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Optically Active Bridgehead Derivatives of Trishomobarrelene and Trishomobullvalene.

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is not fractionated but instead dissolved in ether, filtered,
and, after removal of the ether, recrystallized from acetonitrile
or vacuum sublimed.
Received: March 19, 1976 [Z 443 IE]
German version: Angew. Chem. 88, 444 (1976)
CAS Registry numbers;
( l a j , 36601-47-5; ( l b ) , 18032-39-8;
( l e i , 17828-44-3; ( I f ) , . 58933-93-0;
( 2 b j , 58933-95-2; ( 2 c ) , 58933-96-3;
( 2 f ) , 58933-97-4; ( 2 g ) , 58933-98-5;
( S c l , 58934-01-3; ( 5 d i , 58934-02-4;
(6b1, 17379-47-4; ( 6 c J , 58934-04-6;
( l c ) , 58933-92-9;
( l g ) , 58933-94-1 ;
( 2 d ) , 17881-95-7;
( S R ) , 58933-99-6;
( S e ) , 58934-03-5;
( 6 d ) , 58934-05-7;
( I d ) , 36971-28-5;
( 2 a ) , 15288-53-6:
( 2 e ) , 13132-25-7;
( S b ) , 58934-00-2;
(60). 17379-48-5;
( 6 e ) . 58934-06-8
J . Pfletschinger, Dissertation, Universitat Stuttgart 1975.
[ 2 ] R . West, R . Lowe, H. F . Stewart, and H . Wright, J . Am. Chem. SOC.
93, 282 (1971); R . West and A . Wright, ibid. 96, 3214 (1974); A. Wright
and R . West, ibid. 96, 3227 (1974).
[3] G. A. Gornowicz and R . West, J. Am. Chem. SOC.90, 4478 (1968); R.
West and G. A. Gornowicz, J. Organomet. Chem. 28, 25 (1971).
[4] I . F. Lutsenko, Yu. 1. Baukoa, G . S. Burlaclrenko, and B. N . Khasapou,
[I]
J. Organomet. Chem. 5 , 20 (1966).
We have determined the coalescence temperatures of compounds (2) and calculated the free energy of activation A G *
for inversion using the Eyring equation:
AG+=4.57 T,(9.97+log$)
( T ,=coalescence temperature, Av = maximum difference
between the chemical shifts of the methyl groups). The results
are listed in Table 1. Mislow et al.[*] have determined a free
activation energy of 36 kcal/mol for inversion in the metal-free
phospholane ( 3 ) .
As can be seen from Table 1, there is an almost linear
relationship between the free energy of activation of inversion
at the phosphorus atom and the electronegati~ity[~I
of the
neighboring metal or carbon atoms. These results are in agreement with the observations by Mislow, et al.r41on the corresponding open-chain phosphanes.
Received: February 17, 1976 [Z448 IE]
German version: Angew. Chem. 88.445 (1976)
Inversion at Phosphorus in Sila-, Germa-, and Stannaphospholanes [**I
By C. Couret, J . Escudik, J . SatgP, and G. Redoul2s[*]
We recently reported the synthesis of the first sila-, germa-,
and stannaphospholanes ( I )[I1. The 2,2-dimethyI-l -phenyl
derivatives (2) of these compounds are particularly well suited
for dynamic NMR investigations, since the diastereotopic
methyl groups give rise to two very pronounced doublets
in the NMR spectrum (Table 1).
ill: M
7
R\
RXM,P
I
R'
= Si,
By Werner Spielmann and Armin de Meijerep]
Bridgehead derivatives of trishomobarrelene ( I a ) ( ' ] and
' well as the unsubstituted
of trishomobullvalene ( 2 ~ ) ~ as
hydrocarbon ( 2 a ) itself possess C3 symmetry and are consequently chiral. Such optically active compounds are of interest
in connection with the question whether, and if so to what
extent, the propeller structure of the carbon skeleton makes
a significant contribution to the chiroptical properties.
Optically active compounds ( 1 ) and (2) are accessible
by resolution of the racemic carboxylic acids ( I b ) and ( 2 b ) ,
respectively. Resolution of the diastereomeric salts with
= Si, R = Me, R' = P h
= G e , R = M e , R' = P h
( 2 c j : M = Sn, R = M e , R'
[I] C. Courer, J . Escudib, J . Surge, and G. Redoul25, C.R. Acad. Sci., Ser.
C, 279, 225 ( 1 974).
[ 2 ] W Egan, R. Tang, G . Zon, and K . Mislow, J. Amer. Chem. SOC.92,
1442 (1970).
[3] A . L. Allreed and E. G. Rochow, J. Inorg. Nucl. Chem. 5, 269 (1958);
A . L. Aiired, ibid. 27, 215 (1961).
[4] R . D. Baechler and K . Mislow, J. Amer. Chem. SOC.93, 773 (1971).
Optically Active Bridgehead Derivatives of Trishomobarrelene and Trishomobullvalene[*']
G e , Sn
R = Me, Et, P h
R' = n-Bu, P h
(2a): M
(26): M
CAS Registry numbers:
( 2 a ) , 54770-04-6; ( 2 b ) , 5477047-9; ( Z c ) , 54770-39-7
=
ph
C6H5
Table 1. Physical properties of compounds ( 2 ) and ( 3 )
Cpd.
6Me'
CPPml
J(P-Me')
CHzl
&Mez
[PPml
J(P-Me2j
IHzI
Coalescence
temperature
C"c1
(2a)
(2b)
(2c)
(3)
-0.14 (d) [a]
0.05 (d) [a]
0.02 (d) [b]
1.7
1.75
1.5
0.34 (d) [a]
0.50 (d) [a]
0.42 (d) [b]
7.5
5.25
2.25
140
200
155
AG*
[kcal/mol]
Electronegativity
131
_________
21.3
24.3
21.95
36 PI
Si:1.90
Ge: 2.01
Sn:1.96
C: 2.55
[a] In [DJacetone rs. tetramethylsilane as internal standard.
[b] Neat, u.tetramethylsilane as internal standard.
['I
Dr. C. Couret, Dr. J. Escudie, Prof. J. Satge ['I, Dr. G. Redoulks
Universite Paul Sabatier
Laboratoire de Chimie des Organomineraux
11 8, Route de Narbonne
F-31077 Toulouse-Cedex (France)
['I Author to whom correspondence should be addressed.
[**I The authors wish to thank Professor K . Mislow for critical examination
of the manuscript and Dr. J.Parello, Montpellier University, for his participation in the NMR investigation of the germaphospholane ( 2 b ) .
Angrw. Chem. I n r . Ed. Engl. / Vol. 15 ( 1 9 7 6 ) N o . 7
[*I
DipLChem. W. Spielmann and Prof. Dr. A. de Meijere
Organisch-Chemisches Institut der Universitat
Tammannstrasse 2, 3400 Gottingen (Germany)
[**I Presented in part at the "Chemiedozententagung" (April 1975) at Dusseldorf and the Eleventh Euchem Burgenstock Stereochemistry Conference
(April/May 1975).-This work was supported by the Deutsche Forschungsgemeinschaft, the Fonds der Chemischen Industrie, BASF AG, and Deutsche
Shell-Chemie GmbH.
429
quinine afforded levorotatory material in both cases. Use
of D-( +)-a-phenylethylamine led in the case of ( I b ) to enrichment of the (+)-enantiomer, but to enrichment of the (-)enantiomer in the case of ( 2 6 ) . Dextrorotatory carboxylic
acid ( 2 b ) was obtained using L-( -)-a-phenylethylamine as
the optically active auxiliary base.
(c), x = c1
f d l , X = OH
The maximum rotation of ( 1 b ) and ( 2 b ) could be established for the [carbonyl-’4C]-carboxylic acids by means of
the isotopic dilution method[’]. It could be estimated from
the maximum rotations (Table 1) that in the most favorable
case ( I b ) was obtained in 72 to 73% optical purity with
D-( +)-a-phenylethylamine and ( 2 b ) in 98 to 99 % optical
purity with quinine.
Table 1 . Maximum specific rotations [ima.]kO [“I of optically active trishomobarrelene ( 1 ) and trishomobullvalene derivatives ( 2 ) .
and ( + ) - ( 2 d ) from which ( + ) - ( l c ) and (+)-(2c) could be
regenerated in unchanged optical purity by reaction with
thionyl chloride and concentrated hydrochloric acid, respectively. Thus neither ( 1g) nor ( 2 g ) racemizes undertheseconditions, although this would be feasible by an intermolecular
hydride exchange with the second bridgehead of the molecule
in the case of ( I 9). It appears that this process is not suppressed
for steric reasons[’] but rather because intermediate formation
of a 1,5-trishomobarrelenylene dication would be required.
The chiral skeletons of ( I ) and ( 2 ) each contain six chiral
centers. Calculations with the aid of Brewster’s conformation
dissymmetry modelr61permit prediction of the (all-S) configuration for the dextrorotatory derivatives ( I b)-(I d), (2b)( 2 d ) , and for (-)-(If)[’]. Assuming that this
correctly
reproduces the direction of rotation of compounds ( 1 ) and
( 2 ) for a given configuration, a comparison of the calculated
and experimental molar rotations becomes informative
(Table 2).
Table 2. Calculated [6] and experimental molar rotations [“I of
(2S,4S,6S,8S,9S,I 1s)-1-trishomoharrelene ( I ) and (2S,4S,8S,IOS,l IS,13S)-ltrishomobullvalene derivatives (2). The direction of rotation is given relative
to the (+)-carboxylic acids assuming them to possess the (all-S)-conBguration.
X
(10)
(1b)
(1C)
(Id)
f 1s)
(20)
(26)
(2c)
(2d)
H [a]
COzH
CI
OH
D
H [b]
C02H
c1
OH
[Mica,,
0
[MI,,,
0
+ 238
+ 286
+ 260
+ 443
+ 69
+113
-
-
4
0
260
+ 443
69
+
+
1.8
+ 201
+ 503
+ 562
+ 470
[MIexp- [M]..I~
0
22
-157
+44
2.2
201
243
+ I I9
+401
-
+
+
+
__._
a
b
d
e
H
COzH
CI
OH
OAc
f
D
c
s o
0
125 f 3 ( E t O H )
159 f 4(CH*C12)
70 f 2 (CH,CI,)
103 - 4 (CHzCl,)
1.2
(ccI,)
-1516 f 4 0 (CHICIZ) [b]
+
+
+
+
+
+
+
+
+
[a] (2S,4R,6R,8S,9S,11R)-configuration.
[b] (2S,4R,8R,10S,11S,13R)-configuration.
1 1 7 f 3 (CCI4)
233f 4 (EtOH)
2 7 3 f 5 (CCI4)
250f 5 (CCL)
-
-2473k53 (CHzC12) [b]
[a] Relative direction of rotation based on the (+)-carboxylic acid; average
values of several measurements at concentrations r=0.3-0.7g/lOOml.
[b] Measured at -50°C.
Starting from the optically active carboxylic acids it proved
possible to prepare the optically active compounds ( I c)-(1 f )
as well as ( Z a ) , ( 2 c ) , and ( 2 d ) (Table 1). Thus the reaction
of ( + ) - ( I b) and ( + ) - ( 2 b ) with lead tetraacetate in the presence of N-chlorosuccinimide[31gave the dextrorotatory bridgehead chlorides ( + ) - ( l c ) and (+)-(2c), respectively. The
bridgehead acetates ( + ) - ( 1 e ) and ( + ) - ( 2 e ) , of which only
( + ) - ( I e ) was isolated, were formed as by-products.
Reduction of the (+)-chlorides ( I c) and ( 2 c ) with LiAID4
and LiAlH4 furnished the optically active hydrocarbons [I -D]trishomobarrelene ( - ) - ( 1 f ) and trishomobullvalene (+)(Za), respectively. Hydrolysis of the (+)-chlorides in aqueous
dioxane gave the optically active alcohols ( + ) - ( I d ) and (+)f2d).
The exceptional stability of the bridgehead carbenium ions
of trishomobarrelene and t r i s h o m ~ b u l l v a l e n eprompted
~~~
us
to attempt generation of the free optically active cations ( I g )
and ( 2 g ) . O n reaction of the chlorides ( + ) - ( I c) and (+)-(2c)
in dichloromethane with antimony pentafluoride at - 78°C
(cf.
clear pale yellow solutions were obtained. The
two (+)-chlorides afforded carbenium ion solutions displaying
negative rotations with surprisingly high rotatory powers (cf.
Table 1). The specific rotations of the solutions did not change
within 1 to 2 h at - 50°C; addition of water gave ( + ) - ( I d )
430
It is striking that the values [MIexp- [M],,,, for ( 2 ) are
all positive, while they are negative or only just positive for
( I ) . Thus it is suspected that, at least in the case of the
trishomobullvalene system ( 2 ) , the chiral propeller structure
of the carbon skeleton makes a significant contribution to
the overall rotation. In particular, the pronounced rotation
of the hydrocarbon (2a)-it
contains three (S)- and three
(R)-configurated chiral centers and is predicted by the model
to display no rotation-could only be explained in this manner. Accordingly, ( 2 a ) and especially also the free cations
( I g ) and ( 2 9 ) with their high rotatory powers are suitable
test cases for advanced models of optical activity[81and chirality
Received: March 22, 1976 [Z 450 IE]
German version: Angew. Chem. 88, 446 (1976)
CAS Registry numbers:
roremic-(1 b ) , 59284-86-5; ( + ) - ( l b ) 359246-21-8; ( - ) - ( lb ) , 59246-22-9;
( + ) - ( l c ) . 59246-23-0; ( + ) - ( l d ) , 59187-61-0; ( + ) - ( / e ) , 59187-62-1;
( - ) - ( / J J , 59246-24-1 ; ( - ) - ( l g ) , 59284-82-1 : ( + ) - ( 2 u ) , 59246-25-2;
racemic-(2b), 59246-26-3; ( + ) - ( 2 b ) , 59246-27-4; ( - ) 4 2 b ) , 59246-28-5:
(+)-(2c/, 59246-29-6; ( + ) - ( 2 d ) , 59203-48-4; ( + ) - ( 2 e ) . 59169-65-2;
(-)-(2g), 59203-49-5; quinine, 130-95-0; D-( +)-ix-phenylethylamine,
3886-69-9; L-( -)-u-phenylethylamine, 2627-86-3
[l]
[2]
[3]
[4]
[5]
a) A . de Meijere and C. Weitemeyer, Angew. Chem. 82, 359 (1970):
Angew. Chem. Int. Ed. Engl. 9, 376 (1970): b) A. de Meijere, 0. Schullner,
and C . Weitemeyer, Tetrahedron Lett. 1973, 3483.
For method, see H . Gerlach. Helv. Chim. Acta 49, 2481 (1966).
K . B. Becker, M . Geisel, C . A. Grob, and F . Kuhnen, Synthesis 1973,
493.
a) A . de Meijere, 0. Scliullner, and C . Weiremeyer, Angew. Chem. 84,
63 (1972); Angew. Chem. Int. Ed. Engl. 11, 56 (1972); b) A . de Meijei’e
and 0. Schullner, [bid. 85, 400 (1973) and 12, 399 (1973). respectively.
Hydride abstraction from ( 2 u ) by ( 1 g ) to Corm the cation (217) and
the hydrocarbon ( 1 u ) has been observed. W Spielmanfl and A . de Meijere,
unpublished results.
A n g e w Chem. I n t . Ed. Engl. f Rd. 15 ( 1 9 7 6 ) No. 7
The fact that ( 1 ) and (2) both give the same product
(7) shows the first step of thermolysis of (1) to be rupture
ofthecentral strained bond (path A in ref. ['I). A bicyclo[6.2.0]decatetraene (6) which is unstable under the reaction conditions has been proposed as the first intermediate en route
from ( 1 ) to (7). Its tetrahydro derivative (9), which is no
longer accessible to electrocyclicring opening to form a cyclodecapentaene, should be isolable. The behavior of compound
(3), from which (9) could be formed thermally, therefore
attracted our interest.
Thermolysis of pterodactylane (3), m. p. 57-60°C, prepared from (1) by hydrogenation (Pd/C in CH,OH), in boiling
CCI4 gives not only (9) but also surprisingly compound (10)
(ratio 1 : 1).
The structures (9) and (10) are based on spectral data,
on the oxidative degradation of (9) with ozone or
KMnO,/KIO,, which leads to succinic acid, and on the dehydrogenation of (10) with dichlorodicyanoquinone (DDQ) to
dimethyl 1,5-naphthalenedicarboxylate.
[6] J . H . Brewsster, J. Am. Chem. Soc. 81, 5475, 5483,5493 (1959); Tetrahedron
13, 106 (1961).
[7] The absolute configurations of compounds ( 1 ) and ( 2 ) are unknown;
an X-ray structural study of ( 1 c ) is in progress.
[8] J . H . Brewsrer, Top. Curr. Chem. 47, 29 (1974).
[9] E. Ruch, Acc. Chem. Res. 5, 49 (1972).
Four Linearly Annelated Cyclobutane Rings :
The Tetracyclo[4.4.0.02~
5.079'Oldecane System[**]
By Hans-Dieter Martin and Mirko Hekman"]
We recently reported the synthesis['] of pterodactyladiene
( I ) , a highly strained representative of the (CH),, isomers.
In the present communication we now report:
a) The preparation and an unexpected thermal isomerization
of pterodactylane ( 3 ) , the course of which has been established
by isotopic labeling.
b) The elucidation of the mechanism of thermolysis of (1 ).
c) The synthesis and thermolysis of the azo compounds
( 2 ) and ( 4 ) . Compound ( 2 ) provides an entry to the (CH),,
energy surface which is distinct from (1) and permits a decision
between the various reaction pathways proposed for (1 ).
R
131
I
R = COzCH3
60-80 "C
A
R
R = COzCH3
Reaction of cyclobutadienetricarbonylironand ammonium
cerium(1v) nitrate with the 3,6-disubstituted s-tetrazine ( 5 )
at 0°C affords ( 2 ) , m.p. 103--105°C. Heating of ( 2 ) in per-
The transformation of (9) to (10) only at temperatures
of about 190°C shows that (10) cannot be regarded as a
product of (9) under the given reaction conditions (60-80°C).
Rather both (9) and (10) are formed directly from (3).
The thermolysis of tetradeuteriated (3) furnishes evidence
for the reorganization of the molecule and for the formation
pathway of (9) and (10). In [D4]-(9) the deuterium occupies
the positions 4a,5a,9a, and 10a, and in [D4]-(10) positions
4, 5, 9, and 10. The site of deuteriation in (3) follows from
the NMR spectra of (3) and [D4]-(3) in the presence of
a shift reagent.
R
'N A
ce4+
I
R
(5J
[OI
-
R = C02CH3
+
R
12)
chlorobutadiene (2h, 140°C)gives the naphthalene (8) almost
quantitatively. Transient formation of 4a,8a-dihydronaphthalene (7)"' can be detected by NMR spectroscopy.
rD4]-
I I ) Rupture 1.6
(31
2) Rupture2.517.10
to form bisallyl
radical [2]
3 ) Head-to-tall
linkage 2.1
1
R = COzCH3
D
R = C02CH3
[*I
Prof. Dr. H.-D. Martin and
Dipl.-Ing. M. Hekman
Institut fur Organische Chemie der Universitat
Am Hubland, 8700 Wurzhurg (Germany)
[**I This work was supported by the Deutsche Forschungsgemeinschaft
and the Fonds der Chemischen Industrie. We are indebted to Prof. Dr.
H . Schmid. Zurich, and Dr. D . Belfuf, Basel, for discussions, and to Prof.
Dr. J . Sauer, Regensburg, for communication of unpublished results. A
generous gift of COT from the Badische Anilin- und Sodafabrik AG is
gratefully acknowledged. Small Rings, Part 18.-Part 17: H.-D. Martin, S.
Kagabu, and H . - J . Schiwek, Tetrahedron Lett. 1975, 331 1.
A I I ~ L WCIIPI~.
.
l i l t . Ed. EIIL]~.
! Vol. 15 11976) N o . 7
~
R
[D41-
(101D
D
The azo compound ( 4 ) , m.p. 160--162"C, prepared by
diimide reduction of (2) (potassium azodicarboxylate and
acetic acid at 0°C) affords (9) as major product accompanied
by only about 5 % of (10) on thermolysis. This product
distribution is in accord with results obtained for other azo
The kinetic parameters of ( l ) , (3), ( l l ) , ( 1 2 ) , and (13)
(Table 1) confirm the uniform mechanism, which is initiated
43 1
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