69074 - Organic Chemistry I

Learning outcomes

At the end of the course, the student is able to predict the chemical behavior of monofunctional organic compounds and to solve problems related to the practical application of synthesis and transformation methodologies for simple organic molecules.

Course contents

Prerequisites

Students are expected to have a solid understanding of the fundamental principles of general chemistry, with particular emphasis on: atomic structure and the Periodic Table; nature of chemical bonding; principles of chemical equilibrium and basic kinetics/thermodynamics of chemical reactions; acid-base reactions. Intermediates and transition states; reaction energy diagrams. Meaning of activation energy and the concept of catalysis.

Course Content

Introduction
Definition, relevance, and limitations of Organic Chemistry. Review of chemical bonding. Bonding and antibonding molecular orbitals. Bond energy and bond length. Resonance. Electronegativity, bond polarity, and molecular dipoles. Carbon as the central element of Organic Chemistry.

1) ALKANES and CYCLOALKANES

1.1) Structure: Hybrid orbitals and molecular geometries. Sigma bonds (C-H and C-C) and structure of alkanes. Concept of isomerism. Nomenclature of alkanes. Cycloalkanes. Physical properties. Sources and significance. Conformations of linear alkanes. Structure and conformations of 3-, 4-, 5-, and 6-membered rings. Chair and boat conformations of cyclohexane: axial and equatorial bonds. Ring flip. Substituted cyclohexanes. Cis/trans isomerism in cyclic compounds.

1.2) Reactivity: Combustion and energy use; greenhouse gases and climate change; brief mention of environmental issues in chemistry. Halogenation of alkanes: mechanism and selectivity. Radical stability and hyperconjugation. Allylic halogenation.

 

2) ORGANIC REACTIVITY

 Elementary reaction mechanisms. Bond formation and cleavage via one- or two-electron processes. Nucleophiles, electrophiles, radicals. Types of reactions: substitution, addition, elimination, rearrangement. Oxidation and reduction in organic chemistry. Concept of "functional group oxidation state." Mechanistic representation in organic chemistry.

3) STEREOCHEMISTRY
Molecular chirality and enantiomerism. Representations and Fischer projections. C.I.P. system. Enantiomerism and optical rotation. Racemic mixtures. Compounds with one or more stereocenters. Diastereomerism and meso forms. Importance of chirality.

 

4) ALKENES, CYCLOALKENES, DIENES, AND POLYENES

4.1) Structure and properties: C=C π bonds. Structure and nomenclature. Physical properties. E/Z isomerism. Types of polyenes (isolated, conjugated, cumulated). Stability of polyenes. Structure of allenes. Electronic structure of conjugated dienes: HOMO and LUMO. Interaction of alkenes with electromagnetic radiation; brief mention of the visual process.

4.2) Reactivity: Electrophilic addition to C=C double bonds; mechanism, regioselectivity, carbocation stability and rearrangements. Addition of hydrogen halides. Acid-catalyzed hydration and alcohol addition; oxonium ions. Halogenation and halohydrin formation. 1,2- and 1,4-addition to conjugated dienes. Allylic resonance. Kinetic vs. thermodynamic control. Hydroboration and oxidation. Catalytic hydrogenation. Radical addition of HBr. Oxidations: epoxidation and dihydroxylation (mechanism, stereochemistry). Ozonolysis: mechanism and ozonide conversion.

5) ALKYNES

5.1) Structure and properties: C≡C triple bonds, structure and nomenclature.

5.2) Reactivity: Electrophilic additions: single and double addition of HX, alcohols, and halogens. Acid-catalyzed hydration and keto-enol tautomerism. Hydrogenation and partial hydrogenation. Reduction with solvated electrons. Hydroboration, protonolysis, and oxidation of alkenylboranes. Acidity of C-H bonds. Acetylide anions and their reactivity.

6) ALKYL/ARYL HALIDES
Structure and properties: C–X sigma bonds. Nomenclature and physical properties.
Reactivity: Nucleophilic substitution and β-elimination: SN2 and SN1 mechanisms. Nucleophile examples. Leaving groups (halides, sulfonates, sulfates, phosphates). Influence of substrate structure and reaction conditions. Carbocation stability. Stereochemistry of substitution. E2 and E1 eliminations. Alkene stability and regioselectivity.

7) ORGANOMETALLIC REAGENTS

Synthesis and reactivity of organolithium compounds and organomagnesium compounds.

 

8) AROMATIC COMPOUNDS

8.1) Structure and property: Nomenclature. Structure and stability of benzene (regola di Hückel). Aromatic ions. Heteroaromatic compounds: pyrrole (thiophene and furan) and pyridine. Polycyclic aromatic compounds.

8.2) Reactivity: Electrophilic aromatic substitution. Halogenatio, alchilation and acylations (Friedel-Crafts reactions). Aromatic nitration. Aromatic sulfonation. Electronic effets (inductive and resouncance)of the substituents in the electrophilic substitutions.  Nucleophilic aromatic substituttions. Reactivity on alkylic side-chains of aromatic compounds (radicalic halogenation, oxydation, reduction).

9) ALCOHOLS/ETHERS and THIOLS/THIOETHERS

 
9.1) Structure and properties: Sigma bonds (C–O and C–S). Structure of alcohols, thiols, ethers, sulfides. Nomenclature. Hydrogen bonding. Physical properties of alcohols and ethers. Solvents in organic chemistry.

9.2) Reactivity: Acidity/basicity of alcohols and thiols. Alkoxides and their reactivity. Nucleophilic substitutions on alcohols. Conversion of alcohols to alkyl halides. Formation and substitution of sulfonates. Alcohol dehydration to alkenes. Oxidation of alcohols and diols. Chemoselectivity in primary alcohol oxidation. Toxicity of reagents and an introduction to Green Chemistry. Oxidation of thiols. Williamson ether synthesis and its limitations. Acid-catalyzed ether synthesis. Silyl ethers. Nucleophilic substitutions on ethers. Nucleophilic additions to epoxides under SN1 and SN2 conditions. Sulfide oxidation.

10) AMINES
10.1) Structure and properties: C–N sigma bonds. Nomenclature and physical properties of amines and ammonium ions.

10.2) Reactivity: Basicity and nucleophilicity. Alkylation with alkyl halides and epoxides. Quaternary ammonium salts. Hofmann and Cope eliminations. Synthesis of amines via azides.

11) CARBONYL COMPOUNDS

11.1) Structure and properties: C=O π bonds and structure of the carbonyl group. Nomenclature and physical properties of aldehydes and ketones. C=N π bonds and imine structure. Structure of acyl-containing compounds. Nomenclature and properties of carboxylic acids, carboxylates, acyl halides, anhydrides, esters, thioesters, and amides. C≡N triple bond: structure, nomenclature, and properties of nitriles.

11.2) Reactivity: General reactivity of carbonyl compounds. Nucleophilic addition mechanisms. Basicity and acid catalysis of carbonyls. Organometallic compounds of Mg and Li: structure and addition to C=O and C=N. Complex hydride addition and hydroboration. Catalytic hydrogenation. Addition of weak nucleophiles: water, alcohols, amines. Acetal formation. Imine synthesis. Imine reduction and reductive amination. Enamine, hydrazone, and oxime formation. Aldehyde oxidation.

 

12) CARBOXYLIC ACID COMPOUNDS

12.1) Structure and properties: C=O(X) π bonds and carboxyl group structure. Nomenclature and physical properties of carboxylic acids and derivatives.

12.2) Reactivity: Acidity of carboxylic acids. Nucleophilic acyl substitution mechanisms and relative reactivity/stability. Reactions of acyl halides and anhydrides. Conversion of acids to acyl chlorides. Acid esterification. Acidic/basic hydrolysis of esters. Transesterification. Reactivity of thioesters. Ester aminolysis. Amination of carboxylic acids. Acidic/basic hydrolysis of amides. Nitrile synthesis and hydrolysis. Reduction of acids, esters, amides, nitriles. Organometallic addition to esters and nitriles.

Readings/Bibliography

Most comprehensive university-level Organic Chemistry textbooks are generally valid. Below are some suggested texts.

1. K. Peter, C. Vollhardt, N.E. Schore, "Chimica Organica", Zanichelli, Bologna, (IV edition).

2. W.H. Brown, B.L. Iverson, E.V. Anslyn, C.S. Foote, "Chimica Organica" EdiSES, Napoli (VI edition).

3. T.W.G. SOLOMON, C.B. Fryhle, "Chimica Organica", Zanichelli, Bologna (III edoition).

Teaching methods

Lectures with video projection.
Classroom exercises carried out collectively.

Assessment methods

Written exam.
(No oral examination is предусмотрed.)

The exam consists of a written test (in-person) comprising 10 open-ended questions, each worth between 2 and 5 points.

Duration of the exam: 90 minutes.

The exam is considered passed if the student achieves an overall score greater than or equal to 18/30.

The aim of the exam is to verify the achievement of the following learning objectives: (i) familiarity with the logic, concepts, and tools of organic chemistry; (ii) ability to write, recognize, name, and predict the properties and reactivity of organic molecules; (iii) ability to rigorously and clearly describe the mechanisms of organic reactions; (iv) ability to use the above concepts to solve simple problems related to synthetic strategies, reactivity, and the structure of organic molecules.

An overall unsatisfactory evaluation (grade < 18/30) is determined by significant gaps in the course content, resulting in failure to answer the questions of the written/oral test or in inadequate answers.

An overall sufficient–fair evaluation (18–24/30) indicates an overall acceptable level of preparation, although significant knowledge gaps remain or some topics have not been studied adequately.

An overall good evaluation (25–28/30) indicates that the student has achieved a good knowledge of the course content and a good ability to make connections between the various parts of the syllabus.

An excellent evaluation (29–30/30 with honors) indicates a complete and in-depth preparation covering the entire course syllabus, with a clear and coherent overall understanding.

 

Students with learning disorders and\or temporary or permanent disabilities: please, contact the office responsible (https://site.unibo.it/studenti-con-disabilita-e-dsa/en/for-students ) as soon as possible so that they can propose acceptable adjustments. The request for adaptation must be submitted in advance (15 days before the exam date) to the lecturer, who will assess the appropriateness of the adjustments, taking into account the teaching objectives.

A group review session is scheduled for each exam session.

Teaching tools

The slides will be provided to the students. There are no comprehensive monographs available on the market that cover all the topics of the course. Course organization: all hours, both theoretical lessons and practical exercises, will be held in person in the classroom. 

 

Office hours

See the website of Marco Bandini