Nomenclature Iso, Tert, cis, trans, -ane, -ene, -yne Part III

Branched Chains  Primary carbons are bound to only one other carbon.  A Secondary carbon is bound to two carbons.  A tertiary carbon is bound to three carbons.  A Quarternary carbon is bound to 4 carbons.

Branched carbons  When a secondary carbon from a single carbon group is bound to a secondary carbon in a chain, it forms an iso- group.  Isopropyl group  Iso butyl group

Tert groups  When the carbon group is bound to the tertiary carbon, it is a tert group.  Only one tert group, tert butyl, uses that name.

Naming branched groups  For groups larger than Isopropyl and Tert Butyl; select the longest chain in the group.  The first carbon is the one bound to the primary carbon chain.  Follow IUPAC Rules  That name is then entered in parentheses.

Continued  Alphabetically: if the prefix is hyphenated such as sec- tert-, then it is not included in the alphabetizing.  If not hyphenated, such as Isopropyl, then it is part of the word and is included in the alphabetizing.

Cyclo Alkanes  The name is the alkane preceded by the prefix cyclo-

Cis and trans  In chains of alkanes, the atoms are free to rotate.  In cyclo alkanes, the atoms no longer have the freedom to rotate.  This creates cis and trans isomers.

In a cyclo alkane  The cis form has both functional groups in the same plane  The trans form has the two functional groups in opposite planes.

Cis & Trans

Single Double & Triple Bonds  When all the carbons have single bonds the chain name ends in –ane.  Of the chain contains one double bond, the chain ends in -ene

Naming Alkenes   Examples:   etheneC 2 H 4   propeneC 3 H 6   You can work out the formula of any of them using: C n H 2n   Alkenes are hydrocarbons containing a carbon- carbon double bond.   The table is limited to the first two, because after that there are isomers which affect the names.

Larger than propene  In the longer carbon chains, it is necessary to identify the position of the double bond.  Is it 1-butene  or 2-butene  Or 3-butene?

Isomers with double bonds.  Yes Cis & Trans are back!!  With double bonds the molecule is unable to spin.  This leads to cis & trans isomers.

What about triple bonds?  The longest carbon chain, which now ends in –yne