[g-bones]

i am looking at the total synthesis by Evans of (-)-FR182877 and the first step toward an intermediate is an aldol reaction.  they use a  a ketone (actually with a oxazolidinone on it) and an aldehyde.  the other reagents are dibutylboron triflate and TEA.  they say the reaction is mediated by the dibutyl boron triflate, could this be acting as a lewis acid to further enhance the electrophilic nature of the aldehyde?  also I am not sure what TEA is, could it be triethylamine creating a small equilibrium of enolate to react with the activated aldehyde?

any help would be great

[macman104]

You've got it exactly right if I'm not mistaken.  The boron agent is a lewis acid, which helps the enolization of the carbonyl.  TEA is triethylamine (can anyone think of anything else abbreviated TEA, I've only heard it used for triethylamine), and like you thought, it's purpose is only to be a hindered base that removes the proton.

I imagine, this is the procedure you are looking at?

http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV8P0339

[russellm72]

From what I remember the Boron also acts as a chelating agent locking the enolate in a set geometry.

Remember attack can happen above and below and also from the Z or E enolate.

A decent textbook should contain all this info.

R.

[azmanam]

on that...

http://name.howtochem.com/evans-aldol-addition/

[g-bones]

thanks guys, appreciate the help