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triple bonds vs double bonds

Posted: Mon Mar 06, 2017 8:21 pm
by IssaelG_3E
If a hydrocarbon has a double-bond and a triple-bond at both ends would we want to give the triple bond the lowest numbering or the double bond?

Re: triple bonds vs double bonds

Posted: Mon Mar 06, 2017 8:39 pm
by Chem_Mod
IssaelG_3E wrote:If a hydrocarbon has a double-bond and a triple-bond at both ends would we want to give the triple bond the lowest numbering or the double bond?


From http://www.laney.edu/wp/cheli-fossum/fi ... -rules.pdf:

Alkenes and alkynes are considered to have equal priority.
In a molecule with both a double and a triple bond, whichever is closer to the end of the chain determines
the direction of numbering.
In the case where each would have the same position number, the double bond takes the lower number.
In the name, “ene” comes before “yne” because of alphabetization