[Enantiomer]

Hey all,
Just a quick question, I'm looking at the last question in a problem set I'm doing and I'm pretty sure I know the answer but I wana be 100% sure before I write it down,
The question is "briefly explain why allyl bromide is more reactive than ethyl bromide toward alkylation of tosylamide anion in acetone?"

My answer is most likely that it will give an improved E/Z selectivity, however I noticed the key word in that question is 'acetone' leading me to believe that the real reason would be that allyl bromide might be slightly more polar then it's ethyl brother.
Is it both of these or just the polarity?  I'm leaning more towards polarization, but hesitant to write it down simply because it sounds slightly boring to me.

[azmanam]

unfortunately, you're barking up the wrong tree.  Tosylamide (RHN^-) is a good nucleophile, and acetone (being a polar aprotic solvent) makes nucleophiles even more nucleophilic.  The reaction is going to be an S_N2 reaction.  So what makes allyl bromide (CH₂=CHCH₂Br) a better electrophile toward S_N2 than ethyl bromide?