaction mixtures it is apparent that the substituents

R and R⁰have an inﬂuence on the stability of 2b–i as espe-

cially illustrated by the yields obtained in the reactions at

ꢀ110 ꢀC. The following order of stability depending on R

and R⁰could be established: R/R⁰= Mes/Mes > Mes/Ph >

Ph/Ph > ^tBu/Ph > ⁱPr/Ph > Tip/Ph > Et/Ph ꢁ Me/Ph >

H/Ph. The order of stability at ꢀ110 ꢀC, observed in the

row of compounds (Me₃SiO)RPhSiLi (R = H, Me, Et,

1424

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

R

+ 2 HMe₂SiCl

LiO Si Li

HMe₂SiO Si SiMe₂H

- 2LiCl

R'

R

12e, 12g-i

13e, 13g-i

+ Li(4 eq)

Me₃SiO Si Cl

A or B

R'

1e, 1g-i

R

Me₃SiO Si SiMe₃

R'

6e*, 6h*, 6i*

Yield (%)

Variant 13e

13g 13h 13i

6e* 6h* 6i*

A

B

34

17

4

2

33

31

8

5

9

2

10

5

10

28

Scheme 2. Continuation of Scheme 1.

Table 1

Yields of the trapping products (Me₃SiO)RR⁰SiSiMe₂R⁰⁰(6b–i: R⁰⁰= Me; 7c–i: R⁰⁰= H), Me₃SiO(RR⁰Si)₂SiMe₂R⁰⁰(8a–g: R⁰⁰= Me; 9a–g: R⁰⁰= H) and

Me₃SiRR⁰SiSiMe₂R⁰⁰(10a–h: R⁰⁰= Me; 11a–h: R⁰⁰= H) for the respective lithiumsilanides formed in the reaction of trimethylsiloxychlorosilanes

(Me₃SiO)RR⁰SiCl (1a–i) with lithium at ꢀ78 ꢀC (variant A) and at ꢀ110 ꢀC (variant B) as well as yields of the trisiloxanes (Me₃SiO)₂SiRR⁰(5a–i)

Variant

Trapping agent

Compound

Yield (%)

a

b^a

c

d

e

f ^a

g

h

i

R = H

R⁰= Ph

Me

Ph

Et

Ph

ⁱPr

Ph

^tBu

Ph

Mes

Ph

Tip

Ph

Mes

b

c

A

B

A

B

A

B

A

B

A

B

A

B

A

B

a

Me₃SiCl

HMe₂SiCl

Me₃SiCl

6

–

1

17

–

7

16

3

15

67

70

75

68

6

2

4

2

9

32

10

31

56

36

63

46

17

4

7

3

7

11

6

44

66^c

19

47

18

45

27

28

29

26

22

17

15

8

51^c

66^c

47

62

24

20

28

18

17

8

13

6

3

2

4

48^c

78^c

13

20

–

36

2

31

2

11

5

8

2

71^c

75^c

54

67

–

b

–

b

7

–

4

38

5

4

1

34

7

31

11

2

b

d

7

–

8

10

47

7

45

6

5

3

10

9

71

75

78

Me₃SiCl

8

HMe₂SiCl

Me₃SiCl

9

d

9

–

10

11

5

4

1

3

Me₃SiCl

–

HMe₂SiCl

Me₃SiCl

HMe₂SiCl

Me₃SiCl

d

–

18

10

4

3

5

8

9

5

2

1

2

8

5

10

11

d

HMe₂SiCl

5

–

3

Yields of 5b, 6b, 8b–11b, 5f and 6f–11f (variant A) as well as yields of 5b, 6b, 8b, 10b, 5f, 6f, 8f and 10f (variant B) from [32].

No trapping products (Me₃SiO)HPhSiSiMe₂R⁰⁰for (Me₃SiO)HPhSiLi. In the reaction of 1a with lithium higher-molecular silanes with Si–Si bonds

b

were also obtained beside 8a–11a and 5a after trapping.

c

The yields of 6e, 6g–i are composed of the yields of the lithium derivatives (Me₃SiO)RR⁰SiLi (2e, 2g–i) and (LiO)RR⁰SiLi (12e, 12g–i) trapped with

Me₃SiCl as well as the disilanes (Me₃SiO)RR⁰SiSiMe₃(6e^*,6h^*,6i^*) formed already before the addition of trapping agent.

d

The reaction mixture was not trapped with HMe₂SiCl.

t

ⁱPr, Bu), is attributed to steric shielding of the central sili-

con atom by the substituents R = ^tBu > ⁱPr > Et ꢁ Me >

H. The same holds for the stability series of the diaryl-

substituted species: 2f < 2h < 2i. Step-by-step substitution

of phenyl by mesityl substituents results in an increase

of steric shielding of the Si(Li)-atom. Assuming a

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

1425

Table 2

Proportions of the silyllithiums (Me₃SiO)RR⁰SiLi (2b–i), Me₃SiO(RR⁰Si)₂Li (3a–g) and Me₃SiRR⁰SiLi (4a–h) in the reaction mixture of silanides (formed

in the reaction of siloxychlorosilanes (Me₃SiO)RR⁰SiCl (1a–i) with lithium) determined from yields of the trapping products (Me₃SiO)RR⁰SiSiMe₂R⁰⁰(6b–

d, 6f: R⁰⁰= Me; 7e, 7g–i: R⁰⁰= H), Me₃SiO(RR⁰Si)₂SiMe₂R⁰⁰(8a–g: R⁰⁰= Me; 9a–g: R⁰⁰= H) and Me₃SiRR⁰SiSiMe₂R⁰⁰(10a–h: R⁰⁰= Me; 11a–h: R⁰⁰= H)

Temperature (ꢀC)

a

b

c

d

e

f

g

h

i

R = H

R⁰= Ph

Me

Ph

Et

Ph

ⁱPr

Ph

^tBu

Ph

Mes

Ph

Tip

Ph

Mes

(Me₃SiO)RR⁰SiLi (2) (%)

ꢀ78

–

1^a

17^a

7

16

9

32

4

38

19^a

47^a

47

62

13

20

54

67

ꢀ110

Me₃SiO(RR⁰Si)₂Li (3) (%) from 8a–g/9a–g

ꢀ78

10/7

47/45

71/78^a

75^a/–^b

67/75

70/68

56/63

36/46

5/4

4/1

27/29^a

28/26

24/28

20/18

–/–

ꢀ110

Me₃SiRR⁰SiLi (4) (%) from 10a–h/11a–h

ꢀ78

ꢀ110

a

6/3

5/3

4/3^a

1^a/–^b

6/4

2/2

17/7

4/3

34/31

7/11

22/17^a

17^a/15

17/13

8/6

36/31

2/2

–/–

Values from [32].

b

The reaction mixture was not trapped with HMe₂SiCl.

considerable steric stabilisation in trimethylsiloxysilylli-

thium compounds the yields of (Me₃SiO)^tBuPhSiLi (2e)

at ꢀ78 ꢀC and of (Me₃SiO)TipPhSiLi (2h) at ꢀ78 ꢀC as

well as at ꢀ110 ꢀC are relatively low (Table 2) and can

be attributed to a (Me₃)Si–O bond cleavage. For a detailed

discussion see below.

Eq. (3). The lithiumtrimethylsilanolate formed by self-

condensation, reacts with the corresponding siloxychloro-

silanes (Me₃SiO)RR⁰SiCl (1a–g) to give the trisiloxanes

(Me₃SiO)₂SiRR⁰(5a–g), whose formation already took

place during the reaction of siloxychlorosilanes with

lithium.

The siloxysilyllithiums (Me₃SiO)RR⁰SiLi (2b–g) undergo

bimolecular self-condensation reactions at ꢀ78 ꢀC and

ꢀ110 ꢀC to a diﬀerent extent (Eq. (3), Table 2) aﬀording

the corresponding siloxydisilanyllithiums 3b–g, which were

trapped as siloxytrisilanes Me₃SiO(RR⁰Si)₂SiMe₂R⁰⁰(9b–g:

R⁰⁰= Me; 10b–g: R⁰⁰= H) (Scheme 1, Table 1).

The siloxysilyllithiums (Me₃SiO)Ph₂SiLi (2f) and

(Me₃SiO)MesPhSiLi (2g), in which two aromatic substitu-

ents are bonded to the central silicon atom, tend far less

towards self-condensation than the three alkyl-phenyl-

substituted compounds (Me₃SiO)RPhSiLi (2b: R = Me,

2c: R = Et, 2d: R = ⁱPr) (Eq. (3), Table 2). (Me₃SiO)^tBuPh-

SiLi (2e) takes an exceptional position within the list of

alkyl-phenyl-substituted compounds because of the

(Me₃)Si–O bond cleavage tendency as already mentioned.

Both siloxysilyllithiums (Me₃SiO)TipPhSiLi (2h) and

(Me₃SiO)Mes₂SiLi (2i), which bear also two aromatic sub-

stituents on the Si(Li)-atom like 2f and 2g, do not undergo

self-condensation. The reason for this is of steric nature.

The higher steric shielding of the central silicon atom com-

pared to 2f and 2g suppresses the bimolecular self-conden-

sation process.

- 78 ˚C

or

- 110 ˚C

R

Me₃SiO Si Li

R'

R

Me₃SiO Si Li

R'

R R

Me₃SiO Si Si Li

R' R'

+

+ LiOSiMe₃

2b-g

3b-g

b: R = Me, c: R = Et, d: R = ⁱPr, e: R = ^tBu, f: R = Ph, g: R = Mes; b-g: R' = Ph

ð3Þ

This type of reaction (Eq. (3)), in which one molecule

behaves as an electrophile and the other one as a nucleo-

phile, clearly indicates ambiphilic reactivity, i.e. silylenoid

behaviour, of 2b–g.

The mixtures of products formed in the reaction of sil-

oxychlorosilanes 1a–g with lithium gave no indication for

a b-elimination of lithiumtrimethylsilanolate from the tri-

methylsiloxydisilanyllithiums 3a–g.

For trimethylsiloxysilyllithium (Me₃SiO)HPhSiLi (2a),

which could neither be trapped at ꢀ78 ꢀC nor at

ꢀ110 ꢀC, the self-condensation product (Me₃SiO)HPhSi–

HPhSiLi (3a) was obtained as well. However, the amount

of 3a in the reaction mixture was relatively small, especially

in the reaction of 1a with lithium at ꢀ78 ꢀC. These results

and the formation of higher-molecular silanes with Si–Si

bonds (only observed in the case of reaction of 1a with

lithium) indicate that self-condensation of 2a did not stop

on the level of 3a. But starting from 3a a number of

another Si–Si coupling reactions took place according to

The

formation

of

the

lithiumoxysilyllithiums

(LiO)RR⁰SiL₀i (12e, 12g–i) and the trimethylsiloxydisilanes

(Me₃SiO)RR Si–SiMe₃(6^*), which already existed in the

respective reaction mixtures before quenching with

Me₃SiCl or HMe₂SiCl (Scheme 2), may be explained by

reaction between two trimethylsiloxysilyllithiums. One

molecule of 2 attacks the Me₃Si group of another molecule

of 2 under (Me₃)Si–O bond cleavage and generation of a

Si–Si bond (Eq. (4))

1426

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

R

LiO Si Li

R'

The formation of the trimethylsilylsilyllithium deriva-

tives Me₃Si–RR⁰SiLi (4a–d, 4f, 4g) remains unclear. Pre-

sumably, they are generated in the same way as 4e and

4h: (i) reaction of (Me₃SiO)RR⁰SiLi (2) according to Eq.

(4) aﬀording lithiumoxysilyllithium (LiO)RR⁰SiLi (12)

and siloxydisilane (Me₃SiO)RR⁰Si–SiMe₃(6^*) and (ii)

RR⁰Si–O bond cleavage of 6^*with lithium (Eq. (5)). How-

ever, the formation of compounds, which could conﬁrm

this assumption, was not observed in the reaction of the sil-

oxychlorosilanes 1a–d, 1f and 1g with lithium. According

to the yields of 10a–h, 11a–h (Table 1) and 4a–h (Table

2), respectively, it follows that the processes leading to

the formation of 4a–h are suppressed by lowering the reac-

tion temperature from ꢀ78 ꢀC to ꢀ110 ꢀC.

Si Li

R'

Me₃SiO

2e, 2g-i

12e, 12g-i

variant

A or B

+

R

Me₃SiO Si Li

R'

Me₃SiO Si

SiMe₃

R'

6e*, 6h*, 6i*

2e, 2g-i

e: R = ^tBu, R' = Ph; g: R = Mes,R' = Ph; h: R = Tip, R' = Ph; i: R = R' = Mes

ð4Þ

In case of the reaction of the siloxychlorosilane 1g with

lithium a disilane 6g^*according to 6e^*, 6h^*and 6i^*could

not be detected. Due to the yields of the dimethylsiloxydi-

silanes (HMe₂SiO)RR⁰Si–SiMe₂H (13e: R = ^tBu, R⁰= Ph;

13g: R = Mes, R⁰= Ph; 13h: R = Tip, R⁰= Ph; 13i:

R = R⁰= Mes) (Scheme 2), trapping products of 12e and

12g–i, it is apparent that the (Me₃)Si–O bond cleavage in

2e and 2h is considerable and signiﬁcantly greater than that

of 2g and 2i. Obviously, the high extent of (Me₃)Si–O bond

cleavage in 2e and 2h is the reason for the unexpectedly low

yield of 2e and 2h (Table 2) in the reaction of 1e and 1h

with lithium. In the reaction of the siloxychlorosilanes 1e

and 1g–i with lithium very small amounts of hexamethyl-

and pentamethyldisilane as trapping products were ob-

tained, respectively, suggesting the formation of a little

LiSiMe₃.

2.2. Reaction of selected siloxysilyllithium compounds with

n-butyllithium and 2,3-dimethylbuta-1,3-diene

To gain further insight into the reactivity of tri-

methylsiloxysilyllithium compounds the reaction behaviour

of relatively stable lithiumsilanides (Me₃SiO)RR⁰SiLi (2f:

R = R⁰= Ph; 2g: R = Mes, R⁰= Ph; 2i: R = R⁰= Mes)

towards n-butyllithium and of 2g and 2i towards 2,3-di-

methylbuta-1,3-diene, respectively, have been studied.

Lithiumcarbenoids C(X)Li (X = halogen atom, OR)

react with organolithium compounds RLi under nucleo-

philic substitution of the leaving group X by the organic

moiety R [1,5–7,9,12,14]. This reaction is regarded to be

characteristic of the electrophilic reactivity of carbenoids.

Analogously, Tamao and Kawachi [20,24,29] took the

nucleophilic butylation of the alkoxysilyllithiums (RO)Ph₂-

SiLi (R = Me, ^tBu) with n-butyllithium as expression of the

electrophilic – silylenoid – behaviour of the silicon in these

compounds.

Interestingly, for the siloxydisilanes (Me₃SiO)RR⁰Si–

SiMe₃(6e^*, 6h^*) a RR⁰Si–O bond cleavage by lithium

was observed under formation of lithiumtrimethylsilano-

late and the trimethylsilylsilyllithiums Me₃Si–RR⁰SiLi (4e,

4h) (Eq. (5)).

The solutions of products (Schemes 1 and 2) with about

60% of the respective trimethylsiloxysilyllithium 2f, 2g and

2i formed in the reaction of the siloxychlorosilanes 1f, 1g

and 1i with lithium at ꢀ110 ꢀC, respectively, were mixed

with n-BuLi after separation from excess lithium, then

slowly warmed to room temperature (r.t.) and after 4 h

stirring quenched with chlorotrimethylsilane at the same

temperature. Except for the already known trapping

products (Schemes 1 and 2, Table 1) the n-butyl-substituted

variant

R

A or B

Me₃SiO Si SiMe₃

R'

2 Li

Li Si SiMe₃

R'

+

+ LiOSiMe₃

6e*, 6h*

4e, 4h

e: R = ^tBu, R' = Ph; h: R = Tip, R' = Ph

ð5Þ

With the trapping agents Me₃SiCl and HMe₂SiCl the tri-

methylsilylsilyllithium derivatives 4e and 4h yielded the

trisilanes Me₃Si–RR⁰Si–SiMe₂R⁰⁰(10e, 10h: R⁰⁰= Me;

11e, 11h: R⁰⁰= H) (Scheme 1). The lithiumsilanolate re-

acted with the siloxychlorosilanes 1e and 1h to give the tris-

iloxanes (Me₃SiO)₂SiRR⁰(5e, 5h). The Si–O bond cleavage

according to Eq. (5) was conﬁrmed by reaction of the pure

disilanes (Me₃SiO)RR⁰Si–SiMe₃(6e: R = ^tBu, R⁰= Ph; 6f:

R = R⁰= Ph; 6h: R = Tip, R⁰= Ph) with lithium in THF

at ꢀ78 ꢀC. However, the dimesityl-substituted siloxydisi-

lane (Me₃SiO)Mes₂Si–SiMe₃(6i) did not react with lithium

under the same conditions. Hence, no trimethylsilylsilylli-

thium Me₃Si–Mes₂SiLi according to 4e and 4h was gener-

ated in the reaction of 1i with lithium (Scheme 1).

n

disilanes BuRR⁰Si–SiMe₃(16f, 16g, 16i) were obtained as

new compounds indicating the formation of the n-butyl-

n

substituted silyllithiums BuRR⁰SiLi (15f, 15g, 15i) from

2f, 2g and 2i, respectively (Eq. (6)).

R

Me₃SiO Si Li

R'

R

THF/ Et₂O/ n-pentane

+ 2 Me₃SiCl

ⁿBuLi

ⁿBu

Si Li

R'

Si SiMe₃

R'

+

2 h, - 110 ˚C

4 h, r.t.

r.t.;

-2 LiCl

-(Me₃Si)₂O

-Me₃SiOLi

2f: R= R'= Ph

2g: R= Mes, R'= Ph

2i: R= R'= Mes

15f, 15g, 15i

16f (16 %)

16g (26 %)

16i (15 %)

ð6Þ

Beside self-condensation the nucleophilic butylation of 2f,

2g and 2i is another proof of an electrophilic reactivity

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

1427

Mes

Si

of trimethylsiloxysilyllithium compounds. The nucleo-

THF/ Et₂O/ n-pentane

Me₃SiO Si Li

R'

+

+ (Me₃Si)₂O

philic behaviour was veriﬁed in many cases by trapping

reactions with the electrophiles Me₃SiCl and HMe₂SiCl.

Even 2i, which does not undergo self-condensation under

the chosen reaction conditions, still shows electro-

philic behaviour towards the strong nucleophile n-

butyllithium.

The formation of silacyclopentenes in the reaction of

di- and trihalosilanes with lithium in the presence of 2,3-

dimethylbuta-1,3-diene is often considered as proof of the

formation of silylene intermediates [38,40–42]. However,

the silacyclopentene can also be produced by reaction of

the diene with a halogen silylenoid Si(X)Li (X = halogen

atom) [37,43], a precursor of silylenes. But the alkoxysilyle-

noid (^tBuO)Ph₂SiLi does not react with 2,3-dimethylbuta-

1,3-diene [29].

The trimethylsiloxysilyllithiums 2g and 2i, which are

produced by reaction of the siloxychlorosilanes 1g and 1i

with lithium (4 equiv.) at ꢀ110 ꢀC in THF/Et₂O/n-pentane

(in addition to 2g and 2i further compounds could be

found in the solution), react with 2,3-dimethylbuta-1,3-

diene within the temperature range from ꢀ110 ꢀC to

ꢀ78 ꢀC to give the silacyclopentenes 17g and 17i as well

as lithiumtrimethylsilanolate (Eq. (7)). The silanolate was

trapped with chlorotrimethylsilane resulting in hexa-

methyldisiloxane.

1.) 1 h, -11 0 ˚C

3 h, -78˚C

2.) +Me₃SiCl,

-LiCl

-78 ˚C;

R'

2g: R'= Ph

2i: R'= Mes

17g (16 %)

17i (13 %)

ð7Þ

In case of the reaction of 2g with 2,3-dimethylbuta-1,3-

diene the trapping products Me₃SiO(MesPhSi)₂SiMe₃

(8g) and Me₃SiMesPhSiSiMe₃(10g) (Scheme 1) beside

17g were obtained additionally.

The silacyclopentenes could be produced either by

direct reaction between the siloxysilylenoid and the diene

or by reaction of a silylene, which is formed by a-elimi-

nation of LiOSiMe₃from the siloxysilylenoid, with the

diene. The fact that the reaction already takes place at

ꢀ78 ꢀC is a strong argument for a silylenoid mechanism.

Furthermore this assumption is supported by the reaction

according to Eq. (7), in which the established trapping

agent of silylenes triethylsilane [36,38,41,44–47] was

exchanged for the diene (molar ratio of siloxychlorosi-

lane/Et₃SiH = 1:4; slowly warming to 20 ꢀC). A forma-

tion of products of a silylene insertion R⁰Mes(H)Si–

SiEt₃could not be proved.

Colourless single crystals of 17g suitable for the X-ray

diﬀraction analysis were obtained by crystallisation from

n-pentane. The molecular structure of 17g is shown in

˚

Fig. 1. Molecular structure of 17g with 30% probability thermal ellipsoids. Selected distances (A), bond angles and torsion angles (ꢀ): Si(1)–

C(1) = 1.878(3), Si(1)–C(4) = 1.868(4), C(2)–C(3) = 1.332(5), Si(1)–C(7) = 1.881(3), Si(1)–C(16) = 1.895(3); C(1)–Si(1)–C(4) = 92.7(2), Si(1)–C(1)–

C(2) = 103.8 (2), C(1)–C(2)–C(3) = 16.8(4); C(16)–Si(1)–C(7)–C(8) = 85.1(3), C(7)–Si(1)–C(16)–C(17) = 1.6(3), Si(1)–C(1)–C(2)–C(3) = 16.5(4), Si(1)–

C(4)–C(3)–C(2) = ꢀ15.5(4).

1428

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

Fig. 1. Crystallographic data and essential parameters of

the structure reﬁnement are summarised in Section 3.7.

With exception of the C(1)–Si(1)–C(4) angle the

distances and bond angles in the silacyclopentene ring cor-

respond approximately to those of known silacyclopent-

enes, which were obtained by trapping reactions of

silylenes and a lithiumchlorosilylenoid with 2,3-dimethyl-

buta-1,3-diene, respectively [37,42,48]. In comparison with

the compounds described in [37,42,48] the silicon atom is

clearly outside the mean plane of the ﬁve-membered ring

as can be seen from the torsion angles Si–C–C–C ([37]: –

7.4ꢀ, 5.6ꢀ; [42]: – 1.3ꢀ, 2.2ꢀ; [48]: – 2.3ꢀ, 2.3ꢀ; 17g: – 15.5ꢀ,

products. The dichlorosilanes R(Ph)SiCl₂(R = H [51], Et

[52,53], ⁱPr [54], ^tBu [55], Tip [56]), Mes₂SiCl₂[57] and Mes-

PhSiCl₂(analogously to Mes₂SiCl₂[57] by reaction of

PhSiCl₃with MesLi) were prepared according to published

procedures.

Dichloro(2,4,6-trimethylphenyl)phenylsilane:

Yield:

74%. B.p.: 139–140 ꢀC/0.1 Torr. MS (EI, 70 eV): m/z

(%) = 294 (29) [M]⁺, 216 (100) [MꢀC₆H₆]⁺, 118 (66)

1

[C₉H₁₀]⁺, 77 (13) [C₆H₅]⁺, 180 (26). H NMR: d = 2.03

(s, p-Me, 3H), 2.37 (s, o-Me, 6H), 6.63 (s, HC_ar, 2H),

7.08–7.73 (m, Ph, 5H) ppm. ¹³C NMR: d = 21.1 (p-Me),

25.3 (o-Me); 125.5–145.3 (C_ar) ppm. ²⁹Si NMR:

d = 4.3 ppm. Anal. Calc. for C₁₅H₁₆Cl₂Si (295.287): C,

61.01; H, 5.46. Found: C, 60.76; H, 5.44%.

The lithium wire was purchased from Fluka (unknown

sodium content) as well as from Aldrich (about 0.01%

Na) and converted into very thin plates for the reactions.

The lithium from Aldrich was only used in the reactions

described in Sections 3.2.8–3.2.10 and 3.4–3.6.

˚

16.6ꢀ). In fact the silicon atom in 17g is located 0.5 A above

the mean plane formed by the four carbon ring atoms. The

˚

four Si–C distances (1.868(4)–1.895(3) A) in 17g diﬀer only

slightly from each other. They are within the expected

˚

range of 1.86–1.91 A for Si–C distances in organosilicon

compounds with low steric strain [49,50]. From the torsion

angles C(16)–Si(1)–C(7)–C(8) and C(7)–Si(1)–C(16)–C(17)

it can be concluded that the ring planes of both aromatic

substituents are nearly perpendicular to each other.

The course of reaction of the siloxychlorosilanes 1a–i

with lithium metal was monitored by GC. The compounds

8a, 9a, 6c–9c, 6d–9d, 10d, 6e, 7e, 10e, 11e, 13e, 7f, 9f, 11f,

6g–9g, 6h, 10h, 11h, 6i, 7i could be isolated by fractional

distillation or by recrystallisation, the compounds 10a,

10c, 11c, 11d, 10g, 11g by preparative GC and 17g, 17i

by preparative LPLC. These compounds were identiﬁed

and characterised by their elemental analyses (except them

isolated by preparative GC) as well as mass, NMR and

partially IR spectra. The identiﬁcation of compounds in

mixtures was carried out by GC, GC–MS and spectro-

scopic investigations as well as in the case of the siloxanes

5a–c, 5f, 5h, 5i and of the disilanes 16f, 16g, 16i additionally

by comparison with the data of authentic samples. Well-

known compounds are 5a [58,59], 10a [60]; 5c, 10c [61];

5f [62,63], 7f, 9f, 11f [32]; 10g [44] and 17i [64,65].

The yields given in Schemes 1 and 2, in Tables 1 and 2 as

well as in Eqs. (6) and (7) are based on GC investigations of

all fractions (pure and/or mixed fractions), which were

obtained by work-up of the quenched reaction mixtures.

The yields of the compounds isolated by distillation or

recrystallisation are given in the respective procedures

together with the analytical data. They are clearly lower

than those determined by GC because of the work-up of

complex mixtures with very similar compounds.

3. Experimental

Mass spectra: Mass spectrometer Intectra AMD 402-3.

GC–MS: Coupling gas chromatograph Hewlett–Packard

HP-5890-II – Mass spectrometer HP 59827 A. Gas chro-

matography: Hewlett–Packard HP-5890-II, capillary col-

umn HP1 (FS, non-polar) 25 m; Chrompack CP 9002,

capillary column WCOT (FS, non-polar) 24 m. Preparative

GC: Gerstel HP-5890-II, capillary column HP5 and HP

FFAP 30 m. Preparative LPLC: The separation of com-

pounds was carried out under normal pressure with silica

gel 60 (63–200 lm) and n-heptane as mobile solvent (col-

umn: 30 · 3 cm). The separation process was monitored

by TLC (precoated TLC foil: silica gel 60, layer 0.2 mm).

The compounds on the TLC foil were coloured with iodine.

NMR spectra: Bruker ARX 400 (¹H/¹³C/²⁹Si NMR: 400.1/

100.6/79.5 MHz), Bruker ARX 250 (¹H NMR:

250.1 MHz) or Bruker ARX 300 (¹³C/²⁹Si NMR: 75.5/

59.6 MHz); solutions of 30–50% in C₆D₆, reference C₆D₆,

chemical shifts refer to d_TMS= 0.0 ppm. IR spectra: Nico-

let 205 FT-IR; liquids as ﬁlms between KBr disks, solids in

nujol between KBr disks or in KBr pellets. Elemental anal-

yses: Leco Modell 932, absolute error 0.3%.

The trimethylsiloxychlorosilanes 1a–i were synthesised

under exclusion from moisture. All other reactions were

carried out in dry, degassed solvents under an atmosphere

of argon. The solvents used were dried by standard proce-

dures and distilled under argon. Me₃SiCl and HMe₂SiCl

were treated with small amounts of CaH₂to remove traces

of dissolved HCl. 2,3-Dimethylbuta-1,3-diene and Et₃SiH

3.1. Preparation of the trimethylsiloxychlorosilanes

(Me₃SiO)RR⁰SiCl (1a, 1c–e, 1g–i)

The trimethylsiloxychlorosilanes (Me₃SiO)RPhSiCl (1a:

R = H, 1b: R = Me, 1c: R = Et, 1d: R = ⁱPr, 1e: R = ^tBu,

1f: R = Ph, 1g: R = Mes, 1h: R = Tip) and (Me₃SiO)Mes₂-

SiCl (1i) were synthesised analogously to the preparation of

(Me₃SiO)Me₂SiCl in [32,66] by reaction of the dichlorosi-

˚

were dried over molecular sieves (4 A) and distilled imme-

diately before use.

i

t

lanes R(Ph)SiCl₂(R = H, Me, Et, Pr, Bu, Ph, Mes, Tip)

and Mes₂SiCl₂with NaOSiMe₃in molar ratio 1.1:1 in

n-pentane/Et₂O (volume ratio 3:2) at ꢀ78 ꢀC in yields of

50–85%.

The starting compounds Me₂SiCl₂, MePhSiCl₂,

i

Ph₂SiCl₂, HSiCl₃, PhSiCl₃, SiCl₄, PhBr, PrCl, MesBr, tri-

iso-propylbenzene, ^tBuLi and ⁿBuLi were commercial

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

1429

1-Chloro-3,3,3-trimethyl-1-phenyl-disiloxane (1a): B.p.:

97–98 ꢀC/15 Torr. ¹H NMR: d = 0.16 (s, Me₃SiO, 9H),

5.75 (s, HSi, 1H), 7.13–7.67 (m, Ph, 5H) ppm. ¹³C NMR:

d = 1.5 (Me₃SiO); 128.4, 131.4, 133.4, 134.4 (Ph) ppm.

²⁹Si NMR: d = ꢀ27.2 (SiCl), 15.0 (SiMe₃) ppm;

[MꢀC₁₅H₂₃]⁺, 193 (23) [Me₃SiOSiPh]⁺, 135 (10)

1

[SiMe₂Ph]⁺, 73 (10) [SiMe₃]⁺, 43 (23) [C₃H₇]⁺. H NMR:

d = 0.09 (s, Me₃SiO, 9H), 1.18, 1.34 (2 · d, H₃C, 12H),

1.45 ((d), H₃C, 6H), 2.78 (sept, HC(Me)₂, 1H), 3.83 (sept,

HC(Me)₂, 2H), 7.10 (s, HC_ar, 2H), 7.04–7.71 (m, Ph, 5H)

ppm. ¹³C NMR: d = 24.1 (p-(CH₃)₂CH); 24.5, 25.6 (o-

(CH₃)₂CH), 32.5 (o-CH(CH₃)₂), 34.8 (p-CH(CH₃)₂);

122.1, 125.5, 128.2, 130.3, 133.3, 138.9, 153.1, 157.2 (C_ar)

ppm. ²⁹Si NMR: d = ꢀ20.6 (SiCl), 13.2 (SiMe₃) ppm.

29

1

~

J( Si– H) = 269.7 Hz. IR(ﬁlm): mðSiOSiÞ 1078, d(CH₃Si)

1253, ~mðSiHÞ 2186 cm^ꢀ1. Anal. Calc. for C₉H₁₅OClSi₂

(230.841): C, 46.83; H, 6.55. Found: C, 46.63; H, 6.38%.

1-Chloro-1-ethyl-3,3,3-trimethyl-1-phenyl-disiloxane (1c):

B.p.: 71–72 ꢀC/2.8 Torr. MS (EI, 70 eV): m/z (%) = 258 (1)

[M]⁺, 243 (100) [MꢀMe]⁺, 229 (70) [MꢀEt]⁺, 214 (63)

[MꢀMeꢀEt]⁺, 193 (51) [MꢀClꢀC₂H₆]⁺. ¹H NMR:

d = 0.13 (s, Me₃SiO, 9H), 0.93 (t, H₃C, 3H), 0.99 (q,

H₂C, 2H), 7.14–7.66 (m, Ph, 5H) ppm. ¹³C NMR:

d = 1.8 (Me₃SiO), 6.5 (CH₂), 11.2 (CH₂CH₃); 128.3,

130.8, 133.7, 135.2 (Ph) ppm. ²⁹Si NMR: d = ꢀ8.3 (SiCl),

IR(ﬁlm): mðSiOSiÞ 1080, d(CH₃Si) 1252 cm^ꢀ1. Anal. Calc.

~

for C₂₄H₃₇ClOSi₂(433.187): C, 66.55; H, 8.61. Found: C,

66.31; H, 8.74%.

1-Chloro-3,3,3-trimethyl-1,1-bis(2,4,6-trimethylphenyl)

disiloxane (1i): B.p.: 178–180 ꢀC/0.01 Torr. MS (EI, 70 eV):

m/z (%) = 390 (4) [M]⁺, 375 (16) [MꢀMe]⁺, 355 (2)

[MꢀCl]⁺, 324 (13), 309 (29), 270 (26) [MꢀC₉H₁₂]⁺, 255

(100) [MꢀC₉H₁₂ꢀMe]⁺, 120 (51) [C₉H₁₂]⁺. ¹H NMR:

d = 0.12 (s, Me₃SiO, 9H), 2.08 (s, p-Me, 6H), 2.47 (s, o-

Me, 12H), 6.68 (s, HC_ar, 4H) ppm. ¹³C NMR: d = 1.6

(Me₃SiO), 21.1 (p-Me), 24.1 (o-Me); 130.1, 132.2, 139.9,

143.4 (C_ar) ppm. ²⁹Si NMR: d = ꢀ21.2 (SiCl), 12.6 (SiMe₃)

~

12.8 (SiMe₃) ppm. IR(ﬁlm): mðSiOSiÞ 1075, d(CH₃Si)

1253 cm^ꢀ1. Anal. Calc. for C₁₁H₁₉OClSi₂(258.898): C,

51.03; H, 7.40. Found: C, 51.30; H, 7.59%.

1-Chloro-3,3,3-trimethyl-1-phenyl-iso-propyl-disiloxane

(1d): B.p.: 107–109 ꢀC/5.0 Torr. MS (EI, 70 eV): m/z

i

(%) = 272 (1) [M]⁺, 229 (100) [Mꢀ Pr]⁺, 193 (51)

ppm. IR(ﬁlm): mðSiOSiÞ 1078, d(CH₃Si) 1251 cm^ꢀ1. Anal.

~

[MꢀClꢀC₃H₈]⁺. ¹H NMR: d = 0.13 (s, Me₃SiO, 9H),

1.01 (d, Me₂C, 6H), 1.27 (sept, HC, 1H), 7.12–7.65 (m,

Ph, 5H) ppm. ¹³C NMR: d = 1.8 (Me₃SiO), 16.5 (CMe₂),

17.4 (CMe₂); 128.2, 128.5, 131.0, 134.1 (Ph) ppm. ²⁹Si

NMR: d = ꢀ8.1 (SiCl), 12.8 (SiMe₃) ppm. IR(ﬁlm):

Calc. for C₂₁H₃₁ClOSi₂(391.106): C, 64.49; H, 7.99.

Found: C, 64.58; H, 8.06%.

3.2. Reaction of the trimethylsiloxychlorosilanes 1a, 1c–i

with lithium metal in THF at ꢀ78 ꢀC or in a Trapp mixture

at ꢀ110 ꢀC as well as trapping of the formed lithiumsilanides

with chlorotrimethyl- and chlorodimethylsilane

mðSiOSiÞ 1082, d(CH₃Si) 1253 cm^ꢀ1. Anal. Calc. for

~

C₁₂H₂₁OClSi₂(272.921): C, 52.81; H, 7.76. Found: C,

53.08; H, 7.71%.

1-tert-Butyl-1-chloro-3,3,3-trimethyl-1-phenyl-disiloxane

(1e): B.p.: 103–104 ꢀC/3.7 Torr. MS (EI, 70 eV): m/z

(%) = 286 (4) [M]⁺, 271 (6) [MꢀMe]⁺, 229 (100)

On the analogies of the preparative work a general pro-

cedure is given for the reactions of the trimethylsiloxychlo-

rosilanes 1a, 1c–i with lithium metal and for the following

trapping reactions with Me₃SiCl and HMe₂SiCl. The work-

up of the crude products is described separately. Some

details of reactions are given in Schemes 1 and 2, addition-

ally, the proportions of products in the reaction mixtures,

which were determined by GC, are summarised in Tables

1 and 2.

t

1

[Mꢀ Bu]⁺, 193 (52) [MꢀClꢀC₄H₁₀]⁺, 135 (6). H NMR:

d = 0.13 (s, Me₃SiO, 9H), 0.97 (s, Me₃C, 9H), 7.20–7.63

(m, Ph, 5H) ppm. ¹³C NMR: d = 1.9 (Me₃SiO), 21.1

(CMe₃), 25.5 (CMe₃); 128.1, 130.7, 133.6, 134.8 (Ph)

ppm. ²⁹Si NMR: d = ꢀ7.8 (SiCl), 12.8 (SiMe₃) ppm.

IR(ﬁlm): ~mðSiOSiÞ 1079, d(CH₃Si) 1253 cm^ꢀ1. Anal. Calc.

for C₁₃H₂₃OClSi₂(286.953): C, 54.41; H, 8.08. Found: C,

54.32; H, 7.96%.

3.2.1. General procedure

1-Chloro-3,3,3-trimethyl-1-(2,4,6-trimethylphenyl)-1-

phenyl-disiloxane (1g): B.p.: 133–134 ꢀC/0.1 Torr. MS (EI,

70 eV): m/z (%) = 348 (17) [M]⁺, 333 (32) [MꢀMe]⁺, 297

(15) [MꢀClꢀMeꢀH]⁺, 270 (39) [MꢀC₆H₆]⁺, 255 (100)

[MꢀC₆H₆ꢀMe]⁺. ¹H NMR: d = 0.13 (s, Me₃SiO, 9H),

2.11 (s, p-Me, 3H), 2.47 (s, o-Me, 6H), 6.74 (s, HC_ar,

2H), 7.10–7.76 (m, Ph, 5H) ppm. ¹³C NMR: d = 1.8

(Me₃SiO), 21.1 (p-Me), 24.7 (o-Me); 127.0, 128.4, 130.0,

130.6, 133.5, 138.1, 140.8, 145.4 (C_ar) ppm. ²⁹Si NMR:

A mixture of 0.14 mol very thin lithium plates and

70 ml THF or 70 ml Trapp mixture (THF/Et₂O/n-pen-

tane in volume ratio 4:1:1) was cooled down to ꢀ78 ꢀC

(reactions in THF) and to ꢀ110 ꢀC (reactions in a Trapp

mixture), respectively. To the respective mixture

0.035 mol trimethylsiloxychlorosilane 1a, 1c–i, dissolved

in 30 ml THF or Trapp mixture, was added dropwise

within 15 min with vigorous stirring. The vigorous stir-

ring was continued at ꢀ78 ꢀC or at ꢀ110 ꢀC until the sil-

oxychlorosilane 1 was consumed completely and the

composition of the reaction mixture was nearly constant.

The reaction progress was monitored by GC of samples

quenched with Me₃SiCl and HMe₂SiCl, respectively.

The reaction times t_rctare given in Sections 3.2.2–3.2.9.

The solutions turned brown (reactions of 1a, 1c, 1d and

1i), red (reactions of 1e and 1h) and green (reactions of

~

d = ꢀ20.9 (SiCl), 13.1 (SiMe₃) ppm. IR(ﬁlm): mðSiOSiÞ

1084, d(CH₃Si) 1253 cm^ꢀ1. Anal. Calc. for C₁₈H₂₅OClSi₂

(349.024): C, 61.94; H, 7.22. Found: C, 61.81; H, 7.26%.

1-Chloro-3,3,3-trimethyl-1-phenyl-1-(2,4,6-tri-iso-propyl-

phenyl)disiloxane (1h): B.p.: 142–143 ꢀC/0.04 Torr. MS

(EI, 70 eV): m/z (%) = 432 (9) [M]⁺, 417 (17) [MꢀMe]⁺,

354 (100) [MꢀC₆H₆]⁺, 311 (34), 297 (19), 229 (10)

1430

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

1f and 1g). After the reaction times t_rctas given below the

excess lithium was removed. Then 0.07 mol trapping

agent Me₃SiCl or HMe₂SiCl was added to the solution

of lithiumsilanides stirred at the respective reaction tem-

perature. The reaction mixture was warmed to room tem-

perature (20 ꢀC) within 30 min and was allowed to react

for 24 h at the same temperature. Subsequently, the sol-

vent and excess trapping agent were removed under

reduced pressure at room temperature and 50 ml n-pen-

tane were added to the residue. The resulting suspension

was ﬁltered, and the solvent of the ﬁltrate was evaporated

under reduced pressure. The respective residue was dis-

tilled in vacuo below 0.5 Torr, and that of the reaction

of 1i with lithium (trapping agent Me₃SiCl) was

recrystallised.

In dependence on the trapping agent used the evapo-

rated solvents contained (Me₃Si)₂O or HMe₂SiOSiMe₃as

well as from the reactions of 1e and 1g–i Me₃Si–SiMe₃or

Me₃Si–SiMe₂H.

In the case of the reactions of the siloxychlorosilanes 1e

and 1g with lithium metal in a Trapp mixture at ꢀ110 ꢀC

the siloxydisilanes (Me₃SiO)RR⁰Si–SiRR⁰(OSiMe₃) (14e:

R = ^tBu, R⁰= Ph; 14g: R = Mes, R⁰= Ph) could be

proved and isolated as intermediates (Section 3.2.10). For

this purpose the excess lithium was removed and the

respective reaction mixtures were quenched with 0.07 mol

Me₃SiCl clearly before the siloxychlorosilanes 1e and 1g

were consumed completely.

of 9a and small amounts of 5a as well as 11a. In the

distillation residue higher-molecular products with

Si–Si groups were found.

(4) Trapp mixture, ꢀ110 ꢀC, t_rct= 1 h, trapping agent

HMe₂SiCl.

Distillation of the residue through a Fischer slit pipe

column in the temperature range of 45–125 ꢀC/

0.2 Torr yielded four fractions, which consisted of

5a and minor 11a (45–50 ꢀC), minor 5a and 11a

(50–60 ꢀC), 5a, 11a and 9a (60–122 ꢀC) as well as of

pure 9a (122–123 ꢀC). The distillation residue con-

tained higher-molecular products with Si–Si groups

and minor 9a.

1,1,1,5,5,5-Hexamethyl-3-phenyl-trisiloxane (5a) [58,59]:

C₁₂H₂₄O₂Si₃(284.58). MS (EI, 70 eV): m/z (%) = 284 (12)

[M]⁺, 269 (100) [MꢀMe]⁺, 206 (15) [MꢀC₆H₆]⁺, 191 (19)

1

[MꢀC₆H₆ꢀMe]⁺, 135 (62), 73 (15) [SiMe₃]⁺. H NMR:

d = 0.21 (s, Me₃SiO, 18H), 5.31 (s, HSi, 1H), 7.18–7.73

(m, Ph, 5H) ppm. ¹³C NMR: d = 1.8 (Me₃SiO); 128.4,

130.1, 134.1, 136.0 (Ph) ppm. ²⁹Si NMR: d = ꢀ 48.7

(SiHPh), 10.5 (OSiMe₃) ppm; J(²⁹Si–¹H) = 245.2 Hz.

ꢀ1

~

IR(ﬁlm): mðSiOSiÞ 1063, d(CH₃Si) 1250, mðSiHÞ 2152 cm

.

3,3,3-Trimethyl-1-trimethylsiloxy-1,2-diphenyl-trisilane

(8a): Yield: 1.3 g (20%). B.p.: 130–131 ꢀC/0.1 Torr. GC:

Diastereomeric ratio 1.2:1. MS (EI, 70 eV): m/z

(%) = 374 (5) [M]⁺, 359 (14) [MꢀMe]⁺, 300 (32)

[MꢀSiMe₃ꢀH]⁺, 271 (100) [MꢀSiMe₄ꢀMe]⁺, 255 (41)

[MꢀOSiMe₃ꢀ2Me]⁺, 193 (52), 178 (45) [Me₃SiSiPh]⁺,

1

135 (52), 73 (40) [SiMe₃]⁺. H NMR: d = 0.07, 0.10 (s,

3.2.2. Trapping products of the lithiumsilanides from the

reaction of (Me₃SiO)HPhSiCl (1a) with lithium and the

trisiloxane 5a

Me₃Si, 9H); 0.15, 0.18 (s, Me₃SiO, 9H); 4.29, 4.30 (s, HSi-

SiMe₃, 1H, J(²⁹Si–¹H) = 171.0 Hz); 5.98, 5.99 (s, HSiO-

SiMe₃, 1H, J(²⁹Si–¹H) = 204.1 Hz); 7.10–7.68 (m, Ph,

10H) ppm. ¹³C NMR: d = ꢀ0.4, ꢀ0.3 (Me₃Si); 1.7, 1.8

(Me₃SiO); 128.3–138.0 (Ph) ppm. ²⁹Si NMR: d = ꢀ 65.6,

ꢀ65.3 (SiHPh); ꢀ15.6, ꢀ15.5 (OSiHPh); ꢀ15.0, ꢀ14.8

(1) THF, ꢀ78 ꢀC, t_rct= 0.5 h, trapping agent Me₃SiCl.

Distillation of the residue through a small Vigreux

column (49–136 ꢀC/0.1 Torr) yielded a fraction (49–

56 ꢀC) of 5a and 10a as well as two fractions in the

temperature range of 56–136 ꢀC, which consisted of

mixtures of 8a, 10a and small amounts of 5a. In the

distillation residue higher-molecular products with

Si–Si groups were found. From the ﬁrst fraction

~

(SiMe₃); 12.3, 12.5 (OSiMe₃) ppm. IR(ﬁlm): mðSiOSiÞ

1059, d(CH₃Si) 1253, 1260; mðSiHÞ 2087 cm^ꢀ1. Anal. Calc.

~

for C₁₈H₃₀OSi₄(374.783): C, 57.69; H, 8.07. Found: C,

57.45; H, 7.92%.

3,3-Dimethyl-1-trimethylsiloxy-1,2-diphenyl-trisilane

(9a): Yield: 1.0 g (16%). B.p.: 122–123 ꢀC/0.2 Torr. GC:

Diastereomeric ratio 1.2:1. MS (EI, 70 eV): m/z (%) = 360

(5) [M]⁺, 345 (11) [MꢀMe]⁺, 300 (15) [MꢀSiMe₂HꢀH]⁺,

271 (98) [MꢀSiMe₄ꢀH]⁺, 193 (80) [MꢀSiMe₄ꢀHꢀC₆H₆]⁺,

164 (78) [HMe₂SiSiPh]⁺, 135 (100), 73 (52) [SiMe₃]⁺, 59 (22)

[SiMe₂H]⁺. ¹H NMR: d = 0.09, 0.11 (s, Me₃SiO, 9H); 0.16,

0.17, 0.18, 0.19 (2 · d, Me₂HSi, 6H); 4.28, 4.29 (s, HSiSi-

Me₂H, 1H, J(²⁹Si–¹H) = 171.8 Hz); 4.40, 4.41 (sept,

HMe₂Si, 1H, J(²⁹Si–¹H) = 175.7 Hz); 6.03, 6.04 (s, HSiO-

SiMe₃, 1H, J(²⁹Si–¹H) = 204.3 Hz); 7.08–7.79 (m, Ph,

10H) ppm. ¹³C NMR: d = ꢀ5.3, ꢀ5.2, ꢀ5.1, ꢀ 5.0

(Me₂HSi); 1.6, 1.8 (Me₃SiO); 128.1–138.5 (Ph) ppm. ²⁹Si

NMR: d = ꢀ66.3, ꢀ66.0 (SiHPh); ꢀ37.7, ꢀ37.6 (SiMe₂H);

ꢀ 16.6, ꢀ16.4 (OSiHPh); 12.6, 12.7 (OSiMe₃) ppm. Anal.

Calc. for C₁₇H₂₈OSi₄(360.756): C, 56.60; H, 7.76. Found:

C, 56.39; H, 7.69%.

10a was isolated by preparative GC.

(2) Trapp mixture, ꢀ110 ꢀC, t_rct= 1 h, trapping agent

Me₃SiCl.

Distillation of the residue through a slit pipe column

(Fischer, Mikro-Spaltrohr-System D100) in the tem-

perature range of 50–135 ꢀC/0.1 Torr yielded three

fractions, which consisted of 5a and 10a (50–55 ꢀC),

5a, 10a and 8a (55–130 ꢀC) as well as of pure 8a

(130–131 ꢀC). The resulting residue contained

higher-molecular products with Si–Si groups and

minor 8a.

(3) THF, ꢀ78 ꢀC, t_rct= 0.5 h, trapping agent HMe₂SiCl.

Distillation of the residue through a small Vigreux

column (42–130 ꢀC/0.2 Torr) yielded a fraction (42–

60 ꢀC) of 5a and minor 11a as well as two fractions

(60–105 ꢀC, 105–130 ꢀC), which consisted of mixtures

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

1431

1,1,1,3,3,3-Hexamethyl-2-phenyl-trisilane (10a) [60]:

C₁₂H₂₄Si₃(252.58). MS (EI, 70 eV): m/z (%) = 252 (13)

[M]⁺, 237 (8) [MꢀMe]⁺, 178 (68) [MꢀSiMe₃ꢀH]⁺, 163

(100) [MꢀSiMe₄ꢀH]⁺, 135 (46), 73 (63) [SiMe₃]⁺. ¹H

NMR: d = 0.16 (s, Me₃Si, 18H), 4.08 (s, HSi, 1H), 7.11–

7.56 (m, Ph, 5H) ppm. ¹³C NMR: d = ꢀ0.1 (Me₃Si); 128.3,

130.5, 133.4, 136.1 (Ph) ppm. ²⁹Si NMR: d = ꢀ61.1 (SiHPh),

ꢀ15.4 (SiMe₃) ppm; J(²⁹Si–¹H) = 165.2 Hz. IR(ﬁlm):

3-Ethyl-1,1,1,5,5,5-hexamethyl-3-phenyl-trisiloxane (5c)

[61]: C₁₄H₂₈O₂Si₃(312.64). MS (EI, 70 eV): m/z

(%) = 312 (1) [M]⁺, 297 (25) [MꢀMe]⁺, 283 (100)

1

[MꢀEt]⁺, 135 (47). H NMR: d = 0.16 (s, Me₃SiO, 18H),

0.78 (q, H₂C, 2H), 1.04 (t, H₃C, 3H), 7.12–7.70 (m, Ph,

5H) ppm. ¹³C NMR: d = 2.0 (Me₃SiO), 6.9 (CH₂), 8.5

(CH₂CH₃); 128.1, 129.9, 133.8, 137.6 (Ph) ppm. ²⁹Si

NMR: d = ꢀ33.9 (SiEtPh), 8.0 (OSiMe₃) ppm.

ꢀ1

~

d(CH₃Si) 1253, mðSiHÞ 2068 cm

.

1-Ethyl-2,2,2-trimethyl-1-trimethylsiloxy-1-phenyl-disi-

lane (6c): Yield: 0.7 g (7%). B.p.: 97–98 ꢀC/0.1 Torr. MS

(EI, 70 eV): m/z (%) = 296 (5) [M]⁺, 281 (4) [MꢀMe]⁺,

267 (12) [MꢀEt]⁺, 223 (82) [MꢀSiMe₃]⁺, 195 (100)

[MꢀSiMe₃ꢀC₂H₄]⁺, 135 (29), 73 (23) [SiMe₃]⁺. ¹H

NMR: d = 0.15 (s, Me₃Si, 9H), 0.17 (s, Me₃SiO, 9H),

0.92 (q, H₂C, 2H), 1.07 (t, H₃C, 3H), 7.14–7.60 (m, Ph,

5H) ppm. ¹³C NMR: d = ꢀ1.7 (Me₃Si), 2.3 (Me₃SiO), 7.3

(CH₂), 9.8 (CH₂CH₃); 128.2, 129.2, 133.4, 139.8 (Ph)

ppm. ²⁹Si NMR: d = ꢀ23.0 (SiMe₃), ꢀ3.0 (SiEtPh), 7.9

1,1,1,3,3-Pentamethyl-2-phenyl-trisilane (11a): C₁₁H₂₂Si₃

(238.56). MS (EI, 70 eV): m/z (%) = 238 (4) [M]⁺, 223 (3)

[MꢀMe]⁺, 178 (11) [MꢀSiMe₂HꢀH]⁺, 164 (43)

[MꢀSiMe₃ꢀH]⁺, 135 (100), 73 (14) [SiMe₃]⁺, 59 (20)

1

[SiMe₂H]⁺. H NMR: d = 0.17 (s, Me₃Si, 9H); 0.20, 0.21

(2 · d,

Me₂HSi,

6H);

4.18

(s,

HSi,

1H,

J(²⁹Si–¹H) = 167.4 Hz), 4.23 (sept, HMe₂Si, 1H,

J(²⁹Si–¹H) = 176.2 Hz), 7.10–7.54 (m, Ph, 5H) ppm. ¹³C

NMR: d = ꢀ4.9, ꢀ4.8 (Me₂HSi); 0.5 (Me₃Si); 128.1–

136.0 (Ph) ppm. ²⁹Si NMR: d = ꢀ63.3 (SiHPh), ꢀ37.9

(SiMe₂H), ꢀ17.1 (SiMe₃) ppm.

~

(OSiMe₃) ppm. IR(ﬁlm): mðSiOSiÞ 1068, d(CH₃Si) 1253,

1261 cm^ꢀ1. Anal. Calc. for C₁₄H₂₈OSi₃(296.637): C,

56.69; H, 9.51. Found: C, 56.49; H, 9.42%.

1-Ethyl-2,2-dimethyl-1-trimethylsiloxy-1-phenyl-disi-

lane (7c): Yield: 0.8 g (8%). B.p.: 66–67 ꢀC/0.1 Torr. MS

(EI, 70 eV): m/z (%) = 282 (12) [M]⁺, 267 (7) [MꢀMe]⁺,

253 (8) [MꢀEt]⁺, 223 (87) [MꢀSiMe₂H]⁺, 195 (100)

[MꢀSiMe₂HꢀC₂H₄]⁺, 135 (27), 73 (17) [SiMe₃]⁺, 59 (9)

[SiMe₂H]⁺. ¹H NMR: d = 0.13 (s, Me₃SiO, 9H); 0.14,

0.15 (2 · d, Me₂HSi, 6H); 0.90 (q, H₂C, 2H), 1.03 (t,

H₃C, 3H), 4.01 (sept, HSi, 1H), 7.13–7.56 (m, Ph, 5H)

ppm. ¹³C NMR: d = ꢀ6.2, ꢀ6.1 (Me₂HSi); 2.3 (Me₃SiO),

7.3 (CH₂), 10.2 (CH₂CH₃); 128.2, 129.4, 133.5, 139.3 (Ph)

ppm. ²⁹Si NMR: d = ꢀ44.4 (SiMe₂H), ꢀ2.7 (SiEtPh), 8.7

3.2.3. Trapping products of the lithiumsilanides from the

reaction of (Me₃SiO)EtPhSiCl (1c) with lithium and the

trisiloxane 5c

(1) THF, ꢀ78 ꢀC, t_rct= 2 h, trapping agent Me₃SiCl.

Distillation of the residue through a Fischer slit pipe

column (60–140 ꢀC/0.1 Torr) yielded four fractions,

which contained 5c, 6c and minor 10c (60–95 ꢀC),

6c and 10c (95–120 ꢀC), 10c and 8c (120–135 ꢀC) as

well as pure 8c (136–137 ꢀC). In the distillation resi-

due minor 8c was found beside unknown products.

From the second fraction 10c was isolated by pre-

parative GC.

29

1

~

(OSiMe₃) ppm; J( Si– H) = 174.2 Hz. IR(ﬁlm): mðSiOSiÞ

1066, d(CH₃Si) 1244, 1253; mðSiHÞ 2090 cm^ꢀ1. Anal. Calc.

~

for C₁₃H₂₆OSi₃(282.610): C, 55.25; H, 9.27. Found: C,

55.13; H, 9.18%.

(2) Trapp mixture, ꢀ110 ꢀC, t_rct= 3 h, trapping agent

Me₃SiCl.

1,2-Diethyl-3,3,3-trimethyl-1-trimethylsiloxy-1,2-diphe-

nyl-trisilane (8c): Yield: 3.1 g (41%). B.p.: 136–137 ꢀC/

0.1 Torr. GC: Diastereomeric ratio 1.3:1. MS (EI, 70 eV):

m/z (%) = 430 (12) [M]⁺, 415 (6) [MꢀMe]⁺, 401 (4)

[MꢀEt]⁺, 357 (11) [MꢀSiMe₃]⁺, 223 (100) [Me₃SiO-

SiEtPh]⁺, 194 (88) [Me₃SiOSiPh]⁺, 135 (29), 73 (13)

Distillation of the residue through a Fischer slit pipe

column in the temperature range of 60–120 ꢀC/

0.1 Torr yielded three fractions, which contained 5c,

6c and small amounts of 10c (60–96 ꢀC), pure 6c

(97–98 ꢀC) as well as 6c and minor 10c (99–120 ꢀC).

(3) THF, ꢀ78 ꢀC, t_rct= 2 h, trapping agent HMe₂SiCl.

Distillation of the residue through a Fischer slit pipe

column (50–125 ꢀC/0.1 Torr) yielded four fractions.

The ﬁrst two fractions (50–58 ꢀC, 59–70 ꢀC) contained

mixtures of 5c, 7c and minor 11c. The third fraction

(70–123 ꢀC) consisted of 7c, 11c and minor 9c. In the

last fraction (124–125 ꢀC) pure 9c was found. From

the third fraction 11c was isolated by preparative GC.

(4) Trapp mixture, ꢀ110 ꢀC, t_rct= 3 h, trapping agent

HMe₂SiCl.

1

[SiMe₃]⁺. H NMR: d = 0.10, 0.11 (s, Me₃Si, 9H); 0.13,

0.14 (s, Me₃SiO, 9H); 0.90–1.05 (m, H₂C, 4H); 1.08–1.20

(m, H₃C, 6H); 7.11–7.53 (m, Ph, 10H) ppm. ¹³C NMR:

d = ꢀ0.1, 0.0 (Me₃Si); 2.4, 2.4 (Me₃SiO); 7.3–7.6 (CH₂);

10.5–11.0 (CH₂CH₃); 128.1–140.1 (Ph) ppm. ²⁹Si NMR:

d = ꢀ43.2, ꢀ43.1 (SiEtPh); ꢀ16.7, ꢀ 16.6 (SiMe₃); ꢀ1.4,

ꢀ1.3 (OSiEtPh); 8.4, 8.5 (OSiMe₃) ppm. IR(ﬁlm):

mðSiOSiÞ 1059, d(CH₃Si) 1253, 1260 cm^ꢀ1. Anal. Calc. for

~

C₂₂H₃₈OSi₄(430.892): C, 61.33; H, 8.89. Found: C,

61.07; H, 8.86%.

Distillation of the residue through a Fischer slit pipe

column in the temperature range of 50–123 ꢀC/

0.1 Torr yielded three fractions, which consisted of

5c, 7c and minor 11c(50–65 ꢀC), pure 7c (66–67 ꢀC)

as well as of 7c, 11c and minor 9c (68–123 ꢀC).

1,2-Diethyl-3,3-dimethyl-1-trimethylsiloxy-1,2-diphenyl-

trisilane (9c): Yield: 3.5 g (48%). B.p.: 124–125 ꢀC/0.1 Torr.

GC: Diastereomeric ratio 1.3:1. MS (EI, 70 eV): m/z

(%) = 416 (9) [M]⁺, 401 (6) [MꢀMe]⁺, 357 (4)

[MꢀSiMe₂H]⁺, 329 (4) [MꢀSiMe₂HꢀC₂H₄]⁺, 223 (87)

1432

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

[Me₃SiOSiEtPh]⁺, 195 (98), 192 (100) [SiEtPhSiMe₂]⁺, 135

(32), 73 (11) [SiMe₃]⁺, 59 (8) [SiMe₂H]⁺. ¹H NMR:

d = 0.13, 0.14 (s, Me₃SiO, 9H); 0.17, 0.18, 0.19, 0.20

(2 · d, Me₂HSi, 6H); 1.01–1.07 (m, H₂C, 4H); 1.10–1.14

(m, H₃C, 6H); 4.22, 4.23 (sept, HSi, 1H), 7.12–7.56 (m,

Ph, 10H) ppm. ¹³C NMR: d = ꢀ5.13, ꢀ5.10, ꢀ5.03,

ꢀ4.97 (Me₂HSi); 2.3, 2.4 (Me₃SiO); 7.4–11.0 (CH₂CH₃);

128.2–139.7 (Ph) ppm. ²⁹Si NMR: d = ꢀ42.8, ꢀ42.7 (Si-

EtPh); ꢀ38.4, ꢀ38.3 (SiMe₂H); ꢀ1.92, ꢀ1.86 (OSiEtPh);

(3) THF, ꢀ78 ꢀC, t_rct= 2 h, trapping agent HMe₂SiCl.

Distillation of the residue through a Fischer slit pipe

column (60–147 ꢀC/0.4 Torr) yielded four fractions,

which contained 5d and 7d (60–70 ꢀC), 7d and 11d

(70–85 ꢀC), 11d beside minor 7d, 9d (85–145 ꢀC) as

well as pure 9d (146–147 ꢀC). In the distillation resi-

due small amounts of 9d were found beside unknown

products.

(4) Trapp mixture, ꢀ110 ꢀC, t_rct= 3 h, trapping agent

8.57, 8.62 (OSiMe₃) ppm; J(²⁹Si–¹H) = 176.3 Hz. IR(ﬁlm):

HMe₂SiCl.

ꢀ1

Distillation of the residue through a Fischer slit pipe

column (60–147 ꢀC/0.4 Torr) yielded ﬁve fractions,

which consisted of 5d and 7d (60–71 ꢀC), pure 7d

(72–73 ꢀC), 7d and 13d (73–85 ꢀC), 11d beside minor

7d, 9d (85–145 ꢀC) as well as pure 9d (146–147 ꢀC).

From the third fraction 13d was isolated by prepara-

tive GC.

~

mðSiOSiÞ 1065, d(CH₃Si) 1244, 1252; mðSiHÞ 2093 cm

.

Anal. Calc. for C₂₁H₃₆OSi₄(416.864): C, 60.51; H, 8.70.

Found: C, 60.39; H, 8.77%.

2-Ethyl-1,1,1,3,3,3-hexamethyl-2-phenyl-trisilane (10c)

[61]: C₁₄H₂₈Si₃(280.637). MS (EI, 70 eV): m/z

(%) = 280 (28) [M]⁺, 265 (6) [MꢀMe]⁺, 251 (3) [MꢀEt]⁺,

207 (50) [MꢀSiMe₃]⁺, 179 (100) [MꢀSiMe₃ꢀC₂H₄]⁺, 135

(56), 73 (40) [SiMe₃]⁺. ¹H NMR: d = 0.17 (s, Me₃Si,

18H), 0.76 (q, H₂C, 2H), 1.12 (t, H₃C, 3H), 7.09–7.50

(m, Ph, 5H) ppm. ¹³C NMR: d = ꢀ0.21 (Me₃Si), 8.5

(CH₂), 10.6 (CH₂CH₃); 128.3, 129.9, 133.8, 135.2 (Ph)

ppm. ²⁹Si NMR: d = ꢀ40.1 (SiEtPh), ꢀ16.6 (SiMe₃)

ppm.

1,1,1,5,5,5-Hexamethyl-3-phenyl-3-iso-propyl-trisiloxane

(5d): B.p.: 97–98 ꢀC/1.1 Torr. MS (EI, 70 eV): m/z

(%) = 326 (1) [M]⁺, 311 (14) [MꢀMe]⁺, 283 (100)

i

1

[Mꢀ Pr]⁺, 135 (55), 73 (9) [SiMe₃]⁺. H NMR: d = 0.16

(s, Me₃SiO, 18H), 0.98 (sept, HC, 1H), 1.05 (d, Me₂C,

6H), 7.13–7.68 (m, Ph, 5H) ppm. ¹³C NMR: d = 2.1

(Me₃SiO), 15.0 (CMe₂), 17.5 (CMe₂); 127.9, 129.8, 134.2,

136.7 (Ph) ppm. ²⁹Si NMR: d = ꢀ34.9 (SiⁱPrPh), 7.7

2-Ethyl-1,1,1,3,3-pentamethyl-2-phenyl-trisilane (11c):

C₁₃H₂₆Si₃(266.61). MS (EI, 70 eV): m/z (%) = 266 (11)

[M]⁺, 251 (5) [MꢀMe]⁺, 207 (14) [MꢀSiMe₂H]⁺, 192

(100) [MꢀSiMe₃ꢀH]⁺, 179 (78) [MꢀSiMe₂HꢀC₂H₄]⁺,

135 (87), 105 (44) [SiPh]⁺, 73 (48) [SiMe₃]⁺, 59 (24)

~

(OSiMe₃) ppm. IR(ﬁlm): mðSiOSiÞ 1059, d(CH₃Si)

1251 cm^ꢀ1. Anal. Calc. for C₁₅H₃₀O₂Si₃(326.657): C,

55.15; H, 9.26. Found: C, 54.93; H, 9.16%.

1

[SiMe₂H]⁺. H NMR: d = 0.11 (s, Me₃Si, 9H); 0.14, 0.15

2,2,2-Trimethyl-1-trimethylsiloxy-1-phenyl-1-iso-propyl-

disilane (6d): Yield: 1.0 g (9%). B.p.: 62–63 ꢀC/0.03 Torr.

MS (EI, 70 eV): m/z (%) = 310 (5) [M]⁺, 295 (3) [MꢀMe]⁺,

(2 · d, Me₂HSi, 6H); 0.72 (q, H₂C, 2H), 1.01 (t, H₃C,

3H), 4.15 (sept, HSi, 1H), 7.07–7.47 (m, Ph, 5H) ppm.

¹³C NMR: d = ꢀ5.30, ꢀ5.27 (Me₂HSi); ꢀ0.5 (Me₃Si), 8.5

(CH₂), 10.5 (CH₂CH₃); 128.3, 130.0, 133.9, 135.3 (Ph)

ppm. ²⁹Si NMR: d = ꢀ39.2 (SiEtPh), ꢀ38.8 (SiMe₂H),

ꢀ16.5 (SiMe₃) ppm; J(²⁹Si–¹H) = 175.2 Hz.

i

267 (100) [Mꢀ Pr]⁺, 237 (39) [MꢀSiMe₃]⁺, 209 (70), 193

1

(81) [MꢀSiMe₃ꢀC₃H₈]⁺, 135 (77), 73 (49) [SiMe₃]⁺. H

NMR: d = 0.17 (s, Me₃Si, 9H), 0.19 (s, Me₃SiO, 9H),

1.04 (d, Me₂C, 6H), 1.21 (sept, HC, 1H), 7.14–7.58 (m,

Ph, 5H) ppm. ¹³C NMR: d = ꢀ 1.0 (Me₃Si), 2.4 (Me₃SiO),

16.9 (CMe₂), 17.8 (CMe₂); 128.1, 129.1, 133.5, 134.2 (Ph)

ppm. ²⁹Si NMR: d = ꢀ 23.0 (SiMe₃), ꢀ2.4 (SiⁱPrPh), 7.3

3.2.4. Trapping products of the lithiumsilanides from the

reaction of (Me₃SiO)ⁱPrPhSiCl (1d) with lithium and the

trisiloxane 5d

~

(OSiMe₃) ppm. IR(ﬁlm): mðSiOSiÞ 1060, d(CH₃Si) 1253,

1261 cm^ꢀ1. Anal. Calc. for C₁₅H₃₀OSi₃(310.658): C,

57.99; H, 9.73. Found: C, 58.06; H, 9.64%.

(1) THF, ꢀ78 ꢀC, t_rct= 2 h, trapping agent Me₃SiCl.

Distillation of the residue through a Fischer slit pipe

column (55–145 ꢀC/0.03 Torr) yielded ﬁve fractions,

which contained 5d and 6d (55–65 ꢀC), 5d, 6d and

10d (65–73 ꢀC), pure 10d (74–77 ꢀC), 10d and 8d

(80–140 ꢀC) as well as pure 8d (141–142 ꢀC). In the

distillation residue small amounts of 8d were found

beside unknown products.

2,2-Dimethyl-1-trimethylsiloxy-1-phenyl-1-iso-propyl-

disilane (7d): Yield: 1.3 g (13%). B.p.: 72–73 ꢀC/0.4 Torr.

MS (EI, 70 eV): m/z (%) = 296 (5) [M]⁺, 281 (3) [MꢀMe]⁺,

i

253 (44) [Mꢀ Pr]⁺, 237 (55) [MꢀSiMe₂H]⁺, 209 (59), 193

(53) [MꢀSiMe₂HꢀC₃H₈]⁺, 135 (100), 73 (73) [SiMe₃]⁺,

1

59 (29) [SiMe₂H]⁺, 43 (27) [C₃H₇]⁺. H NMR: d = 0.15

(s, Me₃SiO, 9H); 0.16, 0.18 (2 · d, Me₂SiH, 6H); 1.04 (d,

Me₂C, 6H), 1.14 (sept, HC, 1H), 4.06 (sept, HSi, 1H),

7.12–7.56 (m, Ph, 5H) ppm. ¹³C NMR: d = ꢀ5.9, ꢀ5.8

(Me₂SiH); 2.3 (Me₃SiO), 17.1 (CMe₂), 17.6 (CMe₂);

128.1, 129.4, 133.7, 138.7 (Ph) ppm. ²⁹Si NMR:

d = ꢀ45.2 (SiMe₂H), ꢀ1.9 (SiⁱPrPh), 8.2 (OSiMe₃) ppm;

(2) Trapp mixture, ꢀ110 ꢀC, t_rct= 3 h, trapping agent

Me₃SiCl.

Distillation of the residue through a Fischer slit pipe

column (55–145 ꢀC/0.03 Torr) yielded six fractions,

which consisted of 5d and 6d (55–61 ꢀC), pure 6d

(62–63 ꢀC), 5d, 6d and 10d (64–73 ꢀC), 10d (only

25%) and 8d (74–95 ꢀC), 8d and small amounts of

10d (96–140 ꢀC) as well as pure 8d (141–142 ꢀC).

29

1

~

J( Si– H) = 174.2 Hz. IR(ﬁlm): mðSiOSiÞ 1062, d(CH₃Si)

1245, 1253; mðSiHÞ 2091 cm^ꢀ1. Anal. Calc. for C₁₄H₂₈OSi₃

~

(296.637): C, 56.69; H, 9.51. Found: C, 56.72; H, 9.48%.

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

1433

3,3,3-Trimethyl-1-trimethylsiloxy-1,2-diphenyl-1,2-di-

iso-propyl-trisilane (8d): Yield: 1.8 g (22%). B.p.: 141–

142 ꢀC/0.03 Torr. GC: Diastereomeric ratio 1.4:1. MS

(EI, 70 eV): m/z (%) = 458 (7) [M]⁺, 443 (5) [MꢀMe]⁺,

ꢀ33.3 (SiⁱPrPh), ꢀ16.6 (SiMe₃) ppm; J(²⁹Si–¹H) =

174.7 Hz.

3.2.5. Trapping products of the lithiumsilanides from the

reaction of (Me₃SiO)^tBuPhSiCl (1e) with lithium and the

trisiloxane 5e as well as the siloxydisilane 6e^*

i

415 (35) [Mꢀ Pr]⁺, 373 (31) [Mꢀ PrꢀC₃H₆]⁺, 308 (22),

237 (100) [Me₃SiOSiⁱPrPh]⁺, 209 (63), 195 (70), 135 (52),

1

73 (24) [SiMe₃]⁺. H NMR: d = 0.17, 0.18 (s, Me₃Si, 9H);

0.20, 0.21 (s, Me₃SiO, 9H); 0.98–1.30 (m, Me₂C, 12H);

1.50–1.70 (m, HC, 2H); 7.11–7.58 (m, Ph, 10H) ppm. ¹³C

NMR: d = 1.0, 1.1 (Me₃Si); 2.6, 2.7 (Me₃SiO); 17.8, 17.9

(CMe₂); 20.9, 21.0 (CMe₂); 127.9–140.1 (Ph) ppm. ²⁹Si

NMR: d = ꢀ37.9, ꢀ37.8 (SiⁱPrPh); ꢀ16.5, ꢀ16.3 (SiMe₃);

ꢀ0.1, 0.0 (OSiⁱPrPh); 7.7, 7.8 (OSiMe₃) ppm. IR(ﬁlm):

(1) THF, ꢀ78 ꢀC, t_rct= 2.5 h, trapping agent Me₃SiCl.

Distillation of the residue through a Fischer slit pipe

column in the temperature range of 65–95 ꢀC/

0.05 Torr yielded four fractions, which consisted of

5e and 6e (65–77 ꢀC), pure 6e (78–79 ꢀC), 6e and

10e (80–90 ꢀC) as well as of pure 10e (90–91 ꢀC).

The distillation residue contained 10e and enriched

8e as well as unknown products.

mðSiOSiÞ 1060, d(CH₃Si) 1253, 1261 cm^ꢀ1. Anal. Calc. for

~

C₂₄H₄₂OSi₄(458.937): C, 62.81; H, 9.22. Found: C,

62.63; H, 9.10%.

(2) Trapp mixture, ꢀ110 ꢀC, t_rct= 6 h, trapping agent

3,3-Dimethyl-1-trimethylsiloxy-1,2-diphenyl-1,2-di-iso-

propyl-trisilane (9d): Yield: 2.1 g (27%). B.p.: 146–147 ꢀC/

0.4 Torr. GC: Diastereomeric ratio 1.4:1. MS (EI, 70 eV):

m/z (%) = 444 (1) [M]⁺, 429 (2) [MꢀMe]⁺, 401 (10)

Me₃SiCl.

The result of the fractional distillation of the residue

through a Fischer slit pipe column is in accordance

with that under (1). However, 10e was not isolated

but only a mixed fraction of 6e and 10e (80–90 ꢀC/

i

[Mꢀ Pr]⁺, 359 (11) [Mꢀ PrꢀC₃H₆]⁺, 237 (73) [Me₃SiO-

SiⁱPrPh]⁺, 206 (100) [ⁱPrPhSiSiMe₂]⁺, 164 (59) [PhSi-

SiMe₂H]⁺, 135 (56), 73 (25) [SiMe₃]⁺, 59 (10) [SiMe₂H]⁺,

0.05 Torr) was obtained.

(3) THF, ꢀ78 ꢀC, t_rct= 2.5 h, trapping agent HMe₂SiCl.

43 (14) [ⁱPr]⁺. H NMR: d = 0.16, 0.17 (s, Me₃SiO, 9H);

1

Distillation of the residue through a Fischer slit pipe

column (62–87 ꢀC/0.1 Torr) yielded four fractions,

which consisted of 5e and 13e (62–77 ꢀC), pure 13e

(78–79 ꢀC), 13e, 7e, 11e and minor 6e^*(79–86 ꢀC) as

well as of pure 11e (86–87 ꢀC). Minor 11e and 9e

remained in the distillation residue. By distillation

0.204, 0.208, 0.22, 0.24 (2 · d, Me₂SiH, 6H); 0.95–1.21

(m, Me₂C, 12H); 1.44–1.61 (m, HC, 2H); 4.26, 4.31 (sept,

HSi, 1H); 7.10–7.56 (m, Ph, 10H) ppm. ¹³C NMR:

d = ꢀ4.21, ꢀ4.18, ꢀ4.14, ꢀ4.09 (Me₂SiH); 2.6 (Me₃SiO);

13.1, 13.4, 18.2, 18.3 (CMe₂); 17.7, 17.8, 20.8, 21.0

(CMe₂); 128.0–139.7 (Ph) ppm. ²⁹Si NMR: d = ꢀ39.0,

ꢀ38.6 (SiMe₂H); ꢀ37.4, ꢀ37.3 (SiⁱPrPh); ꢀ0.8, ꢀ0.5

(OSiⁱPrPh); 7.9, 8.0 (OSiMe₃) ppm; J(²⁹Si–¹H) = 176.2 Hz.

of this residue using a ball tube oven (Buchi,

¨

Kugelrohrofen GKR-51), 11e was isolated in the ﬁrst

fraction (<100 ꢀC/0.05 Torr). Both following frac-

tions (100–120 ꢀC, 120–140 ꢀC) and the remaining

residue contained 11e and 9e in diﬀerent proportions

~

IR(ﬁlm): mðSiOSiÞ 1061, d(CH₃Si) 1244, 1252; mðSiHÞ

2090 cm^ꢀ1. Anal. Calc. for C₂₃H₄₀OSi₄(444.919): C,

62.09; H, 9.06. Found: C, 61.91; H, 9.14%.

beside unknown products.

(4) Trapp mixture, ꢀ110 ꢀC, t_rct= 6 h, trapping agent

1,1,1,3,3,3-Hexamethyl-2-phenyl-2-iso-propyl-trisilane

(10d): Yield: 0.6 g (6%). B.p.: 74–77 ꢀC/0.03 Torr. MS (EI,

70 eV): m/z (%) = 294 (40) [M]⁺, 279 (3) [MꢀMe]⁺, 251

HMe₂SiCl.

Distillation of the residue through a Fischer slit pipe

column (62–87 ꢀC/0.1 Torr) yielded ﬁve fractions,

which contained 5e and 13e (62–77 ꢀC), pure 13e

(78–79 ꢀC), 7e, 13e, 11e and minor 6e^*(79–82 ꢀC),

pure 7e (82–83 ꢀC) as well as 7e and 11e (84–87 ꢀC).

In the distillation residue 11e and minor 9e were

found.

i

(51) [Mꢀ Pr]⁺, 221 (26) [MꢀSiMe₃]⁺, 179 (100)

[MꢀSiMe₃ꢀC₃H₆]⁺, 135 (79), 102 (53), 73 (51) [SiMe₃]⁺.

¹H NMR: d = 0.21 (s, Me₃Si, 18H), 1.17 (d, Me₂C, 6H),

1.55 (sept, HC, 1H), 7.12–7.50 (m, Ph, 5H) ppm. ¹³C

NMR: d = 0.8 (Me₃Si), 13.1 (CMe₂), 21.1 (CMe₂); 128.2,

129.1, 135.7, 136.8 (Ph) ppm. ²⁹Si NMR: d = ꢀ34.3

(SiⁱPrPh), ꢀ16.8 (SiMe₃) ppm. Anal. Calc. for C₁₅H₃₀Si₃

(294.659): C, 61.14; H, 10.26. Found: C, 60.85; H, 10.08%.

1,1,1,3,3-Pentamethyl-2-phenyl-2-iso-propyl-trisilane

(11d): C₁₄H₂₈Si₃(280.64). MS (EI, 70 eV): m/z (%) = 280

3-tert-Butyl-1,1,1,5,5,5-hexamethyl-3-phenyl-trisiloxane

(5e): C₁₆H₃₂O₂Si₃(340.69). MS (EI, 70 eV): m/z (%) = 340

t

(1) [M]⁺, 325 (4) [MꢀMe]⁺, 283 (100) [Mꢀ Bu]⁺, 267 (11)

[MꢀSiMe₃]⁺, 251 (8) [MꢀOSiMe₃]⁺, 135 (51), 73 (10)

i

(7) [M]⁺, 265 (1) [MꢀMe]⁺, 237 (12) [Mꢀ Pr]⁺, 206 (74)

1

[SiMe₃]⁺. H NMR: d = 0.08 (s, Me₃SiO, 18H), 0.88 (s,

[ⁱPrPhSiSiMe₂]⁺, 179 (72) [MꢀSiMe₂HꢀC₃H₆]⁺, 164 (68)

Me₃C, 9H), 7.18–7.65 (m, Ph, 5H) ppm. ¹³C NMR:

d = 2.1 (Me₃SiO), 20.4 (CMe₃), 26.0 (CMe₃); 127.9,

129.7, 134.0, 135.2 (Ph) ppm. ²⁹Si NMR: d = ꢀ 35.8

(Si^tBuPh), 8.5 (OSiMe₃) ppm.

[PhSiSiMe₂H]⁺, 135 (100), 73 (62) [SiMe₃]⁺, 59 (21)

1

[SiMe₂H]⁺, 43 (27) [ⁱPr]⁺. H NMR: d = 0.18 (s, Me₃Si,

9H); 0.238, 0.242 (2 · d, Me₂SiH, 6H); 1.05 (d, Me₂C,

6H), 1.15 (sept, HC, 1H), 4.25 (sept, HSi, 1H), 7.11–7.56

(m, Ph, 5H) ppm. ¹³C NMR: d = ꢀ4.5, ꢀ4.4 (Me₂SiH);

0.3 (Me₃Si), 17.5 (CMe₂), 21.0 (CMe₂); 128.1, 129.4,

133.7, 135.9 (Ph) ppm. ²⁹Si NMR: d = ꢀ39.9 (SiMe₂H),

1-tert-Butyl-2,2,2-trimethyl-1-trimethylsiloxy-1-phenyl-

disilane (6e): Yield: 4.1 g (36%). B.p.: 78–79 ꢀC/0.05 Torr.

MS (EI, 70 eV): m/z (%) = 324 (4) [M]⁺, 309 (9) [MꢀMe]⁺,

1434

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

t

267 (100) [Mꢀ Bu]⁺, 193 (39) [MꢀSiMe₃ꢀC₄H₁₀]⁺, 135

70 eV): m/z (%) = 294 (10) [M]⁺, 279 (2) [MꢀMe]⁺, 237

(41), 73 (25) [SiMe₃]⁺. H NMR: d = 0.12 (s, Me₃Si, 9H),

(85) [Mꢀ Bu]⁺, 235 (22) [MꢀSiMe₂H]⁺, 220 (56)

1

t

0.16 (s, Me₃SiO, 9H), 0.95 (s, Me₃C, 9H), 7.11–7.54 (m,

Ph, 5H) ppm. ¹³C NMR: d = ꢀ0.2 (Me₃Si), 2.6 (Me₃SiO),

21.3 (CMe₃), 26.9 (CMe₃); 127.9, 129.2, 133.9, 138.9 (Ph)

ppm. ²⁹Si NMR: d = ꢀ22.9 (SiMe₃), ꢀ1.7 (Si^tBuPh), 6.9

(OSiMe₃) ppm. Anal. Calc. for C₁₆H₃₂OSi₃(324.691): C,

59.19; H, 9.93. Found: C, 59.33; H, 10.08%.

[MꢀSiMe₃ꢀH]⁺, 177 (37) [Me₃SiSiPhꢀH]⁺, 164 (39)

[SiPhSiMe₂H]⁺,163 (33) [SiPhSiMe₂]⁺, 135 (100), 73 (54)

[SiMe₃]⁺, 59 (13) [SiMe₂H]⁺. ¹H NMR: d = 0.24 (s, Me₃Si,

9H); 0.27, 0.28 (2 · d, Me₂HSi, 6H); 1.08 (s, Me₃C, 9H),

4.36 (sept, HSi, 1H), 7.10–7.64 (m, Ph, 5H) ppm. ¹³C

NMR: d = ꢀ3.8 (Me₂HSi), 1.3 (Me₃Si), 20.7 (CMe₃),

30.3 (CMe₃); 128.1, 128.7, 136.1, 137.2 (Ph) ppm. ²⁹Si

NMR: d = ꢀ39.6 (SiMe₂H), ꢀ26.4 (Si^tBuPh), ꢀ16.7

(SiMe₃) ppm; J(²⁹Si–¹H) = 174.2 Hz. IR(ﬁlm): d(CH₃Si)

1-tert-Butyl-2,2-dimethyl-1-trimethylsiloxy-1-phenyl-

disilane (7e): Yield: 1.3 g (12%). B.p.: 82–83 ꢀC/0.1 Torr.

MS (EI, 70 eV): m/z (%) = 310 (3) [M]⁺, 295 (4) [MꢀMe]⁺,

t

253 (100) [Mꢀ Bu]⁺, 251 (15) [MꢀSiMe₂H]⁺, 209 (48)

1246, 1260; mðSiHÞ 2088 cm^ꢀ1. Anal. Calc. for C₁₅H₃₀Si₃

~

[MꢀSiMe₂HꢀC₄H₁₀]⁺, 193 (57), 179 (30), 147 (52), 135

(98), 73 (54) [SiMe₃]⁺, 59 (22) [SiMe₂H]⁺. ¹H NMR:

d = 0.17 (s, Me₃SiO, 9H); 0.22, 0.23 (2 · d, HMe₂Si, 6H);

0.99 (s, Me₃C, 9H), 4.13 (sept, HSi, 1H), 7.12–7.59 (m,

Ph, 5H) ppm. ¹³C NMR: d = ꢀ5.3, ꢀ5.2 (HMe₂Si); 2.4

(Me₃SiO), 21.1 (CMe₃), 26.5 (CMe₃); 128.0, 129.4, 134.0,

137.2 (Ph) ppm. ²⁹Si NMR: d = ꢀ45.7 (SiMe₂H), ꢀ1.1

(Si^tBuPh), 7.9 (OSiMe₃) ppm; J(²⁹Si–¹H) = 174.2 Hz.

(294.664): C, 61.14; H, 10.26. Found: C, 60.98; H, 10.12%.

1-tert-Butyl-2,2-dimethyl-1-dimethylsiloxy-1-phenyl-di-

silane (13e): Yield: 1.7 g (16%). B.p.: 78–79 ꢀC/0.1 Torr.

MS (EI, 70 eV): m/z (%) = 296 (3) [M]⁺, 281 (3) [MꢀMe]⁺,

t

239 (100) [Mꢀ Bu]⁺, 237 (22) [MꢀSiMe₂H]⁺, 209 (17)

t

[Mꢀ Buꢀ2Me]⁺, 195 (28), 179 (30), 135 (48), 73 (48)

[SiMe₃]⁺, 59 (17) [SiMe₂H]⁺. ¹H NMR: d = 0.14, 0.15

(2 · d, Me₂HSiSi, 6H); 0.17, 0.18 (2 · d, Me₂HSiO, 6H);

0.95 (s, Me₃C, 9H), 4.09 (sept, HSiMe₂, 1H), 5.04 (sept,

HSiMe₂O, 1H), 7.09–7.53 (m, Ph, 5H) ppm. ¹³C NMR:

d = ꢀ 5.3 (Me₂HSi), 1.3 (Me₂HSiO), 21.2 (CMe₃), 26.5

(CMe₃); 128.1, 129.5, 134.0, 137.2 (Ph) ppm. ²⁹Si NMR:

d = ꢀ45.7 (SiMe₂H), ꢀ5.0 (OSiMe₂H), 1.0 (Si^tBuPh)

ppm; J(²⁹Si–¹H) = 174.7 (HMe₂Si), 204.2 (HMe₂SiO) Hz.

~

IR(ﬁlm): mðSiOSiÞ 1074, d(CH₃Si) 1245, 1254; mðSiHÞ

2093 cm^ꢀ1. Anal. Calc. for C₁₅H₃₀OSi₃(310.664): C,

57.99; H, 9.73. Found: C, 57.87; H, 9.68%.

1,2-Di-tert-butyl-3,3,3-trimethyl-1-trimethylsiloxy-1,2-

diphenyl-trisilane (8e): C₂₆H₄₆OSi₄(486.99). GC: Diaste-

reomeric ratio 1.1:1. MS (EI, 70 eV): m/z (%) = 486 (1)

[M]⁺, 471 (2) [MꢀMe]⁺, 429 (16) [Mꢀ Bu]⁺, 251 (33)

IR(ﬁlm): mðSiOSiÞ 1075; d(CH₃Si) 1253, 1260; mðHSi_SiÞ

t

~

[Me₃SiOSi^tBuPh]⁺, 209 (100), 147 (83), 135 (71), 73 (29)

2094, mðHSi_OÞ 2121 cm^ꢀ1. Anal. Calc. for C₁₄H₂₈OSi₃

~

[SiMe₃]⁺. H NMR: d = 0.17, 0.18 (s, Me₃Si, 9H); 0.21,

(296.637): C, 56.69; H, 9.51. Found: C, 56.93; H, 9.45%.

1

0.22 (s, Me₃SiO, 9H); 0.83, 0.85, 0.93, 0.95 (2xs, Me₃C,

18H), 7.10–7.87 (m, Ph, 10H) ppm. ²⁹Si NMR:

d = ꢀ32.2, ꢀ32.0 (Si^tBuPh); ꢀ16.8, ꢀ16.7 (SiMe₃); 1.8,

2.2 (OSi^tBuPh); 7.3, 7.4 (OSiMe₃) ppm.

3.2.6. Trapping products of the lithiumsilanides from the

reaction of (Me₃SiO)Ph₂SiCl (1f) with lithium and the

trisiloxane 5f

1,2-Di-tert-butyl-3,3-dimethyl-1-trimethylsiloxy-1,2-

diphenyl-trisilane (9e): C₂₅H₄₄OSi₄(472.97). GC: Diaste-

reomeric ratio 1.1:1. MS (EI, 70 eV): m/z (%) = 472 (0.2)

Trapp mixture, ꢀ110 ꢀC, t_rct= 4 h, trapping agent

HMe₂SiCl.

Distillation of the residue through a Fischer slit pipe col-

umn (80–120 ꢀC/0.3 Torr) yielded four fractions, which

contained 5f and 7f (85–89 ꢀC), pure 7f (89–91 ꢀC), 7f

and 11f (91–109 ꢀC) as well as pure 11f (109–111 ꢀC). In

the distillation residue 9f crystallised out, which could be

puriﬁed by recrystallisation from n-hexane. Yields: 7f

2.4 g (21%), 9f 0.9 g (10%) and 11f 0.8 g (7%). The analyt-

ical data of the compounds obtained from the reaction of

1f with lithium are in accordance with those in [32].

t

[M]⁺, 457 (1) [MꢀMe]⁺, 415 (24) [Mꢀ Bu]⁺, 359 (8)

t

[Mꢀ BuꢀC₄H₈]⁺, 251 (22) [Me₃SiOSi^tBuPh]⁺, 209 (81),

147 (100), 135 (84), 73 (51) [SiMe₃]⁺, 59 (19) [SiMe₂H]⁺.

¹H NMR: d = 0.16, 0.17 (s, Me₃SiO, 9H); 0.24, 0.25,

0.26, 0.27 (2 · d, HMe₂Si, 6H); 0.81, 0.83, 0.90, 0.91 (2xs,

Me₃C, 18H); 4.47, 4.50 (sept, HSi, 1H); 7.11–7.85 (m, Ph,

10H) ppm. ²⁹Si NMR: d = ꢀ37.3, ꢀ37.0 (SiMe₂H);

ꢀ32.8, ꢀ32.7 (Si^tBuPh); 0.9, 1.1 (OSi^tBuPh); 7.5, 7.6

(OSiMe₃) ppm; J(²⁹Si–¹H) = 175.7 Hz.

2-tert-Butyl-1,1,1,3,3,3-hexamethyl-2-phenyl-trisilane

(10e): Yield: 1.4 g (13%). B.p.: 90–91 ꢀC/0.05 Torr. MS (EI,

70 eV): m/z (%) = 308 (14) [M]⁺, 293 (3) [MꢀMe]⁺, 251

3.2.7. Trapping products of the lithiumsilanides from the

reaction of (Me₃SiO)MesPhSiCl (1g) with lithium and the

trisiloxane 5g

t

(100) [Mꢀ Bu]⁺, 135 (81), 73 (49) [SiMe₃]⁺. ¹H NMR:

d = 0.30 (s, Me₃Si, 18H), 1.11 (s, Me₃C, 9H), 7.14–7.68

(m, Ph, 5H) ppm. ¹³C NMR: d = 1.8 (Me₃Si), 21.2

(CMe₃), 30.7 (CMe₃); 128.1, 128.6, 136.8, 137.2 (Ph)

ppm. ²⁹Si NMR: d = ꢀ26.8 (Si^tBuPh), ꢀ17.0 (SiMe₃)

ppm. Anal. Calc. for C₁₆H₃₂Si₃(308.691): C, 62.26; H,

10.45. Found: C, 62.05; H, 10.38%.

(1) THF, ꢀ78 ꢀC, t_rct= 2 h, trapping agent Me₃SiCl.

Distillation of the residue through a Fischer slit pipe

column (120–170 ꢀC/0.1 Torr) yielded three fractions,

which contained 5g and 6g (120–155 ꢀC), pure 6g

(159–160 ꢀC) as well as 6g and 10g (160–170 ꢀC).

From the third fraction 10g was isolated by prepara-

tive GC. In the distillation residue trimethylsiloxytri-

silane 8g crystallised out, which could be puriﬁed and

2-tert-Butyl-1,1,1,3,3-pentamethyl-2-phenyl-trisilane (11e):

Yield: 1.2 g (12%). B.p.: 86–87 ꢀC/0.1 Torr. MS (EI,

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

1435

isolated by distillation using a Buchi ball tube oven

¨

(180–220 ꢀC/0.06 Torr) and by recrystallisation from

n-hexane.

NMR: d = ꢀ5.6, ꢀ5.5 (Me₂HSi); 2.2 (Me₃SiO), 21.2 (p-

Me), 24.8 (o-Me); 128.3, 129.3, 129.6, 131.2, 133.7, 135.1,

138.4, 144.7 (C_ar) ppm. ²⁹Si NMR: d = ꢀ 39.1 (SiMe₂H),

ꢀ10.8 (SiMesPh), 9.3 (OSiMe₃) ppm; J(²⁹Si–¹H) =

(2) Trapp mixture, ꢀ110 ꢀC, t_rct= 4.5 h, trapping agent

Me₃SiCl.

~

176.8 Hz. IR(ﬁlm): mðSiOSiÞ 1039, d(CH₃Si) 1251, 1261;

mðSiHÞ 2092 cm^ꢀ1. Anal. Calc. for C₂₀H₃₂OSi₃(372.735):

The fractional distillation of the residue through a

Fischer slit pipe column gave the same result as under

(1). However, the proportion of 10g in the mixed

~

C, 64.45; H, 8.65. Found: C, 64.54; H, 8.42%.

3,3,3-Trimethyl-1,2-bis(2,4,6-trimethylphenyl)-1-trim-

ethylsiloxy-1,2-diphenyl-trisilane (8g): Yield: 0.5 g (5%).

M.p.: 148–151 ꢀC. GC: Diastereomeric ratio 1.4:1. MS

(EI, 70 eV): m/z (%) = 610 (0.2) [M]⁺, 595 (2) [MꢀMe]⁺,

537 (1) [MꢀSiMe₃]⁺, 460 (3), 313 (100) [Me₃SiO-

SiMesPh]⁺, 297 (4) [Me₃SiSiMesPh]⁺, 237 (9), 193 (14)

fraction is smaller.

(3) THF, ꢀ78 ꢀC, t_rct= 2 h, trapping agent HMe₂SiCl.

Distillation of the residue through a Fischer slit pipe

column (110–150 ꢀC/0.1 Torr) yielded three fractions,

which contained 7g, minor 5g and 13g (110–127 ꢀC),

pure 7g (128–130 ꢀC) as well as 7g and 11g (130–

150 ꢀC). From the third fraction the trisilane 11g

was isolated by preparative GC. In the distillation

residue 9g was mainly found, which was isolated by

1

[Me₃SiOSiPh –H]⁺, 177 (3) [Me₃SiSiPh –H]⁺. H NMR:

d = ꢀ0.05, 0.05 (s, Me₃Si, 9H); 0.18 (s, Me₃SiO, 9H);

2.11, 2.13, 2.14 (s, p-Me, 6H); 2.29, 2.31, 2.32 (s, o-Me,

12H); 6.71, 6.76, 6.77 (s, HC_ar, 4H); 7.08–7.84 (m, Ph,

10H) ppm. ¹³C NMR: d = 0.8, 1.1 (Me₃Si); 2.1, 2.4

(Me₃SiO); 21.0, 21.1 (p-Me); 25.4, 25.5, 27.0, 27.2 (o-Me);

127.9–146.0 (C_ar) ppm. ²⁹Si NMR: d = ꢀ45.8, ꢀ45.3 (Si-

MesPh); ꢀ12.3, ꢀ12.0 (SiMe₃); ꢀ8.5, ꢀ7.7 (OSiMesPh);

distillation using a Buchi ball tube oven (195–

¨

202 ꢀC/0.07 Torr).

(4) Trapp mixture, ꢀ110 ꢀC, t_rct= 4.5 h, trapping agent

HMe₂SiCl.

Distillation of the residue through a Fischer slit pipe

column gave the same result as under (3). However,

the proportion of 11g in the third fraction is smaller.

~

9.6, 10.2 (OSiMe₃) ppm. IR(KBr): mðSiOSiÞ 1065, d(CH₃Si)

1250, 1259 cm^ꢀ1. Anal. Calc. for C₃₆H₅₀OSi₄(611.143): C,

70.75; H, 8.25. Found: C, 70.59; H, 8.14%.

3,3-Dimethyl-1,2-bis(2,4,6-trimethylphenyl)-1-trimethyl-

siloxy-1,2-diphenyl-trisilane (9g): Yield: 1.1 g (11%). B.p.:

195–202 ꢀC/0.07 Torr. GC: Diastereomeric ratio 1.4:1.

MS (EI, 70 eV): m/z (%) = 596 (1) [M]⁺, 581 (3) [MꢀMe]⁺,

537 (2) [MꢀSiMe₂H]⁺, 313 (100) [Me₃SiOSiMesPh]⁺, 282

(14) [Me₂SiSiMesPh]⁺, 237 (8), 193 (12) [Me₃SiOSiPh –

H]⁺. ¹H NMR: d = 0.03, 0.05 (s, Me₃SiO, 9H); 0.09,

0.11, 0.12, 0.13 (2 · d, Me₂HSi, 6H); 2.08, 2.09, 2.10, 2.12

(s, p-Me, 6H); 2.25, 2.28, 2.32, 2.33 (s, o-Me, 12H); 4.44,

4.58 (sept, HSi, 1H); 6.69, 6.73, 6.74 (s, HC_ar, 4H); 7.07–

7.82 (m, Ph, 10H) ppm. ¹³C NMR: d = ꢀ4.8, ꢀ4.4, ꢀ4.1,

ꢀ 3.9 (Me₂SiH); 2.2, 2.4 (Me₃SiO); 20.9–21.2 (p-Me);

25.3–26.9 (o-Me); 127.9–146.2 (C_ar) ppm. ²⁹Si NMR:

d = ꢀ47.3, ꢀ45.7 (SiMesPh); ꢀ29.2, ꢀ28.7 (SiMe₂H);

ꢀ9.1, ꢀ7.8 (OSiMesPh); 9.9, 10.3 (OSiMe₃) ppm;

1,1,1,5,5,5-Hexamethyl-3-(2,4,6-trimethylphenyl)-3-phe-

nyl-trisiloxane (5g): C₂₁H₃₄O₂Si₃(402.76). MS (EI, 70 eV):

m/z (%) = 402 (2) [M]⁺, 387 (7) [MꢀMe]⁺, 324 (26)

[MꢀC₆H₆]⁺, 309 (100) [MꢀC₆H₆ꢀMe]⁺, 283 (39)

[MꢀMes]⁺, 267 (69), 135 (23). ¹H NMR: d = 0.15 (s,

Me₃SiO, 18H), 2.05 (s, p-Me, 3H), 2.38 (s, o-Me, 6H),

6.65 (s, HC_ar, 2H), 7.08–7.82 (m, Ph, 5H) ppm. ¹³C

NMR: d = 2.1 (Me₃SiO), 21.1 (p-Me), 25.3 (o-Me);

127.9–145.4 (C_ar) ppm. ²⁹Si NMR: d = ꢀ45.2 (SiMesPh),

9.0 (OSiMe₃) ppm.

2,2,2-Trimethyl-1-(2,4,6-trimethylphenyl)-1-trimethylsil-

oxy-1-phenyl-disilane (6g): Yield: 3.5 g (26%). B.p.: 159–

160 ꢀC/0.1 Torr. MS (EI, 70 eV): m/z (%) = 386 (2) [M]⁺,

371 (5) [MꢀMe]⁺, 313 (100) [MꢀSiMe₃]⁺, 193 (21)

1

[MꢀC₉H₁₂ꢀSiMe₃]⁺, 73 (5) [SiMe₃]⁺. H NMR: d = 0.04

~

29

1

J( Si– H) = 182.1 Hz. IR(ﬁlm): mðSiOSiÞ 1066, d(CH₃Si)

1252, 1260; mðSiHÞ 2114 cm^ꢀ1. Anal. Calc. for C₃₅H₄₈OSi₄

(s, Me₃Si, 9H), 0.26 (s, Me₃SiO, 9H), 2.13 (s, p-Me, 3H),

2.35 (s, o-Me, 6H), 6.77 (s, HC_ar, 2H), 7.10–7.60 (m, Ph,

5H) ppm. ¹³C NMR: d = ꢀ0.7 (Me₃Si), 2.2 (Me₃SiO),

21.1 (p-Me), 24.9 (o-Me); 127.8, 128.3, 129.3, 131.5,

133.9, 139.0, 140.6, 144.6 (C_ar) ppm. ²⁹Si NMR:

d = ꢀ20.7 (SiMe₃), ꢀ9.8 (SiMesPh), 8.6 (OSiMe₃) ppm.

~

(597.116): C, 70.40; H, 8.10. Found: C, 70.13; H, 7.92%.

1,1,1,3,3,3-Hexamethyl-2-(2,4,6-trimethylphenyl)-2-phe-

nyl-trisilane (10g) [44]: C₂₁H₃₄Si₃(370.76). MS (EI, 70 eV):

m/z (%) = 370 (9) [M]⁺, 355 (3) [MꢀMe]⁺, 297 (69)

[MꢀSiMe₃]⁺, 237 (32), 220 (100) [MꢀPhꢀSiMe₃]⁺, 205

(72) [MꢀSiMe₄ꢀPh]⁺, 73 (14) [SiMe₃]⁺. ¹H NMR:

d = 0.22 (s, Me₃Si, 18H), 2.13 (s, p-Me, 3H), 2.27 (s, o-

Me, 6H), 6.75 (s, HC_ar, 2H), 7.14–7.48 (m, Ph, 5H) ppm.

¹³C NMR: d = 0.7 (Me₃Si), 21.0 (p-Me), 26.7 (o-Me);

127.6, 128.3, 129.6, 130.4, 135.1, 138.2, 142.4, 145.1 (C_ar)

ppm. ²⁹Si NMR: d = ꢀ43.5 (SiMesPh), ꢀ15.0 (SiMe₃)

ppm.

IR(ﬁlm): mðSiOSiÞ 1037, d(CH₃Si) 1250, 1258 cm^ꢀ1. Anal.

~

Calc. for C₂₁H₃₄OSi₃(386.763): C, 65.22; H, 8.86. Found:

C, 65.51; H, 8.73%.

2,2-Dimethyl-1-(2,4,6-trimethylphenyl)-1-trimethylsil-

oxy-1-phenyl-disilane (7g): Yield: 2.7 g (21%). B.p.: 128–

130ꢀC/0.1 Torr. MS (EI, 70 eV): m/z (%) = 372 (1) [M]⁺,

357 (13) [MꢀMe]⁺, 313 (100) [MꢀSiMe₂H]⁺, 235 (16),

193 (24) [MꢀC₉H₁₂ꢀSiMe₂H]⁺, 73 (2) [SiMe₃]⁺. ¹H

NMR: d = 0.10 (s, Me₃SiO, 9H); 0.24, 0.26 (2 · d, Me₂HSi,

6H); 2.14 (s, p-Me, 3H), 2.40 (s, o-Me, 6H), 4.27 (sept, HSi,

1H), 6.75 (s, HC_ar, 2H), 7.13–7.63 (m, Ph, 5H) ppm. ¹³C

1,1,1,3,3-Pentamethyl-2-(2,4,6-trimethylphenyl)-2-phenyl-

trisilane (11g): C₂₀H₃₂Si₃(356.74). MS (EI, 70 eV): m/z

(%) = 356 (15) [M]⁺, 341 (5) [MꢀMe]⁺, 297 (22)

[MꢀSiMe₂H]⁺, 282 (100) [MꢀSiMe₃ꢀH]⁺, 267 (14), 237

1436

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

(28), 205 (44) [MꢀSiMe₃ꢀHꢀPh]⁺, 73 (11) [SiMe₃]⁺. H

NMR: d = 0.21, 0.22 (2 · d, Me₂SiH, 6H); 0.26 (s, Me₃Si,

9H), 2.13 (s, p-Me, 3H), 2.31 (s, o-Me, 6H), 4.40 (sept,

HSi, 1H), 6.77 (s, HC_ar, 2H), 7.09–7.51 (m, Ph, 5H) ppm.

¹³C NMR: d = ꢀ4.5, ꢀ4.4 (Me₂SiH); 0.5 (Me₃Si), 21.0

(p-Me), 26.5 (o-Me); 127.9–145.3 (C_ar) ppm. ²⁹Si NMR:

d = ꢀ44.0(SiMesPh), ꢀ33.5 (SiMe₂H), ꢀ15.2 (SiMe₃)

ppm; J(²⁹Si–¹H) = 178.4 Hz.

70 eV): m/z (%) = 486 (2) [M]⁺, 471 (7) [MꢀMe]⁺, 408

(100) [MꢀC₆H₆]⁺, 393 (33), 283 (20), 283 (20)

[MꢀC₁₅H₂₃]⁺, 207 (20), 135 (28) [SiMe₂Ph]⁺, 73 (10)

1

[SiMe₃]⁺, 43 (4) [C₃H₇]⁺. H NMR: d = 0.17 (s, Me₃SiO,

18H); 1.33 (d, H₃C, 12H); 1.37 (d, H₃C, 6H), 2.82 (sept,

HC(Me)₂, 1H), 3.76 (sept, HC(Me)₂, 2H), 7.13 (s, HC_ar,

2H), 7.05–7.72 (m, Ph, 5H) ppm. ¹³C NMR: d = 2.2

(Me₃SiO), 24.5 (p-(CH₃)₂CH); 25.3, 25.9 (o-(CH₃)₂CH),

31.9 (o-CH(CH₃)₂), 34.7 (p-CH(CH₃)₂); 121.6–157.4 (C_ar)

ppm. ²⁹Si NMR: d = ꢀ 45.2 (SiTipPh), 9.1 (OSiMe₃) ppm.

2,2,2-Trimethyl-1-trimethylsiloxy-1-phenyl-1-(2,4,6-tri-

iso-propylphenyl)-disilane (6h): Yield: 7.9 g (47%). B.p.:

141–142 ꢀC/0.03 Torr. MS (EI, 70 eV): m/z (%) = 470

(<1) [M]⁺, 455 (2) [MꢀMe]⁺, 397 (100) [MꢀSiMe₃]⁺, 355

(3), 320 (4), 277 (10), 245 (4), 193 (4) [Me₃SiOSiPh]⁺, 135

(3) [SiMe₂Ph]⁺, 73 (5) [SiMe₃]⁺, 43 (2) [C₃H₇]⁺. ¹H

NMR: d = 0.11 (s, Me₃Si, 9H), 0.30 (s, Me₃SiO, 9H);

1.17, 1.18 (2 · d, H₃C, 12H); 1.22 ((d), H₃C, 6H), 2.80

(sept, HC(Me)₂, 1H), 3.60 (sept, HC(Me)₂, 2H), 7.12 (s,

HC_ar, 2H), 7.06–7.54 (m, Ph, 5H) ppm. ¹³C NMR:

d = ꢀ0.7 (Me₃Si), 2.5 (Me₃SiO), 24.1 (p-(CH₃)₂CH); 25.3,

25.8 (o-(CH₃)₂CH), 33.2 (o-CH(CH₃)₂), 34.6 (p-

CH(CH₃)₂); 121.8, 127.9, 128.8, 131.1, 133.8, 143.4,

150.6, 156.6 (C_ar) ppm. ²⁹Si NMR: d = ꢀ19.7 (SiMe₃),

ꢀ11.7 (SiTipPh), 8.5 (OSiMe₃) ppm. Anal. Calc. for

C₂₇H₄₆OSi₃(470.925): C, 68.86; H, 9.85. Found: C,

68.74; H, 9.81%.

2,2-Dimethyl-1-trimethylsiloxy-1-phenyl-1-(2,4,6-tri-iso-

propylphenyl)-disilane (7h): C₂₆H₄₄OSi₃(456.90). MS (EI,

70 eV): m/z (%) = 456 (<1) [M]⁺, 441 (3) [MꢀMe]⁺, 397

(100) [MꢀSiMe₂H]⁺, 277 (13) [MꢀSiPhOSiMe₂]⁺, 193 (9)

[Me₃SiOSiPh]⁺, 135 (5) [SiMe₂Ph]⁺, 73 (7) [SiMe₃]⁺, 59

(8) [SiMe₂H]⁺, 43 (4) [C₃H₇]⁺. ¹H NMR: d = 0.13 (s,

Me₃SiO, 9H); 0.26, 0.28 (2 · d, Me₂HSi, 6H); 1.15, 1.16

(2 · d, H₃C, 12H); 1.23 ((d), H₃C, 6H), 2.78 (sept,

HC(Me)₂, 1H), 3.87 (sept, HC(Me)₂, 2H), 4.22 (sept,

HSi, 1H), 7.09 (s, HC_ar, 2H), 7.02–7.66 (m, Ph, 5H) ppm.

¹³C NMR: d = ꢀ5.6, ꢀ5.3 (Me₂HSi); 2.2 (Me₃SiO), 24.6

(p-(CH₃)₂CH); 25.3, 25.5 (o-(CH₃)₂CH), 33.1 (o-

CH(CH₃)₂), 34.5 (p-CH(CH₃)₂); 121.8, 127.9, 129.0,

130.0, 134.1, 139.9, 150.1, 156.6 (C_ar) ppm. ²⁹Si NMR:

d = ꢀ38.8 (SiMe₂H), ꢀ12.1 (SiTipPh), 9.3 (OSiMe₃)

ppm; J(²⁹Si–¹H) = 177.7 Hz.

2,2-Dimethyl-1-(2,4,6-trimethylphenyl)-1-dimethylsiloxy-

1-phenyl-disilane (13g): C₁₉H₃₀OSi₃(358.71). MS (EI,

70 eV): m/z (%) = 358 (2) [M]⁺, 343 (21) [MꢀMe]⁺, 299

(100) [MꢀSiMe₂H]⁺, 221 (23) [MꢀSiMe₂HꢀC₆H₆]⁺, 179

1

(26) [PhSiOSiMe₂]⁺, 135 (6), 59 (4) [SiMe₂H]⁺. H NMR:

d = 0.17, 0.18 (2 · d, Me₂HSiSi, 6H); 0.23, 0.24 (2 · d,

Me₂HSiO, 6H); 2.13 (s, p-Me, 3H), 2.42 (s, o-Me, 6H),

4.29 (sept, HSiSi, 1H), 5.03 (sept, HSiO, 1H), 6.76 (s, HC_ar,

2H), 7.11–7.65 (m, Ph, 5H) ppm. ¹³C NMR: d = ꢀ5.4

(Me₂HSi), 1.0 (Me₂HSiO), 21.1 (p-Me), 24.7 (o-Me);

128.1–145.0 (C_ar) ppm. ²⁹Si NMR: d = ꢀ 38.7 (SiMe₂H),

ꢀ8.9 (SiMesPh), ꢀ4.9 (OSiMe₂H) ppm; J(²⁹Si–¹H) =

176.3 (SiMe₂H), 204.7 (OSiMe₂H) Hz.

3.2.8. Trapping products of the lithiumsilanides from the

reaction of (Me₃SiO)TipPhSiCl (1h) with lithium and the

trisiloxane 5h as well as the siloxydisilane 6h^*

(1) THF, ꢀ78 ꢀC, t_rct= 2.5 h, trapping agent Me₃SiCl.

Distillation of the residue through a Fischer slit pipe

column (120–160 ꢀC/0.03 Torr) yielded four frac-

tions, which contained 5h and 6h (120–141 ꢀC), pure

6h (141–143 ꢀC), 6h and 10h (143–159 ꢀC) as well as

pure 10h (159–160 ꢀC).

(2) Trapp mixture, ꢀ110 ꢀC, t_rct= 4.5 h, trapping agent

Me₃SiCl.

The residue was fractionated as under (1) and at ﬁrst

mixed fractions of 5h and 6h (120–141 ꢀC/0.03 Torr)

and after that a pure fraction of 6h (141–142 ꢀC/

0.03 Torr) were obtained. In the distillation residue

10h was found beside minor amounts of 6h.

(3) THF, ꢀ78 ꢀC, t_rct= 2.5 h, trapping agent HMe₂SiCl.

Distillation of the residue through a Fischer slit pipe

column (115–149 ꢀC/0.04 Torr) yielded ﬁve fractions,

which contained mainly 13h beside 5h, 7h and small

amounts of 6h^*(115–135 ꢀC). It followed a mixed

fraction of 7h, 11h, minor 13h and 6h^*(135–148 ꢀC)

as well as a fraction of pure 11h (148–149 ꢀC).

(4) Trapp mixture, ꢀ110 ꢀC, t_rct= 4.5 h, trapping agent

HMe₂SiCl.

1,1,1,3,3,3-Hexamethyl-2-phenyl-2-(2,4,6-tri-iso-propyl-

phenyl)-trisilane (10h): Yield: 2.4 g (14%). B.p.: 159–

160 ꢀC/0.03 Torr. MS (EI, 70 eV): m/z (%) = 454 (<1)

[M]⁺, 439 (3) [MꢀMe]⁺, 381 (56) [MꢀSiMe₃]⁺, 304 (37)

[MꢀSiMe₃ꢀC₆H₅]⁺, 245 (100), 230 (92), 187 (17), 145

(11), 135 (28) [SiMe₂Ph]⁺, 73 (25) [SiMe₃]⁺, 43 (5)

[C₃H₇]⁺. ¹H NMR: d = 0.27 (s, Me₃Si, 18H); 1.12 (d,

H₃C, 12H); 1.28 (d, H₃C, 6H), 2.79 (sept, HC(Me)₂, 1H),

3.37 (sept, HC(Me)₂, 2H), 7.10 (s, HC_ar, 2H), 7.04–7.43

(m, Ph, 5H) ppm. ¹³C NMR: d = 1.0 (Me₃Si), 24.1 (p-

(CH₃)₂CH); 25.3, 25.9 (o-(CH₃)₂CH), 34.6 (o-CH(CH₃)₂),

35.9 (p-CH(CH₃)₂); 122.0, 127.8, 128.9, 130.3, 135.8,

140.8, 150.1, 156.8 (C_ar) ppm. ²⁹Si NMR: d = ꢀ45.4 (Si-

TipPh), ꢀ14.7 (SiMe₃) ppm. Anal. Calc. for C₂₇H₄₆Si₃

Distillation of the residue through a Fischer slit pipe

column (115–145 ꢀC/0.04 Torr) yielded several mixed

fractions, which consisted of 13h beside 7h, 6h^*and

small amounts of 5h (115–130 ꢀC) and of 13h, 7h,

6h^*beside small amounts of 11h (130–145 ꢀC),

respectively.

1,1,1,5,5,5-Hexamethyl-3-phenyl-3-(2,4,6-tri-iso-propyl-

phenyl)-trisiloxane (5h): C₂₇H₄₆O₂Si₃(486.92). MS (EI,

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

1437

(454.926): C, 71.29; H, 10.19. Found: C, 71.05; H,

10.28%.

mixed fraction of 7i and 6i^*(178–190 ꢀC). By recrys-

tallisation of the third fraction from n-hexane the

disilane 7i was isolated.

1,1,1,3,3-Pentamethyl-2-phenyl-2-(2,4,6-tri-iso-propyl-

phenyl)trisilane (11h): Yield: 1.5 g (9%). B.p.: 148–149 ꢀC/

0.04 Torr. MS (EI, 70 eV): m/z (%) = 440 (1) [M]⁺, 425

(6) [MꢀMe]⁺, 381 (31) [MꢀSiMe₂H]⁺, 367 (28)

[MꢀSiMe₃]⁺, 307 (34) [MꢀSiMe₃ꢀSiMe₂HꢀH]⁺, 245

(78), 230 (100), 187 (21), 135 (26) [SiMe₂Ph]⁺, 73 (17)

[SiMe₃]⁺, 59 (8) [SiMe₂H]⁺. ¹H NMR: d = 0.25 (d, Me₂HSi,

6H), 0.27 (s, Me₃Si, 9H); 1.13, 1.14 (2 · d, H₃C, 12H); 1.21

((d), H₃C, 6H), 2.80 (sept, HC(Me)₂, 1H), 3.40 (sept,

HC(Me)₂, 2H), 4.34 (sept, HSi, 1H), 7.12 (s, HC_ar, 2H),

7.02–7.41 (m, Ph, 5H) ppm. ¹³C NMR: d = ꢀ4.1, ꢀ3.6

(Me₂HSi); 0.6 (Me₃Si), 24.2 (p-(CH₃)₂CH); 25.6, 25.8 (o-

(CH₃)₂CH), 34.5 (o-CH(CH₃)₂), 36.1 (p-CH(CH₃)₂);

122.0, 127.9, 129.5, 133.8, 135.6, 140.2, 150.0, 156.7 (C_ar)

ppm. ²⁹Si NMR: d = ꢀ46.6 (SiTipPh), ꢀ33.6 (SiMe₂H),

ꢀ13.8 (SiMe₃) ppm; J(²⁹Si–¹H) = 178.7 Hz. Anal. Calc.

for C₂₆H₄₄Si₃(440.899): C, 70.83; H, 10.06. Found: C,

70.69; H, 9.95%.

2,2-Dimethyl-1-dimethylsiloxy-1-phenyl-1-(2,4,6-tri-iso-

propylphenyl)-disilane (13h): C₂₅H₄₂OSi₃(442.87). MS

(EI, 70 eV): m/z (%) = 442 (1) [M]⁺, 427 (3) [MꢀMe]⁺,

383 (100) [MꢀSiMe₃]⁺, 263 (21) [MꢀSiPhOSiMe₂]⁺, 179

(7) [SiPhOSiMe₂]⁺, 59 (6) [SiMe₂H]⁺. ¹H NMR:

d = 0.21, 0.22 (2 · d, Me₂HSiO, 6H); 0.25, 0.26 (2 · d,

Me₂HSiSi, 6H); 1.12, 1.13 (2 · d, H₃C, 12H); 1.18 ((d),

H₃C, 6H), 2.78 (sept, HC(Me)₂, 1H), 3.61 (sept,

HC(Me)₂, 2H), 4.23 (sept, HSiSi, 1H), 5.02 (sept, HSiO,

1H), 7.13 (s, HC_ar, 2H), 7.06–7.53 (m, Ph, 5H) ppm.

¹³C NMR: d = ꢀ5.4 (Me₂HSi), 1.4 (Me₂HSiO), 24.5 (p-

(CH₃)₂CH); 25.3, 25.5 (o-(CH₃)₂CH), 33.4 (o-CH(CH₃)₂),

34.7 (p-CH(CH₃)₂); 122.3, 128.1, 129.1, 133.7, 135.7,

142.0, 149.0, 156.8 (C_ar) ppm. ²⁹Si NMR: d = ꢀ38.1

(SiMe₂H), ꢀ10.7 (SiTipPh), ꢀ4.6 (OSiMe₂H) ppm;

J(²⁹Si–¹H) = 177.6 (SiMe₂H), 204.9 (OSiMe₂H) Hz.

(4) Trapp mixture, ꢀ110 ꢀC, t_rct= 6 h, trapping agent

HMe₂SiCl.

Distillation of the residue using a Buchi ball tube

¨

oven gave the same result as under (3). However,

the yield of pure 7i was higher.

1,1,1,5,5,5-Hexamethyl-3,3-bis(2,4,6-trimethylphenyl)-

trisiloxane (5i): C₂₄H₄₀O₂Si₃(444.84). MS (EI, 70 eV): m/z

(%) = 444 (3) [M]⁺, 429 (8) [MꢀMe]⁺, 324 (47)

[MꢀC₉H₁₂]⁺, 309 (100) [MꢀC₉H₁₂ꢀMe]⁺. ¹H NMR:

d = 0.10 (s, Me₃SiO, 18H), 2.11 (s, p-Me, 6H), 2.45 (s, o-

Me, 12H), 6.72 (s, HC_ar, 4H) ppm. ¹³C NMR: d = 1.9

(Me₃SiO), 21.2 (p-Me), 23.2 (o-Me); 129.7, 130.8, 138.9,

143.6 (C_ar) ppm. ²⁹Si NMR: d = ꢀ43.7 (SiMes₂), 8.6

~

(OSiMe₃) ppm. IR(ﬁlm): mðSiOSiÞ 1036, d(CH₃Si)

1250 cm^ꢀ1

.

2,2,2-Trimethyl-1,1-bis(2,4,6-trimethylphenyl)-1-trimethyl-

siloxy-disilane (6i): Yield: 8.0 g (53%). M.p.: 109–110 ꢀC.

MS (EI, 70 eV): m/z (%) = 428 (2) [M]⁺, 413 (5) [MꢀMe]⁺,

355 (100) [MꢀSiMe₃]⁺. ¹H NMR: d = 0.07 (s, Me₃SiO,

9H), 0.26 (s, Me₃SiSi, 9H), 2.11 (s, p-Me, 6H), 2.41 (s, o-

Me, 12H), 6.72 (s, HC_ar, 4H) ppm. ¹³C NMR: d = ꢀ0.6

(Me₃SiSi), 2.0 (Me₃SiO), 21.1 (p-Me), 24.4 (o-Me); 129.5,

135.8, 138.5, 142.8 (C_ar) ppm. ²⁹Si NMR: d = ꢀ 17.5

(SiMe₃), ꢀ10.8 (SiMes₂), 8.3 (OSiMe₃) ppm. IR(nujol):

mðSiOSiÞ 1032, d(CH₃Si) 1251, 1260 cm^ꢀ1. Anal. Calc. for

~

C₂₄H₄₀OSi₃(428.844): C, 67.22; H, 9.40. Found: C,

67.27; H, 9.42%.

2,2-Dimethyl-1,1-bis(2,4,6-trimethylphenyl)-1-trimethyl-

siloxy-disilane (7i): Yield: 6.0 g (41%). M.p.: 69–70 ꢀC, b.p.:

176–178 ꢀC/0.3 Torr. MS (EI, 70 eV): m/z (%) = 414 (2)

[M]⁺, 399 (11) [MꢀMe]⁺, 355 (100) [MꢀSiMe₂H]⁺, 235

(26), 133 (30), 73 (8) [SiMe₃]⁺, 59 (7) [SiMe₂H]⁺. ¹H

NMR: d = 0.08 (s, Me₃SiO, 9H), 0.26 (d, Me₂HSi, 6H),

2.12 (s, p-Me, 6H), 2.44 (s, o-Me, 12H), 4.25 (sept, HSi,

1H), 6.73 (s, HC_ar, 4H) ppm. ¹³C NMR: d = ꢀ5.0 (Me₂HSi),

1.9 (Me₃SiO), 21.1 (p-Me), 24.0 (o-Me); 129.6, 134.9, 138.7,

143.0 (C_ar) ppm. ²⁹Si NMR: d = ꢀ34.3 (SiMe₂H), ꢀ10.8

(SiMes₂), 9.1 (OSiMe₃) ppm; J(²⁹Si–¹H) = 177.3 Hz.

~

IR(ﬁlm): mðSiOSiÞ 107_ꢀ6₁, d(CH₃Si) 1251, 1261; mðHSi_SiÞ

~

2094, mðHSi_OÞ 2122 cm

.

3.2.9. Trapping products of the lithiumsilanides from the

reaction of (Me₃SiO)Mes₂SiCl (1i) with lithium and the

trisiloxane 5i as well as the siloxydisilane 6i^*

~

IR(nujol): mðSiOSiÞ 1030, d(CH₃Si) 1250, 1260; mðSiHÞ

2100 cm^ꢀ1. Anal. Calc. for C₂₃H₃₈OSi₃(414.817): C,

66.60; H, 9.23. Found: C, 66.54; H, 9.27%.

(1) THF, ꢀ78 ꢀC, t_rct= 3 h, trapping agent Me₃SiCl.

The solid residue contained the siloxydisilane 6i and

minor 5i. Recrystallisation from n-heptane yielded

2,2-Dimethyl-1,1-bis(2,4,6-trimethylphenyl)-1-dimethyl-

siloxy-disilane (13i): C₂₂H₃₆OSi₃(400.79). MS (EI, 70 eV):

m/z (%) = 400 (2) [M]⁺, 385 (8) [MꢀMe]⁺, 341 (100)

[MꢀSiMe₂H]⁺, 266 (38) [SiMes₂]⁺, 147 (61) [SiMes]⁺, 59

pure 6i.

(2) Trapp mixture, ꢀ110 ꢀC, t_rct= 6 h, trapping agent

Me₃SiCl.

1

(28) [SiMe₂H]⁺. H NMR: d = 0.09 (d, Me₂HSiSi, 6H),

The residue was recrystallised from n-heptane as

0.24 (d, Me₂HSiO, 6H), 2.11 (s, p-Me, 6H), 2.41 (s, o-

Me, 12H), 4.34 (sept, HSiSi, 1H), 4.97 (sept, HSiO, 1H),

6.72 (s, HC_ar, 4H) ppm. ¹³C NMR: d = ꢀ4.4 (Me₂HSi),

0.7 (Me₂HSiO), 21.2 (p-Me), 24.1 (o-Me); 129.1–144.4

(C_ar) ppm. ²⁹Si NMR: d = ꢀ33.2 (SiMe₂H), ꢀ9.1 (SiMes₂),

ꢀ5.3 (OSiMe₂H) ppm; J(²⁹Si–¹H) = 181.6 (SiMe₂H), 204.3

(OSiMe₂H) Hz.

under (1) and the compound 6i was isolated.

(3) THF, ꢀ78 ꢀC, t_rct= 3 h, trapping agent HMe₂SiCl.

Distillation of the residue using a Buchi ball tube

¨

oven (145–190 ꢀC/0.3 Torr) yielded two fractions in

the temperature range of 145–176 ꢀC, which consisted

of mixtures of 5i, 13i and 7i, a fraction of nearly pure

7i with very small amounts of 6i^*(176–178 ꢀC) and a

1438

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

3.2.10. Isolation of the intermediates (Me₃SiO)RR⁰Si–

SiRR⁰(OSiMe₃) (14e: R = ^tBu, R⁰= Ph;14g: R = Mes,

R⁰= Ph)

Isolation of the siloxydisilane 14e from the reaction of

1e with lithium.

Distillation of the residue through a Fischer slit pipe col-

umn (60–95 ꢀC/0.05 Torr) yielded three fractions (60–

75 ꢀC, 75–85 ꢀC, 85–95 ꢀC), which contained 1e, 5e, 6e

and 10e in diﬀerent proportions. Additionally, 14e and

minor 8e remained in the distillation residue. By distillation

General procedure. To 4 equivalents (4 equiv.) of very

thin lithium plates in 70 ml THF the siloxydisilane 6e

(4.2 mmol), 6f (2.8 mmol) and 6h (1.1 mmol), dissolved

in 30 ml THF, was added dropwise within 5 min at

ꢀ78 ꢀC with vigorous stirring. For completion of the

reaction the mixture was stirred for 24 h at ꢀ78 ꢀC and

for 4 h at room temperature (reaction of 6e), for 3.5 h

at ꢀ78 ꢀC (reaction of 6f) and for 20 h at ꢀ78 ꢀC (reac-

tion of 6h). The solutions turned brown (reactions of 6e

and 6h) and green (reaction of 6f). Afterwards the excess

lithium was removed. Then 2.5 equiv. HMe₂SiCl were

added to the solution of lithiumsilanides at the respective

reaction temperature. The reaction mixture was allowed

to react for 24 h at room temperature. The reaction pro-

gress could be observed by the colour change of the solu-

tion from brown or green to colourless. After completion

of quenching the work-up of the reaction mixture was

carried out in analogy to Section 3.2.1. All three distil-

lates of solvent contained Me₃SiOSiMe₂H. The residues

of this residue using a Buchi ball tube oven nearly pure 14e

¨

(160–180 ꢀC/0.05 Torr) was obtained. Recrystallisation

from n-hexane yielded pure 14e.

1,2-Di-tert-butyl-1,2-bis(trimethylsiloxy)-1,2-diphenyl-

disilane (14e): Yield: 0.3 g (3%). M.p.: 215–218 ꢀC. MS (EI,

70 eV): m/z (%) = 502 (7) [M]⁺, 487 (31) [MꢀMe]⁺, 445

t

(100) [Mꢀ Bu]⁺, 251 (41) [Me₃SiOSi^tBuPh]⁺, 209 (30),

1

147 (17), 135 (58), 73 (22) [SiMe₃]⁺. H NMR: d = 0.12

(s, Me₃SiO, 18H), 1.09 (s, Me₃C, 18H), 7.15–7.69 (m, Ph,

10H) ppm. ²⁹Si NMR: d = ꢀ 15.1 (Si^tBuPh), 8.4 (OSiMe₃)

ppm. Anal. Calc. for C₂₆H₄₆O₂Si₄(502.999): C, 62.09; H,

9.22. Found: C, 62.27; H, 9.13%.

Isolation of the siloxydisilane 14g from the reaction of

1g with lithium.

Distillation of the residue through a Fischer slit pipe col-

umn in the temperature range of 105–155 ꢀC/0.05 Torr

yielded two fractions (105–130 ꢀC, 130–155 ꢀC), which con-

sisted of 1g, 5g, 6g and 10g in diﬀerent proportions. Addi-

tionally, 14g and 8g remained in the distillation residue.

were distilled using a Buchi ball tube oven. The respec-

¨

tive main fractions contained the trisilanes 11e (80–

95 ꢀC/0.1 Torr, yield: 0.91 g (74%)), 11f (100–120 ꢀC/

0.3 Torr, yield: 0.70 g (79%)) and 11h (150–170 ꢀC/

0.1 Torr, yield: 0.31 g (64%)). The analytical data of 11f

are given in [32].

3.4. Reaction of the mixtures of lithiumsilanides from

reaction of 1f, 1g, 1i and lithium metal at ꢀ110 ꢀC with

ⁿBuLi and trapping with Me₃SiCl – formation of the

n

Distillation of this residue using a Buchi ball tube oven

¨

disilanes BuPh₂SiSiMe₃(16f), BuMesPhSiSiMe₃(16g)

n

and BuMes₂SiSiMe₃(16i)

yielded the pure siloxydisilane 14g (210–215 ꢀC/0.02 Torr).

1,2-Bis(2,4,6-trimethylphenyl)-1,2-bis(trimethylsiloxy)-

1,2-diphenyl-disilane (14g): Yield: 0.6 g (5%). B.p.: 210–

215 ꢀC/0.02 Torr. GC: Diastereomeric ratio 1:1.4. MS

(EI, 70 eV): m/z (%) = 626 (0.2) [M]⁺, 611 (1) [MꢀMe]⁺,

537 (3) [MꢀOSiMe₃]⁺, 313 (100) [M/2]⁺, 235 (9), 193

On the analogies of the preparative work a general

procedure is given for the reactions of 1f, 1g and 1i with

lithium at – 110 ꢀC and for the following ones of the mix-

n

tures of the lithiumsilanides with BuLi as well as for the

1

(14) [M/2ꢀC₉H₁₂]⁺. H NMR: d = 0.15, 0.17 (s, Me₃SiO,

trapping with Me₃SiCl. The work-up of the crude products

is described separately. Some details of reactions are shown

in Eq. (6). The formed n-butyl-substituted disilanes were

identiﬁed by comparison with the data of authentic

compounds (Section 3.5).

18H); 2.08, 2.18 (s, p-Me, 6H); 2.21, 2.47 (s, o-Me, 12H);

6.63, 6.80 (s, HC_ar, 4H); 7.07–7.94 (m, Ph, 10H) ppm.

¹³C NMR: d = 2.0, 2.3 (Me₃SiO); 21.0, 21.1 (p-Me); 25.2,

25.3 (o-Me); 128.1–145.4 (C_ar) ppm. ²⁹Si NMR:

d = ꢀ15.6, ꢀ14.4 (SiMesPh); 9.4, 9.6 (OSiMe₃) ppm. Anal.

Calc. for C₃₆H₅₀O₂Si₄(627.143): C, 68.95; H, 8.04. Found:

C, 68.83; H, 7.96%.

General procedure. To 0.14 mol very thin lithium plates (4

equiv.) in 70 ml Trapp mixture (THF/Et₂O/n-pentane in

volume ratio 4:1:1) 0.035 mol trimethylsiloxychlorosilane

1f, 1g and 1i, dissolved in 30 ml Trapp mixture, was added

dropwise within 15 min at ꢀ110 ꢀC with vigorous stirring.

For completion of the reaction the mixture was stirred for

4 h at ꢀ110 ꢀC (reaction of 1f), for 4.5 h at ꢀ110 ꢀC

(reaction of 1g) and for 6 h at ꢀ110 ꢀC (reaction of 1i).

The solutions turned green (reactions of 1f and 1g) and

brown (reaction of 1i). Afterwards the excess lithium was

removed. Then to the respective solution of lithiumsilanides

0.175 mol ⁿBuLi (1.6 M in n-hexane, cooled down to

ꢀ78 ꢀC) were added dropwise within 30 min at ꢀ110 ꢀC

with vigorous stirring. Subsequently, the reaction solution

was warmed to room temperature within 2 h, stirred further

for 4 h and quenched with 0.245 mol (7 equiv.) Me₃SiCl at

3.3. Reaction of the pure siloxydisilanes 6e, 6f and 6h with

lithium metal in THF and trapping with HMe₂SiCl –

formation of the trisilanes Me₃Si–Si^tBuPh–SiMe₂H (11e),

Me₃Si–SiPh₂–SiMe₂H (11f) and Me₃Si–SiTipPh–SiMe₂H

(11h)

On the analogies of the preparative work a general

procedure is given for the reactions of 6e, 6f and 6h with

lithium in THF and for the following trapping with HMe₂-

SiCl. The trisilanes formed were identiﬁed by comparison

with the data of the pure compounds, which are described

in Sections 3.2.5, 3.2.6 and 3.2.8

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

1439

(ii) Reductive coupling of chlorosilanes ⁿBuRR⁰SiCl with

Me₃SiCl.

the same temperature. The reaction mixture was allowed to

react for 24 h at room temperature. The reaction progress

could be observed by the colour change of the solution from

green or brown to colourless. After completion of quenching

the work-up of the reaction mixture was carried out in

analogy to Section 3.2.1. The obtained residues were dis-

tilled in vacuo.

n

To the crude chlorosilanes BuRR⁰SiCl 15.2 mmol

Me₃SiCl and 20 ml THF were added. The solution

of chlorosilanes was added dropwise to a mixture of

30.4 mmol of very thin lithium plates and 50 ml

THF at room temperature with vigorous stirring.

After a reaction time of 2 h at room temperature

Reaction of the solution of lithiumsilanides, formed

n

(reactions with BuPh₂SiCl or BuMesPhSiCl) or of

4 h (reaction with ⁿBuMes₂SiCl) at room temperature

the excess lithium was removed. Work-up of the reac-

tion mixtures analogously to Section 3.2.1. yielded

from 1f and lithium, with BuLi.

Distillation of the residue through a Fischer slit pipe

column (90–130 ꢀC/0.03 Torr) yielded three fractions

(90–100 ꢀC, 100–110 ꢀC, 110–130 ꢀC), which consisted of

mixtures of 5f, 10f, 16f and minor 6f in diﬀerent propor-

tions. In the second fraction (100–110 ꢀC) the disilane 16f

was enriched to 25%. In the distillation residue 8f crystal-

lised out.

residues, which were distilled in vacuo using a Buchi

¨

ball tube oven.

1-n-Butyl-2,2,2-trimethyl-1,1-diphenyl-disilane

(16f):

Yield: 0.7 g (28%). B.p.: 109–110 ꢀC/0.3 Torr. MS (EI,

Reaction of the solution of lithiumsilanides, formed

from 1g and lithium, with BuLi.

70 eV): m/z (%) = 312 (20) [M]⁺, 297 (2) [MꢀMe]⁺, 255

n

(10) [Mꢀ Bu]⁺, 239 (29) [MꢀSiMe₃]⁺, 183 (100)

Distillation of the residue through a Fischer slit pipe

column (105–160 ꢀC/0.3 Torr) yielded three fractions

(105–120 ꢀC, 120–140 ꢀC, 140–160 ꢀC), which contained

mixtures of 5g, 10g, 16g and small amounts of 6g in

diﬀerent proportions. Especially, the second fraction

(120–140 ꢀC) consisted of the disilane 16g enriched to

36%. In the distillation residue the trimethylsiloxytrisilane

8g was found.

[MꢀSiMe₃ꢀC₄H₈]⁺, 135 (10), 105 (14) [SiPh]⁺, 73 (5)

[SiMe₃]⁺. ¹H NMR: d = 0.21 (s, Me₃Si, 9H); 0.85 (t,

H₃C, 3H); 1.23, 1.34, 147 (3xm, H₂C, 6H); 7.13–7.58 (m,

Ph, 10H) ppm. ¹³C NMR: d = ꢀ1.1 (Me₃Si), 12.9 (CH₃

(ⁿBu)); 13.8, 27.0, 27.2 (CH₂(ⁿBu)); 128.2, 129.0, 135.5,

136.7 (Ph) ppm. ²⁹Si NMR: d = ꢀ 19.6 (SiMe₃), ꢀ19.1

(SiⁿBuPh₂) ppm. Anal. Calc. for C₁₉H₂₈Si₂(312.607): C,

73.00; H, 9.03. Found: C, 72.83; H, 8.92%.

Reaction of the solution of lithiumsilanides, formed

n

1-n-Butyl-2,2,2-trimethyl-1-(2,4,6-trimethylphenyl)-1-

phenyl-disilane (16g): Yield: 1.1 g (41%). B.p.: 81–82 ꢀC/

0.06 Torr. MS (EI, 70 eV): m/z (%) = 354 (11) [M]⁺, 339

from 1i and lithium, with BuLi.

Distillation of the residue using a Buchi ball tube oven

¨

(130–175 ꢀC/0.5 Torr) yielded four fractions (130–150 ꢀC,

150–165 ꢀC, 165–170 ꢀC, 170–175 ꢀC), which contained

mixtures of 6i, 16i and minor 5i in diﬀerent proportions.

Especially, in the second fraction (150–165 ꢀC) the disilane

16i was enriched to 21%.

n

(2) [MꢀMe]⁺, 297 (6) [Mꢀ Bu]⁺, 281 (80) [MꢀSiMe₃]⁺,

225 (100) [MꢀSiMe₃ꢀC₄H₈]⁺, 73 (7) [SiMe₃]⁺. MS (CI,

iso-butane): m/z (%) = 354 (7) [M]⁺, 339 (28) [MꢀMe]⁺,

307 (12), 281 (15) [MꢀSiMe₃]⁺, 277 (11), 235 (100)

[MꢀC₉H₁₁]⁺, 179 (20) [MꢀC₉H₁₁ꢀC₄H₈]⁺, 175 (25), 157

(12) [MꢀC₉H₁₁ꢀC₆H₆]⁺. ¹H NMR: d = 0.20 (s, Me₃Si,

9H), 0.84 (t, H₃C, 3H), 1.37 (m, H₂C, 6H), 2.13 (s, p-Me,

3H), 2.32 (s, o-Me, 6H), 6.76 (s, HC_ar, 2H), 7.12–7.47 (m,

Ph, 5H) ppm. ¹³C NMR: d = ꢀ0.2 (Me₃Si), 13.9 (CH₃

(ⁿBu)); 14.8, 27.1, 27.8 (CH₂(ⁿBu)); 21.0 (p-Me), 25.7 (o-

Me); 128.2, 129.4, 134.4 (C_arH); 130.7, 138.7, 140.9, 145.3

(C_ar) ppm. ²⁹Si NMR: d = ꢀ 22.0 (SiⁿBuMesPh), ꢀ16.5

(SiMe₃) ppm. Anal. Calc. for C₂₂H₃₄Si₂(354.688): C,

74.50; H, 9.66. Found: C, 74.45; H, 9.62%.

3.5. Preparation of the n-butyl-substituted disilanes

n

ⁿBuPh₂SiSiMe₃(16f), BuMesPhSiSiMe₃(16g) and

ⁿBuMes₂SiSiMe₃(16i)

General procedure

n

(i) Syntheses of chlorosilanes BuRR⁰SiCl (R = Ph,

R⁰= Ph, Mes; R = R⁰= Mes).

To a solution of 7.6 mmol dichlorosilane RR⁰SiCl₂

(R = Ph, R⁰= Ph, Mes; R = R⁰= Mes) and 50 ml

n-hexane 7.6 mmol ⁿBuLi in 50 ml n-hexane were

added dropwise within 1 h at ꢀ78 ꢀC with vigorous

stirring. For completion of the reaction the mixture

was stirred for 3 h at room temperature (reaction

with R = R⁰= Ph), for 2 h at reﬂux (reaction with

R = Mes, R⁰= Ph) and for 24 h at reﬂux (reaction

with R = R⁰= Mes), respectively. After the respec-

tive reaction times LiCl was ﬁltered oﬀ. The solvent

was distilled from the ﬁltrate under reduced pressure.

The resulting colourless chlorosilanes were used with-

out puriﬁcation in the next procedure.

1-n-Butyl-2,2,2-trimethyl-1,1-bis(2,4,6-trimethylphenyl)-

disilane (16i): Yield: 1.8 g (60%). B.p.: 133–134 ꢀC/

0.1 Torr. MS (EI, 70 eV): m/z (%) = 396 (3) [M]⁺, 381 (1)

n

[MꢀMe]⁺, 339 (3) [Mꢀ Bu]⁺, 323 (33) [MꢀSiMe₃]⁺, 267

(100) [MꢀSiMe₃ꢀC₄H₈]⁺, 73 (8) [SiMe₃]⁺. MS (CI, iso-

butane): m/z (%) = 397 (12) [M+H]⁺, 396 (8) [M]⁺, 381

n

(55) [MꢀMe]⁺, 339 (10) [Mꢀ Bu]⁺, 323 (86) [MꢀSiMe₃]⁺,

1

277 (100) [MꢀC₉H₁₁]⁺, 221 (19) [MꢀC₉H₁₁ꢀC₄H₈]⁺. H

NMR: d = 0.25 (s, Me₃Si, 9H), 0.82 (t, H₃C, 3H), 1.28

(m, H₂C, 6H), 2.13 (s, p-Me, 6H), 2.31 (s, o-Me, 12H),

6.72 (s, HC_ar, 4H) ppm. ¹³C NMR: d = 0.5 (Me₃Si), 13.9

(CH₃(ⁿBu)); 18.7, 27.2, 28.5 (CH₂(ⁿBu)); 21.1 (p-Me),

25.1 (o-Me), 129.4 (C_arH); 134.6, 137.8, 143.3 (C_ar) ppm.

1440

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

²⁹Si NMR: d = ꢀ22.4 (SiⁿBuMes₂), ꢀ13.9 (SiMe₃) ppm.

Anal. Calc. for C₂₅H₄₀Si₂(396.770): C, 75.68; H, 10.16.

Found: C, 75.53; H, 10.31%.

Me), 24.5 (o-Me), 29.1 (CH₂), 127.9–145.1 (C_arand

C@C) ppm. ²⁹Si NMR: d = ꢀ 0.7 ppm. Anal. Calc. for

C₂₁H₂₆Si (306.527): C, 82.29; H, 8.55. Found: C, 82.05;

H, 8.72%.

3.6. Reaction of the mixtures of lithiumsilanides from

reaction of 1g, 1i and lithium metal at ꢀ110 ꢀC with 2,3-

dimethylbuta-1,3-diene – formation of 3,4-dimethyl-1-(2,4,6-

trimethylphenyl)-1-phenyl-silacyclopent-3-ene 17g and 3,4-

dimethyl-1,1-bis(2,4,6-trimethylphenyl)-silacyclopent-3-ene

17i

Reaction of the solution of lithiumsilanides, formed

from 1i and lithium, with 2,3-dimethylbuta-1,3-diene.

The residue consisted of a mixture of 5i, 17i and

unknown compounds. Distillation of the residue using a

Buchi ball tube oven (120–240 ꢀC/0.07 Torr) yielded a frac-

¨

tion (160–195 ꢀC), which contained 17i enriched to about

30%. From this fraction 17i was isolated as an amorphous

compound by preparative LPCP.

On the analogies of the preparative work a general pro-

cedure is given for the reactions of 1g and 1i with lithium

metal at ꢀ110 ꢀC and the following ones of the mixtures

of the lithiumsilanides with 2,3-dimethylbuta-1,3-diene as

well as for the quenching with Me₃SiCl. The work-up of

the crude products is described separately. Some details

of reactions are shown in Eq. (7).

3,4-Dimethyl-1,1-bis(2,4,6-trimethylphenyl)-silacyclo-

pent-3-ene [64,65] (17i): Yield: 0.25 g (2%, referring to 1i).

MS (EI, 70 eV): m/z (%) = 348 (2) [M]⁺, 266 (3)

[MꢀC₆H₁₀]⁺, 228 (100) [MꢀC₉H₁₂]⁺, 147 (28) [SiMes]⁺,

1

119 (13) [C₉H₁₁]⁺. H NMR: d = 1.74 (s, H₃CC@, 6H),

2.11 (s, H₂CC@, 4H), 2.11 (s, p-Me, 6H), 2.37 (s, o-Me,

12H), 6.71 (s, HC_ar, 4H) ppm. ¹³C NMR: d = 19.3 (Me),

21.0 (p-Me), 24.1 (o-Me), 30.6 (CH₂); 129.5, 131.2, 134.5,

138.3, 143.9 (C_arand C@C) ppm. ²⁹Si NMR: d = ꢀ 2.6

ppm. Anal. Calc. for C₂₄H₃₂Si (348.609): C, 82.69; H,

9.25. Found: C, 82.44; H, 9.37%.

General procedurze. To 0.14 mol (4 equiv.) very thin

lithium plates in 70 ml Trapp mixture (THF/Et₂O/n-pen-

tane in volume ratio 4:1:1) 0.035 mol trimethylsiloxychlo-

rosilane 1g or 1i, dissolved in 30 ml Trapp mixture, was

added dropwise within 15 min at ꢀ110 ꢀC with vigorous

stirring. For completion of the reaction the mixture was

stirred vigorously for 4.5 h at ꢀ110 ꢀC (reaction of 1g)

and for 6 h at ꢀ110 ꢀC (reaction of 1i). The solutions

turned green (reaction of 1g) and brown (reaction of

1i). Afterwards the excess lithium was removed. Then to

the respective solution of lithiumsilanides 0.105 mol (3

equiv.) 2,3-dimethylbuta-1,3-diene were added with stir-

ring. The reaction solution was warmed from ꢀ110 ꢀC

to ꢀ78 ꢀC within 1 h, stirred further 3 h at ꢀ78 ꢀC and

quenched with 0.07 mol (2 equiv.) trapping agent Me₃SiCl

at the same temperature. The reaction mixture was

allowed to react for 24 h at room temperature. The reac-

tion progress could be observed by the colour change of

the solution from green or brown to colourless. After

completion of quenching the work-up of the reaction mix-

ture was carried out in analogy to Section 3.2.1. The

respective residues obtained were distilled in vacuo using

3.7. Single crystal X-ray diﬀraction analysis of 17g

Empirical formula: C₂₁H₂₆Si; formula weight: 306.51;

crystal size: 0.52 · 0.38 · 0.24 mm³; crystal system: mono-

˚

clinic; space group: C2/c; a = 23.300(4) A, b = 13.080(4)

3

˚

A, c = 14.908(3) A, b = 124.61(1)ꢀ; V = 3739(2) A , Z =

8, q_calcd= 1.089 g cm^ꢀ3, l = 0.121 mm^ꢀ1, F(000) = 1328,

T= 293(2) K, k = 0.71073 A; scan range (h): 2.07–23.00ꢀ;

˚

hkl ranges: ꢀ1/25, ꢀ1/14, ꢀ16/13; number of collected

reﬂections = 3134, number of independent reﬂec-

tions = 2611, reﬂections with I > 2r(I) = 1666, reﬁned

parameters = 204, GOOF = 1.015, R₁[I > 2r(I)] =

0.0603, R₁(all data) = 0.0986, wR₂(all data) = 0.1718;

largest diﬀ. peak and hole: 0.16/ꢀ0.29 e A^ꢀ3. The data col-

˚

lection was done on a Bruker P4 diﬀractometer by means

of Mo Ka radiation (graphite monochromator), perform-

ing x-scan for each frame. The structure was solved by

direct methods (Bruker ^SHELXTL[67]), and for the reﬁne-

ment against F²a full-matrix least-squares target was used

(^SHELXL-97 [68]). The hydrogen atoms were placed at geo-

metrically calculated positions and reﬁned by means of a

riding model.

a Buchi ball tube oven.

¨

Reaction of the solution of lithiumsilanides, formed

from 1g and lithium, with 2,3-dimethylbuta-1,3-diene.

Distillation of the residue in the temperature range of

120–210 ꢀC/0.1 Torr yielded several fractions. In the frac-

tion (170–180 ꢀC), 17g was enriched to 50%. Preparative

LPLC of this fraction yielded pure 17g. Subsequently, sin-

gle crystals of 17g could be obtained by crystallisation from

n-pentane.

4. Supplementary material

3,4-Dimethyl-1-(2,4,6-trimethylphenyl)-1-phenyl-sila-

cyclopent-3-ene (17g): Yield: 0.35 g (3%, referring to 1g).

M.p.: 76 ꢀC. MS (EI, 70 eV): m/z (%) = 306 (87) [M]⁺,

228 (33) [MꢀC₆H₆]⁺, 224 (23) [MꢀC₆H₁₀]⁺, 186 (100)

[MꢀC₉H₁₂]⁺, 105 (33) [PhSi]⁺. ¹H NMR: d = 1.78 (s,

H₃CC@, 6H), 2.11, 2.13 (2xs, H₂CC@, 4H); 2.18 (s,

p-Me, 3H), 2.29 (s, o-Me, 6H), 6.81 (s, HC_ar, 2H), 7.10–

7.54 (m, Ph, 5H) ppm. ¹³C NMR: d = 19.1 (Me), 21.2 (p-

CCDC 610626 contains the supplementary crystallo-

graphic data for this paper. These data can be obtained

free of charge via http://www.ccdc.cam.ac.uk/conts/

retrieving.html, or from the Cambridge Crystallographic

Data Centre, 12 Union Road, Cambridge CB2 1EZ,

UK; fax: (+44) 1223-336-033; or e-mail: deposit@ccdc.

cam.ac.uk.

J. Harloﬀ et al. / Journal of Organometallic Chemistry 692 (2007) 1421–1441

1441

[34] N. Tokitoh, K. Hatano, T. Sadahiro, R. Okazaki, Chem. Lett. (1999)

931.

Acknowledgement

[35] M.E. Lee, H.M. Cho, M.S. Ryu, Ch.H. Kim, W. Ando, J. Am.

Chem. Soc. 123 (2001) 7732.

[36] N. Wiberg, W. Niedermayer, J. Organomet. Chem. 628 (2001) 57.

[37] M.E. Lee, H.M. Cho, Y.M. Lim, J.K. Choi, Ch.H. Park, S.E. Jeong,

U. Lee, Chem. Eur. J. 10 (2004) 377.

[38] A. Kawachi, Y. Oishi, T. Kataoka, K. Tamao, Organometallics 23

(2004) 2949.

[39] P.D. Lickiss, C.M. Smith, Coord. Chem. Rev. 145 (1995) 75.

[40] J. Grobe, T. Schierholdt, in: N. Auner, J. Weis (Eds.), Organosilicon

Chemistry II – From Molecules to Materials, Wiley–VCH, Weinheim,

1996, p. 317.

[41] P.P. Gaspar, R. West, in: Z. Rappoport, Y. Apeloig (Eds.), The

Chemistry of Organic Silicon Compounds, vol. 2, Wiley, Chichester,

1998, p. 2463.

[42] M.E. Lee, H.M. Cho, C.H. Kim, W. Ando, Organometallics 20

(2001) 1472.

[43] R. Corriu, G. Lanneau, C. Priou, F. Soulairol, N. Auner, R. Probst,

R. Conlin, C. Tan, J. Organomet. Chem. 466 (1994) 55.

[44] M.J. Michalczyk, M.J. Fink, D.J. De Young, C.W. Carlson, K.M.

Welsh, R. West, J. Michl, Silicon, Germanium, Tin Lead Compd. 9

(1986) 75.

[45] P. Boudjouk, U. Samaraweera, R. Sooriyakumaran, J. Chrisciel,

K.R. Anderson, Angew. Chem. 100 (1988) 1406;

P. Boudjouk, U. Samaraweera, R. Sooriyakumaran, J. Chrisciel,

K.R. Anderson, Angew. Chem., Int. Ed. Engl. 27 (1988) 1355.

[46] N. Takeda, H. Suzuki, N. Tokitoh, R. Okazaki, J. Am. Chem. Soc.

119 (1997) 1456.

[47] N. Wiberg, W. Niedermayer, Z. Naturforsch. B 55 (2000) 406.

[48] M. Haaf, T.A. Schmedake, B.J. Paradise, R. West, Can. J. Chem. 78

(2000) 1526.

[49] W.S. Sheldrick, in: S. Patai, Z. Rappoport (Eds.), The Chemistry of

Organosilicon Compounds, vol. 1, Wiley, Chichester, 1989, p. 227.

[50] M. Kaftory, M. Kapon, M. Botoshansky, in: Z. Rappoport, Y.

Apeloig (Eds.), The Chemistry of Organic Silicon Compounds, vol. 2,

Wiley, Chichester, 1998, p. 181.

[51] H.J. Emeleus, S.R. Robinson, J. Chem. Soc. (1947) 1592.

[52] F.S. Kipping, J. Chem. Soc. 91 (1907) 215.

[53] G.V. Motsarev, V.T. Inshakova, V.I. Kolbasov, R.V. Dshagaipanjan,

Zh. Obshch. Khim. 41 (1971) 1573.

[54] K.A. Andrianov, G.V. Kotrelev, L.I. Nosova, Zh. Obshch. Khim. 42

(1972) 854.

[55] L.H. Sommer, L.J. Tyler, J. Am. Chem. Soc. 76 (1954) 1030.

[56] C.N. Smit, F. Bickelhaupt, Phosphorus, Sulfur, Silicon Rel. Elem. 30

(1987) 357.

[57] N. Wiberg, B. Neruda, Chem. Ber. 99 (1966) 740.

[58] U. Scheim, H. Grosse-Ruyken, K. Ruhlmann, G. Schmidt, GDR-Pat.

¨

DD226567 (1984); CA (1984) 267446.

[59] R. Wagner, L. Richter, Y. Wu, J. Weissmuller, J. Reiners, E. Hengge,

¨

Appl. Organomet. Chem. (1997) 645.

[60] M. Nanjo, A. Sekiguchi, H. Sakurai, Bull. Chem. Soc. Jpn. 71 (1998)

741.

[61] Z.-E. Lin, S.-H. Wu, Z.-P. Yao, Org. Mass Spectrom. 26 (1991)

24.

[62] P.E. Lebedev, A.D. Fedorov, V.O. Reichsfeld, Zh. Obshch. Khim. 46

(1976) 931.

[63] R.E. Swaim, W.P. Weber, J. Am. Chem. Soc. 101 (1979) 5703.

[64] H. Sakurai, K. Oharu, Y. Nakadaira, Chem. Lett. (1986) 1797.

[65] S. Zhang, R.T. Conlin, J. Am. Chem. Soc. 113 (1991) 4272.

[66] R. West, P. Nowakowski, P. Boudjouk, J. Am. Chem. Soc. 98 (1976)

5620.

[67] Bruker ^SHELTXVersion 5.10 SGI/IRIX 5.3, Copyright ꢁ, Bruker

Analytical X-ray Systems, 1997.

[68] G.M. Sheldrick, SHELXL-97, Universita¨t Go¨ttingen, Go¨ttingen, Ger-

many, 1997.

We thank the Fonds der Chemischen Industrie for the

material support of this work.

References

[1] G. Ko¨brich, Angew. Chem. 84 (1972) 557;

G. Ko¨brich, Angew. Chem., Int. Ed. Engl. 11 (1972) 473.

[2] D. Seebach, H. Siegel, J. Gabriel, R. Ha¨ssig, Helv. Chim. Acta 63

(1980) 2046.

[3] H. Siegel, Top. Curr. Chem. 106 (1982) 55.

[4] G. Boche, M. Marsch, A. Muller, K. Harms, Angew. Chem. 105

¨

(1993) 1081;

G. Boche, M. Marsch, A. Muller, K. Harms, Angew. Chem., Int. Ed.

¨

Engl. 32 (1993) 1032.

[5] G. Boche, F. Bosold, J.C.W. Lohrenz, A. Opel, R. Zulauf, Chem.

Ber. 126 (1993) 1873.

[6] A. Maercker, Angew. Chem. 105 (1993) 1072;

A. Maercker, Angew. Chem., Int. Ed. Engl. 32 (1993) 1023.

[7] M. Topolski, M. Duraisamy, J. Rachon, J. Gawronski, K. Gaw-

ronska, V. Goedken, H.M. Walborsky, J. Org. Chem. 58 (1993) 546.

[8] M. Shimizu, T. Hata, T. Hiyama, Tetrahedron Lett. 38 (1997) 4591.

[9] M. Braun, Angew. Chem. 110 (1998) 444;

M. Braun, Angew. Chem., Int. Ed. Engl. 37 (1998) 430.

[10] H. Hermann, J.C.W. Lohrenz, A. Kuhn, G. Boche, Tetrahedron 56

¨

(2000) 4109.

[11] Y. Naruse, A. Hayashi, S. Sou, H. Ikeda, S. Inagaki, Bull. Chem.

Soc. Jpn. 74 (2001) 245.

[12] G. Boche, J.C.W. Lohrenz, Chem. Rev. 101 (2001) 697.

[13] Th. Baumgartner, P. Moors, M. Nieger, H. Hupfer, E. Niecke,

Organometallics 21 (2002) 4919.

[14] M. Braun, in: Z. Rappoport, I. Marek (Eds.), The Chemistry of

Organolithium Compounds, vol. 2, Wiley, Chichester, 2004, p. 829.

[15] P.J. Stang, Chem. Rev. 78 (1978) 383.

[16] A.F. Burchat, J.M. Chong, S.B. Park, Tetrahedron Lett. 34 (1993)

51.

[17] A.R. Katrizky, M. Qi, Tetrahedron 54 (1998) 2647.

[18] R.E. Gawley, E. Low, Q. Zhang, R. Haris, J. Am. Chem. Soc. 122

(2000) 3344.

[19] K. Tamao, A. Kawachi, Adv. Organomet. Chem. 38 (1995) 1.

[20] A. Kawachi, K. Tamao, Bull. Chem. Soc. Jpn. 70 (1997) 945.

[21] K. Tamao, A. Kawachi, M. Asahara, A. Toshimitsu, Pure Appl.

Chem. 71 (1999) 393.

[22] J. Belzner, U. Dehnert, in: Z. Rappoport, Y. Apeloig (Eds.), The

Chemistry of Organic Silicon Compounds, vol. 2, Wiley, Chichester,

1998, p. 779.

[23] K. Tamao, A. Kawachi, Y. Ito, J. Am. Chem. Soc. 114 (1992) 3989.

[24] K. Tamao, A. Kawachi, Organometallics 14 (1995) 3108.

[25] A. Kawachi, N. Doi, K. Tamao, J. Am. Chem. Soc. 119 (1997) 233.

[26] I. Rietz, E. Popowski, H. Reinke, M. Michalik, J. Organomet. Chem.

556 (1998) 67.

[27] A. Kawachi, K. Tamao, J. Am. Chem. Soc. 122 (2000) 1919.

[28] C. Strohmann, O. Ulbrich, D. Auer, Eur. J. Inorg. Chem. (2001)

1013.

[29] K. Tamao, A. Kawachi, Angew. Chem. 107 (1995) 886;

K. Tamao, A. Kawachi, Angew. Chem., Int. Ed. Engl. 34 (1995) 818.

[30] A. Kawachi, K. Tamao, Organometallics 15 (1996) 4653.

[31] A. Kawachi, H. Maeda, H. Nakamura, N. Doi, K. Tamao, J. Am.

Chem. Soc. 123 (2001) 3143.

[32] J. Harloﬀ, E. Popowski, H. Fuhrmann, J. Organomet. Chem. 592

(1999) 136.

[33] J. Harloﬀ, E. Popowski, in: N. Auner, J. Weis (Eds.), Organosilicon

Chemistry V – From Molecules to Materials, Wiley–VCH, Weinheim,

2003, p. 175.

Article Doi

Substituted lithiumtrimethylsiloxysilanides LiSiRR′(OSiMe3) - Investigations of their synthesis, stability and reactivity

DOI: 10.1016/j.jorganchem.2006.11.033

Source and publish data:

Authors:

Article abstract of DOI:10.1016/j.jorganchem.2006.11.033

Full text of DOI:10.1016/j.jorganchem.2006.11.033

Products guided by the article

R&D Labs maybe for 823207-19-8

Relevant to this article

Hot Product