Question

Can someone please explain the steps to getting this answer?

In the boxes indicated assign the E/Z configuration to the C=C bonds in the molecules below:

Answer 1

Solution:- When we have different groups present at the double bonded carbons then cis and trans is not used as cis and trans is used only if we have similar groups. If same groups are on same side then we call it cis and if they are on opposite sides then we call it trans. Examples are given bellow...

When the groups are not similar then we use E and Z in place of cis and trans. We assign the priorities to the groups. If high priority groups are on same side(direction) then we call it Z-isomer and if they are on opposites sides then we call it E-isomer.

Br Trans

High priority is given to the high atomic number atom bonded directly to the double bonded carbons. If two carbons of the alkene have the high priority groups on same side then it is Z and if they are on opposite sides then it is E.

Detailed explanations are given for bond the compounds along with the pics.

for the top mentioned double bond the high priority groups are marked with number 1 and the reason is, on left side first point of difference is oxygen atom which has high prioty than H on left side the first point of difference is Nitrogen atom that gets higher priorty than carbon since atomic number of N is greater than carbon. So, high priority groups are on same side and so it is Z configuration High priority atoms are marked as number 1 on both sides. Since they are on same side, it is Z-configuration 0 here for this bottom mentioned double bond the high priority groups are on opposite sides so it is E-configuration.

Br Cl high prior groups on same here for left side double bonded carbon, two side, it is Z here, for the left side double bonded carbon the high priority goes to the bottom group since first directly bonded atom is carbon so we look for the next atom to get the first point of difference and we notice that next atom at the top is H where as at the bottom side it is again carbon present in the 6-carbon ring) so the high proty goes to the bottom side and it is marked as1. For the right side carbon the high priority again goes to the bottom side since the caron bonded directly to the double bonded carbon is a tertiary carbon where as the top one is just secondary High priority groups are on same side so it is Z-configuration. yhere the two bonded atohs are C and H, high priority goes to C and and Br. atomic number of Br is higher than C, so the high priority goes to the Br and it is marked as 1. is marked as number 1. Since high priority groups are on opposite sides, it is E-configuration.