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cis trans-1 5-Cyclooctadienes.

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because of their chiroptical properties and since their racemization by consecutive nitrogen inversions"] must proceed uia
two enantiomeric transition states, whereas the equilibration
kinetics''] for thediastereoisomers of ( I ) are more complicated.
3-Benzyl-I,2,3-trimethyldia~iridine'~~l,
( +)-(2),
in ethanol/H20 (96 :4) was passed through a column of triacetylcellulose['I (85g, particle size 0.056 to 0.071 mm, column length
30cm, internal diameter 2.5cm, 22°C). A membrane pump
generated a flow of % 135ml/h. Figure 1 shows an analytical
chromatogram. Preparative separations were performed with
1Wmg of(+)-(2) which were conducted through two columns
in such a way that a total of seven passages took place ("recycling"). This was achieved with a manual gauge[61which, in
addition, separated the first 10% of eluate containing predominantly (+)-(2). Thus, the remaining eluate resulted in practically pure (-)-(2) when divided by a fraction collector:
26mg, [a]&= - 141f 4 " (0.05 g/100ml CCI,), enantiomeric
purity['] P = 97 f3 %. Together the seperated frontier eluates
contained 46 mg of (+)-(2), [a]::6 = + 85 f5" (0.35 g/100ml
CCI4),P = 59 3 %. The 'H-NMR spectra were in agreement
with those of (+)-(2)['33bl although they showed ~ 2 (by
%
weight) of n-hexane originating from the eluent. The
intensities of 'H-NMR signals in the presence of an optically
active auxiliary compound served for the measurement of
'I. (+)-(2) in [DJ-toluene at 34°C exhibits two C-CH3
singlets at 6 =2.87 and 2.93 (line widths 1.5 Hz) in the presence
of 0.27 equivalents of (+)-tris[3-heptafluorobutyryl)-D-camphorato]europium(~~~).
In the samples with enriched (+)-(2)
the signal intensity at 2.87 prevailed; the (-)-(2) fractions
showed practically only the signal at 2.93. The P values were
determined by repeated cutting out of diagrams, dividing into
the components, and weighing of the pieces. The CD spectrum
of (-)-(2) in n-hexane at 25"C, calculated for P = 100 %,
exhibited maxima at 268 nm (A&= -0.12 1 cm-' mol-'), 262
(-0.12),256(-0.08),219(x+1.6),and214(~+11.7).
+
P[1349
A . Mannschreck, W Seitz in IUPAC: XXIIrd Int. Congr. Pure Appl.
Chem., Vol. 2. Butterworths, London 1971, p. 309.
G . Hesse, R. Hagel, Justus Liebigs Ann. Chem. 1976, 996, and earlier
papers.
a) A . Mannschreck, R . R d e g l i a , E. Griindemann, R. Ohme, Chem. Ber.
100, 1778 (1967); b) we refer to these two stereoisomers because of
the formulae given; in fact, however, the racemates of the two diastereoisomers were separated: A. Mannschreck, !+I Seitr, Angew. Chem. 81,
224 (1969); Angew. Chem. Int. Ed. Engl. 8,212 (1969).
H . Hiikli, A . Mannschreck, unpublished results.
a) R . G. Kostyanovskii, A . E. Polyakou, K I . Markov, Bull. Acad. Sci.
USSR, Div. Chem. Sci. 1975, 191; Chem. Abstr. 82, 170758 (1975);
b) R . G . Kostyanouskii, A. E . Polyakou, G. G: Shustou, Tetrahedron Lett.
1976, 2059.
Dreh-Probenaufgahe-Ventil, Latek GmbH, Heidelberg, Germany.
M . Raban, K . Mislow, Top. Stereochem. 2, 199 (1967).
A . Mannschreck, Nachr. Chem. Tech. 23,295 (1975).
cis,trans-l,5Cyclooctadienes[**I
By Hans-Dieter Martin, Mirko Hekman, Giinther Rist, Hanspeter Sauter, and Daniel BelluS"1
In some cases, eight-membered rings having trans-configurated double bonds differ considerably in their ground state
energy"', their reactivity['], and their spectroscopic propertied3] from the cis-configurated stereoisomers. This confers
interest upon methods for the preparation of such strained
cycl~olefins[~~.
We here report thermal valence isomerizations
permitting productive syntheses of cis,trans-1,5-cyclooctadienes (21, which are either isolated or, if isolation is precluded
by excessive reactivity, can be trapped by dienes.
(1)
(2)
( a ) , R = COOCH,, R' = H;
( b ) , R = CN, R' = H;
(c), R = R' = COOCH,
t
0.0
'
Y
The inversion of a C atom known to occur on thermal
cleavage of bicyclo[2.2.0]hexanes to form 1,Shexadienes is
also applicable to tricyclo[4.2.0.02~5]octanes~5*
61. The valence
isomerization (1 ) -+(2) can therefore be regarded as providing
a synthetic entry to strained trans-cycloalkanes.
'
100
8
-ai t
Fig. 1. Analytical chromatogram of 50mg of (+)-(2) in ethanol/H20 (96:4)
after passage through a triacetylcellulose column (cf. text): 2: Rotation angle
(-)
at 365nm, measured by flow through a polarimeter. E : Extinction
(-..----)
at 254nm, measured by flow through a photometer. V: Volume
of the eluate (injection at V=O).
R
The thermal racemization of (+)-(2), obtained by chromatography, in toluene at 89.9"C was monitored by polarimetry
at 436nm. This process was of first order with a half-life
of 56.9 min and AG+ =27.57f0.02 kcal/mol for a trans-cis
nitrogen inversion[', 3b1. This is in satisfactory agreement with
the value 27.2 & 0.1 kcal/mol['l (CZCl4,89.9"C) for an inversion
in the diastereoisomers of (I) mentioned above.
Received: March 17, 1977 [Z 699 IE]
German version: Angew. Chem. 89,419 (1977)
CAS Registry numbers:
(+)-(2), 23191-19-7; ( + ) - ( 2 ) , 62413 - 5 2 : (.-)-(2), 62413-56-3; triacetylcellulose, 9012-09-3; ( + )-tris[3-(heptafluorohutyryl)-D-~amphorato]europ~um(lll), 34788-82-4
406
(4)
(5)
( a ) , R = COOCH,
( b ) , R = CN
(6)
(7)
(8)
[*] Prof. Dr. H.-D. Martin, DipLlng. M. Hekman
Institut fur organische Chemie der Universitat
Am Huhland, D-8700 Wiirzburg (Germany)
Dr. G. Rist, Dr. H. Sauter, Dr. D. BelluS
Zentrale Forschung, Ciha-Geigy AG
CH-4002 Basel (Switzerland)
[**I This work was supported by the Deutsche Forschungsgemeinschaft,
the Fonds der Chemischen Industrie, and BASF AG.-Part 23 of the series
"Small Rings".-Part
22: H.-D. Martin, H . - J . Schiwek, J . Spanget-Larsen,
R . Gleiter, Tetrahedron Lett., in press.-Also Part 7 of the series "Synthesis
and Reactivity of Four-Membered Ring Compounds".-Part 6: D. BelluS,
Helv. Chim. Acta 58, 2509 (1975).
Angew. C k m . I n t . Ed. Engl. 16 (1977) No. 6
Reaction of dimethyl cyclobutenedicarboxylate ( 4 a ) with
the cyclobutadienecarbonyliron complex (5) at 0°C furnishes
the two stereoisomers ( 6 a ) (m.p. 47-48°C) and ( 7 a ) in
the ratio of 10: 1.
Both isomers undergo thermal cleavage to give the cyclooctatriene derivative (8)"' (m.p. 68-69 "C), ( 7 a ) somewhat
faster than ( 6 a ) . Hydrogenation of ( 6 a ) (Pd/C, CH30H)
affords ( l a ) (m.p. 42-44°C). Heating of (1 a ) to 75°C in
inert solvents gives ( 3 a ) as the only isolable monomer (m.p.
77-78 "C). However, if a mixture of CHC13 and furan is used
as reaction medium, not only ( 3 a ) but also an adduct (Ya)
or ( I O U ) (m.p. 78-80°C) of ( 2 a ) to furan is obtained on
chromatographic separation. Compound (3 a ) does not
undergo cycloaddition under these conditions.
The dinitrile ( 4 b ) likewise adds to the cyclobutadiene
complex ( 5 ) to form the relatively labile tricyclics ( 6 b ) and
( 7 b ) in the ratio of 4: 1. Detectable isomerization to ( 8 b )
(m.p. 140--142°C) occurs already at 25°C. Hydrogenation
of ( 6 b ) (Pd/C, CH30H, 0°C) leads to ( I b), which on account
of the high reactivity and lability of ( 2 b ) is reacted directly
with furan (5OoC, 1h). Unlike (I a), ( I b ) yields ( 3 b ) (m.p.
125-126°C) and, via the intermediate ( 2 b ) , a pair of stereoisomers (Yb) and ( f o b ) (m.p. 166-168°C and 154--156"C,
respectively).
( a ) . R = COOCH3, R' = H;
(b), R
=
(9)
( 3 c ) . 34271-69-7: (4a), 1128-10-5; (46). 3716-97-0: ( 5 ) , 12078-17-0: ( 6 a ) ,
62302-02-7: ( 6 b ) , 62302-03-8; ( 7 ~ ) ,62357-29-3; (7b), 62357-30-6; ( 8 ~ ) ,
62302-04-9; f 8 b ) , 62302-05-0; (9a), 62302-06-1; (96), 62302-07-2; ( I O U ) ,
62351-31-7; (lob), 62357-32-8; furan, 110-00-9
[I] R. 8. Turner, W R. Meador, J. Am. Chem. SOC.79,4133 (1957).
[2] K . Ziegler, H . Sauer, L. Bruns, H . Froitzheim-Kiihlhorn, J . Schneider,
Justus Liebigs Ann. Chem. 589, 122 (1954); K . T Burgoine, S. G. Dauies,
M . J . Peagram, G . H . Wkitham, J. Chem. SOC. Perkin I, 1974, 2629.
[3] C . Batich, 0. Ermer, E. Heilbronner, J . R. Wisemann, Angew. Chem.
85, 302 (1973): Angew. Chem. Int. Ed. Engl. 12, 302 (1973); A . C . Cope,
C . F . Howell, J . Bowers, R. C . Lord, G . M . Whitesides, J. Am. Chem.
SOC.89, 4024 (1967).
[4] See e.g., M. Jones, P . Temple, E . J . Thomas, G. Wkitkam, J. Chem.
SOC.Perkin I, 1974, 433.
[ S ] D. BelluS, H.-C. M e z , G. Rihs, H . Sauter, J . Am. Chem. SOC.96, 5007
(1974).
[6] H.-D. Martin, E . Eisenmann, Tetrahedron Lett. 1975, 661.
[7] E. Vogel, 0.Roos, K . H . Disch, Justus Liebigs Ann. Chem. 653, 55
(1 962).
[8] H.-D. Martin, M . Hekman, Angew. Chem. 88,447 (1976): Angew. Chem.
Int. Ed. Engl. 15, 431 (1976).
(RPNCH&, Cyclotetra(h3-phosphazanes)
Synthesis and Crystal Structure Analysis
By Werner Zeiss, Wolfgang Sckwarz, and Heinz Hessp1
While attempting to prepare the hitherto unknown permethylated 1,3,2h3,4h3-diazadiphosphetidine( I a) from methyldichlorophosphane and heptamethyldisilazane we obtained
a compound which had the correct composition but twice
the desired molecular mass ( 2 u ) in good yield:
(10)
7%
CN, R ' = H
The instability of the disubstituted cispans-cyclooctadienes
(212) and ( 2 b ) results from the joint action of ring or torsional
strain and the electron-withdrawing substituents, both of
which increase the molecules' reactivity. However, it may
be expected that, as the number and size of the substituents
increase, the reactivity in cycloadditions will decrease and
the configurative stability increase. This is indeed observed
in the comparatively stable tetracarboxylic ester ( 2 c).
At 105°C ( I c ) [ ~ ]isomerizes to a 2: 1 mixture of ( 2 c ) and
(3 c ) which can be separated by chromatography over silica
gel. The 3C-NMR spectrum of (2 c) recorded between - 20°C
and + 90°C displays a clear temperature dependence owing
to conformational mobility, which however is frozen at - 20°C
)
CD3N02): (+90°C) 31.2, 36.1
[13C-NMR of ( 2 ~ (TMS,
(CHZ), 52.5, 52.6 (OCHj), 140.4, 149.5 (C--C), 169.7, 170.2
(C=O);(-20°C) 25.3, 35.8, 35.9, 36.9 (CHZ), 52.9, 53.0, 53.1,
53.3 (OCH3), 134.5, 145.5, 149.1, 150.8 (C=C), 168.0, 169.7,
170.1, 172.7 (C+O)].
Compound ( 2 c ) fails to give a Diels-Alder adduct on heating to 105°C in furan, presumably because of excessive steric
the ratehindrance. As in tetracyclo[4.4.0.02~s.07~10]decanes~6~,
determining step in the thermolysis of (1 ) and ( 6 ) is probably
cleavage of the internal substituted bond of the four-membered
ring. This is evidenced by the kinetic parameters compared
with those of the reference compound dimethyl bicyclo[2.2.0]hexane-I ,4-dicarboxylate ( 1 1 ) [Ea (kcal/mol), log A, solvent:
(I a ) 25.5, 12.6, CDC13; (I c), 26.5, 12.2, C6DsC1; ( 6 a ) , 24.1,
11.5,CC14;(12),25.5,12.1, C4C16;24.6, 11.7, C6DSCD3;24.6,
11.7, C ~ D S N O ~ ] .
Received: March 21, 1977 [Z 701 IE]
German version: Angew. Chem. 89,420 (1977)
CAS Registry numbers:
(1 a ) , 62301-96-6; ( I b ) , 62301-97-7: ( I c ) , 62357-28-2: ( Z a ) , 62301-98-8;
( Z b ) , 62301-99-9; (ZC), 62302-00-5; ( 3 0 ) , 62301-98-8; ( 3 b ) , 62302-01-6:
Angew. Chem. Int. Ed. Engl. 16 (1977) No. 6
' I z R-P\
/
N
\
P-R
(1)
nT
( a ) : R = CH,
( b ) : R = CzHs
The reaction with ethyldichlorophosphane took place in precisely the same way to give (2 b).
In the 31P{'H}-NMR spectrum, ( 2 a ) shows a signal at
-91.7ppm, and ( 2 b ) one at -100ppm['l, which both lie
In contrast,
in the usual range for alkyldiaminophosphanes[2].
l,3,2h3,4h3-diazadiphosphetidines having methyl groups
attached to the phosphorus and tert-butyl groups attached
to the nitrogen, or vice versa, give 31P shifts of -171.4ppm
or - 201.7 and -281.7 ~ p m [ ~respectively.-The
],
'H-NMR
spectra['] of compounds (2) are complex owing to virtual
H-P coupling. Compound ( 2 a ) exhibits approximately two
quintets in the ratio 1 : 1 ; while deviation from the signal
shape and intensity distribution of a quintet is only slight
for the NCH3 protons (6=2.95), i. e. ca. 1 : 3 :4: 3 : 1, it leads
to a broad accumulation of signals in the case of the PCH3
protons (6= 1.41).The spectrum of (2 b ) also shows a "quintet"
[*I
Dr. W Zeiss
Institut fur Anorganische Chemie der Universitat
Meiserstrasse 1, D-8000 Miinchen 2 (Germany)
Dr. W. Schwarz, Prof. Dr. H. Hess
Iustitut fur Anorganische Chemie der Universitat
Pfaffenwaldring 55, D-7000 Stuttgart 80 (Germany)
407
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