[maria123]

I really need some clarification if possible on SN2, SN1, E1, E2. I'm having trouble telling which is which. For example my book says that a tertiary haloalkane with a strongly basic, hindered nucleophile would undergo E2, but I thought that tertiary carbons underwent either SN1 or E1 do to their ability to easily form carbocations. How is a tertiary haloalkane undergoing E2? Is it just because it is with a strong base? Or is it because of hinderance of the base? even though there is also hindrance do to it being a tertiary haloalkane.
Any clarification on what to initially look at to determine what kind of reaction is taking place would be great? Would it just be whether its a strong or weak base to undergo SN1/E1? Any help is much appreciated.

[azmanam]

Start here: http://www.masterorganicchemistry.com/2013/11/04/sn1-sn2-e1-e2-electrons-guest-post/

[beardy]

Big bulky strong bases like tert-butoxide suck as nucleophiles so they act as bases instead. Due to their bulkiness, they'll attack from the less hindered side, leading to an elimination reaction. They're strong bases, so they'll still initiate the reaction. Weak bases can't initiate reaction, so they have to wait til the leaving group detaches to form the carbocation.

[beardy]

Strong bases love primary carbons. In this example the substrate is just that. Secondary carbons are sluggish and sometimes give mixed results. You'll notice a common theme through SN/Elimination reactions: the outcome depends. Some reactions are black and white, while others take the form of both as you'll see in ochem II.