Which of the above compounds will react most SLOWLY in a nucleophilic addition reaction?单项选择题
A
C
B
D
C
B
D
A
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类似问题
Consider the following electron movement: This is the ‘rate determining step’ of the reaction you are going to investigate today. This specific electron movement dictates how fast the overall reaction will be (hence, ‘rate determining’). Electrons are moving from the deprotonated ketone to the carbon of the carbonyl group in a process known as Blank 1 Question 6[select: , nucleophilic attack/addition, electrophilic attack/addition] . As the reaction requires electron donation to the carbon of the carbonyl group, the reaction rate will be increased if the electron density of that site is as Blank 2 Question 6[select: , low, high] as possible. The electron density of a specific site can be altered by the presence of various substituents on the aromatic ring, labelled X in the above image. Consider the following table: [table] X | Effect on reactive site NO2 | Large decrease in electron density. Cl | Moderate decrease in electron density. H | Parent system. Hence, no effect. CH3 | Moderate increase in electron density. OCH3 | Large increase in electron density. [/table] Using the information above, the substituents that would increase the reaction rate (as compared to the parent X=H system) would be Blank 3 Question 6[select: , NO2 and Cl, CH3 and OCH3] .
Consider the following electron movement: This is the ‘rate determining step’ of the reaction you are going to investigate today. This specific electron movement dictates how fast the overall reaction will be (hence, ‘rate determining’). Electrons are moving from the deprotonated ketone to the carbon of the carbonyl group in a process known as Blank 1 Question 6[select: , nucleophilic attack/addition, electrophilic attack/addition] . As the reaction requires electron donation to the carbon of the carbonyl group, the reaction rate will be increased if the electron density of that site is as Blank 2 Question 6[select: , low, high] as possible. The electron density of a specific site can be altered by the presence of various substituents on the aromatic ring, labelled X in the above image. Consider the following table: [table] X | Effect on reactive site NO2 | Large decrease in electron density. Cl | Moderate decrease in electron density. H | Parent system. Hence, no effect. CH3 | Moderate increase in electron density. OCH3 | Large increase in electron density. [/table] Using the information above, the substituents that would increase the reaction rate (as compared to the parent X=H system) would be Blank 3 Question 6[select: , NO2 and Cl, CH3 and OCH3] .
Typically a strongly basic irreversible nucleophile will add to the C of the C=O , this is known as 1,2-addition .
The main mechanism of aldehydes and ketones is:
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