Tips for tomorrow's Quiz

Hi All,
These are a few things we can all remember that may be helpful for the quiz tomorrow:

- Secondary and tertiary alcohols undergo SN1 with halides(can form elimination product which is converted back to SN1 product) and E1(dehydration of alcohols) reactions. Since a carbocation is formed, there is the possibility rearrangement. Ring expansions can also happen if there is ring strain(3 or 4-membered rings).

- Primary alcohols undergo SN2 with halides(no eilimination product because the halide ion is a weak base and cannot remove a hydrogen from beta-carbon) and E2 (alcohol dehydration).

-Rearrangements can be avoided if PBr3, PCl3 or SOCl2 with pyridine are used instead of HBr, HI, or HCl with ZnCl2 with heat.

- SN2 reactions leads to inversion of stereochemistry, but double inversions can restore the molecule to the same sterochemistry as the starting material.

-Phosphoric and sulphuric are commonly used for dehydrating alcohols.

- In dehydration, -OH and a hydrogen from a beta carbon is removed to form an alkene. Since the reaction is heated (distillation) to remove water which is a product, the reaction is displaced to the right so that hydration does not occur(Le Chatelier's principle).

- For chromium oxidation, adding excess chromic acid to primary alcohol forms carboxylic acid instead of stopping at the aldehyde stage. However, PCC can stop this reaction at the aldehyde stage.

-Secondary alcohols normally form ketones. 

I know this does not cover everything we have done so far, but I hope it helps.