close

Вход

Забыли?

вход по аккаунту

?

Nucleophilic 1 3-Rearrangement at SiliconЧIndirect Evidence for a Silicon-Nitrogen Ylide.

код для вставкиСкачать
The existence of (3) is confirmed by elemental analysis
and the mass spectrum (70eV): m/e= 167 molecular ion (rel.
int. 36.7 %), 148 OS-NSOF2 (9.8), 100 NSOFz (1.7), 86 SOF2
(S), 70 SF'? (3.3), 67 SOF (IOO), 65 NSF (1.9), 62 NSO (5.3),
51 SF (3.1), 48 SO (10.5), 46 NS (9.1), 32 S (2.5), and 30?
(6.6).-The IR spectrum contains bands at 1425 (vs, vS0,
NSOF'), 1271 (m, vSO), 1182 (vs, vNS), 872 (vs, vSF), 735
(w), 698 (w), 655 (w), 490 (m), and 450 cm-' (m).
Compound ( 3 ) gives an unusual "F-NMR spectrum.
Instead of the expected doublet and triplet it contains a quartet
at -57.98 ppm (SOF) and an octet at -52.48ppm (ABX
type), i. e. the fluorine atoms ofthe NSOF2 group are diastereotopic and couple with each other as well as with the fluorine
atom attached to the unsymmetrically substituted sulfur atom
=
8 ~=
of the sulfinyl group: 8x= -57.98, 8 ~ -52.54,
52.43 ppm; JAB= 193.6, JAX= 8.3, JBX= 8.3 HZ (Fx-SONSOFAFB).
I
I
I
+ 2 C&Li
2 R,N-Si-N-R'
- 2 LiF. - 2 C4H,,
I
F H
R,N-Si-N-R'
I
I
R'-N-y
-NR
@
R = Si(CH3),, R' = C(CH3),
(1)
However, if a fluorine atom of tert-butylaminodifluorosilane
is replaced by an aryl groupf4]the reaction takes an unusual
course: The product obtained is an unsymmetrically substituted cyclic dystem whose formation can be attributed to
a nucleophilic 1,3-rearrangement at silicon (comparable with
the known methyl shift in a carbon skeleton) and also be
regarded as evidence for generation of a silicon ylide. The
absence of oligomerization products of type (1) shows the
steric influence of the nitrogen atoms alone to provide insuficient stabilization of such a species with silicon having the
coordination number 3[']. Instead, the expected extremely
high reactivity of this intermediate leads to intramolecular
nucleophilic substitution with migration of a methanide ion
and ring closure to give ( 2 ) .
Received: February 24, 1976 [Z 428 IE]
German version: Angew. Chem. 88,338 (1976)
CAS Registry numbers:
(I), 14177-25-4; ( 2 ) , 31618-64-1 ; (3), 58816-64-1
Procedure.
C4H9Li (0.11 mol, as 15 % solution in hexane) is added
dropwise at room temperature to monoalkylaminofluorosilane
(0.1 mol) with stirring. An exothermic reaction ensues, liberating lithium fluoride and butane, which is condensed in a
cold trap. After boiling for 12h the hexane is distilled of
in uacuo and the residue vacuum sublimed.
[l] P. W Schenk and H . Blocking, Chem. Ber. 92,2333 (1959).
[2] W Lidy, Dissertation, Universitat Heidelberg 1974.
[3] H . - J . Krannich and W Sunderrneyer, Angew. Chem. 88.88 (1976); Angew.
Chem. Int. Ed. Engl. IS, 110 (1976).
[4] H. S . Booth and F . C . Mericola, J. Am. Chem. SOC.62, 640 (1940).
[5] K . Seppelt and W Sunderrneyer, Angew. Chem. 82, 931 (1970); Angew.
Chem. Int. Ed. Engl. 9, 905 (1970).
R
+C~HPLX
-----+
-LIF.-C~HIO
I
(CH3)3Si-N-Si-N-R
I
I
F H
r
0
R
(CH3)3Si-N-
Si-N-R
R
I
cc
/
0
ct
(CH3)3Si-N-
Si=fj-R
\
- :CH3
H,C-Si-N-R
I
I
R-N-Si-CH3
I
(2)
1/2 (CH,),Si-N-Si-N-R
I
I
R-N-Si -N-Si(CH3),
CH3
R = C(CH3)3
Nucleophilic 1,SRearrangement at Silicon-Indirect
Evidence for a Silicon-Nitrogen Y l i d e c * * ]
The composition of the new compounds was confirmed
by elemental analysis and vibrational spectroscopy:
By Uwe Klingebiel and Anton Meller"]
Apart from bimolecular ring closure reactions of halosilanes
with amines or ammonia['], stable monoalkylaminofluorosilanes['] can be cyclized directly by the action of n-butyllithiumc3I,the reaction mechanism being interpretable in intramolecular or intermolecular terms:
I ,3-Di-tert-butyl-2,4-di[bis (trimethylsilyl)amino] -2,4-difluorocyclodisilazane (1)
[*] Prof. Dr. A. Meller and Dr. U. Klingebiel
Anorganisch-chemisches Institut der Universitat
Tammannstrasse 4, 3400 Gottingen (Germany)
p * ] This work was supported by the Deutsche Forschungsgemeinschaft
and the Fonds der Chemischen Industrie.
312
Yield 65%; m.p. 204°C; MS (70eV): m/e=556 (rel. int.
3%, M'); 'H-NMR (in CH,CI,, TMS int. standard): -0.15,
-0.31 [(Me3Si)'N, cisltrans isomers; JHF=0.9Hz] - 1.29 ppm
(tBu); "F-NMR (with C6F6 as internal standard): -56.25,
- 57.33 ppm.
1~-Di-tert-butyl-2,2,4-trimethyl-4-phenylcyclodisilazane
(2)
Yield 88%; m.p. 57°C; MS (70eV): m/e=320 (rel. int.
3 %, MC);'H-NMR (in CH2CI2,TMS int. standard): -0.38,
Angew. Chem. Int. Ed. Engl.
/ Vol. 15 (1976) N o . 5
- 0.47 (Me&), - 0.68 (MeSi), - 1.04 (tBu), - 7.52 ppm (Ph);
z9Si-NMR (in C6F6, TMS int. standard; 'H-noise decoupled):
- 1.2 (Me&),
11.5 ppm (MeSi).
+
Received: January 21, 1976;
revised: February 9, 1976 [Z 420 IE]
German version: Angew. Chem. 88, 307 (1976)
CAS Registry numbers:
( l ) ,58816-84-5; (Z), 58816-85-6; [(CH,),Si12NSiF2NHC(CH3),, 58816-86-7;
(CH,),SiN[C(CH,),]SiF(Ph)NHC(CH,),,
58816-87-8
[l] W Fink, Angew. Chem. 78, 803 (1966); Angew. Chem. Int. Ed. Engl.
5, 760 (1966); U . Wunnagnt and M . Schlingmann, 2. Anorg. Allg. Chem.
406, 7 (1974).
[2] U . Klingebiel, D. Fischer, and A. Meller, Monatsh. Chem. 106, 459
( 1 975).
[3] U . Klingebiel and A. Meller, Chem. Ber., in press.
[4] U.Kleingebiel and A. Meller, to be published.
[5] P . Jutzi, Angew. Chem. 87, 269 (1975); Angew. Chem. Int. Ed. Engl.
14, 232 (1975).
Synthesis of an N-LithioaminofluorosilaneI**J
By Uwe Klingebiel and Anton Mellerpl
Although fluorosilanes differ from other halosilanes in their
reaction with amines, they nevertheless undergo analogous
substitution reactions with the lithium salts of arnined']. The
action of n-butyllithium on monoalkylaminofluorosilanes
leads via loss of lithium fluoride and butane to ring closures
of various kindsrzJ.With the aim of suppressing such cyclizations and of stabilizing an intermediate silicenium ylide[']
we have prepared the aminofluorosilane ( I ) , exhibiting optimal steric shielding, by reaction of di-tert-butyldiflu~rosilane[~~
with lithium tert-butylamide :
As expected, (1) shows little tendency to react with n-butyllithium relative to other aminofluorosilanes. Evolution of
butane is only observed on raising the temperature, whereupon
a colorless solid crystallizes which proves to be the first
aminofluorosilane lithiated on the nitrogen atom (2):
The ready hydrolysis of (2) and its solubility in organic
solvents correspond to those of other lithium amides. However,
the thermal stability of this compound is remarkable: it only
sublimes above 125"C with partial decomposition and formation of polymeric products. The unusually large upfield shifts
of the I9F-NMR signals of (1) and (2) is explained by the
electron pressure of the tert-butyl groups. Molecular weight
determination and the spatial structure of the compound rule
out association of (2). Elemental analysis and vibrational
spectra support the structures given.
p] Prof. Dr. A. Meller and Dr. U. Klingebiel
Anorganisch-chemisches Institut der Universitat
Tammannstrasse 4, 3400 Gottingen (Germany)
This work was supported by the Deutsche Forschungsgemeinschaft
and the Fonds der Chemischen Industrie.
[**I
Angew. Chem. Int. Ed. Engl.
j Vol. 15 (1976) No. 5
Procedure :
C4H9Li(0.1 mol, 15 %solution in hexane) is added dropwise
at room temperature under Nz to compound (1) (0.1mol)
with stirring. Warming of the reaction mixture to ca. 50°C
effects liberation of butane which is condensed in a cold trap.
The metalation is driven to completion by boiling for another
2 h. The product (2) can be purified by recrystallization from
hexane or by sublimation at 120"C/O.l torr.
Di-tert-butyl(tert-buty1amino)jluorosilane( I )
Yield 85 %; b.p. 80°C/8 torr; MS (70eV): m/e=233 (rel.
int. 1 %, M'); 'H-NMR (in C6H6, TMS int. standard-: - 1.05
(tBuSi; JHF=
l.OHz), -1.20ppm (tBuN; JHF=0.8 Hz); 19FNMR (in C,&,
CFC13 ext. standard): +168.09ppm,
JHNF=8.0Hz;29Si-NMR (in C6F6, TMS int. standard; 'Hnoise decoupled): - 0.7 ppm, JsiF= 300.3 Hz.
N-Lithiodi-tert-butyl(tert-buty1amino)jluorosilane
(2)
Yield 80%; m.p. >125"C (dec.); MW (osmometric in
CHC13):252; 'H-NMR (in C6H6, TMS int. standard): - 1.20
(tBuSi), - 1.23 ppm (tBuN); "F-NMR (in C6H6, CFC13 ext.
standard): + 162.41 ppm.
Received: February 13, 1976 [Z 425 IE]
German version: Angew. Chem. 88,304 (1976)
CAS Registry numbers:
( l ) ,58802-36-1 ; (Z), 58802-37-2; [(CH,),C],SiF,,
37828-54-9; 29Si, 14304-87-1
558-63-4; LiNHC(CH,),,
[1] U . Klingebiel and A. Meller, Chem. Ber., in press.
[2] U . Klingebiel and A. Meller, Angew. Chem. 88, 307 (1976); Angew.
Chem. Int. Ed. Engl. 15,312 (1976).
[3] M . Weidenbruch and W Peter, Angew. Chem. 87, 670 (1975); Angew.
Chem. Int. Ed. Engl. 14, 642 (1975).
Nucleophilic Arninoalkylation.
Lithiated N,N-Dirnethylthiopivalarnide[l][**I
By Dieter Seebach and Winfried Luboschp]
In the search for activating groups X in (1) which permit
metalation to (2) (CH acidification of amines) several derivatives have been examined. The group X should be such that
it is neither attacked by the deprotonating reagent employed
(as with X=CN['], CHOC3], and CHSr4])nor undergo facile
departure from (2) as LiX (as with X=NO2['] and Tosyl['J);
nor should self-condensation with the precursor (1 ) occur
8
on generation of (2) (as with X=benzoylr6]and C(C6H,)z[7J),
(a).X
=
(1)
NO; ( b ) . X
=
(CH,),C-C
s
(2)
p] Prof. Dr. D. Seebach and Dipl.-Chem. W. Lubosch
Institut fur Organische Chemie des Fachbereichs 14 der Universitat
Heinrich-Buff-Ring 58, 6300 Giessen (Germany)
[**I This work was supported by the Deutsche Forschungsgemeinschaft
(Projects Se 158/7, 10 and 12) and the Fonds der Chemischen Industrie.
We are indebted to G. W H . Protschuk for his assistance in some of the
experiments.
313
Документ
Категория
Без категории
Просмотров
0
Размер файла
200 Кб
Теги
rearrangements, siliconчindirect, evidence, nitrogen, silicon, ylide, nucleophilic
1/--страниц
Пожаловаться на содержимое документа