Klayden's Organic Chemistry

I will be a form 5 (year 12) student from Hong Kong coming September. Currently, I have finished studying for everything thats covered in the A-Level Chemistry syllabus.
During the process (which is fun btw) I have developed profound interest in Organic Chemistry from within.
Thats why now I want to study Klayden's Organic Chemistry, which I believe is the best organic chemistry book out there for undergraduate level studies.
How much of klayden's is already covered in the a-level syllabus, and do you think claiming to possess at least some of the knowledge written in the book will give me a huge advantage when applying to oxford chem/chemeng?
Does klayden's require any maths or physics prerequisites, particularly calculus or thermodynamics?
Thanks a lot!

Clayden’s Organic Chemistry is well above A level in terms of the content it covers. Everything A level covers (minus the oversimplifications) will be included somewhere in the book.
Some thermodynamics will be involved, but not a huge amount if memory serves. I recall some parts of the book explain certain reactions taking place due to there being an enthalpic driving force (e.g a particularly strong bond is formed) and that entropy can be of relevance.
If applying to Oxford chemistry, it will make little difference unless you happen to learn what you will be interviewed on in your organic interview. You can write about it in your personal statement / UCAS application and why it was beneficial to read it, but know that the personal statement isn’t usually an important factor in deciding it you get in.
Also, Oxford doesn’t offer ChemEng, but Cambridge does. It’s the largely same as the above with whether it would help you in an Oxford chemistry application, but I imagine it would be less beneficial. ChemEng is 10% chemistry and 90% maths and physics, so it would likely be of more benefit to find books on physical chemistry, thermodynamics etc to read.

I thought they interview me based on what I claim to know in my personal statements?
Can you tell me more about the organic interview?

My experience of the Oxford interviews was they didn’t assess a lot that I mentioned in my personal statement. It was only after getting my place for chemistry at Oxford and discussing with my tutors and other coursemates that I learnt
that everyone at a given college is given the same set of initial questions to answer - the discussion itself depends a lot on what points you do/don’t bring up.
There are limits as to what I can tell you as per the code of conduct. What I will advise you to do, however, for the organic interview is brush up on your mechanisms and drawing structures of compounds. A book by Peter Sykes called “Guidebook to Mechanism in Organic Chemistry” is well worth a read if you can find an affordable copy of it, given it has been out of print for a long while.

Thanks a lot for your valuable advice.
What prerequisites are required for Sykes’s guidebook? Is A-Level Math Physics and Chem good enough?
Speaking of books for physical chemistry, a friend at imperial suggests Atkin’s Physical Chemistry, claiming its of great reference value, and they use it from year 1 to 3. Compared to Klayden’s, do you think Atkin’s would be a better preparation for both Chem and ChemEng, alongside Sykes’ guidebook?

A level knowledge should be sufficient to understand a fair bit of it. Just be aware that the book is aimed at undergraduates and so many mechanisms introduced in it will be new to you, but all should be explained.
If you decide you would prefer to study chemistry over chemical engineering, I would probably read Clayden’s Organic Chemistry and write about that as it sounds as though organic chemistry interests you more and it would give you an easier time writing about how reading it benefitted you. Atkin’s Physical Chemistry is good for either course. There’s no harm in reading bits of both, but if you decide on applying to one course over the other, it’s better to write more about the more relevant book than the other.

Alright, I will go for Sykes’ first, which seemingly has the least content.
Btw, the UCAS website suggest 100% applicants with 3A* were accepted to cambridge chem eng, oxford chem, imperial chemeng, and imperial chemistry. Does that mean if I can get at least a 3A* its pretty much that I have guaranteed admission to those programs?

I'd ask why are you looking to use Atkins or Clayden's in year 12? It's completely unnecessary and way over the top. Focus on what you're meant to learn and become good at that. If you're exceptionally gifted or have some entrance exams then I understand but for regular A-level students it could get confusing very quickly and the level is far too much. I hardly used those books at uni nevermind school.