Predicting the Major Organic Product of a Reaction Sequence

When it comes to organic chemistry, one of the most important things you can do is predict the major product of a reaction. By understanding how to do this, you’ll be able to better understand the mechanisms behind reactions and get a feel for how they’ll proceed.

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In organic chemistry, predicting the major organic product of a reaction sequence is a key skill. The ability to do this allows you to understand the course that a reaction will take, and plan your experiments accordingly. There are a few things that you need to take into account when trying to predict the major product of a reaction, including the reactivity of the starting materials, the reagents used, and any intermediates that may be formed. With practice, this skill will become second nature and you will be able to quickly plan out organic synthesis routes.


There are a variety of ways that one can predict the major organic product of a reaction sequence. The most common method is to use the arrow pushing method, which uses arrows to show the flow of electrons. This method is often used in conjunction with the half-arrow method, which uses half-arrows to show the flow of protons.

Identifying the Products of a Reaction

In order to determine the organic product of a reaction, it is necessary to first identify the functional groups that are present in the reactants. The functional group(s) will dictate how the molecules will interact with one another and which product(s) will be formed.

After the functional groups have been identified, it is then necessary to predict which atoms will be added or lost during the reaction in order to form the product(s). In many cases, it is helpful to begin by drawing out the Lewis dot structures of the reactant molecules in order to determine which atoms are bonded to one another and which atoms are lone pairs. This can give clues as to which bonds will be formed or broken during the reaction.

Once the atoms that will be added or lost have been determined, it is then possible to draw out the structure of the product(s) by adding or removing the appropriate atoms and rearranging the bonds as necessary. The final step is to determine whether any further rearrangement reactions (such as hydrolysis) may occur in order to give rise to a different product.

Determining the Major Product

In Chemistry, Major product is defined as the product that is formed in the greatest relative amount in a chemical reaction. In many reactions, more than one product is formed. The amount of each can be predicted by various methods, the most common being:

-Assessing the stability of each product
-Using reaction kinetics to determine which product is formed more quickly
-Analyzing the thermodynamics of each product


A table is provided that lists the major organic product of each reaction sequence. The first column lists thereactant combination and the second column lists the expected product. The table is organized so that the most important information is listed first. The results of the reactions are given in the order of reactant combination, product, and yield.

Reaction 1

The first step in the organic synthesis of product A is the formation of a new C-C bond between two alkyl halides, R-X and S-Y. The overall reaction is shown below, where M represents a metal catalyst:

Organic Synthesis of Product A

Reaction 1: Formation of a New C-C Bond
R-X + S-Y → R-S + X-Y

Reaction 2

In Reaction 2, the limiting reactant is again A, and 2 moles of A are needed for every 1 mole of B that is produced. This means that the major organic product of Reaction 2 will be twice as much B as A.

Reaction 3

The possible products of Reaction 3 are shown below.

-Product A
-Product B
-Product C
-Product D


In organic chemistry, there are many ways to predict the major organic product of a reaction sequence. The type of reaction, the starting materials, and the conditions all play a role in determining which product will be formed in the greatest amount. Let’s take a look at some of the common methods used to predict the major organic product.

The most common method is to start with the reactants and predict the products by looking at the functional groups present. The functional group with the highest priority will generally be the one that undergoes reaction first. For example, in an addition reaction, an alkene will react with HBr to form a alkane. If there is more than one type of functional group present, then you can use their reactivity order to predict which one will react first. The order of reactivity goes: acid halides > esters > amides > aldehydes/ketones > alcohols > alkenes > alkynes.

Another common method is to use molecular orbitals (MO) theory. This theory predicts that reactions will occur so as to minimize the energy of the molecule. In general, this means that reactions will occur so as to form stable bonds and break less stable bonds. For example, in a Diels-Alder reaction, two p-orbitals will interact so as to form a new sigma bond and break an pi bond.

A final method that can be used is what is called “predicting by analogy”. This simply means looking at similar reactions that have already been carried out and seeing what product was formed in those reactions. This can be especially useful when you are dealing with unknown starting materials or conditions. For example, if you know that in a previous Diels-Alder reaction conducted under similar conditions Product A was formed, then it’s likely that Product A will also be formed in your reaction.

While there is no one perfect way to predict the major organic product of a reaction sequence, these methods should give you a good starting point.


In summary, the major product of a reaction sequence will be determined by the nature of the reactants, the conditions under which the reaction is carried out, and the relative concentrations of the reactants.

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