majortom - 13-9-2010 at 14:32
I know I am probably going get flamed for bringing up this much rehashed topic but I think I found something interesting. I am just going to say that
this is most likely going to be wrong if it hasn't been done already. It's really just speculation and I haven't been able to dig up much of anything
related to it with out some strange catalysts.
While recalling that ketones isomerise in basic or acidic conditions due to enol formation I thought about the possibility that a stereo-specific
amine with an alpha branched carbon chain (think R-2-aminobutane) might be oxidised to an imine which could be reduced by formic acid to produce a
racemic mixture of the formerly stereo specific isomer.
That might be possible, but another option yielding a racemic mixture but from a different starting chemical would be something akin to what is done
with alkynes and their conversion to vinyl alcohols and subsequent ketone formation. I wonder if that could be done with an imine.
I was thinking that the first option could be done by reaction of the amine with an alkali metal in a polar apriotic solvent, perhaps with the
corresponding alkali hydroxide as well, that may disassociate the anionic amide and possibly allow for very brief lose of a proton at the carbon alpha
to the anionic amide. Of course it would come back, but in a racemic fashion just as with enols.
Yes I know everyone is going to flame me for lack of research, but I have searched everywhere for a convenient method of doing either but in the case
of the first I came up with exotic catalysts and in the latter nothing.
Panache - 13-9-2010 at 17:55
what are the exotic catalyst and conditions that you lit review uncovered?
majortom - 29-9-2010 at 17:51
Sorry for the slow reply. I found some information of a dinuclear copper ligand whose science is beyond my understanding (http://www.ncbi.nlm.nih.gov/pubmed/20536143). also N-tert-Butylphenylsulfinimidoyl Chloride (http://www.jstage.jst.go.jp/article/cl/30/5/30_390/_article/...). then there was phenyl hypoiodate and some ruthenium halide phenylphosphine
ligand (http://tiny.cc/kv2pe). There were a few reactions with reagents just as strange. I don't have any idea how you would begin to get these compounds,
at the end of the day it seems easier just to go through the trouble of making a alkene or alkyne from scratch and making it into a ketone.
Its all possible to do, but the difficulty involved seems to outweigh any benefits this route could have. It seems like such a rudimentary concept
analogous to oxidation of alcohols.