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Catalytic Carbon-Carbon Bond Formation with Carbene Intermediates.

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Methyl-l,6-dioxaspiro[4.5]decanes as Odors of Parauespula vulgaris (L.)[**]
By W t t k o Francke, Gerd Hindovf, and Wolfgang Reith[*l
In contrast to other social insects, no volatile components
have yet been identified from the common wasp P. uulgaris['l.
After the identification of 2-ethyl-l,6-dioxaspiro[4.5]nonane
(chalcogran) ( 1 )['I as the principal aggregation pheromone
of Pityogenes chalcographus L., we have now studied the massspectrometric fragmentation of volatile spiroketal~[~]
and
found (GLC-MS coupling[41)spiroketals to be present in the
pentane extracts of the abdomina of P. uulgaris workers.
Ibl
151
The main component and a trace substance proved to be,
respectively, (2)-and (E)-7-methyl-l,6-dioxaspiro[4.5]decane
(2)r5I, while two minor components were identified as equal
amounts of (Z)- and (E)-2-methyl-l,6-dioxaspiro[4.5]decane
(3)c61, along with traces of 2-nonanone.
The racemic compounds (2) and ( 3 ) were prepared from
y-butyrolactone and 6-caprolactone, and y-valerolactone and
&valerolactone, respectively, according to the procedure of
Erdmann and Strom['I. The synthetic substances purified by
preparative GLC showed the same mass spectra and had
similar retention times on GLC as the natural products, the
chirality of which have not yet been clarified.
Remarkably, the new spiroketals (2) and (3) show an
unbranched dihydroxynonanone skeleton, as do chalcogran
( I ) , 7-ethyl-5-methyl-6,8-dioxabicyclo[3.2.1]octane(brevicomin) (4)[81, and 1,3-dimethyl-2,9-dioxabicyclo[3.3.l]nonane
(5)f91.( 4 ) is an attractant, and ( 5 ) is a compound occurring
specifically in attacked spruce. Genetic relations cannot be
excluded.
Preliminary bioassays showed that the new compounds
might serve as repellents or aggression inhibitors, which could
protect the individuals from attack by its fellow wasps. Dead
extracted wasps hanging 12cm in front of the entrance hole
of an earth nest frequented by 40 individuals per minute
were attacked within two minutes and then at intervals of
30-60 s. In contrast, extracted wasps previously treated with
0.1 mg of the spiroketals mixed in the naturally occurring
proportions or freshly killed ones were only attacked after
8-10 min, the intervals between further attacks being much
longer than before. Application of 0.1 mg of the spiroketal
mixture to heavily frequented dummies inhibited any attack
for 8-12min. Each series of assays was repeated twelve times.
Received' March 1978:
supplemented: August 31, 1978 [Z 75 IE]
German version: Angew. Chem. 90. 915 (1978)
CAS Registry numbers:
( 7 ) - ( 2 ) , 68108-89-4; (E)-(2), 68108-90-7; ( Z ) - ( 3 ) , 68108-91-8; ( E ) - ( 3 ) ,
68108-92-9; 7-butyrolactone, 616-45-5; 6-caprolactone, 823-22-3, ;walerolactone, 108-29-2; 6-valerolactone, 542-28-9
[l] D . H. Calam, Nature 221, 856 (1969).
[2] W Francke, V Heemann, B. Gerken, .
I
A.
.A. Renwick, J . P. Vitt, Naturwissenschaften 64, 590 (1977).
[37 W Reith, Diplomarbeit, Universitat Hamburg 1978.
[4] Varian MAT 111, 50m capillary 0.25mm i.d.; Marlophen 87; 323413K; 2K/min; 1 bar He.
[5] a) MS: m/e 87 (100%); 84 (81); 97=43 (23); 112=86 (18); 55 (13);
56 (11); 41 (10); 115=85=69=42 (8); 57 (7); 73=45 (5); 72=71=39
(4); 156 [Me]=70 (3); 126 (2); 141=128 (1); b) J. E. Blackwood, C.
L. Gladys, K . L. Loening, A . E . Petrarca, 3. E. Rush, J. Am. Chem.
SOC.90, 509 (1968); the unsuhstituted ring serves as reference plane.
[6] MS: m/e 101 (100%); 98=83 (40); 100 (33); 55 (28); 56=43 (20): 41
(17): I l l =85 (12); 112 (11); 57 (10); 59 (9); 70=39 (6); 156 [Me]=128
(5); 141 =71 (4); 69 (3); 67 (2).
[7] H. Erdmann, Justus Liebigs Ann. Chem. 228, 176 (1885); 7: Strom, J.
Prakt. Chem. 48, 209 (1893).
[8] R. M . Silverstein, R. G. Brownlee, 7:E. Bellas, D. L. Wood, L. E. Browne,
Science 159, 889 (1968).
[9] !I Heemarh, W Francke, Naturwissenschaften 63, 344 (1976).
Catalytic Carbon-Carbon Bond Formation with Carbene Intermediates
By Gisela Henrici-Olive' and Salvador Oliue'rl
Dedicated to Professor E. 0. Fischer on the occasion of his
60th birthday
We wish to report the transformation of methylamine (C,)
into acetonitrile (Cz), and on the mechanism of this process.
Methylamine is a low cost, coal based, industrial chemical,
obtained by alkylation of ammonia with methanol:
c
Oxygen
*
CO
- Hydrogen
CH,OH
Allllll0"la
CH,NH,
When methylamine is passed over a silica/molybdenum
catalyst at 400-500"C, at a flowrate of 0.8 x
mol/min,
it decomposes almost quantitatively. Traces of acetonitrile
are formed, together with large amounts of HCN and NH3.
However, the yield of CH3CN is greatly increased, if hydrogen
accompanies the amine. At a molar ratio of Hz:CH3NH2
of 12: I, 20-30 % of the methylamine is converted into acetonitrile['! Some propionitrile (< 1 %) is also formed; nonnitrogen containing by-products are mainly methane, with
minor amounts of higher hydrocarbons ( C Z X 4 ) .
The catalyst is prepared by impregnating silica (particle
size 0.2-0.5 mm, Merck) with a water-soluble molybdenum
compound (e.g. [NH4]6M07024.4H20);after drying, the
catalyst is oxidized with oxygen (8 h, 50O0C),and subsequently
reduced with ammonia (17 h, 500°C). It has about 5 x
g/
atom of Mo per gram of catalyst. Molybdenum can be replaced
by other transition metals, although with decreasing activity,
in the series Mo > W > Cr > Ru > Fe & Co zz Ni.
On silica alone, the methylamine is recovered essentially
unchanged. If silica is replaced by alumina in the catalyst,
a carbonaceous deposit covers the alumina; no acetonitrile
is observed.
The formation of acetonitrile according to the overall equation (1) is thermodynamically favorable; the equilibrium constant at 500°C is K,= 1.6 x lo6atm21zl.
2 CH,NH,
KP
CH,CN + NH, + 2 H2
(1)
To elucidate the detailed mechanism of the reaction depicted
in Eq. (I), we carried out the process using deuterium instead
['I
Dr. W. Francke, Dipl.-Chem. G. Hindorf, Dip1.-Chem. W. Reith
Institut fur Organische Chemie und Biochemie der Universitat
Martin-Luther-King-Platz 6, D-2000 Hamburg 13 (Germany)
[**I This work was supported by the Deutsche Forschungsgemeinschaft
862
p] Dr. G. Henrici-Olivt,
Prof. Dr. S. Olive
Monsanto Triangle Park Development Center Inc.
Research Triangle Park, N. C. 27 709 (USA)
Angew. Chem. Int. Ed. Engl. 1 7 (1978) No. I 1
of hydrogen, all other conditions remaining the same. Mass
spectroscopic analysis[31of the major hydrocarbon by-product,
methane, yielded a very useful piece of information. Two
samples of the noncondensable part of the product stream
were taken, 30 and 90min after the onset of the catalytic
process. The isotopic distribution in the methane is given
in Table 1.
trile from methylamine. This proposal is essentially inspired
by the work of E. 0. Fischer et aLr6],who reported the insertion
of the carbene ligand of a chromium-carbene complex into
the H-C bond of HCN, giving rise to a nitrile. Assuming
an intermediate oxidative addition of HCN, we formulate
for the present case:
Table 1. Isotopic distribution in methane formed as by-product during the
synthesis of acetonitrile from methylamine and D 2 (SiO,/Mo catalyst;
D2:CH,NHz=t2:1).
H,C=M
Component
Distribution [mol
t = 90 min
15.7
18.2
32.9
25.0
8.2
16.0
20.1
32.5
23.6
7.8
D
I
CHz=M
I
D
CHZD-M-D
( AI
+ CHZDZ
(3)
11 9
it
CHD=M
-HD
IE A
-
CHD,
The formation ofCH4and CH3D takes place in corresponding equilibria, but with HZinstead of D z ;the required hydrogen is continuously formed in the process, according to Eq.
(l),and by the simultaneous thermal decomposition of methylamine to HCN:
CHZNH2
-
HCN
+
2 Hz
(4)
We suggest the carbene complex formed by reaction (2)
to be the key intermediate in the catalytic formation of acetoniAngew. Chem. Int. Ed. Engl. 17 (1978) No. 11
+
1
CHsCN
+
M
(5)
CN
CAS Registry numbers:
Methylamine, 74-89-5; acetonitrile, 75-05-8
CHD=M-H
- HD
H
I
H,C=M
Received: July 21, 1978 [Z 74 IE]
German version: Angew. Chem. 90, 918 (1978)
Evidently the deuterium has taken part in the formation
of the methane. The distribution does not depend on the
reaction time, and there is a distinct maximum for CHzDz.
The latter fact excludes the formation of the deuterated methanes by a metal-catalyzed H/D exchange of CH4 with Dz.
A mechanism involving a carbene intermediate is suggested
for the methane formation, in order to account for the maximum in CH2D2.
Methylamine is assumed to add oxidatively to the metal
[Eq. (2)]. Reductive elimination of ammonia then generates
a carbene ligand (carbene formation by a-elimination of H
from a methyl ligand is known for several transition
Oxidative addition of deuterium leads to species A [Eq. (3)],
from which the metal catalyst can be regenerated oia reductive
elimination of the main methane component, CHZDz.Alternatively, species A can, in a series of equilibria, lead to CHD3
and CD4, in decreasing concentration. (Hydrogenation of carbene ligands to the corresponding saturated hydrocarbons
has been demonstrated recently by Casey et a1.I5l.)
CHz=M + D,
-
The evidence presented for a carbene ligand on a heterogeneous catalyst corroborates the reaction mechanism suggested previously by us for the Fischer-Tropsch synthesis[’!
x]
f =30min
+ HCN
[l] Higher yieldsreported in a recent patent were erroneous, due to problems
encountered in analysis: S. O b i , G . Henrici-Olive, US-Pat. 4058548
(1977), Monsanto Company.
[2] S. R. Auuil, Corporate Research Laboratories, Monsanto Company,
St. Louis; personal communication.
131 We thank Dr. 0 .P. Tanner, Physical Science Center, Monsanto Company,
St. Louis, for carrying out the mass spectroscopic analyses.
141 L. S. Pu, A . Yamamuto, J. Chem. SOC.Chem. Commun. 1974, 9; N .
J . Cooper, M. L. H . Green, ibid. 1974, 761; M. L. H . Green, Pure Appl.
Chem. 50, 27 (1978); R. R. Schrock, J. Am. Chem. SOC.97, 6577 (1975).
[S] C . P . Casey, S . M . Neuman, J. Am. Chem. SOC.99, 1651 (1977).
[6] E . 0 . Fischer, S . Fontana, U . Schubert, J. Organomet. Chem. 91, C7
(1 975).
[ 7 ] G. Henrici-Ofid, S. Ofiui, Angew. Chem. 88, 144 (1976); Angew. Chem.
Int. Edit. Engl. 15, 136 (1976); J. Mol. Catal. 3,443 (1977/78).
Heteronuclear Cobalt Clusters by Metal Exchange[**]
By Harald Beurich and Heinrich VahrenkampC*l
The synthesis of heterometallic clusters is even less predictable than that of clusters of a single metallic element. This
aim has been achieved in various cases with concomitant
cluster enlargement in a semi-systematic manner by “attachment” of additional metal atoms to existing clusters uia addition or substitution reactions[ ‘1. To our knowledge, specific
incorporation of metal atoms by metal exchange has not
previously been reported[’]; it has now been accomplished
by an addition-elimination sequence.
We have repeatedly observed cobalt-containing, arsenicbridged polynuclear complexes to undergo decomposition,
with formation of an oligomeric, sparingly soluble product
of approximate composition [(C0)3Co-AsMez], ( I jr3],leading to the complexes containing one less metal atom [cf.
reaction (A)[4a1and (B)[4b1].Application of this reaction to
the substituted methylidyne-tricobalt cluster (2) effects introduction of the heterometal atom in place of a cobalt atom.
The addition step of this directed cluster synthesis consists
in the attachment of the As-M unit to the R C C O ~ ( C O ) ~
unit by tried and tested
The elimination step
consists in the decomposition reaction (C). So far, we have
prepared eleven new hetero-clusters ( 3 ) by this method (cf.
Table 1).
[*I Prof. Dr. H. Vahrenkamp, DipLChem. H. Beurich
Chemisches Laboratoriurn der Universitat
Albertstrasse 21, D-7800 Freiburg (Germany)
[**I This work was supported by the Fonds der Chemischen Industrie
and by the Computing Center of Freiburg University.
863
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