вход по аккаунту


Nucleophilic Ether Fissions by 1 1-Diphenylhexyllithium.

код для вставкиСкачать
Commun. 1972, 339: D. J . U'utkin and 7: A. Hoinor, I Chem. SOC.
B1971. 2167: K. lhrito, H . Shimunoirchi, and Y So.sudu, Chem. Lett.
lap. 1973,269.
[7] S fro, Y. Fukazawu, and Y Irrnka, Tetrahedron Lett. 1972. 741.
745, H. Shimanmichi and Y. Sosudu, ibid. 1970, 2421 ; Acrd Crysldllogr.
B 2Y, 81 (1973).
[R] Chem. SOC (London), Spec. Publ. No. 18 (1965).
[9] M. Doblrr and J . D . Dunitz, Helv. Chim. Acta 4X, 1429 (1965).
[lo] M Trutwubrrg, J Amer Chem. SOC.K6. 4265 (1964).
[ I I] R . E . Dacis and A. Tulinsky,J. Amer. Chem. SOC.X K , 4583 (1966).
[I21 E. h q r l and H . D . Roth. Angew. Chem 76, 145 (1964): Angew.
Chem. internat Edit. 3, 228 (1964).
Of the various trihalogermanes, only HGeQ and HGeBr3
have been previously reported ; they tend to decompose
according to eq. (1b)['J or to GeX,, GeX, and H,[,].
Triiodogermane, HGe13, has been merely conjectured as
an intermediate in germylation reactions of olefins with
Ge12/50% aqueous
Since we succeeded in preparing pure, GeBr4-free HGeBr3
by dissolving GeBr21sl in anhydrous HBr, we have found
also that HGe13 is formed in quantitative yield when
anhydrous HI is condensed on pure GeI, [eq. ( 1 a)]:
The pale yellowish solution is stable below -50 C but
at room temperature decomposes gradually thus:
+ HI
+ Gela
+ Hz
50% after 7 days); dismutation to H2Ge12 and Ge14
was not observable. When the solvent HI is removed,
even at low temperature, only GeIz is left as solid residue
[eq. ( 1 b)]; and other attempts to prepare it-by
HGeCI3/HI, HGeC13/GeI4 or HGeCI3/HSiI3 as reactants-lead
also to Ge12. However, HGe13 is formed
smoothly when an excess of HI is condensed on GeBr2,
but in a suspension of Ge12 in 57 YOaqueous HI we could
not prove the formation of triiodogermane.
Thus HGe13 can exist only in liquid HI. But in such
solutions we could measure the Raman spectrum, and
this showed, as required for a CSr.molecule, three polarized
and three depolarized lines (Table 1). The frequencies are
in the expected regions, which can be derived from correlations and calculations for comparable vibrations for the
series HGeX3 (X =C1, Br['] or I) and HGeX3/GeX4.
Table I . Fundamental vibrations ( c m - ' ) from the Raman spectrum of
20hX (0.5, p)
203 (10. p)
93 (5. P)
260 (1.5. dp)
66 (6, d p )
643 (0.6, dp)
A-XOIO Graz. Stremayrgiisse 16 (Austria)
This work was supported by the Fonds zur Forderung der wissenschaftlichen Forschung, Vienna
Nucleophilic Ether Fissions by
By Gert Kiibrich and Annegrir Baurnann"]
Because of the role of ethereal solvents in reactions of
organometallic compounds, fission of ethers by organometallic and in particular organolithium compounds is very
important. According to earlier investigations it is normally
initiated by deprotonation at the 2- or P-carbon atom
of the ether"]; very recent
have uncovered
an interesting meshing of a-, 0-and, a',p-eliminations for
thecase ofdiethyl ether/alkyllithium. We propose to collect
together under the general expression "protophilic ether
fission" all those fissions that have proton abstraction
from the ether molecule in the first reaction step as their
common characteristic [eq. (I)]:
Protophilic ether fission:
- C-C
consecutibe reactions
We now report "nucleophilic ether fission" as a further
type of reaction. This is a nucleophilic replacement by
the organolithium compound [eq. (2)], in which an RO
group of the ether constitutes the leaving group, thus
playing the same role as do halogen atoms in the coupling
of alkyl halides.
Nucleophilic ether ,fission:
[*] Doz. Dr. F. Hofler and Dip].-lng. E. Brandstitter
lnstitut fur Anorganische Chemie der Technischen Hochschule
[5] M . D. Ciirirs and P. Wdbvr, Inorg. Chem. 1 J , 431 (1972).
[6] H. Sirherr -Anwendungender Schwingungsspektroskopieinder anorganischen Chemie. Springer, Heidelberg 1966.
.~ .
[ I ] E. Wiberg and E . Ainbrryrr. Hydrides of the Elements of Main
Groups I---IV. Elsevier, London 1971
[2] M . L. D e l w u u l l ~ J~., Phys. Chem. 56, 355 (1952).
[4] I' F . Mironol-, L. N . Kalinino, t;. M . Bvrliner, and 77 K . Cur, Zh.
Obshch. Khim. 40, 2597 (1970).
By Friedrich Hofler and Ernst Brandstatred']
+ HX &
Received: July 30. 1973 [Z X96 IE]
German version: Angew. Chem. KS, 870 (1973)
[3] P. ?ilu:rro//r.s and C . M a i w o l , Bull Soc. Chim. Fr. 1967. 251 I .
vGeH and GHGeI are slightly dependent on concentration,
being S-Scmhigher for very dilute solutions
In thereaction ofstoichiometric amounts of HI with GeBrz
or a GeBr4/Ge12 mixture there are formed, besides HGe13,
the trihalides HGeBr12 and HGeBrJ, which also cannot
be isolated but can be recognized from their main frequencies in the Raman spectrum (220 vs,p and 239 cm- V S , ~ ) .
If we let aside those reactions, formally similar but different
in kind, in which complex formation at the oxygen atom by
a Lewis acid is the first step, as with triphenylmethyl an[*] Prof. Dr. G Kobrich and Dip].-Chem. A. Baumann
lnstitut fur Organische Chemie der Tcchnischen L'niversitiit
3 Hannover, Schneiderberg I B (Germany)
This work was supported hy the Dcutsche Forschungsgemeinschaft
and the Fonds der Chemischcn Industrie.
2-butenyl structure. The preponderating product from the
isomeric 4-phenoxy-2-butene in T H F is the unrearranged
product, but in hexane (in presence of 1 mol of tetramethylethylenediamine) it is mainly the unrearranged, sterically
ions in presence of triphenyl-borane or -aluminum[3a1and
very probably with Grignard reagents'3b1,then nucleophilic
ether fission has been observed only with o x i r a n e ~ [and
o x e t a n e ~ l ~which
~ ] , contain strained rings, and moreover
Table 1 . Conditions and products of the reaction of 1.1-diphenylhexyllithium (DPHLi) with ethers [6, 71
Reaction conditions [b]
Products and relative yields [d]
At 0 C instantaneous in T H F
Tctrahydrofurdn ( T H F )
17 h at room temp. in T H P
120 h at room temp.
and 22 h at 7 0 T
+ DPH-H (307;)
( ' I ] ? - - C H > OH ( l O O " 4 )
DPH -CH ,-CH ,-CH ,-CH ,-OH (84 %)
+ DPH-H (16",,)
Tetrahydropjran ( T H P )
96 h at room temp and 22 h at 70-C
[conversion 16 ""1
H ,C=CH-0-C,H,-n
2: I
2: 1
72 h at
10h at
72 h at
IOh at
18h at
22 h at
1: 1
1 S h at room temp. In T H F
48 h at room temp. in hexane [c]
D P H - C H z C H , (95%)
+ DPH-H ( 5 % )
+ DPH-H (87,)
DPH-H ( < l o % )
( t r a n s 78%,, C I S 147,)
(94 %)
(91 %)
D PH -CH -C H =C H -C H (100 "<!)
a ) Cyclic ethers
b) Acyclic ethers
C',, H s--C'H-C
70 C
70 C
temp and
in T H P
temp. and
in T H P
temp. i n (C,H,),O
3 h at room temp. in T H F
36 h at room temp. In hexane [c]
The cthcr studied served as solvent.
Thc DPHLi was completely consumed, unless stated otherwise.
In presence of I equivalent of tetramethylethylenediaminc
Rctcl-red to DPHLi; about S0-90;,; thereof was isolated.
only occasionally with tetrahydrofuran (THF) (with
R,SiLi'5"l or triphenylrnethyllithi~m[~~~).
As organometallic reagent we used 1 ,I-diphenylhexyllithium (DPHLi)l"l, which smoothly splits not only cyclic
ethers but also alkyl phenyl, allyl and vinyl ethers (Table
I). In all these cases nucleophilic predominates over protophilic fission. as is made evident by the poor yields of
1,l-diphenylhexane (DPH-H) which is the protonation
product of DPHLi. Product analyses permit the following
generalizations :
1. With cyclic ethers the ease of reaction increases with decreasing ring size, corresponding to increasing ring strain.
Tetrahydropyran is no longer attacked nucleophilically ;
and its protophilic fission by DPHLi at 70'C also occurs
only to a small extent, so that this compound is more
suitable as solvent for reactions involving DPHLi than is
the commoner but less resistant THF.
2. Whereas the alkyl group of alkyl phenyl ethers is transferred to DPHLi [eq. ( 3 ) ] , it is the unsaturated group
of alkyl vinyl ethers that is given up [eq. (4)]. This "transpolin&" indicates an addition-L.Iiiiiination reaction as
mechanism for the vinyl ether fissions; it is faster than
the S~Z-likctransfer of alkyl groups.
+ C,,H1--O-Alkyl
+ C'H2=CH-O-Alkyl
+ Alkyl-OLt
3. Allylic rearrangement can accompany fission of substituted allyl ethers: 3-phenoxy-I-butene affords only the
thermodynamically favored, rearranged product with the
disfavored coupling product (Table 1 ). Product formation
is thus influenced by the reaction medium.
4. Ally1 ether bonds are particularly easily split; even
anionized allyl alcohol is smoothly cleaved ( I : 1, 6 h at
70 C in THP, relative yield 100%) [cq. ( 5 ) ] :
+ C'H=CH--CHr-
+ Li2O
5. The relative rates of nucleophilic fission of C-0 bonds
by DPHLi decrease in the order Allyl-0> Vinyl-0> Alkyl-0& Phenyl-0-.
Many of the ethers included in Table I were treated with
benzhydryllithium instead of DPHLi, and the results were
qualitatively identical and quantitatively similar. It is probable that nucleophilic ether fission is a characteristic reaction of mesomeric carbanionoids, being caused by the
fact that their basicity islower than that ofother organolithium compounds and that their nucleophilicity is high,
the latter being made evident by their extremely rapid
coupling with alkyl halides['].
Received: July 25, 1973 [Z 897 lE]
German version: Angew. Chem. 85.916 (1973)
[ I ] P. S d i o r i g ! ~ ~
. Dcut. Chcm. C e s 43. 1931 (1910): G W i t r q and
L. Liihriirrnn. Liebigs Ann. Chem 550, 260 11942): A . L i i ~ / ~ i i i ~ ~ G
Wugnrr-I-. Suiij. E Sir(.lcr. and G . Borth. ihid j57. 46 ( 1944): K . %rc<qlrr
and H . - G Cellvrr, ihid. 567, 185 (1950). H . Giliii~iii. A. H . H d ~ ( , i r iand
H Hrirt:fclrlr, J. Org. Chem. IY. 1034 (1954): R. L. Li,r\iiiycr and D.
F . Po/kirt. J. Amer. Chcm. Soc. 78, 6079 11956).
121 .4.!Ll~ri~r(~Lcr.
and LV D i w i i / / i . Angcw. C'hcm. 85. 90 11973). Angcw.
Chem. internat. t d i t . / 2 . 7 5 ( 1973):sec also 1 .Lfricr<.Lrrand W T / w w h t i .
Licbies Ann. ('hem. 747. 70 (1971).
[ 3 ] a ) C . Wirrug and .A Riiclhri, Ltehigs A n n C'hem. 566. I I 1 (1949):
G. U'irricg and G. Kolh. C'hem Ber. 93. 1469 (1960): h) 2.1.S. hil~rrose~h
and 0.Reiruiziirh Grignard Reactions of Nonmetallic Substances. Pren-
ttcc-Hall. Ncw York. 1954. pp. 961, 1022
[4] a ) Scc c ' . q B. M. MiUioi1or. 1 7 ~Ahad. Nauk SSSR. Otd. Khim.
Nauk 1948. 420: C'hctn. Ahstr. 43. 2OX (1949). If. Gi1nt~rii and J . L
TOidc. Rcc. T r a r . C'him. Pays-Bas 6Y. 42X (19501: h) S. Sror/(,.\. J . Amer.
C'hcm. Soc. 73. 124 (1951)
[j] a ) D. WirrcirhC,r<I,D A o h l . and ti. Cilrwt. !. Amcr. C'hcm. Soc.
tYO. 5933 (1958): A . G . F h o n c . M . L J o i m . and N. f i . R r i x J. C'hcm.
Soc. R 1Y6Y. X94: b) t;. Crrqmrcr. A . C. &m\. and V . H RW\. !.
C'. S. Pcrkin I I 1977. ISYX.
[6] 0 . 5 h l DPHLi boluttons irsed were frce from ltthttlm salts: they were
prepared from 1,l-diphenylethylene and 11-butyllithiumin light petroleum.
The reactions were terminated by addition of an excess ofn-butyl bromide
[7] The products wcre separated by column chromatography. Their
strttctttres were proved by elemental analyses and by spectroscopy. and
in some cases by comparison with samples prepared by independent
methods. The relatrve ytelds shown in Table 1 were determined by gas
chromatography L\ tth thc aid of pure samples.
181 i t ) h / J q / c r . I f r ; j ! w i u i l . /I. h/<,irwr. :tnd 0. S ~ I i ~ r f ~ Llchlg,
A t i n Chcm. 473. I (1929): hJ G h h r c h a n d 1 . S i d i t , r . C'hciii. Ber.
103. 2744 (1970)
By Arinin d r Mrijere and Liirler-Ulrir,h M e j w [ * ]
Prc$~.s.sor H . Brockmunn
compound distilled in the process, together with some
trrt-butyl alcohol, into a trap cooled in liquid nitrogen
and was obtained pure by preparative gas chromatography" 'I.
In its 'H-NMR spectrum (CCI,), (2) shows multiplets
at r=3.61 and ~ = 3 . 9 1(each 2H, AA'BB' system of the
olefinic protons) and at T = 7.79 (6H, cyclobutyl protons).
The IR spectrum of (2) is not characteristic and does
not accord with that reported by Chiiwrtog/tr and 7itrsch1'l.
The longest-wavelength absorption lies at 257 nm, as does
that of ( I ) (see Table 1).
his 70th birthday
Whereas the spiro[n.4]alkadienes ( 1 ) and ( 2 ) are readily
accessible by cycloalkylation of the cyclopentadienyl anion
by, respectively, 1,2-dibromoethane and 1,4-dibroniobutanel '1, the analogous reaction with 1,3-dibromopropane
does not lead t o (2)"l. We report here the preparation
and some of the chemical and spectroscopic properties
of the hydrocarbon 12).
Table I. IJV data of the spiro[n4]alkadtencs f 1 1 - 1 3 ) and of 5.5dimethyl-l..i-cyclopcntadtene[in ethanol. f 2 I i n i~-pentanc].
I500 [a]
~ 5 1
[a] The extinction coefficient found may be too small because ( 2 ) dimcrizcs very rapidly at room temperature.
Compound (2) is of interest in comparison with ( I )
and (3) which differ greatly in their behavior in the
Diels-Alder reaction['] and on gas-phase pyrolysis[5,'I, and
also because of a possible electronic interaction between
the x-orbitals of the diene component and the C-C bonding orbitals of the cyclobutane ringf'l.
Our starting material was spiro[3.4]octan-5-one (4)["1.
On successive bromination in ethylene glycol, dehydrobromination by potassium hydroxide in methanol and hydrolysis of the acetal ( 5 ) this afforded the ketone (6)["]
(yield through 3 steps: 54%). this sequence being analogous to Garbisch's general procedure"''. Attempts to
prepare the tosylhydrazone of ( 6 1 , and thence (2) by
treatment with methyllithi~mI'~l,
failed: 1,4-addition of
tosylhydrazide to (6) was observed in all these attempts.
However, reduction of (6) by aluminum hydridel"1 yielded
thealcohol (7") (74%);subsequent treatment with thionyl
chloridc in tetrahydrofuranipyridine iit room temperature
led to 5-chlorospiro[3.4]oct-6-ene ( 7 b ) (53 %). Dehydrochlorination of ( 7 b ) by potassium tert-butoxide in
tetracthylencglycol dimethyl ether (tetraglyme) at room
temperature in a vacuum (0.01= torr)"" afforded the diene
(2) (yield 67 YO,determined by gas chromatography); this
[*] Do/. Dr. A d e Mcijere and Dipl.-C'hcm. L.-L. Mcycr
Orgatitsch~C'hemtsclicsInstittit dcr Cniversitat
24 Gi,ttitigcri. M'indau\ucg 2 I<;crni;iny)
[**I This work was supported by grants from the Land Niedersachsen
and the Fonds der Chemischen Industrie.
In its chemical behavior, (2) resembles (3) rather than ( I ) .
Pure (2) dimerizes rapidly at room temperature to give
(8)"']. 'H-NMR (CC1,) of ('8): T=4.37 (m, 2 H ) ; 4.50
(m, IH); 4.83 (m, IH); 6.78 (m, IH); 7.51 (m, 3H); 8.35
(m, 12H). The half-reaction time for dimerization in dilute
solution ( 0 . 8 6 ~in CC14) at 50 C amounts to ca. 2.3h.
On treatment with maleic anhydride in benzene (SO C,
5 h), (17) affords the Diels-Alder adduct ( 9 ) [ ' l l (70%; m.p.
86 C; colorless crystals), ' H - N M R (CDC13): r=3.81 ( t ,
2H); 6.47 (dd, 2H); 6.79 (m, 2H); 8.22 (m, 6H).
Thermal rearrangement of ( 2 ) , which ring strain should
cause to be much easier than that of ( I ) and (3)I'"J.
has so far been examined only qualitatively. In a flow
pyrolysis apparatus at 400°C a 1 :0.8 mixture of the isomeric bicyclo[3.3.0] octadienes (11) and (12) was formed.
Thermal decomposition of the dimer (8) led under these
conditions to a product mixture of the same composition.
( 1 1 ) and ( I ? ) can be separated by gas chromatography
and identified by means of their ' H - N M R spectrall'l.
Без категории
Размер файла
309 Кб
fission, ethers, diphenylhexyllithium, nucleophilic
Пожаловаться на содержимое документа