In the Chemical Reactions category, explore the captivating world of molecular transformations. Witness the extraordinary processes that occur when substances interact, leading to new substances with unique properties. Unravel the mysteries of exothermic and endothermic reactions, oxidation and reduction, and the intricacies of reaction kinetics. Unlock the secrets of chemical transformations today.
What are reactions on the pyridine substituents? The reactions on pyridine substituents are those that instead of taking place on the same ring of the heterocycle, take place on the substituents of the ring producing an functional group interconversion (FGI). Reactions on alkyl groups These alkyl groups undergo the same reactions as those attached to … Read more
What is the mechanism of a chemical reaction? The reaction mechanism is the detailed step-by-step description of the transformation of reactants into the corresponding products in a chemical reaction. The description should include the movement of electrons that takes place by means of curved arrows, the formal charge associated with the atoms involved in the … Read more
What are pericyclic reactions? Pericyclic reactions are concerted reactions in a single step (therefore they are not radical reactions involving several steps), and as the name indicates, they occur in a process in which the transition state presents a closed loop of interacting electrons, so that the shape of this loop implies special characteristics of … Read more
What is nucleophilic substitution (SN1 and SN2)? Nucleophilic substitution (SN1 and SN2) is probably one of the most versatile reactions in Organic Synthesis, since it allows to obtain a great variety of functions. The general scheme of the reaction is as follows: where L is the so-called leaving group and Nu a nucleophile. The C–L … Read more
What is elimination (E1 and E2)? As in substitution reactions, elimination reactions follow two distinct mechanisms called E1 and E2. Elimination E1 In reaction E1, the reaction rate depends only on the substrate concentration. The mechanism of the reaction is similar to that of SN1, with the difference that the intermediate carbocation evolves towards the … Read more
Introduction In the following, pericyclic reactions are described from an applications point of view. That is, we will see practical examples of these reactions aimed at demonstrating that pericyclic reactions occur and preferentially versus the non-pericyclic alternative. Moreover, it is approached from an experimental and not a theoretical point of view. We try to obtain … Read more
What are cheletropic reactions and group transfer reactions? They are cycloaddition reactions, however, one of the systems involved is an atom. Normally these reactions are observed in cases of cycloreversion rather than cycloaddition reactions. For example, in this reaction an orbital with a pair of sulfur electrons is involved and so this is actually a … Read more
What are cycloaddition reactions? In cycloaddition reactions, as the name implies, a cyclic system is generated from the various components. They are usually named with numbers indicating the π electrons of each component. An example would be the two ethylene molecules to form cyclobutane: This reaction would be a case of a 2+2 reaction, since one … Read more
What are electrocyclic reactions? Electrocyclic reactions are characterized by the opening or closing of a ring within a single molecule by interconversion of σ bonds into π or vice versa. Typical examples of electrocyclic reactions are: This would be an allyl cation delocalized between the three centers. Where we can also make a simile of … Read more
They are characterized by a bond migrating along a p-system to another position in the molecule. Thus, the nomenclature proposed by Woodward-Hoffmann for sigmatropic transposition reactions uses two numbers in square brackets indicating the positions to which the ends of the s-bond migrate. Suppose the transposition of an R group, where the C-R bond migrates along … Read more
