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Hammett Constants of Substituents Containing Phosphorus.

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I n favor of the presence of the niethanesulfonylsulfone ( I )
are the smooth 1,2-1’,2’-cycloadditions to enamines ( 4 ) ,
yielding compounds (3), and the fact that products (2) and
( 3 ) ‘are formed also on treatment of methanesulfonylmettanesulfonyl chloride Ill/triethylamine with Y H or a n
enamine in tetrahydrofuran at 2OoC.
The H - N M R signal of compound (3a) in CHC13 shows
6.6 (d, J = 8 cps,
signals at 4.6 T (d, J = 8 cps, SOZCHSO~),
, [s, N(CH&], and 8.35 7 [s,
NCH), 6.7 (s, S O Z C H ~ )7.6
C(CH3)2] in the ratio 1 : 1 :3 :6: 6. The doublets for the ring
protons in compound (3b) appear in acetone at 4.3 and
6.6 T, but in pyridine the former signal is shifted to 3.3 7 ;
we have observed similar shifts to lower field for other
1,3-disulfones. Quaternization of (3a) with methyl iodide
and heating of the salt with aqueous-alcoholic sodium
hydroxide gives isopropyl- methanesulfonylmethyl sulfone
(m.p. 101-102OC).
Capture experiments with N-isobutenylpyrrolidine show that
compound ( I ) is stable for several days in acetonitrile at
-4O’C [after 90 hr at -38OC it gives (3b) in 5 2 % yield],
but when warmed it decomposes above about -30°C with
formation of a reddish-brown color. On freeze-drying there
remains a colorless powder composed of an adduct of
triethylamine and ( I ) , elucidation of whose structure is in
progress.
Received: April 26th, 1966
[ Z 208 IE]
German version: Angew. Chem. 78, 604 (1966)
[ I ] G. O / J / I Z
and G. W’olz, unpublished work.
Preparation of trans ,trans- and cis,cis-1,6-Cyclodecadiene from cis,trans-l,5-Cyclodecadiene
By Dr. P. Heimbach
Max-Planck-Institut fur Kohlenforschong,
Mulheim/Ruhr (Germany)
1,3-Cyclooctadiene is formed when 1,5-cyclooctadiene is
heated with Fe(C0)5 for 7 hr at 115 “C [I]. Under similar
conditions cis,trans-1,5-cyclodecadiene(1) [21 yields almost
exclusively cis-I ,2-divinylcyclohexane (2). This valence isomerization [31 is appreciably faster than isomerization of the
double bonds in compound ( I ) . On ultraviolet irradiation
Fe(C0)S is active as isomerizationcatalyst even at 20-50 “ C [41.
We have therefore irradiated a solution of 3 ml of Fe(C0)5
in 400 g of ( I ) at about 60 OC with a low-pressure H g lamp
(Messrs. Grlntzel, Karlsruhe). The products were cis,cis(3) and trans,trans-1,6-cyclodecadiene( 4 ) .
Reaction
time [hrl
0.5
1
4
21
48
1,6-cyclodecadiene - as intermediate in the conversion of
( 4 ) into (3) - can occur in thc reaction mixture with a
concentration of only ca. 0.3
if at all. This result does not
agree with the report by Dale el al. that 8.0 % of cis,trons1,6-cyclodecadiene was identified in the cis,trans-equilibrium
mixture of 1,6-cyclodecadienes (7-hr irradiation of the cis,cisisomer in the presence of diphenyl sulfide at 75 ’C).
The isomerization ( I ) + (3) can also be effected by reduction
of 1 g of a n acetylacetonate of a group VIIlb metal in 10 g
of diene ( I ) with AI(CzH5)3 (I mole per equivalent of metal
acetylacetonate) and heating for 24 hr at about 60 “C.
‘x,
Acefylacetonate
I
Conversion
or ( i i [ % I
61
90
84
73
Yield of ( 3 )
1x1
98
98
79
76
lsomerization of ( I ) to (3) was further observed on partial
hydrogenation of ( I ) to cyclodecene (maximally 3 % of transcyclodecene was formed alongside cis-cyclodecene). When
1 mole of hydrogen had been absorbed in presence of P d ’
Bas04 as catalyst, 65 % of cyclodecene, 19 % of cyclodecane,
and 16 % of (3) (which is difficult to hydrogenate) were
identified. Attempts to isomerize (1) with various hydrogenation catalysts in the presence of catalytic amounts of
hydrogen did not give reproducible results.
[Z 210 IEI
Received: April 21st, 1966
German version: Angew. Chem. 78, 604 (1966)
[I] J . E. Ari7etand R. Pettir, J. Amer. chem. SOC.83, 2954 (1961).
[ 2 ] G. Wilke and P . Hei/nhoclr, Angew. Chem. 75, 10 (1963);
Anyew. Chem. ifiternat. Edit. 2, 113 (1963).
[3] P. Heimboch, Angew. Chcm. 76, 859 (1964); Angcw. Chem.
internat. Edit. 3 , 7 0 2 (1964).
[4] F. Asinger, B. Fell, and K. Schroge, Chem. Ber. 98, 372
(1965).
151 D.J . Cmrn and N . L. A//ingw, J. Amer. chem. SOC.78, 25 I 8
(1956).
[61 J . Dole and C. Moitssebois, J . chem. SOC. (London) 1966,
C 264, obtained ( 3 ) from (/) in 95”., yield by the method of
W. 0. Ifon: a n d H . Pines, J. Amer. chern. SOC.82, 387 (1960).
Hammett Constants of
Substituents Containing Phosphorus
By Dr. G . P. Schiemenz
Institut fur Organische Chemie
der Universitat Kiel (Germany)
Conversion
[a] of ( I ) [ %I
(3)
21.4
36.3
65.7
86.5
90.4
84
84
85.9
90.3
92.0
16
16
13.8
9.4
7.5
-
0.3
0.3 [b]
0.4 [bl
[a] Conversions and yields determined by gas chromatography (50 m
VZA capillary column, silicone oil DC 200, 120”C, 1 atm of argon,
retention time for (3) 12.3 min, for ( 4 ) 13.4 min).
[bl Two compounds in equimolar amounts.
(3) : B.p. 67 “ C / l I mm, m.p. 28- 28.5 OC (from ethanol) (lit. :
21-22’C[sl, 22’C[6]), n3:= 1.4964 (lit.: n g = 1.4972[51); infrared bands of the cis-double bonds at 707 cm-1 (s) and
1655 cm-1 (m).
( 4 ) : B.p. 65OC/ll mm; nko = 1.4917; infrared bands of the
trans-double bonds at 952 and 977 cm-1 (s) and 1667 cm-1
(m).
The 1,6-position of the double bonds in compounds ( 3 ) and
( 4 ) was proved by ozonolysis and oxidation of the ozonide
to glutaric acid. The ratio (3) : ( 4 ) was 5: 1 after reaction for
1 hour and 12:l after 48 hours, i.e. isomerization of (4) to
(3) accompanies the shift of the double bond. Any cis,transAngew. Chem. internat. Edit.
/ Vol. 5 (1966) No. 6
Previously a’-constants [21 for the groups (CsHs)zP-,
(C6HshP(O)-, (CsHs)zP(S)-, and (CsH5)2(CH3)PG- were
calculated from the half-neutralization potentials (HNP) of
p-P-substituted dimethylanilines [3,41. However, owing to
lack of a reliable equation only approximate a-values were
obtained from the pK’, values of the corresponding p-Psubstituted benzoic acids [XI.
Equation (a) was obtained from the pK’, values of eight
reference substances (see table), determined under the same
conditions (67 % aq. CH3OH; 0.02 N NaOH), together with
the known substituent constantsr21, by the method of least
squares. With the parameters r = 0.996, s = 0.058, and p =
1.278, this is a n “excellent”[2] Hammett equation. From it
were obtained the a-values of phosphorus-containing groups
assembled in the table.
pK,
:
+ 5.27
(a)
3
18.385 o f 1621.12
(b)
=
-1.278
CT
A further method of determining a is based on the fact that
the frequency of the amide I infrared bands of p-substituted
N,N-dimethylbenzamides depends linearly on the Hammett
constants of the para-substituents. Wave numbers measured
for seven reference substances in KBr lead to the “satis-
595
factory’”21 equation (b) (r = 0.965); of the three a-values
(see table) determined for phosphorus-containing substituents
with this equation, those of the p-diphenylphosphino and
diphenylphosphhyl groups agree well with the constants
derived from the p K a values of the acids.
Phosphorus behaves throughout as an electron acceptor, the
order being phosphonium- > phosphinyl- w thiophosphinyl- > phosphine-phosphorus. (C,&5)2P(O) has aparaonly
slightly greater than ameta = +0.485 determined by
alkaline cleavage of 3-(dipheny1phosphinyl)benzyltrimethylsilane [a;thus in this case 3d-orbital participation appears not
to be significant. However, the fact that G ( C ~ H ~ ) ~<P
G ( C ~ H ~ ) ~ P ( O-) as in the phosphine p-(C6H5)2P-C&N(CH3)2[31 - indicates a certain amount of 3p-orbital
participation by the phosphine-phosphorus.
X
(i
6.09
-
5.74
5.50
5.34
4.97
4.94
4.38
4.35
5.03
4.64
4.63
3.98
3.86
4.66
la1
-0.660
-0.600
-0.357
-0.170
0.0
+0.227
+0.232
+0.628
10.778
0.19
+0.49
i 0.50
+1.01
-;-1.10
0.48
-i
+
;j
(amide I)
CI
Ial
[cm-11
-
1618
1624
1626
1621
1632
1637
-0.660
-0.600
-0.357
-0.170
0.0
+0.227
+0.232
+0.628
-t 0.778
1625
1637
1632
-1-0.21
10.86
-L0.59
-
-
ca. 1610
-
-
are all in agreement with structure ( I ) . Addition of water to
the compound gives N,N’-diferrocenylurea, Fc-NHCONH-Fc,
m.p. 250 “ C (decomp.) [31; reaction with ethoxide in ethanol
produces the isourea derivative Fc-NH-C(OC~H~)=N-FC,
m. p. 147-1 50 “C.
Fc
FC,
N=C=N
FZ
[I] Aromatic Phosphines with Electron-Attracting Substituents,
Part 1V; Part 111: G. P . Srhiemen; and J.Tobe, Chem. Ber., in
press.
[2] H . H . J n f d , Chem. Reviews 53, 191 (1953).
[3] G. P. Schieinenz, Angew. Chem. 78, 145 (1966), Angew.
Chem. internat. Edit. 5, 129 (1966).
[4] On inclusion of further reference points [p-X-C,jH4-N(CH3)2,
X = H: HNP = -608 mV, a = 0;X = NO: HNP = -595 mV,
a = +0.123; X = S02N(CH3)2: HNP = -481 mV, a = +0.965
(R. W . Bott, C. Enborn, and B. M . Rirshron, J. organomet.
Chemistry 3, 448 (1965)l the best equation (r = 0.971, “satisfactory”) for calculation of IS’ from the previously given HNP
values becomes: a’ = 6 . 5 7 1 10-3
~
HNP + 4.095
[5] Calculated with the reaction constant p = 1.000 (which is
too small for an alcoholic medium [2]) and the measured value
pK’,(C6HsCOOH) = 5.34 as -log KO.
[6] R. W . Bort, B. F. Dowden, and C . Enborn, J . chem. SOC.(London) 1965, 4994.
Received: April 27th, 1966
[ Z 227 IE]
German version: Angew. Chern. 78, 606 (1966)
[I] This work was supported by the U.S. Government under
Contract 61(052)-383.
[2] L . J. Rolland R . Adains, J. Amer. chem. SOC.54,2494 (1932);
W. C. Schneider, ibid. 72, 761 (1950).
[3] K. Schloggl and H. Seiler, Naturwissenschaften 45, 337 (1958).
[4] T . W. Campbell, J. J . Monagle, and V. S. Foldi, J. Amer.
chem. SOC.84, 3673, 4288 (1962).
[5] Average degree of acetylation about 2.5 per glucose unit.
We thank Messrs. Deutsche Rhodiaceta AG., Freiburg (Germany) for the sample.
[6] G. Lowe, Chem. Commun. 1965, 41 1.
Reaction of Substituted Vinylsulfonium Salts with
CH-Acidic Compounds. - A New Route to
Polysubstituted Cyclopropanes
By Priv.-Doz. Dr. J. Gosselck, Dip1.-Chem. L. BCress, and
Dip1.-Chem. H. Schenk
lnstitut fur Organische Chemie
der Universitlt GieBen (Germany)
An Optically Active Carbodiimide
By Prof. K. Schlogl and H. Mechtler “1
Organisch-Chemisches Institut, Universitlt Wien (Austria)
Carbodiimides (R-N=C=N-R) have as their sole element
of symmetry a Cz axis and therefore possess axial chirality;
by analogy to allenes, they should therefore be resolvable
into optical antipodes 121.
We have found that N,N’-diferrocenylcarbodiimide ( I ) is
stable and is therefore suited to attempting racemate resolutions of compounds of this class. We have thus obtained
the first sample of a n optically active carbodiimide.
The racemic form of ( I ) was prepared from Fc-N=C=O[31
by the method of Cambell et 01. [41 in 85 % yield in the form
of crystals, m. p. 140-145 “C (decomp.). Elemental analyses,
a sharp infrared band at 2120 cm-1, and the mass spectrum
596
Fc: C,H5FeC5H4-
Partial resolution of the racemate ( I ) was effected by
chromatography in benzene on a column (4 m longx3 cm
diam.) of partially acetylated cellulose[51: 250 mg of ( I ) was
passed through the column and seven fractions of approx.
50 ml each were collected. Subsequent purification by thinlayer chromatography on silica gel with benzene gave
chemically unchanged (infrared spectrum) dextrorotatory
( I ) , which was enriched in the seventh ‘(last) fraction:
[ E ] : = +4.1
0.2’ (c = 0.4 in dry benzene). All the other
fractions showed practically no optical activity.
Partial reaction of ( I ) with ( + ) - ( R ) or (-)-(S)-6,6’-dinitrodiphenic acid in anhydrous benzene at 25°C to form the
corresponding acylurea effected kinetic resolution of the
racemate. The chemically unchanged carbodiimide ( I )
recovered by preparative thin-layer chromatography after
the reactions was optically active: [a]”= -4.8 i 0.2 (c =0.3)
and +1.6 c 0.1 ’ (c = 0.4 in benzene).
It follows from stereochemical considerations of the preferred
transition state (stereoselective addition of the carboxyl
group from the diphenic acid onto the -N=C= structure)
that ( + ) - ( I ) should have the (S)-configuration. Application
of a rule derived for allenes [61 leads to the same conclusion.
[a] o-Values of phosphorus-free substituents are taken from the literature [ZI.
[ b] In (p-HOOC-CbH4)iPO.
Received: April 21st, 1966
iZ 207 IE]
German version: Angew. Chem. 78, 605 (1966)
N=C=N
F
’ c
Dimethylvinylsulfonium salts (3) with a mono- or disubstituted vinyl group were obtained either by methylation of
the corresponding methyl vinyl sulfides ( I ) with one equivalent of dimethyl sulfate or by heating dimethyl mercaptals
(2) with excess of dimethyl sulfate[”.
R- c =CH- R’
I
SCH,
(1)
Ix@
QCH3
R-C-CH,R’
I
SC H,
(2)
Angew. Chem. internat. Edit.
1 Vol. 5 (1966) / No. 6
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