Nomenclature of Organic Compounds: Significance of -#-yl and E/Z Isomerism

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The discussion focuses on the nomenclature of organic compounds, specifically the significance of the suffix -#-yl and the E/Z isomerism in compounds like bicyclo[2,1,0]pent-5-ylbicyclo[3,3,0]octane and (E)-1,2-diiodo-1-methylcyclohexane. The -#-yl suffix indicates the specific carbon on a bicyclo subunit that connects to the main compound, with the number representing the position of attachment. Additionally, the E designation confirms that substituents are in a trans configuration, while Z indicates a cis configuration, confirming the spatial arrangement of the iodine atoms in the discussed compound.

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newyorkcity
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Hi all,

I have a question regarding the nomenclature of organic compounds. What is the significance of -5-yl in

bicyclo[2,1,0]pent-5-ylbicyclo[3,3,0]octane

? In general, what is the significance of the # in -#-yl in compounds?

Additionally, in (E)-1,2-diiodo-1methylcyclohexane, does the E indicate trans, whereas a Z would indicate cis? As in the two iodine atoms are on the first and second carbons, and they are both trans to each other (both axial)?

Thanks guys!
 
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I think I figured this out. So I think the -#-yl (when used with bicyclo subunits) denotes the carbon on the subunit that attaches to the main compound.

In the case presented above, the bicyclo[2,1,0]pentyl is not attached via a bridgehead C but rather one C over, but since the 'cyclopropyl' side is attached to the bicyclo[3,3,0]octane, we need to first go around the larger 'cyclobutyl' portion of the bicyclo[2,1,0]pentyl, thus getting a -5-yl. Note that I am using 'cyclobutyl' and 'cyclopropyl' as rough descriptors of the portions of the bicyclo[2,1,0]pentyl I am trying to reference; I can't think of a better way to accomplish this without an image.

Similarly, if we had 5-methylbicyclo[3,3,0]oct-2-yl-4-methylnonane, this would indicate that there is a methyl on the bridgehead of methylbicyclo[3,3,0]oct-2-yl and the bond to the main nonane chain is on the second carbon (one over from the bridgehead carbon) of the methylbicyclo[3,3,0]oct-2-yl.

Can someone confirm this analysis?