Exam 23: Carbonyl Condensation Reactions

Exhibit 23-8 Consider the compound 2-methyl-2-carboethoxycyclopentanone,whose structure is shown below,to answer the following question(s). -Refer to Exhibit 23-8.When 2-methyl-2-carboethoxycyclopentanone is treated with sodium ethoxide in ethanol solution followed by a mild aqueous acid work-up,5-methyl-2-carboethoxycyclopentanone is isolated as the major product.This reaction proceeds by a reverse Claisen condensation mechanism followed by a recyclization.On the structures provided below,show electron flow with arrows in this interesting reaction.

Exhibit 23-3 Consider the data below to answer the following question(s): The Friedlander Quinoline Synthesis,first reported in 1882,is the base-catalyzed condensation of 2-aminobenzaldehydes with ketones to form quinoline derivatives. -Refer to Exhibit 23-3.The second step of the Friedlander Quinoline Synthesis is a nucleophilic addition of a primary amine to a ketone yielding an imine.Write the complete stepwise mechanism for this imine forming reaction.Show all electron flow with arrows and show all intermediate structures.

Give the structures of the ester precursors for the following Claisen condensation product and formulate the reaction.

Exhibit 23-8 Consider the compound 2-methyl-2-carboethoxycyclopentanone,whose structure is shown below,to answer the following question(s). -Refer to Exhibit 23-8.Formulate a synthesis of 2-methyl-2-carboethoxycyclopentanone starting with acyclic precursors using a Dieckmann cyclization as a key carbon-carbon bond forming step.Show all reagents and all intermediate structures.

Exhibit 23-5 Consider the reaction below to answer the following question(s). -Refer to Exhibit 23-5.Draw the structure of the enolate ion that is generated during the course of this reaction.

Which of the following does not characterize carbonyl condensation reactions?

Exhibit 23-3 Consider the data below to answer the following question(s): The Friedlander Quinoline Synthesis,first reported in 1882,is the base-catalyzed condensation of 2-aminobenzaldehydes with ketones to form quinoline derivatives. -Refer to Exhibit 23-3.The first step of the Friedlander Quinoline Synthesis is a mixed aldol condensation.Write the complete stepwise mechanism for this reaction. ​

Exhibit 23-11 Give the major organic product(s) for each of the following reactions or reaction sequences. 36. ANSWER: -This question was omitted on the printed copy.This placeholder question is here to maintain the numbering system integrity between the printed copy and ExamView.Therefore,it has been marked "do not use on test" in ExamView's question information dialog.As a result,this placeholder question is automatically prevented from being chosen as a test question.

Ethyl acetate can be prepared from ethanol as the only organic starting material.Show all reagents and structures for all intermediates in this preparation.

​Draw the mechanism of the Claisen condensation reaction between two molecules of methyl acetate in the presence of sodium ethoxide (abbreviated as "EtO^-").

Exhibit 23-2 Consider the reaction below to answer the following question(s): -Refer to Exhibit 23-2.The product of this reaction is:

Oxaloacetic acid is an important intermediate in the biosynthesis of citric acid.Synthesize oxaloacetic acid using a mixed Claisen condensation as a key carbon-carbon bond forming reaction.

Which of the following can result in cyclization?

Which of the following constitutes a difference between an aldol and a Claisen condensation?

What is the structure of the enamine produced in the reaction of cyclohexanone with piperidine? See structure below.

​Draw the mechanism of the Michael reaction between ethyl acetoacetate and hex-5-en-4-one.(The ethyl group is abbreviated as "Et.")