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N2S3OЧThe First Oxide of a Five-Membered Sulfur-Nitrogen Ring.

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The sigmatropic [1,3]-migrations ( 3 ) + (7) ( S ) , and
( 4 ) -+ (7) + ( 8 ) , d o not occur stereospecifically. This too contraindicates worthwhile resonance stabilization of an aromatic
transition state in the [1,3]-rearrangement. The formally orbital symmetry forbidden product (8) is actually formed from
( 4 ) faster than is the allowed product (7)['?
[6] Cf.: R . Zurmiihl: Praktische Mathematik fur Ingenieure und Physiker
(Practical Mathematics for Engineers and Physicists), 4th Edit., p. 407. Springer, Berlin 1963. I wish to thank Prof. M . Saunders for making his computer
program available
171 W uon E. Doering and K . Sachdeu, J . Amer. Chem. SOC.96, 1168 (1974).
[8] Cf., Y . g. [2c].
[9] R. B. Woodward and R . Hofmann,Angew. Chem. 81, 797 (1969); Angew.
Chem. internat. Edit. 8, 781 (1969).
[lo] M . J. S. Dewar, Tetrahedron Suppl. 8, 75 (1966); Angew. Chem. 83,
859 (1971); Angew. Chem. internat. Edit. 10, 761 (1971).
[ I 1 1 An estimate can be made from 49.5 kcal/mol ( E , for the degenerate
methylenecyclobutane rearrangement [12]) minus 12-13 kcal/mol 1131 (for
the allyl resonance energy of C'C*C3).
The epimerization ( 3 ) + ( 4 ) requires, in one phase of the
reaction, an orthogonal non-bonding relation between C 1
and C 7 and can therefore be regarded as non-concerted. Formal cleavage of the C'-C7 bond in ( 3 ) to (6) leads to
the resonance-stabilized cis- and trans-substituted bisallyl diradicals ( 1 1 ) and (12). From the product ratio (7)/(8), as
an example, one can test whether (Ila)z$(llb)
and
(12a)+(12b)
are
equilibrated
intermediates:
(5)*(7)/(8) = 1.33; (6)-+(7)/(8) = 1.43. Then, independently of whatever the cisltrans ratio (11)/(12) may be, the
values for (7)/(8) from ( 3 ) and ( 4 ) should be found to
be between 1.33 and 1.43; however: ( 3 ) + (7)/(8) = 0.134;
( 4 ) -+ (7)/(8) = 0.657. Thediscrepancy between these product
ratios is in conflict with equilibrated diradicals as intermediates, in spite of the high energetic stabilization in ( 2 1 )
and (12).
Non-equilibrating diradicals offer an explanation for the experimental findings. Even in our more complex system such diradicals appear to behave as individual transition states in the
sense of the "continuous diradicals" postulated by Doering
and Suchdev['I. The hypothesis is supported by the individual
rate constants of the rearrangements of ( 3 ) to (6). The diradical character of the transition states is supported by extensive
utilization of the resonance stabilization of both allyl triads
and by the gradual change of the rate constants for the total
decrease of ( 3 ) to (6), which reflects only a substituent effect
of the methyl group (cf. Table 1). The methyl-free compound
( I ) , with k-,1,=100.8x ~ O - ' S - ~ fits
( ~ ]in the middle of the
series. An alternative that cannot be excluded is the existence
of intermediates in flat energy troughs, where product formation competes successfully with rotation around the C 5 - C 6
bond in ( 1 1 ) and (12). Since the stereochemical course of
the rearrangements of ( 3 ) to (6) appears to be severely
influenced by the methyl substituents, investigations are in
progress with substrates that a) exclude this steric factor and
b) increase the flexibility of the system by ring expansion.
Received: November 13, 1974 [Z 158 IE]
German version: Angew. Chem. 87, 252 (1975)
CAS Registry numbers:
( 3 ) , 54739-12-7; ( 4 ) , 54774-07-1 ; ( 5 ) . 54139-13-8; (6). 54739-14-9;
(71, 54739-15-0; (8). 54739-16-1 ; (Y), 28304-67-8; (ZO), 28304-66-7
[I] Part 2. This work was supported by the Deutsche Forschungsgemeinschaft. Part I : D . Hassehmnn, Tetrahedron Lett. 1973, 3739.
[2] a) J . A. Berson, 7: Miyashi, and G . Jones, J. Amer. Chem. SOC.96,
3468 (1974); b) J. J. Cajewski, L. K . Hoffman,
and C. N. Shih, ibid. 96,
3705 (1974): c) F.-C. Kliirner, Angew. Chem. 86, 270 (1974); Angew. Chem.
internat. Edit. 13, 268 (1974).
[3] D. Hasse/mann, Tetrahedron Lett. 1972, 3465.
[4] Thermolyses in solution were carried out in n-heptane, those in the
gas phase in a 20-1 Pyrex round-bottomed flask (temperature constancy
better than 0.1 "C) at ca. I torr.
[5] (3) to ( 1 0 ) were unambiguously characterized by synthesis, elemental
analysis and MS, IR, 'H-NMR and FT-13C-NMR spectroscopy.
258
[12] W uon E . Doering and J. C . Gilbert, Tetrahedron Suppl. 7 , 397 (1966).
1131 W van E. Doering and C . H. Beasley, Tetrahedron 29, 2231 (1973);
W R . Roth, C . Ruf, and P. W Ford, Chem. Ber. 107. 48 (1974).
[14] J . A. Bersoit and L. Salem, J. Amer. Chem. SOC.94, 8917 (1972).
115) The [1,3]-rearrangement of the analogous 6-acetate gives a similar
result: J . A. Berson and G. N. Nelson, J. Amer. Chem. SOC.92, 1096 (1970).
N2S30-The First Oxide of a Five-Membered SulfurNitrogen R i n g [ * * ]
By Herbert ui Roesky and Hartmut Wiezer"]
The recent synthesis of N4S404[11has raised the question
whether oxides of cyclic SN compounds containing less than
six ring members can be prepared.
(CH3)4Sn2N4S4 (1)['. 41, prepared from S4N4 and
[(CH3)3Sn]3N by reaction in a molar ratio of 1 : 1, reacts
with SOF2 with elimination of (CH3)2SnF2according to
H3d CH3
(1)
The reaction product having the composition N2S30 ( 2 )
is isolated as a red liquid which can be vacuum-distilled
without decomposition (b.p. 50°C/0.01 torr); it does not wet
glass. No signs of decomposition were observed, even after
storage for several weeks at room temperature. In contrast,
the previously known isomer formulated as (S=N&SO is
readily decomposable[4!
The structure of the new compound was elucidated by elemental analysis, IR spectrum, and mass spectrum.
The molecular ion is observed at m/e 140 with a relative
intensity of 11 %, accompanied by the following fragments
m/e 94 NS2O (473,92 N2S2 (4%), 80 S20 (lo%), 78 S2N
(28%), 76 NzSO (12%), 64 Sz(S0z) (50%), 60 NzS @%),
48 SO (46%), and 46 NS (100%).
In the IR spectrum (cm-') the band at 1125vs could be
assigned to the SO stretching mode, and those at 981 s, 910s,
and 734 s to the ring skeleton. Further absorptions were registered at 1181 m, 663 s, and 583 m.
Procedure:
An excess of SOF2 is passed into a suspension of (1) (9.9g)
in CH2C12 (600ml). The mixture is then stirred for 3 h, the
[*] Prof. Dr. H. W. Roesky and Dr. H. Wiezer
Anorganisch-chemisches Institut I der Universitat
6 Frankfurt am Main 50, Niederurseler Hang (Germany)
[**I This work was supported by the Fonds der Chemischen Industrie
and the Deutsche Forschungsgemeinschaft.
Angnv.
Chem. inrernor. Edir. 1 Vol. 14 ( 1 9 7 5 ) 1 No. 4
The organolithium compounds were identified by the usual
derivatizations, with ketones, C 0 2 , and chlorosilanes. Definite
proof for the presence of lithium hydride ( 4 ) is still lacking.
After reaction with phenyldimethylchlorosilane (9), phenyldimethylsilane (If)) can be isolated; ( 1 0 ) is probably formed
by reaction of ( 4 ) with (9)“).
insoluble ( C H 3 ) ~ S n Ffiltered
2
off, the solvent removed in vacuo,
and the residue distilled. Yield: 4.1 g (70%) of (2).
Received: October 15. 1974;
revised: November 14. 1974 [ Z 159 IE]
G e r m a n version: Angew. Chem. 87. 154 11975)
C A S Registry numbers:
[ I ) , 54517-19-0: ( 2 ) . 54460-74-1 ; SOF,, 7783-42-8
-~
. ~-
Interpretation and Discussion :
[ I ] H . M! R n c 4 r and 0. Percx\en. Angew. Chem. X4. 946 (19721: Angew.
Chem. internat. Edit. f /. 918 (1972).
A transfer of lithium to ethyle,ne takes place. This leads
to the formation of one or several reactive short-lived intermediates. These react to give vinyllithium (3), lithium hydride
( 4 ) , and i,r)-dilithiobutane ( 5 ) .Two parallel overall reactions
(1) and (2) ean be formulated.
[2] According to structural studies by B. Krehs. Bielefeld. the compound
has a n almost planar cyclic skeleton with Sn-N distances of 2.135 and
2.316A: the Sn-S distance of 2.603A is remarkably long. ( 1 ) is the first
SnN four-membered ring whose structure has been determined by X-ray
methods [ 3 ] .
[3] Cf. D. Hih.\.~qm and 1. Polil. Angew. Chem. X6. 676 (19741: Angew.
Chem. internat. Edit. /.?~ 607 (1974).
[4] 4 . M c i r i i . c r r i and M . Liisri. 2. Anorg. Allg. Chem. 271. 220 (1953).
CH,=CH,
+
2 Li
-+
CH,=CH-Li
(31
2 CHpCH, + 2 Li
+
+
LiH
(1)
(4)
Li-CH,-CH,-CH,-CH,-Li
(5)
(2)
The structures and mechanisms which play a role in these
reactions are largely unknown. In particular, it is not known
in what way the system biphenyl/naphthalene/lithium is
involved in the transfer process12!
Transfer of lithium to ethylene should lead to an “ethylene
anion radical with lithium cation as the counterion”
and
perhaps also to a “1,2-dilithioethane” (2)[31.An obvious
hypothesis is that ( / ) and/or ( 2 ) are intermediates in our
reactions (see scheme). It is striking that both a
decompositionl’l of ( 2 ) into vinyllithium ( 3 ) and lithium
Vinyllithium and 1,6Dilithiobutane from Ethylene and
Lithium
By Valrntin Ratctenstrauc~h[*]
Procwiur e :
A solution of biphenyl (70 mg, 0.45 mmol) and naphthalene
(10 mg, 0.08 mmol) in dimethoxymethane (DMM) (2 ml) is
stirred at room temperature (RT) in a Schlenk tube under
argon with lithium pieces (a.
500 mg, 72 mmol) until the
CH,=CH2
1
-tr:!n..r<~r
Li-CH,-CH,.
C H3-C H,-C H2-C H,-L i
0)
-Irnn-(cr
-
18)
f
( ‘ I 1*’CI I 2
Li-CH,-CH,-Li
121
1
CH,=CH-Li
(31
+
LiH
1
CH,=CH-CH,-CH,-Li
14)
solution turns dark brown (2-10 min). The stirred mixture
(RT) is then diluted with DMM (18 ml) over a period of
cu. 1 h, and stirring is continued for another 30 min. A 2 1
flask containing ethylene (normal pressure, ca. 90 mmol)
is fitted to the Schlenk tube, ethylene is condensed into the
solution by cooling it to cu. - 1 t O T , and the system is brought
to normal pressure by introduction of argon. The solution
is then stirred with the lithium for ca. 20 h at - 10°C. The
Schlenk tube and the 2 I flask form a closed system; the
gas mixture over the cooled solution remains at RT. The
solution then contains 3.0 mmol of vinyllithium ( 3 ) , 1.2 mmol
of 1,4-dilithiobutane ( 5 ) , 0.04 mmol of 1,6-dilithiohexane (6),
0.04 mmol of 3-butenyllithium ( 7 ) . 0.07 mmol of butyllithium
( 8 ) , and probably at least 3.3 mmol of lithium hydride ( 4 )
(along with biphenyl, naphthalene, products derived therefrom,
and unreacted lithium).
None of these, products is formed at lower temperatures
(below -30°C): ( 5 ) is not stable at higher temperatures (RT
and above).
[*] Dr. V. Rautenstrauch
Firmenich SA, Research Laboratory
CH-I21 I Geneve 8. B. P. 239 (Switzerland1
(,IIFC I I,
Li-CH,-CH,-CH,-CH,-Li
(5)
(71
+
Li-CH,-CH,-CH,-CH,-CH~-CH~-Li
(6)
LiH
14)
hydride ( 4 ) and an addition of ethylenef51 to ( 2 ) , which
would give 1,4-dilithiobutane ( 5 ) , would have direct analogies
in the behavior of “normal” alkyllithium compounds. Both
reactions would bring about a separation of the neighboring
charges in ( 2 ) , and would therefore be especially favored.
Precisely this “normal” behavior is observed in the slow
further reactions of 1,4-dilithiobutane ( 5 ) (scheme). Addition
of ethylene leads to the next higher homolog[’], 1,6-dilithiohexane ( 6 ) , and loss of lithium hydride gives 3-butenyllithium
( 7 ) ; in addition, (5) metalates the solvent with formation
of butyllithium (8).
To our knowledge, compounds of type ( 1 ) are unknown,
and compounds of type ( 2 ) have not been identified conclusively[’]; no theoretical studies have been carried out on ( 1 )
and (2). The overall reaction ( 1 ) has parallels in known reactions‘’]: reaction (2) is novel.
The postulated formation of ( I ) and ( 2 ) is plausible. Lithium is a very powerful reducing agent in donor solvents and
can form electron-deficient multicenter bonds with carbon:
(2) would entail two bonds to primary carbon atoms.
Received: November 17. 1974:
revised: January 13. 1975 [Z 160 IE]
German version: Angew. T h e m . 87, 254 (1975)
259
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