Textbook Question
Give IUPAC names for the following compounds.
(a)
(b)
(c)
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4. Alkanes and Cycloalkanes
Cis vs Trans
2:35 minutesProblem 2d
Textbook Question
Identify the following alkenes as E or Z, if appropriate.
(d) 
Verified step by step guidance1
Step 1: Identify the double bond in the molecule. In this structure, the double bond is located between the two carbon atoms in the chain.
Step 2: Assign priorities to the groups attached to each carbon of the double bond using the Cahn-Ingold-Prelog priority rules. Higher atomic number groups get higher priority. For the left carbon, the groups are the carbonyl group (C=O) and the alkyl chain. For the right carbon, the groups are the alkyl chain and the hydrogen atom.
Step 3: Determine the relative positions of the highest priority groups on each side of the double bond. If the highest priority groups are on the same side, the configuration is Z (zusammen). If they are on opposite sides, the configuration is E (entgegen).
Step 4: Analyze the structure visually. The carbonyl group (C=O) has higher priority than the alkyl chain on the left carbon, and the alkyl chain has higher priority than the hydrogen atom on the right carbon.
Step 5: Based on the positions of the highest priority groups, assign the configuration of the double bond as either E or Z.
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Video duration:
2mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
E/Z Configuration
E/Z configuration is a method used to describe the stereochemistry of alkenes based on the priority of substituents attached to the double bond. The 'E' (entgegen) designation indicates that the highest priority groups are on opposite sides, while 'Z' (zusammen) indicates they are on the same side. This system is crucial for understanding the geometric isomerism in alkenes.
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E/Z Diastereoisomerism
Cahn-Ingold-Prelog Priority Rules
The Cahn-Ingold-Prelog priority rules are used to assign priorities to the substituents attached to the double bond in alkenes. The priority is determined based on atomic number; the higher the atomic number of the atom directly attached to the double bond, the higher the priority. If the first atoms are the same, the comparison continues to the next atoms in the substituent chain.
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Alkene Structure and Bonding
Alkenes are hydrocarbons that contain at least one carbon-carbon double bond (C=C). The presence of this double bond affects the geometry of the molecule, leading to potential isomerism. Understanding the structure and bonding of alkenes is essential for determining their reactivity and stereochemistry, particularly when identifying E/Z configurations.
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