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SN1 Reaction: First-Order Nucleophilic Substitution – When tert-butyl bromide is placed in boiling methanol, methyl tert butyl ether can be isolated from the reaction mixture. – Because this reaction takes place with the solvent acting as the nucleophile, it is called a solvolysis (solvo for “solvent,” plus lysis, meaning “cleavage”) …

Stereochemistry of the SN2 Reaction – As we have seen, the reaction SN2 requires attack by a nucleophile on the back side of an electrophilic carbon atom (see Figure) – A carbon atom can have only four filled bonding orbitals (an octet), so the leaving group must leave as the …

Reactivity of the Substrate in SN2 Reactions – We will often refer to the alkyl halide as the substrate: literally, the compound that is being attacked by the reagent. – Just as the nucleophile is important in the SN2 reaction, the structure of the alkyl halide is equally important. – …

Factors Affecting SN2 Reactions: Strength of the Nucleophile – we will discuss Factors Affecting SN2 Reactions especially Strength of the Nucleophile – We will use the SN2 reaction as an example of how we study the properties of the species that participate in the reaction. – Both the nucleophile and …

In this subject Second-Order Nucleophilic Substitution: The SN2 Reaction of Alkyl halides will be discussed Reactions of Alkyl Halides: Substitution and Elimination – Alkyl halides are easily converted to many other functional groups. – The halogen atom can leave with its bonding pair of electrons to form a stable halide …

Preparation of alkyl halides – Most Methods of preparation of alkyl halides exploit the chemistry of functional groups we have not yet covered. – For now, we review free-radical halogenation and only summarize other, often more useful, syntheses of alkyl halides. – The other Methods of preparation of alkyl halides …

Physical Properties of Alkyl Halides will be discussed such as dipole moment, London force, Dipole–dipole attractions, densities of common alkyl halides. Structure of Alkyl Halides – In an alkyl halide, the halogen atom is bonded to an carbon atom. – The halogen is more electronegative than carbon, and the bond …

Introduction to Alkyl Halides – In this subject , we consider Nomenclature of alkyl halides. – Our study of organic chemistry is organized into families of compounds classified by their functional groups. – We use alkyl halides to introduce substitution and elimination, two of the most important types of reactions …

Essential terms in Stereochemistry stereochemistry – stereochemistry is The study of the three-dimensional structure of molecules. – It is the systematic presentation of a specific field of science and technology that traditionally requires a short preliminary excursion into history. – Stereochemistry is the (chemistry of space). – In this subject …

Resolution of Enantiomers – Pure enantiomers of optically active compounds are often obtained by isolation from biological sources. – Most optically active molecules are found as only one enantiomer in living organisms. – For example, pure (+)-tartaric acid can be isolated from the precipitate formed by yeast during the fermentation …

What is Diastereomers? – We have defined stereoisomers as isomers whose atoms are bonded together in the same order but differ in how the atoms are directed in space. – We have also considered enantiomers (mirror-image isomers) in detail. – All other stereoisomers are classified as diastereomers, which are defined …

Meso Compounds – Compounds that are achiral even though they have asymmetric carbon atoms are called meso compounds. – The (2R,3S) isomer of 2,3-dibromobutane is a meso compound. – most meso compounds have this kind of symmetric structure, with two similar halves of the molecule having opposite configurations. – In …

Chiral Compounds without Asymmetric Atoms – Most chiral organic compounds have at least one asymmetric carbon atom. – Some compounds are chiral because they have another asymmetric atom, such as phosphorus, sulfur, or nitrogen, serving as a chirality center. – Some compounds are chiral even though they have no asymmetric …

Diastereomers – We have defined stereoisomers as isomers whose atoms are bonded together in the same order but differ in how the atoms are directed in space. – We have also considered enantiomers (mirror-image isomers) in detail. – All other stereoisomers are classified as diastereomers, which are defined as stereoisomers …

In this subject we will discuss How to draw Fischer projections Introduction to Fischer Projections – We have been using dashed lines and wedges to indicate perspective in drawing the stereochemistry of asymmetric carbon atoms. – When we draw molecules with several asymmetric carbons, perspective drawings become time consuming and …

Racemic Mixtures – Suppose we had a mixture of equal amounts of (+)-butan-2-ol and (-)-butan-2-ol – The (+) isomer would rotate polarized light clockwise with a specific rotation of +13.5o ,and the isomer (-) would rotate the polarized light counterclockwise by exactly the same amount. – We would observe a …

Biological Discrimination of Enantiomers – If the direction of rotation of polarized light were the only difference between enantiomers, one might ask whether the difference would be important. – Biological systems commonly distinguish between enantiomers, and two enantiomers may have totally different biological properties. – In fact, any chiral probe …

– Rotation of the plane of polarized light is called optical activity, and substances that rotate the plane of polarized light are said to be optically active. – There are alot of Organic Compounds have optical activity Introduction to Optical activity Mirror-image molecules have nearly identical physical properties. Compare the …

(R) and (S) Nomenclature of Asymmetric Carbon Atoms – Alanine is one of the amino acids found in common proteins. – Alanine has an asymmetric carbon atom, and it exists in two enantiomeric forms. – These mirror images are different, and this difference is reflected in their biochemistry. – Only …

What is Chirality? – What is the difference between your left hand and your right hand? They look similar, yet a left-handed glove does not fit the right hand. – The same principle applies to your feet. They look almost identical, yet the left shoe fits painfully on the right …