Organic Chemistry: Help~!

[FlatteredPawn]

I have an Organic Chemistry final in three days and I'm in some trouble. I can't seem to grasp some concepts fully, and I was wondering if there was anyone available for a discussion via PM (or even in this thread for others that may be curious) that would mostly be me asking a bazillion questions and hoping for some in depth feedback.

I've also used Khan Academy for help, but it's not... detailed enough. I have so many questions that need specific answers~!

I'm having the most issues with identifying products of reactions when given the reagents and the conditions of the experiment, two step experiments involving what looks like Grignard reagents... and just even figuring out where to start on some of my practise questions. My teacher likes to use odd chemicals (he's definitely not a textbook type, but he is super knowledgeable about compounds you can use if you don't have the 'go-to' chemical around) and sometimes I have trouble figuring out what they are used for.

I'm not sure how many Chemistry genius' there are around, but please help! A sample question looks something like:

(What looks like) Methyl-cyclohexene in a first step reaction with Hg(oAc)2 and water/THF then a second step reaction with NaBH4, equals what product(s)?

[britneylover3]

This is an oxymercuration reaction where you form a hydroxyl group at the site of the double bond. This reaction follows Markonokov's rule so the OH group will be added to the side that is more substituted. Below is the reaction that you mentioned:

[FlatteredPawn]

britneylover3

This is an oxymercuration reaction where you form a hydroxyl group at the site of the double bond. This reaction follows Markonokov's rule so the OH group will be added to the side that is more substituted.

Thank-you~! May have more questions later if you're floating around like the Chemistry goddess you are.

[britneylover3]

FlatteredPawn

britneylover3

This is an oxymercuration reaction where you form a hydroxyl group at the site of the double bond. This reaction follows Markonokov's rule so the OH group will be added to the side that is more substituted.

Thank-you~! May have more questions later if you're floating around like the Chemistry goddess you are.

No problem, feel free to ask me anything. I'll try to help you to the best of my ability.

[FlatteredPawn]

I have three different enantiomers for 2-3-dichlorobutane (R,R), (S,S) and (2R,3S) and I need to identify which one is a meso compound. Versions (R,R) and (S,S) have a plane of symmetry right up the middle which is why I automatically thought they were meso compounds... but they're not. I was thinking that may they're not because of a second plane of symmetry perpendicular to the first... but wouldn't one end of butane be pointing up and the other down? So it wouldn't be spatially symmetrical? Then I thought by that same logic... the Cl groups and H's would be one up one down as well... so there are no planes of symmetry in (R,R) and (S,S)?

Since by the process of elimination... (2R,3S) is the meso compound (which is also what my text confirms) so I was trying to find a plane of symmetry... is it diagonally? Is there a trick to this I'm just not seeing?

[britneylover3]

I never liked doing these meso form problems, but the way how I normally do these is that I draw out the structures in a fisher diagram form (with wedges and dash) to indicate the stereochemistry of the structure 1st. Then I try to find the plane of symmetry from there. Below is how I would do the problem that you gave. From your explanation above, I think that your problem may have been that you had drawn the structures wrong because the R/S should have the plane of symmetry in the middle while the R/R and S/S don't.