1. In the previous list “n” stands for normal. In this case the bond is from the first carbon of the longest chain. Three other prefixes that occur commonly are: sec- short for secondary tert- short for tertiary iso (no hyphen is used) Examples: 2161 sec-butyl

2. In the previous list “n” stands for normal. In this case the bond is from the first carbon of the longest chain. Three other prefixes that occur commonly are: sec- short for secondary tert- short for tertiary iso (no hyphen is used) Examples: 2162 sec-butyltert-butyl

3. In the previous list “n” stands for normal. In this case the bond is from the first carbon of the longest chain. Three other prefixes that occur commonly are: sec- short for secondary tert- short for tertiary iso (no hyphen is used) Examples: 2163 sec-butyltert-butylisobutyl

4. The term isoalkane is used to denote a branched chain alkane with a methyl group attached to the penultimate carbon atom of the main chain. 2164

5. The term isoalkane is used to denote a branched chain alkane with a methyl group attached to the penultimate carbon atom of the main chain. As the number of carbon atoms increase, the prefixes become less useful, because an increasingly large number of prefixes would be needed. In this case, the standard numbering scheme (described about nine slides later) is used. 2165

6. Structures of some alkanes 2166

7. Structures of some alkanes 2167

8. Structures of some alkanes 2168

9. Structures of some alkanes 2169

10. Structures of some alkanes 2170

11. Structures of some alkanes These are straight chain examples. 2171

12. Structures of some alkanes These are straight chain examples. Note that the alkanes have only single bonds. 2172

13. Branched alkanes 2173

14. Branched alkanes 2174

15. Branched alkanes 4 3 2 1 2175

16. Branched alkanes 4 3 2 1 2-methylbutane (the 2 is a bit redundant) 2176

17. Branched alkanes 4 3 2 1 2-methylbutane (the 2 is a bit redundant) Number the longest chain so as to give the lowest number to the substituent (in this case a methyl group) off the main chain. 2177

18. 2178

19. 5 4 3 2 1 2179

20. 5 4 3 2 1 2,3-dimethylpentane 2180

21. 5 4 3 2 1 2,3-dimethylpentane There is more than one form of the preceding compound. We will discuss later how to name the different forms of this compound. 2181

22. 2182

23. Note: there is a methyl and an ethyl group off the main chain. 2183

24. 1 2 3 4 5 6 7 8 Note: there is a methyl and an ethyl group off the main chain. 2184

25. 8 7 6 5 4 3 2 1 5 and 6 bigger than 3 and 4 – so this is wrong numbering Note: there is a methyl and an ethyl group off the main chain. 2185

26. 1 2 3 4 5 6 7 8 Note: there is a methyl and an ethyl group off the main chain. 2186

27. 3-methyl-4-ethyloctane (complexity order) 1 2 3 4 5 6 7 8 Note: there is a methyl and an ethyl group off the main chain. 2187

28. 3-methyl-4-ethyloctane (complexity order) 4-ethyl-3-methyloctane (alphabetical order) 1 2 3 4 5 6 7 8 Note: there is a methyl and an ethyl group off the main chain. 2188

29. Summary of the simple rules to name an alkane. Summary of the simple rules to name an alkane. Prefix + root + suffix 2189

30. Ways of depicting an alkane 2190

31. The impact of free rotation about carbon – carbon single bonds. 2191

32. When assigning groups in alphabetical order, the prefixes are not considered. For example, for an alkane with an ethyl and two methyl groups as substituents, the ethyl substituent group is named first, followed by the dimethyl. E.g. 4-ethyl-2,2-dimethylnonane and not 2,2-dimethyl-4-ethylnonane 2192

33. When you have two (or more) alkyl substituents, number the longest chain in the direction that gives the smallest number to the first named substituent. E.g. 3-ethyl-5-methylheptane and not 3-methyl-5-ethylheptane (Draw out the structure) Where there are two or more longest chains of identical length, select the chain with the greater number of substituents. E.g. 3-ethyl-2-methylhexane and not 3-isopropylhexane (Draw out the structure) 2193

34. Exercises: Draw the structures of: (1) 2,2,3-trimethylbutane (2) 4-ethyl-2-methylnonane (3) 2,4-dimethyloctane 2194

35. Exercises: Draw the structures of: (1) 4-isopropyldecane (2) 2-methyl-4-(1-methylethyl)heptane (3) 4-isopropyl-2-methylheptane (4) 5-tert-butylnonane 2195

36. Physical properties of the alkanes The series of straight-chain alkanes shows a very smooth gradation of physical properties. As the series is ascended, each additional CH 2 group contributes a fairly constant increment to the boiling point and to the density – and to a lesser extent to the melting point. This makes it possible to estimate the properties of an unknown member of the series from those of its neighbors. 2196

37. Alkenes 2197

38. Alkenes These are hydrocarbons with at least one or more double bonds. 2198

39. Alkenes These are hydrocarbons with at least one or more double bonds. The parent alkanes are used to name the alkene family of compounds. 2199

40. Alkenes These are hydrocarbons with at least one or more double bonds. The parent alkanes are used to name the alkene family of compounds. The name ending change is: ane ene 2200

41. alkane alkene structure ethane ethene 2201

42. alkane alkene structure ethane ethene propane propene 2202

43. alkane alkene structure butane butene 2203

44. alkane alkene structure butane butene In this case there are three possible compounds. 2204

45. alkane alkene structure butane butene In this case there are three possible compounds. 1-butene 2205

46. alkane alkene structure butane butene In this case there are three possible compounds. 1-butene The number 1 indicates on which carbon the double bond starts. 2206

47. alkane alkene structure butane butene In this case there are three possible compounds. 1-butene The number 1 indicates on which carbon the double bond starts. 2- butene 2207

48. alkane alkene structure butane butene In this case there are three possible compounds. 1-butene The number 1 indicates on which carbon the double bond starts. 2- butene 2208

49. alkane alkene structure butane butene In this case there are three possible compounds. 1-butene The number 1 indicates on which carbon the double bond starts. 2- butene cis-2-butene trans-2-butene 2209

50. Z and E isomers Some cases arise in which it is very difficult to name a compound unambiguously, e.g. 2210

51. Z and E isomers Some cases arise in which it is very difficult to name a compound unambiguously, e.g. 2211

52. Z and E isomers Some cases arise in which it is very difficult to name a compound unambiguously, e.g. Is this a cis or trans compound? 2212

53. Z and E isomers Some cases arise in which it is very difficult to name a compound unambiguously, e.g. Is this a cis or trans compound? A way to sort out this problem is to use the symbols 2213

54. Z and E isomers Some cases arise in which it is very difficult to name a compound unambiguously, e.g. Is this a cis or trans compound? A way to sort out this problem is to use the symbols Z (zusammen = together) 2214

55. Z and E isomers Some cases arise in which it is very difficult to name a compound unambiguously, e.g. Is this a cis or trans compound? A way to sort out this problem is to use the symbols Z (zusammen = together) E(entgegen = opposite) 2215

56. Rules 1. Compare the two groups on one carbon atom of the carbon-carbon double bond. 2216

57. Rules 1. Compare the two groups on one carbon atom of the carbon-carbon double bond. 2. Assign the two groups priorities using the Cahn- Ingold-Prelog rules for R and S configurations. 2217

58. Rules 1. Compare the two groups on one carbon atom of the carbon-carbon double bond. 2. Assign the two groups priorities using the Cahn- Ingold-Prelog rules for R and S configurations. 3. Repeat steps 1 and 2 for the second carbon of the carbon-carbon double bond. 2218

59. Rules 1. Compare the two groups on one carbon atom of the carbon-carbon double bond. 2. Assign the two groups priorities using the Cahn- Ingold-Prelog rules for R and S configurations. 3. Repeat steps 1 and 2 for the second carbon of the carbon-carbon double bond. 4. If the two groups of highest priority are on the same side of the double bond, we have the Z isomer. If the two groups are on opposite sides we have the E isomer. 2219

60. Arrange the atoms in decreasing order of atomic number, e.g. I, Br, Cl, S, P, F, O, N, C, H 2220