Faculty of Allied Medical Sciences Organic chemistry (MGOC-101)
Alkenes Supervision: Prof.Dr.Shehata El-Sewedy Dr. Fatma Ahmed
Outcomes By the end of this lecture, the students will be able to 1-Recognize formula of alkenes 2-Knownnomenclature of alkenes 3- learn to preparation of alkenes 4-Differentiate between reaction of alkenes
Alkenes 1-Alkenes are fully unsaturated hydrocarbons • 2-General formula C2H2n • 3-Double bonds (-C=C-) • 4-Straight or branched chain.
Nomenclature • 1-Common name • Alkyl +ene • (Prefix) 2-IUPAC name 1-Select the long continuous chain which contain c=c as parent name (alkyl+ene) or (prefix+ene) 2-Number the chain from side which give lowest number for c=c 3-Priority of numbering must be considered 4-The position of C=C must write 5-The name& position of substituent must write 6-For similar substituent add di, tri or tetra
EX: √√√ XXX √√√ xxx
Preparation of alkene Dehydration of alcohol
Reaction of alkene (1) Addition of Hydrogen Halidesto Alkenes Eample 2-Butene 2-Chlorobutane
(80%) (20%) Addition to an Unsymmetrically substituted alkenes according for Markovnikov’s Markovnikov’s Rule: In the addition of HX to an alkene, the H attaches to the carbon with fewer alkyl groups and X attaches to the carbon with more alkyl groups.
(I) (II) Explanation for “Markovnikov’s rule” The stabilities of carbocation: (I) > (II) Electrophilic addition to an unsymmetri- cally substituted alkene give the more highly substituted carbocation.
(2) Addition of Halogen to Alkenes Vicinal dihalide (3) Oxidative cleavage of alkenes: Ozonolysis of Alkenes
Complete How can you prepare the following compound? , Vicinal dihalide , 2-Chlorobutane Write the chemical formula for the following compounds?
Write the nomenclature for the following compounds? Show more stable compound of (I) & (II) and why?
How can you prepare the following compound? , 2-Chlorobutane , Vicinal dihalide Write the chemical formula for the following compounds? Complete
Recommended textbooks: 1-Raymond Chang. Chemistry: An introduction to organic chemistry. 10th ed. 2009 2008 2-Zumdehl. Organic Chemistry; study guide and solution manual. 2008