Chapter 7, Problem 53P

Interpretation Introduction

Interpretation:

The systematic name of $\text{α}\text{-}$ farnesene including E and Z configuration should be determined.

Concept Introduction:

IUPAC NOMENCLATURE RULES:

• The first step is to find out the parent chain of the hydrocarbon.  Parent chain should contain maximum number of multiple bonds, maximum number of substituents of the functional group which is used as main suffix.
• Other functional group, if any, should be identified and name it as prefix.
• Numbering should be done in such a way that to get the lowest number for suffix functional group, multiple bonds.
• The punctuation used to separate numbers is commas and hyphen is used to separate a number and alphabet.
• If the ‘ane’ ending of the alkane is replaced by ‘yne’ ending, the name of alkyne is obtained.
• Select the longest chain which contain the triple bond in such a way to get lowest value for the functional group.
• Two types of alkynes will be there according to the position of triple bond.  Terminal alkyne is the one which contain triple bond at the end of the chain and internal alkyne is the one which contain triple bond not at the end but present in any other positions in the chain.
• When the counting is done from either sides of triple bond in a compound which contain same number for the functional group suffix, the correct name will be the one which have lowest substituent number.  In the case of more than one substituent, alphabetical order should be followed.