[quadsofdgods]

I`m  not confident in chem and i`d consider myself still new so maybe I`m not even asking the right questions (currently at undergraduate level, i did my chemistry GCSE`s/Ordinary level qualifications in 6months, i was previously studying Alvl maths/physics which i`m both extremely confident in)

I`m having trouble understanding them (see subject title) properly, the problem i think i have is i`m failing to see the common action that will always happen say in a sub or addition by the nucleo/electro...s.

For me unless i see the mechanism before and study it i would not be able to do it if you just gave me the molecule and told me the type of attack that will take place. I kind of see each one as something new to learn rather than, knowing the concept and being able to apply it in different situations. I know (perhaps could know better) what a nucleo/electro.. are, sub and addition are but still, my ability to combine and apply the knowledge is abysmal.

This is probably why i didn't have a clue how to deduce the other products in the iodoform thread i quite recently opened.



Could you give me advice or some help?...

[opsomath]

Hi, I think you are overthinking this. Chemistry is not as elegant as maths, and you need to spend more time internalizing the principles before you can just "know" what a reaction will do. (I say this as a guy who got his BS in the USA in both)

Why don't you post some more problems and we'll see what we can do with them?

[Dan]

A large part of it is practice. Knowing about patterns of reactivity is one thing, but you need to practice mechanism questions in order to understand and identify them.

I will recommend two books to you which I found extremely useful at the start of my university studies.

A Guidebook to Mechanism in Organic Chemistry - Peter Sykes
This is an entry level organic text. Though it will be of limited use after 1-2 years of study, it is a truly excellent text to start with. Explanations are clear and the book is written in an engaging and concise manner. It is old fashioned though - that puts some people off, but I would really recommend giving it a try.

For practice, this is a great collection of problems:

Reaction Mechanisms at a Glance - Mark Moloney
This is written as a series of tutorials with accompanying problems to work through. It is specifically written to teach a student to work out the answer from scratch using general principles of reactivity rather than a memory-based approach; from what you're saying it sounds right up your street, take a look.

[orgopete]

In that case, I also recommend my book, A Guide to Organic Chemistry Mechanisms. It is an ancillary to a regular textbook. It presents problems that I assure you that you can do. I suggest you print out and do the examples from the sampler. At this point this book is short on explanations, if you were to see the organization of the book, you could understand why. However, the better you know what happens, the easier you will understand why. There are some additional explanations, especially where I try to provide an alternate viewpoint, in an appendix.

[quadsofdgods]

thanks guys, i will go through the books you mentioned.

[Honclbrif]

"I kind of see each one as something new to learn rather than, knowing the concept and being able to apply it in different situations."

Kiss of death in organic chem. Best get the basics before things get away from you.

Start by breaking the words down.

"Nucleophile" = "loves nucleus". A nucleophile is something that is relatively electron rich. Nucleophiles are usually the easiest thing to spot because draw electron density as lone pairs or bonds. These are electron rich sites, and in an arrow pushing mechanism, its where the arrow always starts.

"Electrophile" = "loves electrons". An electrophile is something that is relatively electron poor. Electrophiles can be trickier to spot because they lack electrons. Since in most structures we only draw where electrons are, you're in essence looking for something that's missing. The best way to find one is to look for a positive charge, but not all electrophiles are cationic. Another way is to look for a relatively electropositive atom bonded to a relatively electronegative atom. The electropositive atom is frequently an electrophile: e.g C in a C=O group, H in H-Br, C in H₃C-Cl.

Get your text book out and do the practice problems and things will start to come to you.