Looking for info on the pinacol rearrangent I noticed that in fact it was discovered after a copuling reaction with the same name in witch acetone added to it self with the aid of metalic sodium to make a new substance, a glycol named pinacol, this same substance while refluxed with dilute sulfuric acid would rearrange to it's corresponding ketone, pinacolone. What happens in the pinacol coupling is that two carbonyl groups join to them selves making a vicinal diol, just like ethylene glycol.
More info on the pinacol coupling: h ttp://en.wikipedia.org/wiki/Pinacol_coupling_reaction
Knowing this left me wondering, what would happen if one used a mixture of aldehydes? Will he obtain a mixed diol? For example a mixture of benzaldehyde and an excess of acetaldehyde will yield 1-phenylpropane-1,2-diol, 2,3-butanediol and some 1,2-diphenylethane-1,2-diol? But not only sodium could be used on this coupling reaction, a lot more other reagents like magnesium or activated aluminum could be used, even H2O + Aluminum + NaOH in methanol worked under microwave irradiation. One might add benzaldehyde to aqueous acetaldehyde, methanol, sodium hydroxide and aluminum, and microwave that mess to obtain the interesting phenylpropanediol, I think that is interesting since that same substance could be refluxed in dilute sulfuric acid or Hydrochloric acid to obtain P2P...
So, lurking throug an on-line chemistry book if found this (page 116, scheme 5) h ttp://books.google.com/books?id=ROeVSE-zBuMC&pg=PA113&dq=pinacol+coupling&hl=es&cd=3#v=onepage&q=pinacol%20coupling&f=false
This means that may be, aminoalcohols like for example ephedrine can be synthethised from its corresponding aldehyde (benzaldehyde) and imine (acetaldehyde and methylamine schiff's base) looking over the net for more info on this reaction only gave assimetric synthesis in witch exotic catalizers were used, a common thing on this kind of enantioselective syntheses, the most interesting being the zinc-copper couple by far. A couple of refs on this:
http://sciencelinks.jp/j-east/article/200415/000020041504A0465296.php
http://sciencelinks.jp/j-east/article/200415/000020041504A0465297.php
http://pubs.acs.org/doi/abs/10.1021/ja054401w
Cross-pinacol coupling to aminoalcohols might be aplicable with more OTC catalyst like for example an aluminum amalgam, if you dont care to get a racemic mixture... or might only be usefull for the home chemist while making glicol derivatives from aldehydes... So, what do you guys think, do pinacol couplings look interesting? Usefull or not, theory and experiment will decide.
More info on the pinacol coupling: h ttp://en.wikipedia.org/wiki/Pinacol_coupling_reaction
Knowing this left me wondering, what would happen if one used a mixture of aldehydes? Will he obtain a mixed diol? For example a mixture of benzaldehyde and an excess of acetaldehyde will yield 1-phenylpropane-1,2-diol, 2,3-butanediol and some 1,2-diphenylethane-1,2-diol? But not only sodium could be used on this coupling reaction, a lot more other reagents like magnesium or activated aluminum could be used, even H2O + Aluminum + NaOH in methanol worked under microwave irradiation. One might add benzaldehyde to aqueous acetaldehyde, methanol, sodium hydroxide and aluminum, and microwave that mess to obtain the interesting phenylpropanediol, I think that is interesting since that same substance could be refluxed in dilute sulfuric acid or Hydrochloric acid to obtain P2P...
So, lurking throug an on-line chemistry book if found this (page 116, scheme 5) h ttp://books.google.com/books?id=ROeVSE-zBuMC&pg=PA113&dq=pinacol+coupling&hl=es&cd=3#v=onepage&q=pinacol%20coupling&f=false
This means that may be, aminoalcohols like for example ephedrine can be synthethised from its corresponding aldehyde (benzaldehyde) and imine (acetaldehyde and methylamine schiff's base) looking over the net for more info on this reaction only gave assimetric synthesis in witch exotic catalizers were used, a common thing on this kind of enantioselective syntheses, the most interesting being the zinc-copper couple by far. A couple of refs on this:
http://sciencelinks.jp/j-east/article/200415/000020041504A0465296.php
http://sciencelinks.jp/j-east/article/200415/000020041504A0465297.php
http://pubs.acs.org/doi/abs/10.1021/ja054401w
Cross-pinacol coupling to aminoalcohols might be aplicable with more OTC catalyst like for example an aluminum amalgam, if you dont care to get a racemic mixture... or might only be usefull for the home chemist while making glicol derivatives from aldehydes... So, what do you guys think, do pinacol couplings look interesting? Usefull or not, theory and experiment will decide.