Organic Chem help please!

[ChickenCh0wM1en]

Hi Guys! I was just reading some noes for the organic chem lectures we are covering and when summarised said:
SN2 substitution occurs when a good nucleophile is used while E2 elimination occurs if a strong base is used.

May someone help explain this? I understand that Nucleophiles are bases etc, but does that mean a "good" nucleophile is a "strong" base?

Thank You!

[Shenz0r]

From what I remember, SN2 substitution occurs when you have a strong nucleophile. Whether a nucleophile is "good" or "poor" doesn't only take into account how basic it is, but it also depends on steric hinderance. To have a good nucleophile, you want a strong base and low steric hinderance.

For E2 elimination reactions, you want a strong base to pluck off one of the H atoms from the molecule. However, you want it to also be sterically hindered so it will not attack the electrophile. So for E2 elimination reactions you'd use long, "bulky" sort of molecules.

[LeviLamp]

Taking advantage of this thread to suggest we turn it into Chem 2 help general b/c it would be useful for a whole bunch of us :3
./selfish
(Also, even though I wasn't the one to ask, I was wondering the same thing as Sashimi, so thanks Shenz0r )