Monday, October 8, 2007

protection of ketone by Li enolate.

convert ketone into Li enolate by LDA in THF at -70 C.
the enolate formed is very stable below -30C, LAH can't reduct it.
LAH can't reduce ester below -40C at THF. So warm up to -40- -30C, the ester will be reduced while the ketone remained.
In one run, the Li enolate is stable even at about 0 C!


Anonymous said...

i wanted to reduce ester to aldehyde using DIBAL-H.. but, there is a ketone in my ring system..can i use this method (convert ketone into Li enolate by LDA in THF at -70 C) together with DIBAL-H? if can, could u send me the journal that you used...thanks

Weiwei TIAN said...

I guess you can do it with DibalH. But I can't find any paper describing it. So if you are successful, please share it here.