вход по аккаунту


Deoxygenation of Oxaziranes by Sulfur-Containing Nucleophiles.

код для вставкиСкачать
C 0 M MU N I CAT1 0 N S
Dehalogenation of c( -Haloketones via a-Oxocarbonium Ions to Stable Oxonium Salts
By Jean Pierre Bkggue' and Micheline Charpentier-Morize["
hydrolysis of (5), B=OH, and ( 5 ) , B=CH,O, to the
ketone (6), which loses water on treatment with iodine
in xylene. Compounds similar to ( 5 ) have been obtained
by dehalogenation of the haloketones (7)16'
The existence of a-oxocarbonium ions has only recently
been suggested in several reactions"], including the
dehalogenation of a-haloketonesf2? We describe results
proving unambiguously the intermediacy of these highly
reactive ions.
The two stereoisomeric ketones (1) [in the serics ( I and h ]
were reacted with the powerful electrophileAgSbF,[31. Both
epimers of ( I ) yielded the same crystalline salt, which
is stable at room temperature. Its structure was deduced
from its spectroscopic properties and its reactions.
[IR of ( 3 a ) and ( 3 b ) : ~ C = O = 1 6 0 0 c m - ' [ ~ ~NMR
(CDCI,), ( 3 a ) : 6=7.1-8.5 (5 aromatic H); 4.4 (1 H);
1.8-2.6 (4 CH,); 1.2 (C4H,); ( 3 b ) : 7.17, 8.37 (4 aromatic
H/AB system), JA,=9 Hz; 4.15 (1 H); 4.04 (OCH,); 1.75
to 2.5 (4 CH,); 1.19 (C4H9)J.
Comparable oxonium ions['] have similar spectra.
Received: February 11, 1971 [Z 366 IEJ
German version: Angew. Chem. 83.327 (1971)
[l] H. Dahn, H. Gold, M . Ballenegger, J . le Noir, G . Diderrch, and
R. Malherbe, Helv. Chim. Acta 5J, 2065 (1968); S. P. Singh and J. Kagan,
J. Amer. Chem. SOC.91, 6198 (1969); G.P. Nilles and R.D. Schultz,
Tetrahedron Lett. 1969, 4313; K. Okamoto, 1. Nitta, and H. Shingu,
Bull. Chem. SOC. Jap. 42, 1464 (1969); R.N. McDonald and R . N .
Sreppel, J. Amer. Chem. SOC.92, 5664 (1970).
[2] D. Baudry, J.P . Bigue, and M . Charpentier-Morize, Tetrahedron
Lett. 1970, 4707.
[3] G. Olah and H . W Quinn: FriedelLCraft and Related Reactions.
Interscience, New York 1965, Ch. XIII, p. 255.
[4] G. Olah, J. Chem. SOC.Spec. Publ. 19, 21 (1965).
[ 5 ] H.R. Ward and P.D. Sherman jr., J. Amer. Chem. SOC.89, 4222
[6] G. Baddeley, E.K. Baylis, B.G. Heaton, and J.W Rasburn, Proc.
Chem. SOC.(London) 1961,451.
Deoxygenation of Oxaziranes by Sulfur-Containing
(a). Ar
= CeH,;
(b), A r
= p-H,CO-CBH,
The isolation of 3-aryl-l-tert-butyl-2-oxoniabicyclo[2.2.2]oct-2-ene hexafluoroantimonates (30) implies the initial
formation of the a-oxocarbonium compounds l-benzoyl( 2 a ) and I-anisoyl-4-tert-butylcyclohexyliumhexafluoroantimonate (Zb), leading by hydride migration (either
stepwise or transannular) to the more stable carbonium
compounds ( 4 ) and finally to the salt ( 3 ) .
B = H(LiA1H4), OCH,, R ( R Mg X) , O H
( 3 ) reacts with nucleophilic reagents to give the 2-oxabicyclo[2.2.2Joctanes (5). Their structure is deduced from
IR, NMR, and mass spectra and confirmed by the acid
p] Dr. J. P. Begue and Dr. M. Charpentier-Morize
Groupe de Laboratoires du C.N.R.S.
2 a 8, Rue Henri Dunant
F-94 Thiais (France)
Angew. Chem. internat. Edit. J Vol. 10 (1971) 1 No. 5
By David St. Clair Black and Keith G . Watson[']
Thiourea, potassium thiocyanate, potassium ethyl xanthate,
and potassium selenocyanate are well known to react
with oxiranes. In the case of the first three
thiiranes are formed, but the last reagentc4] converts
oxiranes to alkenes, via unstable seleniranes, from which
selenium is eliminated.
We now report that oxaziranes are deoxygenated, not only
by potassium selenocyanate, but also by the above sulfurcontaining nucleophiles. The reactions are mild, simple
and conversion to the related imine is effectively
quantitative. All the above reagents are comparable in
their effect, but thiourea is marginally the most convenient.
When thiourea and 2-tert-butyl-3-phenyloxazirane( I a)[']
were heated together under reflux in ethanol for six
hours, N-ben~ylidene-tert-butylamine[~]
was formed in
almost quantitative yield and crystalline sulfur was also
isolated in 30% yield. These results suggest that the
reaction is similar to the conversion of oxiranes to thiiranes
and that it proceeds via a thiazirane intermediate, from
Dr. D.St.C. Black and Mr. K.G. Watson
Department of Chemistry, Monash University
Clayton, Victoria 3168 (Australia)
which sulfur is spontaneously eliminated. Thiaziranes
have recently been
as reactive intermediates
in the photochemical rearrangement of thiazoies[61and
but are as yet unknown.
[8] 1.P. Carteau, A . Lablanche-Combier, and A. Pollet, Chem. Commun. 1969,1018.
[9] Prepared in the standard manner-details to be reported.
[ l o ] J. B. Bapat and D. Sr. C . Black, Austral. J. Chem. 21,2507 (1968).
[ I l l R. P . Linstead and E. M . Meade, J. Chem. SOC. 1934,935; W E .
Grigsby, J . Hind, J . Chanley, and F. H . Westheimer, J. Amer. Chem. Sot.
64,2606 (1942).
1121 F. G. Riddell, J . M . Lehn, and J . Wagner, Chem. Commun. 1968,
By P. W Jolly, 1. Tkatchenko, and Giinther Wilke"]
The observation"] that in 1,5,9-cyclododecat~enenickel(0) (CDT. Ni), for example, the all-trans-CDT can
be exchanged for atl-cis-CDT led us to attempt to replace
the CDT in CDT-Ni.phosphane complexes by other
olefins. We report below the preparation and characterization of the new types of bis(olefin)nickel(O) complexes
(1) -(3).
The reaction of oxaziranes with sulfur-containing nucleophiles is influenced by stereochemical factors to a certain
extent. For instance, 2-tert-butyl-3-methyloxazirane
(1 b)[91
remained unchanged in the presence of thiourea after
twelve hours at room temperature; more vigorous conditions led to extensive tar formation. However, various
fused bicyclic oxaziranes were smoothly converted to
the related imines. In contrast to (I b), 2,2-dimethyl-3phenyl-6-oxa-l-azabicyclo[3.1.O]hexane (Za) [''I was completely deoxygenated after reaction for eight hours at
room temperature. The more hindered oxaziranes (2 b)['*]
and ( 2 ~ ) ' ~required
a reaction temperature of 80°C for
five hours for complete deoxygenation, while compound
(2d)"'I was only totally converted to the imine after
twenty eight hours at 80°C.
In general, the behavior of fused bicyclic oxaziranes is
similar to that of simple ones, in marked contrast to the
behavior of some fused oxiranes. Cyclopentene oxide is
particularly resistant"] to any reaction with thiourea
or potassium thiocyanate. This result is consistent with
the necessary formation of an unfavorable" 'I transfused bicyclic intermediate, e.g. (3), according to the
postulated mechanistic pathwayf2- 31. However, in the
case of bicyclic oxaziranes,a cis-fused bicyclic intermediate,
e. g. (4),can always be formed, as a consequenceof inversion
of configuration at the nitrogen atom, even if such inversion
Received: February 15. 1971 [Z 367 I E ]
German version: Angew. Chem. 83,355 (1971)
[l] C. C. J . Culuenor, W Dauies, and K . H . Pausacker, J. Chem. SOC.
[ 2 ] E. E . van Tamelen, J. Amer. Chem. SOC. 73, 3444 (1951).
[ 3 ] C. C . J . Culuenor, W Dauies, and W B. Sauige, J. Chem. SOC. 1952,
4480; C. C. Price and P. F. Kirk, J. Amer. Chem. SOC. 75, 2396 (1953);
F. G. Bordwell and H . M . Andersen, ibid. 75,4959 (1YS3).
[4] C . C . J . Culuenor, W Davies, and N . S. Heath, J. Chem. SOC. 1949,
[ 5 ] W D. E m m n s , J. Amer. Chem. SOC. 79, 5739 (1957).
[ 6 ] M . Kojima and M . Maeda, Chem. Commun. 1970,386.
[ 7 ] M. Ohashi, A . Iio, and 7: Yonezawa, Chem. Commun. 1970, 1148.
+ 2 Olefl"
A f
L-- N i
L=P(C,H,,), for ( l a ) , R = H ; ( l b ) , R = C H , ; ( l c ) ,
R=3-cyclohexenyl; (2); and (3). L = P(C,H,), for ( I d ) , R = H
( l a ) is
formed in 80-90% yield as an almost white precipitate
when ethylene is passed into an ethereal suspension of
all-trans-I ,5,9-cyclododecatrienetricyclohexylphosphanenickel ( 4 ) at -20°C. (I a) reacts with triphenylphosphane
at 80°C with displacement of the theoretical amount of
ethylene. The structure of ( l a ) is proved by the IR
spectrum [v(C=C) at 1490 cm-'1 and the 'H-NMR
spectrum(z = 7.22/s, W,,, = 4Hz)(cf. [(C6Hll),P],NiC2H,,
singlet at z = 7.949.
The complexes ( 1 b) and ( I d ) are prepared analogously.
The 'H-NMR spectrum of the propene complex ( l b )
[G(C=C) = 1485 cm-'1 shows that several isomers are
present in solution. The exchange reaction between propene and (C,H,),PNi-CDT
at -20°C leads only to
separation of metallic nickel. The propene in ( l b ) is
readily replaced on reaction with ethylene, with formation
of (la).
(Ic) and (2) are formed on reaction of ( 4 ) with vinylcyclohexene or divinylcyclobutane (DVCB), respectively,
in ether at -20°C. Both these compounds, which are
white powders and extremely sensitive to air, react with CO
at -78°C with quantitative replacement of the vinylcyclohexene or divinylcyclobutane.
[*] Dr. P.W. Jolly, Dr. I. Tkatchenko, and Prof. Dr. G. Wilke
Max-Planck-Institut fur Kohlenforschung
433 Miilheim-Ruhr, Kaiser-Wilhelm-Platz 1 (Germany)
Angew. C h e m . internat. Edit.J Vol. 10 (197i) J N o . 5
Без категории
Размер файла
200 Кб
containing, deoxygenation, sulfur, oxaziranes, nucleophilic
Пожаловаться на содержимое документа