Which is the correct arrow pushing formalism to convert between the following resonance contributors?

• A.
• B.
• C.
• D.

Answer: (A)

Verified step by step guidance

1. Identify the resonance contributors: The first structure has a carbon-oxygen double bond and a lone pair on the oxygen, while the second structure has a carbon-oxygen single bond with a negative charge on the oxygen and a positive charge on the adjacent carbon.
2. Determine the electron movement: In resonance, electrons move to form different structures without breaking any sigma bonds. Here, the movement involves the pi electrons of the carbon-oxygen double bond and the lone pair on the oxygen.
3. Analyze the arrow pushing: The correct arrow pushing should show the movement of the pi electrons from the carbon-oxygen double bond to the oxygen, forming a lone pair and creating a negative charge on the oxygen.
4. Consider the lone pair on the oxygen: The lone pair on the oxygen can move to form a pi bond with the adjacent carbon, neutralizing the negative charge on the oxygen and creating a positive charge on the carbon.
5. Verify the formal charges: Ensure that the formal charges are correctly assigned in the resulting resonance structure, with the oxygen having a negative charge and the carbon having a positive charge in the second structure.