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Stereochemistry of the Cycloaddition of Sulfonyl Isocyanates and N-Sulfinylsulfonamides to Enol Ethers.

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peroxide without a base gives exclusively (S), m.p. 211 to
213 "C (90 % yield).
Treatment of (2) or (3) with methanolic 0.01 N NaOCH3
solution causes a sugar degradation by a new type of perester degradation. The anomalous peroxy ester (3) is completely decomposed within 5 h at room temperature, yielding
70 % of D-arabinose (crystalline, paper-chromatographically
pure), 66 P: of carbon dioxide, t-butyl alcohol, and methyl
acetate, with 30 % of methyl o-gluconate as by-product
(percentages calculated with respect t o compound (3)). Complete decomposition of the normal peroxy ester (2) requires
more energetic conditions: after 8 hours' warming at 60 'C,
D-arabinose was isolated in 51 % yield.
The diperoxy compounds (4) and (5) are not degraded with
C-C cleavage by sodium methoxide solution; only transesterification and deacetylation occur, yielding dimethyl
mucate (90 %).
We interpret the decomposition of (3) as fragmentation [31
of a n intermediate pyranoid compound (6). Presumably, (2)
also decomposes by way of a cyclic intermediate.
Reaction of (2)
with ( l a )
with (Ib)
time (min)
Received May 19th and August 18th. 1967
[ Z 600b 1E)
German version: Angew. Chem. 7Y, 940 f1967
Po I
[*I Dr. Manfred Schulz and Dip].-Chem. P. Berlin
Institut fur Organische Chemie der Deutschen Akademie
der Wissenschaften zu Berlin
An der Rudower Chaussee
DDR 1199 Berlin-Adlershof (Germany)
111 An analogous synthesis of 5,s-disubstituted 2-t-butylperoxy1,3-dioxola1i-4-ones was recently discovered independently by
Ch. Riichardt and G. Hatnprechr, Angew. Chem. 79, 939 (1967);
Angew. Chern. internat. Edit. 6, 949 (1967).
[2] For neighboring group participation of cr-acetoxy groups in
esterifications compare A. R. Mnrtocks, J. chern. SOC.(London)
1964, 1918, 4840.
[31 For fragmentations of other types of sugar peroxides compare M . Schulz, H.-F. Boedeiz, and P. Berlin, Liebigs Ann. Chem.
703, 190 (1967); M . Schulz and L. Somogyi, Angew. Chem. 79,
145 (1967); Antew. Chem. internat. Edit. 6, 168 (1967).
Stereochemistry of the Cycloaddition of Sulfonyl
Isocyanates and N-Sulfinylsulfonamides to Enol
Ethers 1'1
By F. Efenbrrger and G. Kiefrrl*J
4-Alkoxyazetidin-2-ones (3) are formed on cyclaaddition of
sulfonyl isocyanates to enol ethers under mild conditions [*I.
We have now studied the stereochemistry of this reaction in
order to decide between a synchronous mechanism, as
proposed by Huisgen et al. [3J for the cycloaddition of
ketenes t o enol ethers, and a two-stage reaction involving
an intermediate compound of type ( 4 ) .
The proportions of the $-lactams (30) and (3h) formed (see
table) can be obtained from the newly appearing resonance
signals of the proton HA in (3u) o r (3h) with a n accuracy of
about :4 %. (3u): HA gives a doublet at T = 4.5, JAB5.3
Hz; (3h): HA gives a doublet at T = 4.81, JAB = 2 Hz. The
structures (30) and (3b) are assigned on the basis of the
coupling constants JAB[41.
From the table it can be seen that (fu) reacts stereospecifically with (2) and that (Ib) reacts stereoselectively, but that
after somewhat more than an hour an equilibrium mixture
containing 27 % of (30) and 73 % of (36) is formed from
- (36)
either pure ( I n ) or pure ( I h ) . The isomerization (30) %
is formulated as occurring by way of a resonance-stabilized
polar intermediate ( 4 ) .
When kept for several days in DCCI3 the equilibrium mixture
of (3u) and (3h) rearranges to the thermodynamically more
stable compound (5), the compound (4) being again assumed
as intermediate.
Enol ethers combine with N-sulfinylsulfonamides to give 1,2thiazetidine 1-oxides (7) 151. N M R spectroscopic studies
conducted during this cycloaddition in DCCI3 show a stereospecific reaction of both ( l a ) and (Ib). The products (7.)
and (76) do not isomerize and do not rearrange o n long
storage in DCCI,.
The cis- and trans-1-butenyl ethyl ethers ( l a ) and ( I b ) ,
which are separable by preparative gas chromatography,
were treated separately in DCC13 with p-tosyl isocyanate (2)
in the molar proportions 1 :1, and the progress of the reaction
was followed by N M R spectroscopy (Table).
One minute after the reactants had been mixed the signals of
( I n ) (HA = doublet at T =: 4.1 8, H B = quadruplet at T = S.74;
JAB= 6.3 Hz) and ( I b ) (HA = doublet at 7 = 3.82, H B = 2
triplets at T = 5.32; JAB= 12.6 Hz) had disappeared, whence
it is concluded that there is very rapid reaction with (2).
Angew. Chem. internat. Edit.
/ Vol. 6 (1967) 1 No. I1
The results show that in the reaction of enol ethers with polar
reagents the kinetically controlled cycloaddition occurs
largely synchronously. Quite possibly, different bond lengths
are to be considered for the transition state I6l. Depending o n
the ring strain, isomerization and removal of a proton occur,
95 1
both under thermodynamical control, to give a stable substitution product.
Received: August 9th, 1967
12 603 IE]
German version: Angew. Chem. 79, 936 (1967)
[*I Doz. Dr. F. Etrenberger and Dip1.-Chem. G. Kiefer
Institut fur Organische Chemie der Universitat
Azenbergstr. 14/16
7 Stuttgart (Germany)
[l! This work was supported by the Deutsche Forschungsgemeinschaft and the Fonds der Chemischen Industrie.
[2] F. Efenberger and R . Gleiter, Chem. Eer. 97, 1576 (1964).
[3] R. Huisgen, L. Feiler, and G. Binsch, Angew. Cliem. 76, 892
(1964); Angew. Chem. internat. Edit. 3, 753 (1964).
[4] K. D . Barrow and T. M . Spotswood, Tetrahedron Letters
1965, 3325.
[S] F. Efenberger and R . Gleiter, Chem. Ber. 99, 3903 (1966).
[6] R. Huisgen, R. Grashey, and I. Sauer in S. Patai: The
Chemistry of Alkenes. Interscience, New York 1964, pp. 786-757.
The structure of compounds ( l a ) to ( l c ) follows from their
elemental analysis, IR and IH-NMR spectra, and the lack
of conductivity of freshly prepared solutions.
The behavior of the compounds is similar to that of the SO,amine adducls, e.g. stronger bases replace weaker ones from
their linkage to the S atom. With liquid ammonia they give a
quantitative yield of the NH4+ salt of imidobissulfamide,
which was identified by conversion into free imidobissulfa().
mide 7
The action of primary or secondary amines on compounds
(In) to ( I c ) provides a synthesis of trialkylammonium salts
of monosubstituted (4) and asymmetrically di-N-substituted
imidobissulfamides (5). They can be converted by ionexchangers or by treatment of their silver salts with the
calculated amounts of hydrochloric acid into the free,
hitherto unknown asymmetrically substituted imidobissulfamides (6) and (7) in yields exceeding 90 %.
Derivatives of Imidobissulfamide
By R. AppeI and R . Helwerth[*I
Sulfimide, HNS02, has been assumed to be a reactive intermediate in the reaction of sulfamoyl chloride with nitrogenous bases. Hitherto, however, it has been isolated only as
the pyridinium salts of the oligomers, tri- and tetra-sulfimidefzl. Atkins and BurgessC31 proved the formation of Nsubstituted derivatives of sulfimide, RNS02 (N-sulfonylamines), on treatment of N-substituted sulfamoyl chlorides
with tertiary amines at -78 "C.
We have found that sulfamoyl(trialky1ammonio)suIfonyl
imides ( I ) are formed when a solution of sulfamoyl chloride
in acetonitrile is treated at -40 "C with tertiary nitrogenous
bases such as trimethyl- or triethyl-amine or pyridine in the
molar ratio 2:3. They are nitrogen analogues of the mesylsulfenamine adductsi recently described by Opitz and Biicher 141.
2 HzNSOzCl
+ 3 XR3
HzN-S02-N-S02-NR3 ( I )
M.p. ("C)
167- 168
124- 125
Compounds (6) and (7) dissolve readily in water, giving
strongly acid solutions. Sulfate ions can be detected therein
only after addition of sodium nitrite. These well-crystalline
materials are stable in air.
Received: August 7th. 1967
[Z 605 IE]
German version: Angew. Chern. 79, 937 (1967)
[*I Prof. Dr. R. Appel and Dip1.-Chem. R. Helwerth
Rearrangement above 105 "C
The compounds ( I ) are precipitated, sometimes with the
amine hydrochlorides, from which they can be separated
readily by utilizing their poor solubility in cold water.
When sulfamoyl chloride is treated with pyridine below
-80 ' C , a very reactive intermediate (m.p. 57-65 "C) can be
isolated, which dissolves in water to an acid solution. Within
a few seconds this clear solution deposits the neutral compound ( I c ) . Slow heating of the reactive intermediate affords
first this product flc), which, when further heated, resolidifies and is converted into the known pyridinium salts of triand tetra-sulfimide 121. Further experiments areto be performed
to decide whether the reactive intermediate is the pyridine
adduct (2) of monomeric HNS02, which is isoelectronic
with the known pyridine-SO3 adduct (3).
Anorganisch-Chemisches Institut der Universitlt
Meckenheimer Allee 168
53 Bonn (Germany)
[l] Part 111 of Investigations on Sulfimide - Part 11: [2].
[Z] R. Appel and G. Berger, 2. anorg. allg. Chem. 327,114 (1964).
[3] G. M. Atkins and E. M. Burges, J . Amer. chem. SOC.89,2502
[4] C. Opitz and D. Bucher, Tetrahedron Letters 43, 5263 (1966).
(51 A. V. Kirsanov and M. Zolotov,
obSE. Chim. 20, 165@
(1950); Chem. Abstr. 45, 1950 c-i (1951).
Model Reactions for Biological Ring Opening of
By B. Franck, V. Radtke, and U . ZeidIer[*]
Although the biosynthesis of more than 100 natural anthraquinone pigments is largely clarified [ 3 , 4 1 , very little is known
about their biological degradation. This must begin with an
oxidative opening of the quinonoid ring. We have previously
reported the detection of such a ring opening as a metabolic
reaction[21. It was shown by feeding experiments with
radioactively labeled precursors that ergochromes [51, e.g.
secalonic acid A (3), are formed from emodin (1) by way of
the acid (2). We have now found a reaction sequence thai may
serve to explain this oxidative ring opening ( I ) + (2) that
was previously unknown in anthraquinone chemistry.
Angew. Chem. internat. Edit. / Vol. 6 (1967) / N o . I 1
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ethers, cycloadditions, enol, isocyanates, sulfinylsulfonamides, sulfonyl, stereochemistry
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