summerclass38 - 21-5-2008 at 13:15
What carbon has the most acidic hydrogens on 1,3-cyclohexadione?
I think its the one in between the two ketones because they are electron withdrawing and will leave THAT carbon with the least electron density,
making the hydrogens on that carbon most acidic... Is that reasoning and answer correct?
But what about the carbon 5? Can the electron withdrawing oxygens have enough pull through the sigma framework to make that carbons hydrogens acidic
too? If so, which one is more acidic?
Thanks
12AX7 - 21-5-2008 at 15:59
Draw the resonance structures. The 6 and 4 hydrogens are the next most acidic, being alpha to the ketones. The hydrogens "most alpha" to both are
inbetween, which you guessed correctly but didn't reason correctly. The reason is resonance stabilization, which delocalizes the negative charge over
both oxygens and the central carbon between them.
There is nothing special about carbon 5. There is no delocalization through an unconjugated ring.
Tim
summerclass38 - 21-5-2008 at 16:07
Ahhhh I gotcha, makes sense now
Thanks