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Nucleophilic Aminoalkylation.

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- 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
and finally the extent of acidification by X should be sufficient
to obviate any need for additional stabilization of the carbanionoid center of ( 2 ) (as with X=POX,[81). So far only
the nitrosamines ( I a ) have proved to be aminomethylation
agents of broad scope"].
We have now found the thiopivaloyl group to be another
substituent permitting quantitative metalation to give stable
derivatives (up to -50°C) of type (2). Thus conversion of
(3) into the organolithium compound ( 4 ) can be accomplished under the conditions given in the reaction scheme.
Reaction of ( 4 ) with alkyl halides and carbonyl compounds
proceeds via C-C linkage to form the products (5) (Table
1). Alkylations are more successful than hydroxyalkylations;
see -BuLi
CAS Registry numbers:
( 3 ) , 25530-28-3; (4), 58832-32-9; (6), 58832-33-0; (7), 58832-34-1
Table 1. Electrophiles (from top to bottom):
74-88-4: 628-17-1 ; 112-2943; 100-39-0; 100-52-7; 199-61-9; 78-84-2: 108-94-1 ;
127-19-5
Table 1. ( 5 ) (from top to bottom):
58856-07-8 ; 58832-24-9; 58832-25-0; 58832-26-1 ; 58832-27-2; 58832-28-3;
58832-29-4; 58832-30-7; 58832-31-8
[l] Part of the projected Thesis by W L., Universitat Giessen.
[2] D . Seebach and D . Enders, Angew. Chem. 87, 1 (1975); Angew. Chem.
Int. Ed. Engl. 87, 15 (1975); D. Enders, Thesis, Universitat Giessen
1974.
[3] B. Bdnhidai and U . Schollkopf, Angew. Chem. 85, 861 (1973); Angew.
Chem. Int. Ed. Engl. 85, 836 (1973); R . R . Fraser and P. R . Hubert,
Can. J . Chem. 52, 185 (1974).
[4] a) D . Enders and D . Seebach, Angew. Chem. 85, 1104 (1973): Angew.
Chem. Int. Ed. Engl. 85, 1014 (1973); b) D. Seebach, W Lubosch, and
D . Enders, Chem. Ber., in press.
[5] R . Dach, unpublished experiments, Universitat Giessen (1974/75).
(41
[6] P. Beak and R . Farney, J. Am. Chem. SOC.95, 4771 (1973).
[7] H . Bohme and P. Plappert, Chem. Ber. 108, 2827 (1975).
[S] P . Sauignac et al., C. R. Acad. Sci. C279, 609 (1974): Tetrahedron
Lett. 1974, 2651; J. Organomet. Chem. 57, C 4 7 (1973); Tetrahedron
31, 877 (1975).
[9] H . Vorbriiggen and P. Srrehlke, Chem. Ber. 106, 3039 (1973).
[lo] M . W C r o n y and J . E. Goodrich, J. Am. Chem. SOC.74, 3936 (1952).
Electrophile
)t/"
H,C/"CH
lE
(5)
E = A l k y l , B e n z y l , RR'C , R C O
I
OH
Table 1. Reactions of (4) with electrophiles to form products of type (5)
[a, bl.
Yield "/,
Electrophile
CHJ
n-C5H I
n-C loHz Br
C6H5CH2Br
C 6 H5 C H 0
(CeHs)2CO
(CH,),CH-CHO
Cyclohexanone
CHsCON(CHa)2
'H-NMR rdl
spectr.
pure
c1.
PI
95
91
80
48
85
78
80
27
56
80
82
79
44
70
63
23
17
33
3.97 (4)
3.86 (br. t)
3.87 (br. t)
4.08 (m)
4.18 (m)
5.16 (s)
3 . 7 3 4 . 0 2 (m)
4.24 (s)
4.71 (s)
[a] NMR data not listed as well as other spectroscopic data (e.g. two
broad thioamide bands at 1330-1420 and 1 4 5 0 - 1 5 1 0 ~ m - ~ ) and elemental
analyses (within 0.3 %) all accord with the expected structures.
[b] Apart from the adducts with benzaldehyde (m. p. 105"C), benzophenone
(m.p. 150"C), and cyclohexanone (m.p. 104.5"C) compounds ( 5 ) are oils
which were purified by chromatography.
[c] From weight of crude product and NMR comparison with analytically
pure material.
[d] The a-N-CH, signal is given. The tert-butyl group appears between
1.38 and 1.46, the methyl group between 3.2 and 3.5ppm (both singlets).
Solvent CCln or CDC13.
[6 +21 Cycloadditions of Pentafulvene.
A Facile Pentalene Synthesis[**]
By Klaus Hafner and Minoru Suds"]
The hitherto known syntheses of pentalene and its derivatives require several reaction steps and frequently the isolation
of rather unstable intermediated']. We have found that the
[6 + 2]cycloaddition~'~of 6-dimethylaminofulvenes with electron-deficient acetylene derivatives offers a facile synthesis of
pentalenes which can be carried out as a "one batch procedure"
at 20°C.
While 6-dimethylaminofulvene undergoes a Michael addition with dimethyl acetylenedicarboxylate at 20°C in benzene13], 1,3-di-tert-butyl-6-dimethylaminofulvene
combines with the alkyne under the same reaction conditions,
presumably via the dipolar intermediate (2) and its cyclization
product ( 3 ) , to give the thermally- and air-stable dimethyl
4,6-di-tert-butylpentalene-l,2-dicarboxylate
( 4 ).
this contrasts with the situation in the case of lithiated nitrosamines which can be described as typical carbonylophiles['].
The thioamides ( 5 ) can be smoothly transformed into
amides by alkaline HzOz[9], as we have demonstrated by
preparing compound (6) (93%, m.p. 95.5"C).Neopentylamines are accessible from ( 5 ) by desulfuration with
LiA1H4[4b.101(example: (7); 88 %; m.p. 84.5"C).
Received: March 23, 1976 [Z 432 I€]
German version: Angew. Chem. 88,339 (1976)
314
[*] Prof. Dr. K . Hafner and Dr. M. Suda
lnstitut fur Organische Chemie der Technischen Hochschule
Petersenstrasse 15, 6100 Darmstadt (Germany)
[**I This work was supported by the Deutsche Forschungsgemeinschaft
and the Fonds der Chemischen Industrie.
Angew. Chem. Inr. Ed. Engl.
1 Vol. 15 (1976) N o . 5
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