Organic Chemistry

1. Organic Chemistry The Chemistry of Carbon

2. Why call it Organic? • Fewer than 200 years ago, it was thought that only living organisms could synthesize carbon compounds. • So, they called carbon compounds “organic”

3. How can carbon form 4 bonds? • Carbon is in the 4th group on the periodic table. • This means carbon has 4 valence electrons. • Carbon will want to bond with 4 other atoms to achieve the octet rule.

4. Hydrocarbons • Hydrocarbons – any molecule that contains only hydrogen and carbon • Simple Hydrocarbons Methane and Ethane

5. Fats are Hydrocarbons

6. Group 1: Alkanes • Alkanes are hydrocarbons made of single bonds only. • Draw Methane • Draw Ethane • Draw Propane • Draw Butane

8. Branched Alkanes – Each branch is called a SUBSTITUENT.

9. Naming Branched Alkanes • Find the longest chain of carbons. • (8 – Octane)

10. Naming Branched Alkanes • Number the longest chain starting with the end that will give substituents the smallest numbers.

12. Naming Branched Alkanes • To name these substituents, start with the number. Add a dash. Add the type of substituent (drop the –ane ending and add the –yl ending) • 4-methyl, 4-ethyl, 5-propyl

13. Naming Branched Alkanes • Add prefixes to indicate that the same substituent appeared more than once. • If there were two methyl groups on carbon 4, we would put 4,4 dimethyl

14. Naming Branched Alkanes • List substituents in alphabetical order (ignore prefixes di, tri, tetra) • Combine all parts and use proper punctuation. Write the entire name without any spaces. Use commas to separate numbers and hyphens to separate numbers and words.

15. 4-ethyl-4-methyl-5-propyloctance

16. You Try!

17. 4-ethyl-2-methylhexane

18. Group 2: Alkenes • Alkenes are hydrocarbons that contain one or more double bonds. • The rules for naming is mostly the same, except for… • We drop the ending –ane and use –ene. • We use numbers to indicate the position of the double bond.

20. Group 3: Alkynes • Alkynes are hydrocarbons that contain one or more triple bonds. • The same rules apply with alkenes and alkynes. The only difference is that you drop the –ene ending and add –yne.

22. Isomers • Isomers - compounds that have the same molecular formula, but have different structures. • Example: • C4H10

23. Stereoisomers • Stereoisomers are molecules in which the atoms are joined in the same order, but the positions of the atoms in space are different.

24. Cis-Trans Isomers • Molecules with double bonds prevent rotating with respect to each other. • Because of this lack of rotation, the groups on either side of the double bond can have different orientations.

25. Cis-Trans Isomers • Cis Configuration • Similar groups are on the same side of the double bond.

26. Cis-Trans Isomers • Trans Configuration • Similar groups are on opposite sides of the double bond.

27. Cis-Trans Significance • Cis-Trans configurations have different physical and chemical properties.

29. Enantiomers • Enantiomers – Optical Isomers • Enantiomers have identical physical properties, but behave differently when they react. • Enantiomers have asymmetric carbons.

31. Why are some enantiomers more effective as medicines? • Substrates and enzymes must fit correctly (like puzzle pieces) for the enzyme to function correctly. Certain enantiomers work better than their mirror image.

32. Cyclic Hydrocarbons • Clycloalkane • Contains only single bonds

33. Aromatic Hydrocarbons • An aromatic compound contains a benzene ring.