MYTUTOR SUBJECT ANSWERS

579 views

What are the stereochemical implications of bimolecular and unimolecular nucleophilic substitution?

If a chiral molecules undergoes nucleophilic substitution what happens to its stereochemistry?

SN1: These reactions occur with the production of a cationic intermediate. These contain an sphybrdised carbon atom with vacant p orbitals (hence the positive charge). The nucleophile can attack from above or below the plane of the molecule therefore producing a racemic mixture of product. If a single enantiomer is reacted with a nucleophile and the reaction proceeds via unimolecular nucleophilic substitution then equal amounts of both possible enantiomer will be formed (providing the carbon atom remains a chiral centre).

SN2: These reactions proceed via a transition state (anionic if the nucleophile is anionic) where the nucleophile attacks from one side and the leaving group leaves from the other. This results in something that resembles an umbrella turning inside out as the three unaffected groups switch sides. This means that if one enantiomer is reacted with a nucleophile then only a single enantiomer will be present in the products, although it's absolute configuration may have changed.

Henry S. A Level Chemistry tutor, A Level Biology tutor, A Level Math...

2 years ago

Answered by Henry, an A Level Chemistry tutor with MyTutor


Still stuck? Get one-to-one help from a personally interviewed subject specialist

86 SUBJECT SPECIALISTS

£26 /hr

Hannah G.

Degree: Chemistry (Other) - Liverpool University

Subjects offered: Chemistry, Science+ 1 more

Chemistry
Science
Biology

“First year Chemistry undergraduate, looking to help you achieve your full potential in Chemistry and Biology. ”

£20 /hr

Firat G.

Degree: Biochemistry (Bachelors) - Bristol University

Subjects offered: Chemistry, Economics+ 1 more

Chemistry
Economics
Biology

“Currently, I am studying Medicinal Biochemistry at the University of Bristol. I tutor numerous students at both GCSE and A level and thoroughly enjoy being able to help individuals improve their confidence and understanding of Biology ...”

£22 /hr

Thomas D.

Degree: Neuroscience (Bachelors) - Kings, London University

Subjects offered: Chemistry, Science+ 3 more

Chemistry
Science
Physics
Maths
Biology

“I am currently in my second year of a Neuroscience Bachellors' degree at a Russel Group institution, that is King's College London. Having done five (yes 5) A2s, and achieved an A* and 5 As, I know a few tricks of the trade so to spea...”

About the author

Henry S.

Currently unavailable: for regular students

Degree: Chemistry (Masters) - Durham University

Subjects offered: Chemistry, Science+ 4 more

Chemistry
Science
Maths
Extended Project Qualification
Biology
-Personal Statements-

“Durham University chemistry student here to help with A-level chemistry, biology and maths!”

You may also like...

Other A Level Chemistry questions

Can you explain what stoichometry actually is and why the ratio is not the same as the number of moles?

How do I calculate the percentage by mass of a metal within an impure substance?

What are the different types of isomers?

What is a mole?

View A Level Chemistry tutors

Cookies:

We use cookies to improve our service. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok