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Inversion at Phosphorus in Sila- Germa- and Stannaphospholanes.

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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
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