Write structures for the carbonyl electrophile and enolate nucleophile that react to give the aldol below. OH

Complete the synthesis of ethyl (E)-2,2,4-trimethyl-3-oxo-5-phenylpent-4-enoate from the starting material given (ethyl propionate). You must list out all reagents/solvents next to the reaction arrows and draw the intermediate structures in the boxes. I am giving you one restriction. You are not allowed to introduce any enolates as reagents next to the reaction arrows. orff ion

draw the product, show its sterochemistry

1. Each of the following compounds can be prepared by a mixed aldol condensation reaction. Give the structures of the aldehyde and/or ketone precursors for each aldol product shown. so

providing the chemical structure of the missing reactants or the products.

5. In the transition state for the proline-catalyzed aldol addition, a hydrogen bond is shown between the carboxylic acid of proline and isobutyraldehyde. Explain how this could lower the energy barrier for the reaction.

Write the structures of all the possible enolates for the following ketone. Label the kinetic and thermodynamic enolates. Indicate reagents and conditions (including solvent, temperature etc.) under which each product would predominate. Sketch a labelled reaction coordinate diagram indicating the progress of the formation of the enolates.

4. Please give the starting materials that would be necessary to make the following imines and enamines. a C d N. N at

Show how crossed Claisen condensations, malonic ester syntheses,acetoacetic ester syntheses, andRobinson annulations can synthesize a wide variety of ketone, ester,and acid derivatives.

We have seen that the alpha carbon atom of an enamine can function as a nucleophile in a Michael reaction, and in fact, enamines can function as nucleophiles in a wide variety of reactions. For example, an enamine will undergo alkylation when treated with an alkyl halide. Draw the structure of intermediate A and the alkylation product B in the following reaction scheme (J. Am. Chem. Soc. 1954, 76, 2029-2030): TSOH -H₂O NH A 1) CHgI 2) H₂O+ B + NH Modify the given copy of the starting material to draw compound A. If needed, use the single bond tool to interconvert between double and single bonds. Edit Drawing