defenestrated23
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Reaction of Dichlorocarbene with Ketone
First off, hello all! I am new to this particular board but not in the k3wl sense, I was on the E&W for a long time until something happened where
I could no longer access that site  . I was happy to stuble across this board, and
it relit my interest in chemistry.
Annnyways... I've had some free time on my hands lately and the gears in my head have been turning, and I think I may have come up with some really
interesting syntheses. However, I need to know this tidbit of information:
Am I correct in assuming that bubbling CCl2 through acetone will form 2,2-dichloro-3,3-dimethyloxirane (epoxy group with two methyls on one end and
two chlorines on the other)?
My readings and notes tell me intuitively that the dichlorocarbene should break open the ketone oxygen bond and substitute in a carbon, specifically a
dichloromethylene. This is the behavior expected if it were a C=C bond. However, my one concern is that the enthalpy of the C=O would be greater than
the enthalpy of C=C, and this would somehow affect the reaction adversely. If it does form the epoxy group though....I've got a rather elegant lab
that I'm working on.
Questions? Comments? Constructive criticism? Thank you in advanced!
-Kyran
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BromicAcid
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How are you going to bubble :CCl2 through anything considering the reactivity of it, I've never worked with it but I was under the assumption that it
is rediculously reactive, hence its use insitu produced from a strong base and chloroform. But about your reaction, the electrophillic (actually
looking it back up it would depened on if singlet of triplet carbene is formed what kind of reactivity it shows.... and I forget which kind we're
dealing with here...) Strange, I can't find a concrete example of what it would do in my chem book except to alkenes... looking it up on wiki I'm
reminded that it can do the [1+2] addition trick.... I'll think about it some more later.
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vulture
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Reaction with ketones will not produce any epoxycompound. You need an electron rich molecule for that, as you lack one electron pair to form the epoxy
structure.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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garage chemist
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Reaction of chloroform, acetone and NaOH will make chlorobutanol, search the board for it and you will find an excellent long thread on the subject.
I think that it is not possible to react acetone with dichlorocarbene, since chloroform immediately reacts with acetone directly to chlorobutanol when
a base is added.
Dichlorocarbene is interesting for making aromatic aldehydes.
Reaction of dichlorocarbene with sodium phenoxide produces salicylaldehyde (though the yields are really low, and isolation of the product is a pain).
[Edited on 23-3-2006 by garage chemist]
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defenestrated23
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Alright...maybe I'll just let the cat out of the bag, maybe that will clarify what I'm trying to accomplish in the end.
Organic peroxides pique my curiousity. You could say they interest me to death ;-). Back in ye olde k3wl days, I synthesized AP quite a bit, but never
more than 5-10 grams at a time (both for sanity's sake and due to the 3% H202 I was limited to). Except for the time I got my hands on 30% (my goddess
the liquid was nearly gone and it was just a pile of wet crystals left in the jar!) But it is the mother of satan, and I refuse to ever synth it
again.
I've always wanted to develop a less sensitive organic peroxide (of course I will be taking extreme percautions and making it on the miligram level
until I figure out how (un)stable these compounds are). Just stable enough to function as a useful primary.
Thinking along the lines that greater molecular weight to weight of peroxides in the molecule ratio would result in a less sensitive energetic
compound ( one, longer hydrocarbon chains would make the molecule more "oily" and less of a rigid crystal, two, more energy required to break down a
larger molecule should hopefully make it less sensitive) I came up with 2-hydroperoxy 2-methylbutanoic acid. The theoretical plan of action was to
subject MEK with dichlorocarbene, forming either 2,2-dichloro 3-ethyl 3-methyloxirane, or 2-chloro 2-methylbutanoyl chloride. When this is mixed with
hydrogen peroxide and an acid catalyst, it would oxidize to 2-hydroperoxy 2-methylbutanoic acid, releasing Cl2 or HCl. It might exist as a monomer,
but I think it would most likely form a cyclic dimer.
A more advance synth would be photolysis of 2-diazobutane with 1415 Angstrom UV light, to yield methyl ethyl carbene (but-2-ylidene). This is reacted
with MEK to form 2,3-diethyl 2,3-dimethyloxirane. When this is mixed with a peroxidizing solution, it forms 4-hydroperoxy 3,4-dimethylhexan-3-ol.
This is all purely theoretical at this point, but I have a batch of CHCl3 brewing in my basement as I am typing this, so hopefully I might be able to
make a few mLs over the weekend.
If you have any inkling if this will work or not, or if you know a more efficient way of doing this, or if I sound like a total dumbass (but I've researched the bajeebus out of this and to the best of my knowledge this is
how it would behave).
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