Mechanism Problems

In these problems you will be asked to draw chemically reasonable curved (curly) arrows to account for the transformations.  (Problems using the 'dotted line' convention, in which the formation of new bonds must be indicated by drawing dotted lines between the atoms, are also available.)

The mechanism of a reaction is the sequence of steps in the reaction, including details of the bonds are formed and/or broken in each step.  Understanding mechanisms is key to understanding the reactions of organic compounds, and is essential to being able to use those reactions to make useful compounds.


a reaction mechanism

Curved (curly) arrows, aka 'elecron pushers', are used to represent the movement of pairs of electrons in the bond forming and breaking events in the mechanism.

Note that 'correct' curved arrow mechanisms are provisional, further research may show that some of them are wrong.  Moreover, they only show reasonable pathways of electron flow, and do not include any information about other aspects such as the relative energies of the species involved.

It is best to think of curved arrow 'mechanisms' as greatly simplified models that are nevertheless very useful because they help chemists to understand key aspects of the reactions.

On This Page:

On this page you will be given the starting materials, intermediates and products for common organic reactions and can practise drawing the curved (curly) arrow mechanisms for the transformations.

Only the most common mechanisms are inlcuded, and they are organised by type (e.g. 'acyl substitution') in the way that most students will encounter them.

Learning Objectives:

  • Draw curved arrow mechanisms for common reactions.
  • Understand the reactivity of organic compounds.

Scroll down to try the problems.

Get problems below to test your ability to draw curved arrow mechanisms.

Problem settings

1.  Select mechanism type(s)

Select one or more types of mechanism by clicking the checkboxes below.


2.  Set problem difficulty

Select the level of difficulty of the initial problems.



3.  

Problems

Select one or more mechanistic types using the checkboxes on the left, and choose the difficulty level of the initial problems, then click the Get Problem button.

When the problem is displayed, further instructions will be provided here.


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