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Basic IUPAC Organic Nomenclature

Alkenes as substituents

Alkenyl group
Common name Systematic name
CH2=CH-
vinyl-
ethenyl
CH2=CHCH2-
allyl-
2-propenyl
CH3CH=CH-
1-propenyl
  • Functional group is a (tri) alkene, therefore suffix = -ene
  • The longest continuous chain with 2 C=C is C6 therefore root plus "a" = hexa
  • There are two alkenes in the parent chain, so insert the multiplier di
  • Number from the right as drawn to give the C=C the lowest locants : therefore 1- and 4-
  • The line drawing shows a trans- or E-alkene at C4.
  • The substituent is a C2 alkenyl group i.e. an ethenyl group
  • The substituent is on C3
trans-3-ethenylhexa-1,4-diene
or
(E)-
3-ethenylhexa-1,4-diene
alkenes
CH3CH=CHCH(CH=CH2)2

 

organic chemistry ©Dr. Ian Hunt, Department of Chemistry University of Calgary