aren't alkoxides considered strong bases and therefore more likely to attack the hydrogen of the secondary carbon to kick out bromine? Additionally, isn't ammonia considered a good nucleophile (thus a weak conjugate base) and thus unable to attack the hydrogen of the hydroxyl group in example 2?
Steric hindrance at the electrophilic carbon prevents SN2 here. DMF doesn't prohibit the formation of a carbocation per se, although a protic solvent may be better at stabilizing it (mainly through interactions with the leaving group). The problem with a protic solvent here would be competitive coordination of the solvent (e.g., ethanol) to the carbocation instead of the intramolecular alcohol. I would guess that DMF minimizes the issue...although that's an empirical optimization thing, I'm sure.
Yes. This will happen reversibly (hydroxide and alkoxide are of comparable strength), but the ensuing "kick" of bromide by the alkoxide is irreversible.
we owe you one, michael. thanks
How did we know the stereochemistry of the last example ???
aren't alkoxides considered strong bases and therefore more likely to attack the hydrogen of the secondary carbon to kick out bromine?
Additionally, isn't ammonia considered a good nucleophile (thus a weak conjugate base) and thus unable to attack the hydrogen of the hydroxyl group in example 2?
This video was soo helpful,thank you sir I was stuck on this for a long time.
This will surely help me in jee mains
nice, explanation is simple...
DMF is a polar aprotic solvent hence how can we produce a carbocation . Shouldn't it be SN2?
Steric hindrance at the electrophilic carbon prevents SN2 here. DMF doesn't prohibit the formation of a carbocation per se, although a protic solvent may be better at stabilizing it (mainly through interactions with the leaving group). The problem with a protic solvent here would be competitive coordination of the solvent (e.g., ethanol) to the carbocation instead of the intramolecular alcohol. I would guess that DMF minimizes the issue...although that's an empirical optimization thing, I'm sure.
Yes you are right
Yes you are right
thanks
excellent video
So in number 1 example, the NaOH will act as a base to grab the hydrogen of 4-bromobutanol?
Yes. This will happen reversibly (hydroxide and alkoxide are of comparable strength), but the ensuing "kick" of bromide by the alkoxide is irreversible.
thanks a lot
great vid!
Thanks, Nikhil!