Presentation on theme: "University of Victoria CHEM 232 ORGANIC CHEMISTRY with BIOLOGICAL APPLICATIONS Course website: web.uvic.ca/~chem232 (postings of course information, midterm."— Presentation transcript:
WileyPlus 1.Purchase of WileyPlus is required to access the online quizzes for this course. We have negotiated a discounted package price that also includes the e-text, e-solutions manual, and the lecture book. 2.There are 7 online quizzes that covers the major chapters of this course. It is worth a total of 7% of your course mark. The quizzes can be written anytime before the end of the last day of classes. 3.The online quizzes should be regarded as minimal preparation for this course. You should also do the assigned problems, past midterms and final exams, etc. 4.Plan ahead 4.Plan ahead: no excuse will be accepted for failure to complete the quizzes by the end of the term. 5.WileyPlus is also more than a place to do your quizzes. It has extensive resources such as the e-text, video presentations, sample lectures, worked out problems, etc. Check it out! 6.Your access code for WileyPlus is good for one academic year. You can use the same code purchased for Chem 231 in September 2013.
Learning Organic Chemistry 1.It is not possible to learn every facet of organic chemistry but key is know what you need to know. 2. Persistence, repetition, and practice are necessary. You may not understand it the first time. Do the practice problems. 3. Some problems in organic chemistry have exact solutions; others have more than one correct answer. 4. Organic chemistry is based on a relatively small number of basic principles that must be mastered. The diversity of structures and reactions also present a challenge. 5. The aim is to teach you to recognize, understand, manipulate, and build organic compounds. DRAWING molecules in one form or another is essential. 6. The 3D nature of molecules (STEREOCHEMISTRY) present another challenging aspect of organic chemistry. A molecular model set will help immensely.
Organic Chemistry can be conveniently divided into four main subtopics: 1.Structures 1. Structures 2. Reactions 3. Mechanisms 4. Synthesis There will be something in organic chemistry that will interest you, if not now, then certainly later. Be optimistic about this and you will find a reason to engage yourself.
13. CONJUGATED UNSATURATED SYSTEMS. ( approx. lecture time: 2 lectures) Topics covered: , How to Spot Conjugated Systems: A conjugated system involves at least one atom with a p z -orbital bonded (adjacent) to at least one bond. Cinnamaldehyde responsible for the taste and odour of cinnamon spice.
If you can draw at least one good resonance structure involving a double bond and an adjacent atom (or atoms), it usually means it is conjugated conjugated systems are very common and important in organic chemistry
The Importance of Conjugated Systems Conjugated dienes (or conjugated polyenes) are thermodynamically more stable than isomeric isolated alkenes. This has major consequences in their structure and reactivity! This is conjugated. It is lower in energy than two separate alkenes.
Graphene: The Ultimate Conjugated System 1.One of the most exciting materials to be discovered since C60. Nobel Prize in Physics (2010) 2.Geim and Novoselov received the Nobel Prize in Physics (2010) for ground-breaking experiments with graphene. 3.One of the strongest materials known; 200 times stronger than steel, with many possible uses including new mechanical materials and in computer chips, etc. (The organic compound from pencils that seems to do everything)
A better picture of bonding in conjugated systems requires Molecular Orbital (MO) Theory According to this molecular orbital, there is a bond between any two adjacent atoms!
The Allyl System is the Simplest Conjugated System Possible (The MOs shown below are the lowest energy ones) The allyl system can be a radical, a cation, or a carbanion!
Reactions that generate conjugated systems are easier (faster) compared to similar reactions that lack the conjugation Which reaction will be the fastest?
But reactions of conjugated systems are more complex!
Principle of Kinetic vs Thermodynamic Control Which pathway is for kinetic control? Which is for thermodynamic control?
The Diels-Alder Reaction
Thermodynamic product (major product at high temp when reaction is taken to equilibrium) Exo vs Endo Products (It is easiest to see exo and endo products with the [2,2,1] system) Kinetic product (product formed fastest and is major product at room or low temperature) diastereomers
Exo vs Endo Products (The hardest part about the Diels-Alder reaction is to be able to draw and recognize exo and endo products) Exo Endo
Exo vs Endo Products
"for the discovery of the Diels-Alder reaction for making carbocyclic rings that has immense utility in organic chemistry ” Otto Diels Kurt Alder The Nobel Prize in Chemistry 1950 The dimerization of cyclopentadiene via the Diels-Alder reaction