Contents
How to Draw the Organic Product of the Nucleophilic Substitution Reaction: The nucleophilic substitution reaction is a type of organic reaction that occurs when the nucleophile (a molecule that donates electrons) attacks the electrophile (a molecule that accepts electrons).
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Introduction
In organic chemistry, nucleophilic substitution is a fundamental class of reactions in which an electron-rich nucleophile selectively replaces another atom or group of atoms in a compound.
A good example of a nucleophilic substitution reaction is the S N 2 reaction. The nucleophile attacks the carbon from behind, pushing the leaving group off of the carbon. This type of reaction works best with small, symmetrical molecules like methyl bromide.
The other main type of nucleophilic substitution is the S N 1 reaction. In this case, the leaving group leaves first, and then the nucleophile attacks. It’s called an “S N 1” because there is only one step in the rate-determining step of the reaction. This type of nucleophilic substitution works best with molecules that have a good leaving group (like halides) and are not too big or complex.
In this guide, we will walk you through how to draw the organic product of a nucleophilic substitution reaction using both the S N 2 and S N 1 mechanisms.
The nucleophilic substitution reaction
The nucleophile
In organic chemistry, a nucleophile is an atom or molecule that donates an electron pair to form a new covalent bond in relation to a electrophile. All nucleophiles are Lewis bases, although not all Lewis bases are nucleophiles. The term nucleophile is often used interchangeably with base, even though hydrogen ion is nearly always the electrophile.
A nucleophilic reagent is a chemical reagent that acts as a nucleophile. Nucleophilic reagents are concerned with the formation of new bonds. In general, they are attracted to electrons (they are Lewis bases). The nucleophile donates a pair of electrons to form a new covalent bond; this donation is generally depicted as happening at the electrophile.
The arrow in the reaction below indicates the movement of electrons:
The nuclophile (ammonia) joins with the methyl group of chloromethane by sharing electrons, leaving behind a proton (H+). This proton can be replaced by another water molecule (shown in brackets), and so this reaction can also be considered as one taking place in water.
The leaving group
In a nucleophilic substitution reaction, the nucleophile (Chloride ion in this case) attacks the carbon atom to which the leaving group is bonded.
The Convention
In organic chemistry, we draw the Leaving Group (LG) on the outside of the tetrahedral carbon.
The substrate
The substrate is the molecule that is attacked by the nucleophile. The nucleophile is attracted to the electron-rich carbon atom in the substrate, and this attraction makes the carbon atom more likely to be attacked.
The products
The nucleophilic substitution reaction is one of the most important types of organic reactions. The basic idea is that a molecule (the “nucleophile”) attacks another molecule (the “electrophile”), causing it to break apart and form a new bond.
The products of a nucleophilic substitution reaction depend on the composition of the reactants. If the electrophile is an ion, the products will be two ions. If the electrophile is a molecule, the products will be two molecules.
In either case, the nucleophile will end up bonded to the electron-deficient atom in the electrophile (usually carbon), and the electrons that were involved in the old bond will end up bonded to the electron-rich atom in the nucleophile (usually nitrogen, oxygen, or chlorine).
The organic product
The organic product of the nucleophilic substitution reaction is determined by the nature of the electrophile, the nucleophile, and the solvent. The products of the reaction can be either alkenes or alkynes.
The carbon-carbon bond
The most important thing to remember about drawing the organic product of the nucleophilic substitution reaction is that the carbon-carbon bond is not broken. The carbon atom that was bonded to the halogen (X) in the reactant molecule is still bonded to that same halogen in the product molecule.
The carbon-oxygen bond
In organic chemistry, a carbon–oxygen bond is a polar covalent bond between carbon and oxygen.
Carbon has 6 valence electrons, and oxygen has 6 valence electrons. When carbon and oxygen form a single bond, they each share one electron, so each atom has 4 unpaired electrons. This means that the carbon–oxygen bond is polar.
The electronegativity of oxygen is higher than that of carbon, so the electron pair is pulled closer to the oxygen atom. This creates a partial negative charge on the oxygen atom (δ−) and a partial positive charge on the carbon atom (δ+).
The carbon–oxygen bond can be formed by the oxidative addition of an organic compound to an organic substrate. The organic compound donates an electron pair to the π* molecular orbital of the organic substrate, forming a new σ-bond and a new π-bond between the two atoms.
The carbon-nitrogen bond
The carbon-nitrogen bond is one of the strongest bonds in organic chemistry. It is formed when the nitrogen atom shares a pair of electrons with the carbon atom. This bond is so strong that it is often used to form the backbone of complex molecules. The carbon-nitrogen bond is also responsible for the vast majority of the properties of organic compounds.
Conclusion
The nucleophilic substitution reaction is a type of organic reaction in which a nucleophile replaces another nucleophile in a molecule. The nucleophilic substitution reaction is one of the most important types of reactions in organic chemistry and is used extensively in synthetic organic chemistry.
