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N N-Bis(trimethylsilyl)aminomethylation of Grignard Compounds Ч A Versatile Amine Synthesis.

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COMMUNICATIONS
1 N hydrochloric acid or by passage of gaseous HCl into a
solution of 7 in moist diethyl ether; the siloxane 10 is
formed concomitantly"].
Hence, primary halides such as 2 can either be converted into silylated amines such as 3 by nucleophilic substitution with 1 or, after umpolung via a Grignard compound, into compounds such as 7 containing an additional CH2 group, by electrophilic substitution.
Procedure
N,N-Bis(trimethylsily1)aminomethylation of Grignard
Compounds- A Versatile Amine Synthesis
By Hans Jurgen Bestmann* and Gerhard Wolfel
Dedicated to Professor Karl Winnacker on the occasion
of his 80th birthday
Sodium bis(trimethylsily1)amide 11']
reacts with primary
halides 2 (R'= R-CH2, R = H, alkyl, alkenyl, alkynyl,
aryl) to give N,N-bis(trimethylsily1)amines 3[']. We have
now converted the a-haloethers 4 with 1 into the N,Nbis(trimethylsily1)aminomethyl ethers 5. These react with
the Grignard compounds 6 (R', see Table 1) to give the
N,N-bis(trimethylsily1)amines 7 and the magnesium alkoxides 8. Table 1 shows the scope of the reaction. Grignard
compounds 6 can be employed in which the MgBr residue
is attached to an sp3, sp2 or sp. hybridized C-atom. In the
case of the propargyl moiety (Example d in Table 1). use
of the aluminum "Grignard compound"[41has once againI3]
proven better than that of the magnesium compound.
NaN[Si(CH,),]2 + R'-X
1
- NaX
3
R~-O-CH~-CI
4 (R2 = CH3, C6Hi3)
Hz-N[ Si ( C H3)312
+ R' M gB r
5 ( R 2 = CHs, C,jH13)
-
R'-C H2-N[ Si(C H3), ]
6
I
8
- O[Si(CH&],
10
Stable Cyclopentadienylium Salts**
R1-CH2-NH3C1
9
Table 1. Yields and boiling points of the N,N-bis(trimethylsi1yl)amines 7
l
R'
Yield [Oh] [a]
B.p. ["C/torr]
a
b
CH3
CtMsCH2
HzC=CH-CH2
HC=C-CH2 [c]
C6Hs
a-Naphthyl
H7Ca-Cd
82
71 Ibl
70
52
64
52
65
60/20
63/0.05
81/16
80/18
52/0.1
64/0.01
52/0.1
d
e
f
g
CAS Registry numbers:
1, 1070-89-9; 4a, 107-30-2; 4b, 39979-92-5; 5a, 88211-44-3; 5b, 88211-45-4;
6a, 75-16-1; 6b, 1589-82-8; 6c, 1730-25-2; 6d, 13254-27-8; 6e, 100-58-3; 6f,
703-55-9; 6g, 41246-05-3; 7a, 2477-39-6; 7b, 58367-45-6; 7c, 88211-46-5; 7d,
88211-47-6; 7e, 18406-59-2; 7f, 88211-48-7; 7g, 88211-49-8; 9a, 557-66-4;
9b, 156-28-5; 9c, 17875-18-2; 9d, 88211-50-6; 9e, 3287-99-8; 9f, 39110-74-2;
9g, 88211-51-2.
-R~-OM~B~
HCliH20
C
Received: July 21, 1983 [ Z 495 IE]
German version: Angew. Chem. 96 (1984) 52
[I] U. Wannagat, H. Niederpriim, Chem. Ber. 94 (1961) 1540.
[2] K. Riihlmann, Chem. Ber. 94 (1961) 2311; H. J. Bestmann, G. Wolfel, W.
Rieck, ibid., in press.
[3] Cf. H. J. Bestmann, R. Schobert, Angew. Chem. 95 (1983) 810; Angew.
Chern. Int. Ed. Engl. 22 (1983) 780.
[4] E. Truscheit, K. Eiter, Justus Liebigs Ann. Chem. 658 (1962) 65.
R'-N[Si(CH,),l2
2
1
R '-0-
-
5: 4 (0.1 mol) is added dropwise at 0°C to a stirred solution of 1 (18.4 g, 0.1 mol) in hexamethyldisilazane (50 mL).
After 8 h at room temperature, NaCl is removed from the
reaction mixture by filtration; the solvent is distilled off
from the filtrate and the residue is fractionally distilled;
5a; b.p. 73"C/16 torr; 5b: b.p. 124"C/16 tom-7: A solution of 5 (0.02 mol) in anhydrous ether (25 mL) is added
dropwise to an ethereal Grignard solution of 2 (0.025
mol). After 12 h, precipitated 8 is filtered off and the solvent is removed from the filtrate by distillation. The residue is fractionally distilled. All operations are carried out
under nitrogen.-9: HCl is passed into a solution of 7
(0.02 mol) in moist ether (25 mL). 9 precipitates out and is
recovered by filtration.
[a] Not optimized. m] Same yields also in the reaction with 5b. [c] The Al"Grignard compound" was employed.
The silylamines 7 can easily be converted into the amine
hydrochlorides 9 in yields of over 90% by treatment with
[*] Prof. Dr. H. J. Bestmann, Dip1.-Chem. G. Wolfel
Institut fiir Organische Chemie der Universittit Erlangen-Niirnberg
Henkestrasse 42, D-8520 Erlangen (FRG)
Angew. Chem. Int. Ed. Engl. 23 (1984) No. I
By Rudolf Gompper* and Heinrich Glockner
According to Breslowl'], cyclopentadienylium salts are
antiaromatic compounds. The parent compound and the
pentachloro derivative have a triplet ground state (cf. I2]),
and the pentaphenyl and pentakisk-methoxyphenyl) derivatives a low-lying triplet state.
Previously, cyclopentadienylium salts have only been
obtained in solution. However, cyclopentadienylium ions
can be dramatically stabilized by ring N atoms in a compound with donor substituents: azacyclopentadienylium
saltsL3]and 1,3-diazacyclopentadienyliumsalts are extraordinarily thermally stable and display no indication of antiaromaticity. Since the pentakisb-methoxypheny1)cyclopentadienylium ion is stable in solution at room temperature['], it should be possible to find combinations of substituents which lead to isolable cyclopentadienylium salts ;
[*I Prof. Dr. R. Gompper, DiplXhem. H. Glockner
Institut fur Organische Chemie der Universittit
Karlstrasse 23, D-8000 Miinchen 2 (FRG)
[**I This work was supported by the Deutsche Forschungsgemeinschaft and
by the Fonds der Chemischen Industrie.
0 Verlag Chemie GmbH, 0-6940 Weinheim, 1984
0570-0833/84/0101-0053 $ 02.50/0
53
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trimethylsilyl, versatile, synthesis, aminomethylation, compounds, amin, grignard, bis
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