91影视

How would you prepare the following compound using a Robinson annulation reaction between a饾泝-diketone and an饾泜,饾泝 -unsaturated ketone? Draw the structures of both reactants and the intermediate Michael addition product

Show the products you would expect to obtain by Claisen condensation of the following esters:(a) (CH₃)₂CHCH₂CO₂Et (b) Ethyl phenylacetate (c) Ethyl cyclohexyl acetate

As shown in Figures 23-4, the Claisen reaction is reversible. That is, a饾泝-keto ester can be cleaved by base into two fragments. Using curved arrows to indicate electron flow, show the mechanism by which this cleavage occurs.

What product would you expect from the following mixed Claisen-like reaction?

Dieckmann cyclization of diethyl 3-methylheptanedioate gives a mixture of two饾泝-keto ester products. What are their structures, and why is a mixture formed?

Show how you might use an enamine reaction to prepare each of the following compounds:

What enone product would you expect from aldol condensation of each of the following compounds?

Aldol condensation of 3-methyl cyclohexanone leads to a mixture of two enone products, not counting double-bond isomers. Draw them.

Which of the following compounds are aldol condensation products? What is the aldehyde or ketone precursor of each?

(a) 2-Hydroxy-2-methylpentanal (b) 5-Ethyl-4-methyl-4-hepten-3-one