What two carbonyl compounds are needed to synthesize each of the following compounds, using a Robinson annulation?
a.

Verified step by step guidance

1. Step 1: Understand the Robinson annulation reaction. The Robinson annulation is a reaction that combines a Michael addition and an intramolecular aldol condensation to form a six-membered ring. It typically involves a ketone (or aldehyde) and an α,β-unsaturated carbonyl compound.
2. Step 2: Analyze the target compound. Look at the structure of the given compound and identify the six-membered ring formed during the Robinson annulation. Determine which bonds in the ring were likely formed during the reaction.
3. Step 3: Break the target compound into its precursors. Work backward by identifying the α,β-unsaturated carbonyl compound and the ketone (or aldehyde) that could have combined to form the product. Focus on the positions of the double bond and the carbonyl group in the final product.
4. Step 4: Assign the α,β-unsaturated carbonyl compound. The α,β-unsaturated carbonyl compound will contribute the double bond and part of the six-membered ring. Ensure that the structure matches the connectivity in the target compound.
5. Step 5: Assign the ketone (or aldehyde). The ketone (or aldehyde) will contribute the other part of the six-membered ring. Verify that the combination of the two precursors through a Michael addition and aldol condensation would yield the target compound.

Key Concepts

Robinson Annulation

The Robinson annulation is a key reaction in organic chemistry that involves the formation of a six-membered ring through the condensation of a ketone with an α,β-unsaturated carbonyl compound. This reaction typically proceeds via an initial Michael addition followed by an intramolecular aldol condensation, leading to the formation of complex cyclic structures. Understanding this mechanism is crucial for identifying the appropriate carbonyl compounds needed for synthesis.

Carbonyl Compounds

Carbonyl compounds are organic molecules that contain a carbon atom double-bonded to an oxygen atom (C=O). They include aldehydes, ketones, and carboxylic acids, each with distinct reactivity patterns. In the context of the Robinson annulation, recognizing the types of carbonyl compounds that can participate in the reaction is essential for determining the correct starting materials for synthesis.

Synthesis Strategy

Synthesis strategy in organic chemistry refers to the planning and execution of a series of chemical reactions to construct a desired compound from simpler precursors. This involves understanding the reactivity of different functional groups, the mechanisms of reactions, and the overall reaction conditions. In the case of the Robinson annulation, a strategic approach is necessary to select the right carbonyl compounds that will yield the target compound efficiently.