Chemical Forums

Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: mimogkas on September 11, 2011, 07:15:32 AM

Title: Opening epoxides with furans
Post by: mimogkas on September 11, 2011, 07:15:32 AM

Hello fellow chemists!!
I'm working with furan and for a year now i can't open with high yield a long chain terminal epoxide.
I usually make the anion in the 2-position of a monosubstituted furan with n-buli in THF, at zero for 30'. and then
dropwise the epoxide, and r.t overnight. Usually I take back the starting materials.
Recently I tried with a monosubstituted furan with an alkyl chain (I hoped that furan would be more nucleophilic) but nothing...
Thinking of using Bf3.Et2O but I have an acetonide and a TBS protection...
I would be very grateful if you give me any advice...

Title: Re: Opening epoxides with furans
Post by: orgopete on October 20, 2011, 09:19:28 AM

Is this a rate effect? I don't know the pK_as. Is deprotonation of THF outcompeting your reaction?