Methyl-l,6-dioxaspiro[4.5]decanes as Odors of Para- uespula vulgaris (L.)[**] By Wttko 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 mass- spectrometric 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 (brevico- min) (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: [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, ;walero- lactone, 108-29-2; 6-valerolactone, 542-28-9

supplemented: August 31, 1978

['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

[l] D. H. Calam, Nature 221, 856 (1969). [2] W Francke, V Heemann, B. Gerken, .I. A. A. Renwick, J . P. Vi t t , Naturwis-

senschaften 64, 590 (1977). [37 W Reith, Diplomarbeit, Universitat Hamburg 1978. [4] Varian MAT 111, 50m capillary 0.25mm i.d.; Marlophen 87; 323-

413K; 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 Car- bene 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:

Allllll0"la c Oxygen * CO - Hydrogen CH,OH - 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 ace- tonitrile['! Some propionitrile (< 1 %) is also formed; non- nitrogen 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 equa- tion (1) is thermodynamically favorable; the equilibrium con- stant at 500°C is K,= 1.6 x lo6 atm21zl.

(1)

To elucidate the detailed mechanism of the reaction depicted in Eq. (I), we carried out the process using deuterium instead

KP 2 CH,NH, CH,CN + NH, + 2 H2

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[31 of 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.

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).

Component Distribution [mol x] f= 30min t = 90 min

15.7 18.2 32.9 25.0

8.2

16.0 20.1 32.5 23.6 7.8

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 meth- anes 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 maxi- mum 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. Alterna- tively, species A can, in a series of equilibria, lead to CHD3 and CD4, in decreasing concentration. (Hydrogenation of car- bene ligands to the corresponding saturated hydrocarbons has been demonstrated recently by Casey et a1.I5l.)

D I

I D

CHz=M + D, CHz=M CHZD-M-D + CHZDZ ( A I

CHD=M-H 11 9

(3)

- HD it CHD=M - CHD,

-HD IE A

The formation ofCH4 and CH3D takes place in correspond- ing equilibria, but with HZ instead of Dz; the required hydro- gen is continuously formed in the process, according to Eq. (l), and by the simultaneous thermal decomposition of methyl- amine 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 acetoni-

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:

H I

1 CN

(5) H,C=M + HCN - H,C=M + CHsCN + M

The evidence presented for a carbene ligand on a hetero- geneous catalyst corroborates the reaction mechanism sug- gested previously by us for the Fischer-Tropsch synthesis[’!

Received: July 21, 1978 [Z 74 IE] German version: Angew. Chem. 90, 918 (1978)

CAS Registry numbers: Methylamine, 74-89-5; acetonitrile, 75-05-8

[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

[7 ] G. Henrici-Ofid, S. Ofiui , Angew. Chem. 88, 144 (1976); Angew. Chem. (1 975).

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 predict- able 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 “attach- ment” of additional metal atoms to existing clusters uia addi- tion 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, arsenic- bridged polynuclear complexes to undergo decomposition, with formation of an oligomeric, sparingly soluble product of approximate composition [(C0)3Co-AsMez], ( I jr3], lead- ing to the complexes containing one less metal atom [cf. reaction (A)[4a1 and (B)[4b1]. Application of this reaction to the substituted methylidyne-tricobalt cluster (2) effects intro- duction 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 RCCO~(CO)~ 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 Angew. Chem. Int. Ed. Engl. 17 (1978) No. 11