ORGANIC CHEMISTRY II

The course aims to provide a critical and scientific mentality and rational use of mnemonic abilities, favoring the ability to apply theoretical knowledge to problem-solving.

This means overcoming the limit of mere "mnemonic repetition" of concepts that, in doing so, would be aimed at simple learning. Critical and scientific mentality at the same time constitute a high-level objective; it requires a synthesis between mental operation and actual realization: the first is expressed in the design of an experiment, in the rational-intuitive control of the execution and calculation phases and the evaluation phase of the results; the second is expressed in the actual execution of the experiment, even at the virtual level.

Therefore, at the end of the course, the student must be able to:

D1 KNOWLEDGE AND UNDERSTANDING ABILITY

• Know in-depth the reactivity of new classes of organic compounds and the reaction mechanisms through which they react.

• Illustrate the criteria that allow to carry out processes with a pronounced chemical, position, and stereochemical selectivity.

D2 ABILITY TO APPLY KNOWLEDGE AND UNDERSTANDING

• Identify the nature of the synthetic process to which the organic molecules are subjected based on the described reaction conditions.

• Correctly describe the reaction mechanism for the related processes.

• Discuss the nature of the selective processes that these mechanisms involve.

D3 AUTONOMY OF JUDGMENT

• Choose the most suitable reagents to carry out the required synthetic process with the desired selectivity degree.

• Use the most efficient method available to perform the synthesis of even multi-functionalized structures.

D4 COMMUNICATION SKILLS

• Communicate, using appropriate technical-scientific terminology, with the teacher and experts in the subject of study.

• Competently discuss, even in the context of an oral examination, the synthetic techniques learned.

D5 LEARNING SKILLS

• Find and learn the information, new compared to those provided during the training activity, necessary to broaden the knowledge on topics more or less correlated with those covered by the course.

• Understand and process the contents of scientific publications containing the results of new research.

• Use the knowledge acquired to make it easier to understand topics related to organic chemistry delivered in other educational activities.

The course activities consist of lectures and classroom exercises. To these will be added some "case studies" concerning molecules of chemical-pharmaceutical interest. The student is required to actively participate in the discussion of the topics presented and in particular, in the case studies.

MODULE 1. BIO-ORGANIC COMPOUNDS

20. THE ORGANIC CHEMISTRY OF CARBOHYDRATES

Classification of carbohydrates - The notation D and L - Configuration of aldoses - Configuration of ketoses - Reactions of monosaccharides in basic solution - Oxidation-reduction reactions of monosaccharides - Chain elongation: Kiliani-Fischer synthesis - Chain shortening: degradation of Wohl - Stereochemistry of glucose: the Fischer demonstration - Monosaccharides form cyclic hemiacetals - Glucose is the most stable among aldohexose - Glycosides formation - The anomeric effect - Reducing and non-reducing sugars - Disaccharides - Polysaccharides - Some natural products derived from carbohydrates - carbohydrates on the cell surface - synthetic sweeteners.

21. AMINO ACIDS, PEPTIDES, AND PROTEINS

Amino acid nomenclature - Amino acid configuration - Acid-base properties of amino acids - The isoelectric point - Amino acid separation - Amino acid synthesis methods - Resolution of a racemic amino acid mixture - Peptide bonds and disulfide bonds - Some interesting peptides - Synthesis strategies peptide - Automated peptide synthesis - Introduction to protein structure - How to determine the primary structure of a polypeptide or protein.

22. CATALYSIS IN ENZYMATIC REACTIONS

Catalysis in biological reactions - An enzymatic reaction similar to the hydrolysis of acid-catalyzed amides - Another enzymatic reaction similar to the hydrolysis of acid-catalyzed amides - An enzymatic reaction that involves two successive SN2 reactions - An enzymatic reaction similar to the transposition enediolic catalyzed by bases - An enzymatic reaction similar to the retro-aldol reaction.

MODULE 2. SPECIAL TOPICS

12. RADICALS

Reactivity of alkanes - Natural gas and oil - Fossil fuels: a source of problematic energy - Chlorination and bromination of alkanes - Stability of radicals - Distribution of products depends on probability and reactivity - The principle of reactivity-selectivity - Training of explosive peroxides - Addition of radicals to alkenes - Stereochemistry of radical substitution and addition reactions - Radical substitution of allyl and benzyl hydrogens - Cyclopropane - SYNTHETIC STRATEGY III: Examples of multi-stage synthesis - Radical reactions in biological systems - Radicals and stratospheric ozone.

19/29/30. CHEMISTRY OF HETEROCYCLIC COMPOUNDS AND AROMATIC HETEROCYCLES

Classification of aromatic heterocycles - Heteroaromaticity - Electrophilic substitution: general aspects - Electronic systems: pentatomic heterocycles containing only one heteroatom - Preparation: Paal-Knorr synthesis of furan, pyrrole and thiophene - Synthesis of pyrrole Knorr - Synthesis of Feist-Bernary del furan and pyrrole Hantzsch synthesis - Reactivity: Acid-base, electrophilic substitution, addition and cycloaddition, oxidation and reduction reactions - Electron systems: benzocondensed pentatomic heterocycles containing only one heteroatom - Preparation: Fischer synthesis of indole - Reactivity: Acid-base, electrophilic substitution, oxidation and reduction reactions - Electron poor systems: exatomic heterocycles containing only one heteroatom - Preparation: Hantzsch synthesis of pyridine - Reactivity: Acid-base reactions, Nitrogen reactions with electrophiles , Electrophilic replacement reactions , of nucleophilic substitution, of oxidation and reduction - Pyridine N-oxide and electrophilic substitution - Electron-poor systems: benzocondensed heterocyclic heterocycles containing only one neutral heteroatom - Preparation: Skinup synthesis of quinoline, Isochinoline Bischler-Napieralski synthesis - Reactivity: Main reactions.

27. SYNTHETIC POLYMERS

There are two main classes of synthetic polymers - Introduction to polymers for chain growth - Radical polymerization - Teflon: an accidental discovery - Recycling codes - Cationic polymerization - Anionic polymerization - Polymerization with ring-opening - Stereochemistry of polymerization • catalysts of Ziegler-Natta - Polymerization of dienes - Copolymers - Nanocontainers - Introduction to polymers for staged growth - Classes of polymers for staged growth - Health concerns: bisphenol A and phthalates - Designing a polymer - Physical properties of polymers - Melamine poisoning - Polymer recycling - Biodegradable polymers

28/34/35. PERICYCLIC REACTIONS

The three types of pericyclic reactions: Electrocyclic reactions, of cycloaddition and sigmatropic transpositions - Molecular orbitals and orbital symmetry - Electrocyclic reactions - Cycloaddition reactions - Sigmatropic transpositions - Pericyclic reactions in biological systems - Bioluminescence - Sun vitamin - Animals, birds, fish and vitamin D - Summary of selection rules for pericyclic reactions. A new sort of reaction – General description of the Diels-Alder reaction – The frontier orbital description of cycloadditions – Regioselectivity in Diels-Alder reactions – The Woodward-Hoffmann description of the Diels-Alder reaction – Trapping reactive intermediates by cycloadditions – Other thermal cycloadditions – Photochemical [2 + 2] cycloadditions – Thermal [2 + 2] cycloadditions – Making five-membered rings: 1,3-dipolar cycloadditions – Two very important synthetic reactions: cycloaddition of alkenes with osmium tetroxide and with ozone – Sigmatropic rearrangements – Orbital descriptions of [3,3]-sigmatropic rearrangements – The direction of [3,3]-sigmatropic rearrangements – [2,3]-Sigmatropic rearrangements – [1,5]-Sigmatropic hydrogen shifts – Electrocyclic reactions.

36. Participation, rearrangement, and fragmentation

Neighboring groups can accelerate substitution reactions – Rearrangements occur when a participating group ends up bonded to a different atom – Carbocations readily rearrange – The pinacol rearrangement – The dienone-phenol rearrangement – The benzylic acid rearrangement – The Favorskii rearrangement – Migration to oxygen: the Baeyer–Villiger reaction – The Beckmann rearrangement – Polarization of C–C bonds help fragmentation – Fragmentations are controlled by stereochemistry – Ring expansion by fragmentation – Controlling double bonds using fragmentation – The synthesis of nootkatone: fragmentation showcase.

38. Synthesis and reactions of carbenes

Diazomethane makes methyl esters from carboxylic acids – Photolysis of diazomethane produces a carbene – How do we know that carbenes exist? – Ways to make carbenes – Carbenes can be divided into two types – How do carbenes react? – Carbenes react with alkenes to give cyclopropanes – Insertion into C–H bonds – Rearrangement reactions – Nitrenes are the nitrogen analogues of carbenes – Alkene metathesis.

11/40. Organometallic chemistry of palladium, boron, tin, rhodium, and ruthenium

Palladium-catalyzed coupling reactions - Alkenes metathesis - Grubbs, Schrock, Suzuki, and Heck receive the Nobel prize – Transition metals extend the range of organic reactions – The 18 electron rule – Bonding and reactions in transition metal complexes – Palladium is the most widely used metal in homogeneous catalysis – The Heck reaction couples together an organic halide or triflate and an alkene – Cross-coupling of organometallics and halides – Allylic electrophiles are activated by palladium(0) – Palladium-catalyzed amination of aromatic rings – Alkenes coordinated to palladium(II) are attacked by nucleophiles – Palladium catalysis in the total synthesis of a natural alkaloid – An overview of some other transition metals.

39. Determining reaction mechanisms

There are mechanisms and there are mechanisms – Determining reaction mechanisms: the Cannizzaro reaction – Be sure of the structure of the product – Systematic structural variation – The Hammett relationship – Other kinetic evidence for reaction mechanisms – Acid and base catalysis – The detection of intermediates – Stereochemistry and mechanism – Summary of methods for the investigation of mechanism.

MODULE 3. Retrosynthesis and Stereoselectivity

28. Retrosynthetic analysis

Creative chemistry – Retrosynthetic analysis: synthesis backward – Disconnections must correspond to known, reliable reactions – Synthons are idealized reagents – Multiple-step syntheses: avoid chemoselectivity problems – Functional group interconversion – Two-group disconnections are better than one-group disconnections – C–C disconnections – Available starting materials – Donor and acceptor synthons – Two-group C–C disconnections – 1,5-Related functional groups – “Natural reactivity” and “umpolung”.

31. Saturated heterocycles and stereoelectronics

Introduction – Reactions of saturated heterocycles – Conformation of saturated heterocycles – Making heterocycles: ring-closing reactions – Ring size and NMR – Geminal (²J) coupling – Diastereotopic groups.

32. Stereoselectivity in cyclic molecules

Introduction – Stereochemical control in six-membered rings – Reactions on small rings – Regiochemical control in cyclohexene epoxides – Stereoselectivity in bicyclic compounds – Fused bicyclic compounds – Spirocyclic compounds – Reactions with cyclic intermediates or cyclic – transition states.

33. Diastereoselectivity

Looking back – Prochirality – Additions to carbonyl groups can be diastereoselective even without rings – Stereoselective reactions of acyclic alkenes – Aldol reactions can be stereoselective – Single enantiomers from diastereoselective reactions

41. Asymmetric synthesis

Nature is asymmetric – The chiral pool: Nature’s chiral centres “off the shelf” – Resolution can be used to separate enantiomers – Chiral auxiliaries – Chiral reagents – Asymmetric catalysis – Asymmetric formation of carbon-carbon bonds – Asymmetric aldol reactions – Enzymes as catalysts.

1. Organic Chemistry – P. Y. Bruice – 8ª Ed. Pearson.
2. Organic Chemistry – J. Clayden, N. Greeves, and S. Warren – 2^nd Ed. Oxford University Press.
3. Solutions Manual to Accompany Organic Chemistry – J. Clayden, N. Greeves, and S. Warren – 2^nd Ed. Oxford University Press.