Characteristics Preparation

Characteristics
Molecular weight: 130,19 g/mol
MP: 60-62°C
BP: 185,2 (760Torr)
Density: 1,373 (20°C,760Torr)
Vapour pressure: 0,968 Torr (25°C)
Preparation
To get Snoutene, you take Cyclooctadien. By a Diels-Alder-reaction with maleic
anhydride, you access (3). After irradiating light, you get the basketen-derivate (4). In
this reaction, the two double-bonds react by a [2+2]cycloaddition. In the next step this
molecule reacts with the Anhydridpart to an ester (5). By a catalysis with silver the
basketenepart transformes to (6). The correct mechanism is not found , but it seems
to be similar to the Rh(I)- catalysis. In the last step the ester- bonds are eliminated
and the double bond is obtained.
Another way to get Snoutene is by a Rhodiumcatalysed Transformation. With
Diademane (8), a Rhodium(I)-complex reacts with two of the three cyclopropanrings.
Then you get a doublebond and the rhodiumaddition. In the next step, the
Rhodium(I)-complex gets eliminated and the two bonds, which were related to the
Rhodium(I)- atom, form a new bond and Snoutene is obtained.
(8)
Use
One way to use Snoutene is to get Diademane. By a balance reaction initiated by
light the doublebond reacts with the cyclopropanering and a doubleradical is formed.
The two radicals react to a bond. The obtained molecule is Diademan.
From Diademane you get Triquinacene by a transformation. With energy the
cyclopropanrings transformes and double- bonds will be created. This was originally
wanted by the researchers. Snoutene was found during the research to get
Triquinacene.
“Snout”- ene
Very interesting of Snoutene is the name Snoutene itself. The discoverer of
Snoutene, Professor Pasquette from the State University of Ohio, saw in Snoutene
the face, especially the nose, of Pinocchio. By this picture inspired, he thought of the
snout of a crocodile.
Hence, he suggested the name Snoutene. But other names were suggested, too. If
you take the molecule and regard from different sides, you can see a maybasket, or,
in another position, you can see a large scoop.
So there were three names, for the new molecule: Snoutene, maybasketene and
large Scoopene. The name maybasketene would be interesting, too, because
Snoutene is achieved by a reaction channel via a basketene derivative. But the name
Snoutene was prefered, supposebly by reason of the funny picture of the snout of a
crocodile.
Reactivity
In the molecule, there are one double- bond and two rings of three carbonatoms.
Those rings can react like a double- bond. Which reaction will be favoured is addicted
to the reaction terms.
With HOAc you protonate one of those rings. The protonated form can be transfered
in another form. So with addition of the –Oac- anion there are two products, molecule
1 or 2, possible.
(1)
(2)
In the second molecule, there can be obtained the exo- and the endo- product.
By gold- catalysis you get basketene and this reacts to molecule 3.
In this reaction there is a catalysed rearrangement. To get Diademane, there is used
a catalyses by light.
Addicted to those reactions there are normal reactions with double- bond, like
addition or apoxidation possible.
With Hydrogen you get Snoutane.
Membership
Snoutene belongs to the family of the (CH)10 Hydrocarbons. There are 71 Isomere
possible, if you draw them. Actually, there are 18 Isomere, which were synthesized.
Also, there are 34 transformations known to get one Isomere from another one.
Some of those transformations are katalysed by metals. By a metal- catalysis, the
metal- ions react with a small- ring of the molecule by an oxidative addition. After
that, you get a reangerrement via the metal- atom and finally the metal- atom will be
eliminated. Those reactions are also the specials of Snoutene.
Sources
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Hydrierungen“; D. Kaufmann, O. Schallner, L.U. Meyer, H. H. Fick, A. de Meijere;
Org.-Chem. Institut, Univ. Göttingen; Chemische Berichte (1983), 116(4), 1377-85
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Wiley-VCH, Weinheim 2000
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Umlagerungen“; A.de Meijere, D.Kaufmann, O. Schallner; Org.-Chem. Institut,
Univ. Göttingen; Tetrahedron Letters (1973), (8), 553-6
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