The stepwise mechanism for the given Robinson annulation is to be drawn. Concept introduction: Robinson annulation is a combination of Michael addition and intramolecular aldol condensation reactions. It takes place between an α,β -unsaturated carbonyl compound and a carbonyl compound. The enolate formation takes place from carbonyl compound which attacks the α,β -unsaturated carbonyl compound to form 1 , 5 -dicarbonyl compound. This compound undergoes intramolecular aldol condensation which leads to the formation of a ring.

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Chapter 24, Problem 24.53P

Interpretation Introduction

Interpretation: The stepwise mechanism for the given Robinson annulation is to be drawn.

Concept introduction: Robinson annulation is a combination of Michael addition and intramolecular aldol condensation reactions. It takes place between an α,β-unsaturated carbonyl compound and a carbonyl compound. The enolate formation takes place from carbonyl compound which attacks the α,β-unsaturated carbonyl compound to form 1,5-dicarbonyl compound. This compound undergoes intramolecular aldol condensation which leads to the formation of a ring.

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Interpreting NMR spectra is a skill that often requires some amount of practice, which, in turn, necessitates access to a collection of NMR spectra. Beyond Labz Organic Synthesis and Organic Qualitative Analysis have spectral libraries containing over 700 1H NMR spectra. In this assignment, you will take advantage of this by first predicting the NMR spectra for two closely related compounds and then checking your predictions by looking up the actual spectra in the spectra library. After completing this assignment, you may wish to select other compounds for additional practice. 1. Write the IUPAC names for the following two structures: Question 2 Question 3 2. Predict the NMR spectra for each of these two compounds by listing, in the NMR tables below, the chemical shift, the splitting, and the number of hydrogens associated with each predicted peak. Sort the peaks from largest chemical shift to lowest. **Not all slots must be filled**

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