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Hydrogenation of Polyenes by Tricarbonylcyclopentadienylhydrido-molybdenum and -tungsten.

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If a tetrahydrofuran/hexane solution of ( 3 ) is kept for three
months at 25 ‘ C , deep red crystals of composition C16HlgNi~
separate, apparently owing t o the transmetalation:
The mass spectrum [31 of the complex ( 4 ) shows the expected
signals. The IH-NMR spectrum shows three sharp signals
(see Table 1).
3-methyl-l-butene, and unchanged ( 4 ) in the molar ratio
82: 6:3:9.
1,3,5,7-0ctatetraene ( 6 ) 131 (0.5 g, 4.1 mmoles) in n-pentane
(20 ml) was treated with tricarbonylcyclopentadienylhydridotungsten (3) L31 (3.2 g. 9.6 mmoles); red crystals of bis(tricarbonylcyclopentadienyltungsten) (7) separated at once.
After 4.7 h the reaction mixture was analyzed by gas chromatography. It contained 2,4,6-octatriene (8) and unidentified products (three components) in the ratio 89:ll. The
tetraene ( 6 ) was completely consumed. The triene ( 8 ) was
gas-chromatographically identical with a sample obtained
by another route141.
An X-ray structure analysis confirms the x-ally1 structure
assigned t o (4)’ the nickel atoms and the cyclopentadienyl
rings being in trans-positions to one another 141. The complex
( 5 ) has not yet been isolated with complete spectral and
analytical purity.
Received: June 10, 1968
[Z 811 IE]
German version: Angew. Chem. 80, 968 (1968)
Publication delayed at author’s request
[*I Dr. W. Keim
Shell Development Company
Emeryville, Calif. 94608 (U.S.A.)
[l] G. Wilke et al., Angew. Chem. 78, 157 (1966); Angew. Chem.
internat. Edit. 5, 151 (1966).
[2] M . S . Lupin, J . Powel, and B. L . Shaw, I. chem. SOC.(London)
A 1966, 1687; R. Schulz, Tetrahedron 20,2809 (1964).
[3] The mass spectra were determined o n a high-resolution
spectrometer C.E.C. 21-llOB. We thank Dr. P. A. Wadsworth for
these measurements and for discussion of the spectra.
[4] A . E. Smith, paper read at the American Crystallographic
Association Meeting in Tucson, Arizona, U.S.A., in February
1968.
Table 1 . Half-reaction time for hydrogenation of polyenes by hydrido
complexes.
Hydridocomplex
Polyene
2,4-Hexadiene
2.4-Hexadiene
4-MethylI Jpentadiene
4-Methyl1,3-pentadiene
2,4,6-0ctatriene
I ,3,5-Hexatriene
4-Methyl1.3-pentadiene
I ,3,5-Hexatriene
I ,3,S,7-Octatetraene
Products
59
0.2
20
20
0.1
0.03
20
6o
il&,
[a1 Half-reaction time for the polyene in a mixture with initial concentrations: polyene 0.5 mole/l; hydrido complex 1 mole/l.
Hydrogenation products:
[b] rrans-2- and -3-Hexene 89%. cis-2- and -3-hexene 1 1 %.
[cl Irons-2- and -3-Hexene 79 %, cis-2- and -3-hexene 21 %.
[d] 2-Methyl-2-pentene 76 %, 4-methyl-2-pentene 2 4 %.
[el T w o products (probably 3.5-octadiene and 2,4-octadiene) in the
ratio 83: 17.
Hydrogenation of Polyenes by Tricarbonylcyclopentadienylhydrido-molybdenum and -tungsten
By A. Miyake and H. Kondo[*]
Dedicated to Professor K . Ziegler on the occasion of his 70th
birthday
[fl 2,4-Hexadiene, frans,trans 66%, trans,& 31 %, cis,cis 3 %.
[gl 2-Methyl-2-pentene 72 %, 4-methyl-2-pentene 28 %.
[h] 2,4-Hexadiene, rrans,rrons 67 %, fruns,cis 30 %. &.cis 4 %.
[il See text.
Tricarbonylcyclopentadienylhydridochromium ( 1 ) hydrogenates polyenes [II. We have now found that the corresponding complexes of M o [(2)]and W [ ( 3 ) ] react analogously.
As shown in Table 1, the reactivity of the hydrido complexes
decreases in the series ( I ) > (2) > ( 3 ) . ( I ) reacts 102 to lo3
times faster than ( 2 ) , and (2) reacts 102 t o l o 3 times faster
than ( 3 ) . The reactivity of the polyenes increases with increasing number of conjugated double bonds.
If a solution of isoprene (4) (0.23 g, 3.4 mmoles) and tricarbonylcyclopentadienylhydridornolybdenum (2)[21 (1.54 g,
6.3 mmoles) in n-heptane (10 ml) is warmed t o 59 O C , the
solution at once becomes red and bis(tricarbonylcyc1opentadienylmolybdenum) (5) soon separates as red crystals. After
4.7 h the reaction mixture was analyzed by gas chromatography; it contained 2-methyl-2-butene, 2-methyl-l-butene,
The Mo-Mo and W-W bonds in ( 5 ) and (7) are much more
stable than the readily fissile Cr-Cr bond in bis(tricarbony1cyclopentadienylchromium) ( 9 ) [5J. Whereas hydrogenation
of (9) t o ( I ) proceeds smoothly [I 21, reduction of (5) or (7)
by hydrogen t o (2) or (31, respectively, is not t o be expected;
and our attempts t o reduce polyenes catalytically by means
of ( 5 ) or (7) were unsuccessful. When compared with hydroAngew. Chem. internat. Edit. / Vol. 7 (1968)
/ No. I 1
acids such as trifluoroacetic acid, whereupon their fluorescence disappears; compounds (2) are regenerated o n treatment with bases. 1 H-NMR-spectroscopic observations o n
(Zb) and deuteriotrifluoroacetic acid showed that C-2 and C-4
are protonated in the ratio of 3: 1. The low basicity of compounds (2) and comparison of the dipole moments [ ( l a ) :
!r. = 1.54 D; (20): :). = 1.28 D (both in benzene)] indicate
structure (2) rather than (3).
genation catalyzed by (Y), the stoichiometric hydrogenation
by the readily accessible complexes ( 2 ) and ( 3 ) has the advantage that conjugated polyenes can be reduced stepwise.
[Z 870 IE]
Received: August 27, 1968
German version: Angew. C h e m . YO, 968 (1968)
-~
~
[ * ] Dr. A. Miyake and Dipl.-Chem. H. Kondo
Basic Research Laboratories, Toyo Rayon Co., Ltd.
Kamakura (Japan)
The symmetrical structure of compounds (2) is proved by
J H - N M R measurements o n (2b) in CDC13. The protons
attached t o C-3 and C-5 give rise t o a doublet at 8 = -7.93
ppm (JP-LC-C-H 36.5 Hzj; the signal of t h e methoxy
protons (8
-3.40 ppm) is split to a doublet by coupling
with the phosphorus (JP-o-c-H
- 13.5 Hz). T M S as
internal reference.)
[ l ] A . Miyake and H . Kondo, Angew. Chem. 80, 663 (1968);
Angew. Chem. internat. Edit. 7, 631 (1968).
[2] E. 0. Fischer, W . Hafner, and H . 0 . Stnhl, 2. anorg. allg.
Chem. 282, 47 (1955).
[3] G. F. Wood and H . Sanders, J. Amer. chem. SOC.68, 2483
(1946).
[4] R . Kuhn and C. Grundmann, Ber. dtsch. chem. Ges. 71, 442
(1938).
151 R . R. King, J. Amer. chem. SOC.88, 2075 (1966).
The 3IP-NMR signals of (211)-(2d) in benzene lie between
-58 t o -65 ppm and show only a slight shift in trifluoroacetic acid [ ( Z r r ) in benzene: 6 = -65.2ppm, in trifluoro-62.2ppm; ( , a ) in benzene: 8
-178.2
acetic acid: 6
ppm; measured with respect t o 8 5 % H 3 P 0 4 a s external
reference].
i
1,l-Dialkoxy- and 1, 1-Diaryloxy-phosphorins,
a New Class of Organophosphorus Compounds
~
Compounds (2) can be both oxidized t o novel stable phosphorus radical cations [coupling constant for (211) up = 20.1
gauss] a n d reduced t o radical anions that a r e likewise new.
31.6 gauss
During the latter process, a doublet having a p
is first observed, which changes to a broad singlet, having a
suggestion of a fine structure, o n further reduction 131.
By K . Dimruth and W . Studel*l
2
Dedicated to Professor K. Ziegler on the occasion of’ his 70th
birthduy
Treatment of (20) in dimethoxyethane with LiBr, acetic anhydride, and HzO2 affords the isomers ( 4 ) a n d ( 5 ) of l-methoxy-2,4,6- triphenyi-4-hydroxy - 1 -phospha-2,5 - cyclohexadienone (m.p. 198°-2000C and 194 -198OC). Their O H
groups can be acetylated without isomerization with acetic
2.4,6-Trisubstituted phosphorins ( l a ) - ( I f ] a r e oxidized t o
stable radical cations by, inter cilia, mercury(r1) acetate “JJ;
in the presence of alcohols or phenols the reaction proceeds
with separation of mercury t o form the novel, strongly
fluorescent 1,I-dialkoxy- o r 1.I-diaryloxyphosphorins (20)
t o ( 2 f ) a s highly stable crystalline compounds. T h e reaction
probably proceeds via the cation radical stage, which can be
detected by ESR spectroscopy.
The new compounds (2) (for examples, see Table) a r e only
weakly basic. W e were not able t o alkylate them with oxonium salts, n o r acylate them with acyl chlorides. They are insoluble in dilute acids and are protonated only by strong
9’
(41
1i
anhydride in pyridine. However, with trifluoroacetic acid,
( 4 ) and (5) give the same deep blue salt ( 6 ) [Amax in trifluoro335 nrn (E = 0.46 x 104). 394 (0.49 x lO4), 560
acetic acid
(3.54 Y lO4), a n d 695 (2.53 >, lO4)] (cf. referencer41). ( 6 )
affords ( 7 ) a n d (8) when treated with alcohols, and regenerates ( 4 ) and ( 5 ) with aqueous acetic acid.
7.
+
R’ P,
T h e N M R d a t a recorded for compounds (2) show a marked
similarity t o those of l-aIkyl-l-phenyl-2,4,6-triphenylphosphorins, which were obtained by Murk1 et al. [51 a n d for which
a n “aromatic” bonding state with contributions from d,-p,
bonds comes into consideration - as is t h e case with our
compounds (2).
IIg
R’
z 3
(2)
(3)
R’
R2
R3
112
112
107
127
152-154
I92
307
305
283
286
290
288[b]
420
419
423
419
413
406
1.34
1.43
1.76
1.85
1.75
3.17
1.84
1.81
2.00
2.28
1.80
1.67
[a] Fluorescence maximum at 490 nm (in methanol).
[b] No fluorescence (in dichloromethane).
[c] In cyclohexane.
Angew. Chem. internat. Edit.
Vol. 7 (1968) J No. I I
88 1
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