Question #3e390

1 Answer
Feb 13, 2016

Answer:

A conjugated carbonyl group has a #"C=C"# double bond adjacent to it; an unconjugated carbonyl group has no adjacent double bond.

Explanation:

Examples of unconjugated carbonyl compounds are propanal and propanone.

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Typical conjugated (or α,β-unsaturated) carbonyl compounds are propenal

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and

butenone

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In addition to a normal #"C=O"# resonance contributor, an α,β-unsaturated carbonyl compound has another contributor with a positive charge on the β-carbon.

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It can be attacked by nucleophiles at either the β-carbon or the carbonyl carbon.

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Note that the product of 1,4-addition is an enol that will tautomerize to the more stable carbonyl compound.