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Photo-Oxygenation of SelenidesЧA New Pathway to Selenoxides.

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W Kirmse: Carbene, Carbenoide und Carbenanaloge. Verlag Chemie,
Weinheim 1969.
H . Meier and K.-P. Zeller, Angew. Chem. 87, 52 (1975); Angew. Chem.
Int. Ed. Engl. 14, 32 (1975).
H. van Bekkum, P. E. Verkade, and B. M . Wepster, Rec. Trav. Chim.
Pays-Bas 78, 815 (1959); A. J . Gordon and R. A . Ford: The Chemist's
Companion. Wiley, New York 1972.
K . - P . Zeller, H . Meier, and E. Muller, Tetrahedron 28, 5831 (1972).
Photo-Oxygenation of Selenides-A
Selenoxides
New Pathway to
By L. Hevesi and Alain Krief "1
We have found that dialkyl and aryl alkyl selenides ( I )
are transformed by photochemically generated singlet
oxygen['] into selenoxides (2)I21 (see Table I), which possess
interesting synthetic application~[~].
Table 1 . Reactions of selenides with singlet oxygen to form selenoxides.
See procedure for reaction conditions.
R'
R2
Reaction
time [h]
CAS Registry numbers:
(lu),4346-64-9; ( I h ) , 18255-05-5; ( I c ) . 56414-33-6; ( I d ) , 58856-08-9; ( I e ) ,
58873-23-7; ( 2 a ) . 25862-09-3; ( 2 h ) . 13154-1 1-5; (2c). 58856-09-0; ( 2 d ) .
58856-10-3; ( Z e ) , 58873-24-8; 5-octan-4-01, 58856-1 1-4
[l] a) G. 0.Schenck, Angew. Chem. 64, 12 (1952); b) R. W Denny and
A. Nickon, Org. React. 20, 133 (1973).
[2] For analogous reactions of sulfides see a) G. 0.Schenck and C . H .
Kruuch, Chem. Ber. 96, 517 (1963); b) K. Collnick, EUCHEM Research
Conference No. 69, Sept. 1975 at Ghent (Belgium).
[3] See, e.q., H . J . Reich, J . M . Ronyu, and I . L. R e i d ! , 1. Am. Chem.
SOC. 97, 5434 (1975); references cited therein.
141 O n prolonged irradiation the selenide ( I ) decomposes with deposition
of red selenium.
A Mononuclear Paramagnetic Biphosphinotricarbonylcobalt@)Complex
By Dieter Fenske"]
With few exceptions, such as V(CO)6, carbonylmetal(0)complexes are diamagnetic. The same applies to their phosphanesubstituted derivatives. We have now obtained a paramagnetic
cobalt(0) complex (2) in which five electron pair donors are
coordinated to Co. This compound is formed on reaction
of C O ~ ( C Owith
)~
in toluene.
Yield
[X,]
[a] Figures in parentheses refer t o the amount of starting material recovered
at the conclusion of the reaction
[b] 27 X, of 5-octen-4-01 also formed.
[c] I5 'Z of 5-octen-4-01 also formed.
The yields of selenoxides are very high; no selenone formation was observed in any of the reactions. In some cases
the known thermal elimination of selenenic acids RSeOH
occurred, leading to formation of ole fin^[^]. This was especially
pronounced with P-hydroxy selenides which underwent partial
conversion into allyl alcohols (Table 1). The yields of allyl
alcohols increase with rising temperature and duration of
irradiation. Thus the yield of 5-octen-4-01 from ( I e ) increases
from 15 '%,(20"C, 4.5 h) to 42 "/, (50°C, 4.5 h), and that from
( I c ) increases from 27 % (20"C, 3.5 h) to 46 "/, (20°C, 17.5 h)l41.
This allyl alcohol is not oxidized on irradiation.
Compound (2) crystallizes from ether/dichloroethane as
dark green column shaped crystals displaying pronounced
dichroism in transmitted light. They are air-stable; in solution
they decompose slowly to form a red compound which has
yet to be characterized.
If the five electron pair donors (2) were bound according
to the usual rules of complex chemistry then the valence
shell of the Co would contain one electron more than the
krypton shell. Such a state should not be stable. N o distinction
is possible on the basis of spectroscopic and ESCA measurements. We have therefore subjected the compound to X-ray
structure analysis.
Compound (2) crystallizes in the centrosymmetric space
group Pnam with a=16.76(1), b=7.871(6), c=21.24(1)A and
Procedure:
In a typical experiment, compound ( I ) (1 mmol) and Bengal
rose (10 mg) are dissolved in anhydrous methanol (120 ml).
Oxygen is passed through the stirred solution which is irradiated with a Sylvania iodine lamp (220V, 650 W) operated
at 135 V (s325 W). The course of the reaction is monitored
by thin-layer chromatography. After distillation of solvent
the crude mixture is worked up by chromatography.-The
products were identified by comparison (IR, 'H-NMR) with
authentic material.
Received: March I . 1976 [Z 433 IE]
German version: Angew. Chem. 88, 413 (1976)
p]
['I
Prof. Dr. L. Hevesi and Prof, Dr. A. Krief ['I
Dkpartement de Chimie, Facultks Universitaires de Namur
61, rue de Bruxelles, 8-5000 Namur (Belgium)
To whom correspondence should be addressed
Anqew. Chrm. Int. Ed. Enql. 1 Vol. I5 (1976) N o . 6
Fig. I . Molecular structure of [bis(diphenylphosphino)maleic anhydrideltricarbonylcobalt(0) ( 2 ) . Viewed along the h axis.
[*] Dr. D. Fenske
Anorganisch-chemisches lnstitut der Universitat
Gievenbecker Weg 9, 4400 Miinster (Germany)
381
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selenoxides, selenidesчa, photo, pathways, new, oxygenation
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