close

Вход

Забыли?

вход по аккаунту

?

Novel Reactions of Acyl Halides with Bis(trimethylsilyl) Telluride C Te and C C Bond Formation.

код для вставкиСкачать
COMMUNICATIONS
telluroacetate 4 (m/z 246, M e for I3'Te). The decomposition of 4 and the formation of the final products, (E)- and
(a-5,
can be followed by mass spectroscopy.[8'
[ (CH,),Si],Te
0
II
0
II
+ H,C-C-Te-C-CH,
-+
2
H3C,
/CH3
+
,c=c,
(CH,),SiO
Novel Reactions o Acyl Halides with
Bis(trimethylsily1) Telluride:
C,Te and C,C Bond Formation**
Telluro esters with C=Te groups should be of interest
both as 1,2-dipoles and as soft ligands, but little is known
about them. Only compounds with bulky substituents of
the type tBuC(=Te)OR have been identified, the tert-butyl
group being decisive for their stability."] In the course of
seeking new tellurium reagentsf2] and new olefin syntheses,[31we found that bis(trimethylsily1) telluride 2 does
not react with simple
but does undergo spontaneous reaction with acyl halides.
1
c1
a, R = CH,;
2
- 2 (CH,)$CI
0
0
II
II
R-C-Te-C-R
3
b, R = C(CH,),
Diacetyl telluride 3a is obtained in practically quantitative yield when acetyl chloride l a is allowed to react at
- 30°C with a less than stoichiometric amount of 2 ; in the
same way, pivaloyl chloride reacts with 2 at - 10 to
-20°C to give 3b.[5,61
In the IR spectra of 3, the characteristic pair of bands for each of the v(C=O) appears; the
mass spectra exhibit peaks for the molecular ions (correct
isotopic distribution) as well as peaks for the fragments
formed by loss of CO and acyl groups. In contrast to the
dialkyl species, the diacyl tellurides 3 are extremely sensitive to air and moisture; the hydrolysis products include
the corresponding diacyl ditellurides (identified by
MS)."]
Noteworthy is the reaction of 3a with 2 : upon mixing of
the two tellurium compounds (-2O"C, without solvent),
the mixture rapidly turns intense blue and, simultaneously,
tellurium starts to separate out. A mass spectrum (recorded
immediately after mixing) shows the complete consumption of 3a (no group of signals around m/z 216I6l); instead,
new peaks appear which we ascribe to the trimethylsilyl
[*] Prof. Dr. W.-W. du Mont, Dr. T. Severengiz, Priv.-Doz. Dr. D. Lenoir,
H. Voss
Fachbereich Chemie der Universitat
Carl-von-Ossietzky-Strasse 9-1 1, D-2900 Oldenburg (FRG)
[**I This work was supported by the Deutsche Forschungsgemeinschaft and
the Fonds der Chemischen Industrie.
Angew. Chem. Inr. Ed. Engl. 24 (1985) No. 12
/OSi(CH,),
c=c\
(CH3),SiO/
CH,
(E)-5
(Z1-5
By TeuJik Seuerengiz, Wov- Walther du Mont,*
Dieter Lenoir, * and Heike Voss
Dedicated to Professor Max Schmidt on the occasion of
his 60th birthday
40
2 RC\
+ ((CH,),SiJ,Te
OSi(CH,),
I13C,
The intermediacy of 4 is favored by the formation of the
Si-0 bond.[91After 12-15 h at room temperature, the yield
of 5 (mixture of isomers, (E)-5:(z)-5= 55 :45), determined by NMR spectroscopy, is nearly quantitative (yield
after distillation (b.p. = 68-78 "C/20 mbar): 60-70%).['01
The 2-butene derivatives 5 are also formed when 2 is allowed to react with molar equivalent amounts of acetyl
chloride l a (yield after distillation: ca. 70%); tellurium
separates out in an exothermic reaction and a blue color
appears. Accordingly, acetyl chloride l a reacts with 2 in
the sense of an acyloin condensation, leading (as in the
system (CH3)3SiCI/Na) to the disilyl enediol ether." 'I The
deep blue color is due to the labile intermediate 4, which
has a C=Te bond. In the reaction of 2 with equimolar
amounts of pivaloyl chloride l b (or with 3b), the corresponding telluro ester ~ B u C ( = T ~ ) O S ~ ( Cwas
H ~identified
)~
in the mixture;[I2lin the UV/VIS spectrum, the absorptions
characteristic for the C=Te group at A = 624 and 350 nm
(blue solution in n-pentane) are observed.['] In this case, no
acyloin-like C,C bond formation occurs, probably for steric
reasons.['*]
The spontaneous breakdown of the ester 4 (which is free
of bulky substituents) at room temperature with formation
of a C=C bond and elimination of an elemental chalcogen
has no precedent in carbonyl chemistry. Formally, this
reaction is similar to the photochemical desulfurization of
thioesters RC(=S)OR'.['3.'41
Experimental Procedure
3a: 2 (2.26 g, 8.3 mmol) was added dropwise to l a (3.58 g, 45.6 mmol) at
-30°C under argon. The brown suspension was then stirred for 3Omin at
- 3 0 T , and chlorotrimethylsilane and excess acetyl chloride were removed
under reduced pressure. 1.3 g (74%) of 3a remains as a yellow-orange liquid
[6].-Correspondingly. 3b (1.4g, 85%) is obtained as a turquoise liquid from
l b (3.2 g, 26.5 mmol) and 2 (1.5 g, 5.5 mmol) at - 10 to -20°C [6].
Received: July 29, 1985;
revised: September 4, 1985 [Z 1401 IE]
German version: Angew. Chem. 97 (1985) 1051
[l] A. G. M. Barrett, D. H. R. Barton, R. W. Read, J. Cfiern. SOC.Chem.
Commun. 1979, 645.
[2] L. Lange, W.-W. du Mont, J. Organomet. Chem. 286 (1985) C 1.
[3] D. Lenoir, D. Malwitz, B. Meyer, Tetrahedron Left. 25 (1984) 2965; D.
Lenoir, Synthesis 1977. 553.
141 K. Steliou, M. Mrani, J. Am. Chem. SOC.104 (1982) 3104: Compounds
of the type (R3M),S (M=S, Sn) react with ketones to give thioketones.
[S] Synthesis of a telluro phthalic anhydride: J. Bergmann, L. Engman, Org.
Prep. Proced. Int. 10 (1978) 289.
(61 3a: yellow liquid; 'H-NMR (C6D6. TMS ext.): 6=2.1; MS (70 eV/
70°C): m/z 216 (38%, M"), 188 ( I , M"-CO), 174 (4, CH,COTeH"), 173
0 VCH Verlagsgesellschaft mbH. 0-6940 Weinheim, 1985
0570-0833/85/1212-1041$ 02.50/0
1041
(4. CHKOTe'), 143 (7, CH,TeC), 130 (26, Tee"),44 (38, CH3COHD),43
(100, CHKO'), 42 (56, CH,CO"); correct elemental analysis; IR ( C s l i
film): v=260 (m),460 (w), 555 (vs), 800 (w), 845 (w). 910 (m), 942 (m).
1073 (s), 1090 (sh), I122 (w), 1226 (w), 1260 (w), 1342 (m),1410 (in), 1712
(va), 1756(m), 1822 (w), 2915 (w),2990(w), 3410(w)cm-'.-3b: yellowish green liquid, 'H-NMR (C,,H,, TMS ext.): 6= 1.7: MS (70 eV. 70°C):
m/z 300 (Soh,M"), 272 ( 5 , M D - C O ) , 216 (2, C,H&OTeHe), 130 (8,
Te ~ ' )86
, (38, CAHKOH"), 85 (100, C4H,COB); correct elemental analysis; I R (Csl/Nujol): L'= 1705 (vs), 1752 (ni) c m - ' .
[71 The hydrolysis of dibenzoyl selenide to dibenzoyl diselenide proceeds
similarly: H. Ishihara, S. Kato, Tetrahedron Lett. 1972. 3757. Diacyl tellurides are also formed in the reactions of Na2Te with acyl halides: W.W. du Mont, T. Severengiz, unpublished.
[81 MS data for 4 (70 eV, 70°C): m / z 246 (10%. Ma),117 (92, M m- T e + I),
75 (40, (CHl)2SiOHG), 73 (100, (CHl)3Si@),45 (56%, CH,CHOH), 43
(489/0, CH3COa). The signals of 3a decrease in favor of the signals of
( E ) - and (2)-5 ( m / z 232 (MO)); after only 2-3 h at room temperature,
most of 4 has been converted into 5.
[91 For the role of S i - 0 bond formation in thio and seleno esters, see: a) S .
Kato, W. Akada, M. Mizuta, Y . Ishii, BUN. Chem. Soc. Jpn. 46 (1973)
244; b) M. Mikolajczyk, P. Kielbasinski. H. M. Schiebel, J . Chem. SOC.
Perkin Trans. I 1976, 564; c) 171.
[I01 a) For the synthesis of ( 2 ) - 5 , see R. Ugi, R. Schwarz, Angew. Chem. Y3
(1981) 836: Angew. Chem. In/. Ed. Engl. 20 (1981) 789 ('H-NMR
(CDCI?):6=0.09(18H), 1.63 ( 6 H ) ; b.p.=64"C/12 mbar): b)(2)-5i(E)5 : 'H-NMR (C6H6): fi=0.29 and 0.38 (each I8H), 1.83 and 2.0 (each
6H): b.p.=68-78"C/20 mbar; MS: m / z 232 (0.5%, M').
[ I I] K. Riihlmann, Synrhesis 1971, 236.
[I21 tBuC(=Te)OSi(CH,),: MS (70 eV, 70°C): m / z 288 (5%, Ma with ""Te),
I), 130
216(1, C4H,COTeH), 159 (100, C,HUCOHSi(CH3)?G M'-Te+
(4, Te'), 86 (80, C,H,COH'), 85 (100. C4H9COa), 73 (100, (CH,),Si').
Attempts to purify 6 are in progress. Distillation affords the following
decomposition products. B.p.=25-27"C/I mbar: 2 ['H-NMR (C,H,):
6=0.65: MS: m/z 276 (Ma)]and tBu,Te ['H-NMR (C,H,): 6= 1.75;
MS: m / z 244 (Me)]; b.p.= 50-52"C/l mbar: tBu2Te2,['H-NMR (C,H,):
6 = 1.7; MS: m / z 374 (M' for 2 x "'Te)] and (CH,)3Si-Te-/-C4HU ['HNMR (C,H,): 6=0.39, 1.25: MS: m / z 260 (Ma)]. Together ca. 70a/o yield
based on 2 and 3b. The initial fraction contains [(CH1),SijlO (m/i 147
(M" - 15)).
(13) U . Schmidt, K. H. Kabitzke, Angew. Chem. 76 (1964) 687; Angew. Chem.
In!. Ed. Engl. 3 (1964) 641.
(141 A related type of reaction is the decomposition of (Et02C)2C=S=0,
which is unstable, to give, inter alia, the olefin (Et02C)2C=C(02CEt)2:
R. W. Saalfrank, W. Rost, Anyew. Chem. 97 (1985) 870; Angew. Chem.
Inr. Ed. Engl. 24 (1985) 855.
cemic, trans- o r cis-fused dihydropyrans.[21This paper will
show that alkylidene-1,3-dicarbonyland analogous compounds also provide very reactive enophiles if the heteroDiels-Alder reaction is prevented; this can be achieved by
using C = C bonds bearing electron-accepting substituents
that d o not undergo cycloaddition reactions. In this way,
the alkylidene derivatives 3 of acyclic 1,3-dicarbonyl and
analogous compounds may be converted into the transsubstituted cyclohexane derivatives rac-5 by a non-induced
diastereoselective ene reaction.[31
The term non-induced diastereoselective will henceforth
be used to describe reactions that preferably form one of
several possible diastereomeric chiral (racemic) products
from achiral educts in an achiral environment. For transformations under the influence of one or more chiral elements, the term induced diastereoselective will be used. It is
all the more reasonable to distinguish between these two
types as both of them (non-induced as well as induced)
often occur simultaneously in a single reaction with different diastereomeric excess.[41
The educts 3 are easily obtainable in nearly quantitative
yields by Knoevenagel condensation of 1 with the aldehyde Zi5] in the presence of piperidinium acetate (2OoC,
1 h). Heating of 3a-3c in refluxing o-dichlorobenzene
( 1 8 0 T ) leads to the trans-fused ene products rac-5a-5c ;[61
the amount of the cis-fused cyclohexane derivatives rac7a-7c lies between 1 and 8% (Table I). 4 is assumed to be
the conformation of the transition statel'l of the ene reaction leading to rac-5.
0.1 equiv. piperiatptum acetate
lh. room temp.
1
R'
2
Non-Induced, Highly Diastereoselective
Intramolecular Ene Reactions of 1,7-Dienes to
truns-1,2-Disubstituted Cyclohexanes
5
4
By Lutz F. Tietze* and Uwe Beifuss
Dedicated to Professor Hans Jiirgen Bestmann on the
occasion of his 60th birthday
Compared with the mechanistically related Diels-Alder
reaction, the ene reaction has so far been considered as
less important with respect to the formation of C-C bonds,
which may be attributed in many cases to lower stereoselectivity and poorer yields. The intramolecular mode,
which has not yet been investigated in any depth, often
leads to unsatisfactory results, too, especially in the case of
1,7-dienes.li1
We have been able to show recently that in highly diastereoselective (de > 95%) hetero-Diels-Alder reactions alkylidene and arylidene derivatives of cyclic 1,3-dicarbonyl
compounds afford either enantiomerically pure or raProf. Dr. L. F. Tietze, Dip1.-Chem. U. Beifuss
lnstitut fur Organische Chemie der Universitgt
Tammannstrasse 2, D-3400 Gottingen (FRC)
I**]
This work was supported by the Deutsche Forschungsgemeinschaft, the
Fonds der Chemischen Industrie, and the Studienstiftung des
Deutschen Volkes (fellowship for U . B.). We thank Dr. P a p , BASF AG,
Ludwigshafen, for a gift of methyl 5-formylpentanoate.
1042
0 VCH Ver1aysgesellst.hafl mbH. 0-6940 Weinheim. 1985
7
6
8
a, R1 = R2 = C0,Me; b. R1 = R2 = CN;
c, R' = C02Me, R2 = CN; d, R1 = R2 = COMe
0%
rac-9a: R1 = OMe, R2 = CN
Tac-Qb: R' = C%, R2 = COCH,
R2
In the presence of Lewis acids"c1 the reaction temperature is lowered; with ZnBr, (1.1 equivalents) quantitative
conversion is obtained within 15-45 min at 20°C. As byproducts of the reaction of 3a and 3b the isomeric product
6a (4%) and a mixture of the isomeric bicyclooctanes rac-8
0570-0833/8S/1212-1042 $ 02.S0/0
Angew. Chem. lnt. Ed. Engl. 24 (1985) No. 12
Документ
Категория
Без категории
Просмотров
1
Размер файла
249 Кб
Теги
trimethylsilyl, bond, reaction, formation, halide, telluride, bis, novem, acyl
1/--страниц
Пожаловаться на содержимое документа