Peter Sykes : Reaction Mechanisms

Mark my words… Peter Sykes’ Guidebook to Mechanism in Organic Chemistry, has gained the status of a god-book of reaction mechanisms because generations of eminent chemists have used this book in their life. moreover, as regards the high school scenario of India, loads of JEE/AIIMS aspirants have successfully used it to clear their exams with flying colours.

Be sure that any true lover of organic chemistry or any true enthusiast of organic chemistry would have definitely gone through this book, at some point or the other.

what are the best things about the book?

  1. Best teacher of reaction mechanism – It lucidly explains the reaction mechanisms and connects them with basic concepts. this makes the reader understand reactions with fun, yet sound logic.
  2. Reliable – The data & information given in this book is reliable. put your faith in the book… it will never disappoint you.
  3. Perfect for syllabus concerning JEE/AIPMT/AIIMS – Read all the chapters. each and every line. only 5-8%  of the book is not useful so > 90% is of the syllabus covered in the book is apt.
  4. Handy – The book has the ‘anywhere-carry-with-yourself’ feature. it’s only about 2.5 cm thick, and it weighs even lesser than a notebook.
  5. Perfect for self study – You can cover all reaction mechanisms of organic chemistry and syllabus of jee just by using the book yourself.

In 6 years of my teaching experience at various coaching classes, I have found students have trouble understanding Peter Sykes in spite of the fact that the book is easy to understand. The problem, I believe, lies in the fact that the book actually focuses on reaction mechanism and therefore it doesn’t teach stereo chemistry as a chapter. So, a student who is weak in general organic chemistry and stereochemistry can not easily cope up with the book.

The book has some basic chapters to build foundation. These are –

  1. Structure, Reactivity & Mechanisms
  2. Energetics, Kinetics & Investigation of Mechanisms
  3. The strength of acids & bases


Structure, Reactivity & Mechanisms

This chapter is basically for beginners to understand the ABC of organic chemistry. It introduces basics of hybridization, bond formation, basics of conjugation, delocalization and aromaticity. In-depth knowledge, however, is not provided.


Energetics, Kinetics & Investigation of Mechanisms

This one is a crisp chapter. If you are a student of class 11, then follow point 1. Otherwise, follow point 2.

Students who don’t have the basics of the chapter chemical kinetics should read this chapter of peter sykes thoroughly. Class 11th students will have  some trouble as the chapter chemical kinetics is in class 12th. For students who know the basics of chemical kinetics may skip basic kinematics but read carefully the topic – use of isotopes.


The strength of acids & bases

Although it contains the basic info regarding acid and base strengths, there should have been more examples of acid and base strengths. However, since the book primarily focuses on reaction mechanism, it is acceptable.


Nucleophilic Substitution At A Saturated Carbon Atom 

This chapter is important because, after mastering GOC and Isomerism it is always advised to master this chapter and only then proceed to  further chapters.

This chapter makes you understand Sn1, Sn2, Sni and NGP reactions. You have to sharpen your skills here because understanding the  characteristics of nucleophiles adds up to your  power of thinking logically, which is highly essential in Organic Chemistry.

The effects of entering and leaving group are very important and can be used  to understand the driving force of a chemical reaction.


Carbocations, Electron Deficient N And O Atoms And Their Reactions 

The concepts of stability of carbocations, concepts of ring expansion and contraction and carbocationic rearrangements are basic building blocks of understanding mechanism of what is going on in the reaction. Identifying the stability of carbocations boosts your command over solving problems in organic chemistry because carbocations are most important intermediate among all of the intermediates in organic chemistry.

The following topics are present as a great resource of the concepts –

  • Stability of carbocations
  • Carbocationic Rearrangements
  • Ring expansion and Contraction
  • Stereochemistry of the Rearrangements
  • Diazonium Cations

The reactions best explained are

  • Pinacol-Pinacolone rearrangement
  • Allylic rearrangement
  • Reactions of migration to electron deficient Nitrogen and Oxygen, such as Hoffmann, Curtius, Lossen, and Schmidt reactions
  • Beckmann rearrangements are very important and very well explained here
  • Baeyer-Villiger oxidation of Ketones, Hydroperoxide rearrangements and Dakin reaction are few more well-explained reactions given in this Chapter


 Now Comes The Most Scoring Chapter From JEE Point Of View

Electrophilic and Nucleophilic Substitution In Aromatic Systems

Important Topics of this chapter are –

  • Electrophilic attack on benzene, including Nitration, Halogenation, Sulphonation & Friedal-Crafts Reactions.
  • Diazo Coupling
  • Electrophilic attack on Phenyl rings
  • o/p Ratios and how to predict them.
  • Ipso substitution
  • Kinetic vs Thermodynamic control of any reaction
  • Electrophilic attack on other groups
  • Nucleophilic attack on aromatic species
  • Carbon Shifts



Electrophilic and Nucleophilic addition to C=C

Beautifully explained concepts and topics are –

  • Addition of Halogens
  • Effects of substituents on rate of addition
  • Orientation of addition reactions (viz. Stereochemistry of Addition Reactions)
  • Addition to Conjugated Dienes
  • Nucleophilic Addition




Nucleophilic Addition to C=O

Topics most relevant and important for competitive exams are –

  • Structure and Reactivity of Carbonyl compounds
  • Simple addition reactions like Hydration, Addition of Alcohols, Addition of Hydrogen Cyanide, Addition of Bisulphites, Hydrides and other ions
  • Carbon Nucleophile Additions
  • Stereoselectivity in carbonyl addition reactions (Very Important)
  • Addition/Elimination reactions of carboxylic acid derivatives’


There are some important Name Reactions which are MUST for JEE – 

  • Meerwin-Pondorf Reaction
  • Cannizzaro Reaction
  • Aldol Reactions and Retro-Aldol Reaction
  • Perkin Reaction
  • Knoevenagel Reaction and Stobbe Reaction
  • Claisen-Ester Condensation
  • Benzoin Condensation
  • Benzil-Benzilic Acid Rearrangement
  • Wittig reactions




Note on the Remaining Chapters

  • Carbanions and Their Reactions – This chapter includes some important reactions like Riemer-Tiemann reaction (One of the frequently asked name reactions in JEE), Decarboxylation Reactions and Halogenations of Ketones.
  • Radicals and Their Reactions – One of the best collections of concepts related to free radicals. However, as JEE syllabus does not focus much on the reactions of free radicals, this chapter is useful for only the curious reader.
  • Carbohydrate  – The well explained topics are Isomerisation of Sugars, Cyclic structure of Monosaccharides, Reaction with Phenyl Hydrazine and Ring Size in Glucose.


So, that’s our round-up on this amazing book for organic chemistry reactions. Let us know your experience with the book and ask your queries in the comments section below.


10 thoughts on “Peter Sykes : Reaction Mechanisms”

  1. I have got the ‘for JEE’ version of Peter Sykes( +BH Kishan).It has questions too.
    Can I use this version or the original one?

    1. ofcourse sarthak ! u can use that one too !! theory portion is almost same however since the added excercise is new one hence it might have some error.ask your concerned faculty if you find some wrong questions or answers.
      all the best !!

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