MChem Chemistry

This course unit detail provides the framework for delivery in 21/22 and may be subject to change due to any additional Covid-19 impact.  

Stereoselective Synthesis (Dr Nathan Owston, 8 lectures)

1. Diastereoselectivity in ring systems: conformational analysis and stereoelectronics

2. Diastereoselectivity in acyclic systems

Prochirality

Reactions at C=O: Prochirality, Felkin-Anh model, Chelation control

Reactions at C=C: Houk model

Reactions of enolates: alkylation and aldol reactions, cyclic transition states

Diastereoselective reactions in synthesis: production of single enantiomers

3. Asymmetric synthesis

Chiral pool approaches

Chiral auxiliaries (alkylation/aldol reactions)

Chiral reagents

Resolution

4. Introduction to Asymmetric Catalysis

Catalysis with transition metals (asymmetric reduction of ketones)

Organocatalysis (asymmetric conjugate addition)

5. Applications of stereoselective reactions in synthesis (fine chemicals, pharmaceuticals)

Reactive Intermediates (Dr Roger Whitehead, 8 lectures)

1.Introduction

Neutral reactive intermediates

Carbenes, Nitrenes, Arynes              

2. Radicals

What are radicals?

The structure of carbon-centred radicals

The relative stability of different radical species

Historical aspects of radical chemistry

Sources of radical intermediates

Radical reactions in synthesis

Solving unseen problems involving radical intermediates

Pericyclic Reactions (Dr Daniele Leonori, 8 lectures)

1. Introduction

Covalent bonding

Frontier molecular orbitals (FMOs)

2. The Diels-Alder [4 + 2] cycloaddition reaction

FMO interactionsStereoselectivity and regioselectivity

Substituents effects

3. Other cycloaddition reactions

[2 + 2] Processes ('forbidden' and 'allowed' variants)

Other (4n + 2) and 4n pairings

4. Selection rules and orbital symmetry

Cycloadditions exemplified

5. Electrocyclic reactions

Introduction to electrocyclic reactions

Conservation of orbital symmetry in the ring-opening of cyclobutene

Hexatriene–cyclohexadiene

6. Sigmatropic rearrangements

[1,5] and [1,7] Hydrogen shifts

[1,3] Sigmatropic shifts

[3,3] Sigmatropic rearrangements

Cope and Claisen rearrangements

The unit aims to develop further understanding of synthetic and mechanistic organic chemistry with emphasis on reactive intermediates and elements of stereochemistry.

Enhance transferable skills in the areas of problem solving and analysis

Example classes and individual feedback from tutors/lecturers

• C.J.Moody and G.H.Whitham, Reactive Intermediates (An Oxford Chemistry Primer) ISBN: 978-0-198-55672-5

• A.F.Parsons, An Introduction to Free Radical Chemistry (Wiley-Blackwell, 2000) ISBN: 978-0-632-05292-9

• J. Clayden, N. Greeves, S. Warren and P. Wothers, Organic Chemistry (Oxford University Press, 2001) ISBN 0198503466  (Chapters 35 and 36).

• J. Clayden, N. Greeves and S. Warren, Organic Chemistry 2nd edition (Oxford University Press, 2012) ISBN 0199270295  (Chapters 34 and 35).

• I. Fleming, Pericyclic Reactions (Oxford Chemistry Primer, 2nd Edition) (Oxford University Press, 2015)  ISBN 0199680900 (affordable, thorough guidebook).

• I. Fleming, Molecular Orbitals and Organic Chemical Reactions: Student Edition (Wiley-Blackwell, 2009)  ISBN 0470746599 (a comprehensive reference text).

• G. Procter,  Stereoselectivity in Organic Synthesis (Oxford Chemistry Primers) (Oxford University Press, 1998) ISBN 978-0198559573.

• Access to a set of Orbit molecular models is essential.