Compounds with 2 double bonds are called dienes,3 double bonds are trienes,etc. CH2=CH一CH一CH CH:-CH-CH-CH-CH-CH-CH, old IUPAC names 1.3-butadiene 1.3.5-heptatriene 1.3.5.7-cyclooctatetraene new IUPAC names: buta-1,3-diene hepta-1.3.5-triene cycloocta-1,3.5.7-tetraene For branches,each alkyl group is given a number,but the double bond is still given preference when numbering the chain. 2 CH;-CH-C-CH3 CH;-CH-CH-CH2 CH:-CH-C-CHz-CH2-CH-CH3 CH3 CH3 CH3 CH 2-methyl-2-butene 3-mcthyl-1-butene 3.6-dimethyl-2-heptene 2-methylbut-2-ene 3-methylbut-1-ene 3.6-dimethylhept-2-ene CH CH3 1-methylcyclopentene 2-ethyl-1,3-cyclohexadiene 7-bromo-1.3.5-cycloheptatriene 3-propyl-1-heptene 1-methylcyclopentene 2-ethylcyclohexa-1,3-diene 7-bromocyclohepta-1,3,5-triene 3-propylhept-1-ene 2013 Pearson Education.ind Ch07 Alkenes:Struct synth (landscape) Page 7 Ch07 Alkenes; Struct + synth (landscape) Page 7 Compounds with 2 double bonds are called dienes, 3 double bonds are trienes, etc. For branches, each alkyl group is given a number, but the double bond is still given preference when numbering the chain