Continuing on our journey, we move to ketones and their formation. You will soon see that ketones are great electrophiles and are very useful in organic synthesis. One of the very effective ways to make a ketone is through ozonolysis. Ozonolysis uses ozone as the oxidizing agent to break up a double bond. The generic reaction is shown below.
The mechanism for this reaction is not intuitive. It moves through two intermediates referred to as ozonides. The reaction starts when the double bond attacks ozone, as in this reaction ozone is the electrophile. The first intermediate formed is the primary ozonide. This rearranges to form a secondary ozonide, which falls apart to give the main product which are the ketones. Some professors will want you to know this mechanism, but most others will probably say it is too complicated for undergraduate work. 
The reaction is quite useful for making ketones and aldehydes, but one should be careful on their exams using this reaction. As you can see in the reaction below, asymmetric alkenes give two different carbonyl products which can be difficult to separate from each other. On your exam and in the laboratory the best use of this reaction is on symmetric alkenes which only give one product.
Dr. Michael Pa
Dr. Michael Pa got a bachelors degree in chemistry from Binghamton University, a masters degree in organic chemistry from the University of Arizona and a Ph.D. in organic chemistry from the University of Arizona. His research focus was on novel pain killers which were more potent than morphine but designed to have fewer side effects. There may even be a patent or two that came out of it. Prior to all of this, he was a chemist at Procter and Gamble. After all of that, he (briefly) worked as a post-doctoral assistant at Syracuse University, working on novel organic light-emitting diodes (OLEDs). In between, he did NOT compete at the 1996 Olympics, make the Atlanta Braves opening day roster, or become the head coach of the Indiana Pacers, as he had intended. #fail During this entire time, he always loved helping students, especially if they were struggling with organic chemistry. In 2006, Dr. Pa founded AceOrganicChem.com in order to make learning organic chemistry fast and easy. 14 years and about 60,000 students later we are still helping students to learn organic chemistry one reaction at a time at https://www.aceorganicchem.com
