Which of these is an intermediate structure for an aldol condensation? (select all that apply)

Question

BlackTom AI · Accepted Answer

To tackle this question, we first need to recall the typical intermediates encountered in an aldol condensation mechanism.
Option: alkyl oxonium ion. This species is not part of the aldol mechanism; aldol reactions proceed via carbon–carbon bond formation between an enolate and an aldehyde or ketone, not through oxonium intermediates of this type.
Option: enolate ion. This is a classic intermediate formed when the alpha proton is abstracted to give a resonance-stabilized enolate, which then attacks a carbonyl compound to form the new C–C bond characteristic of aldol reactions.
Option: iminium ion. Iminium ions arise in other reaction contexts (like certain organocatalytic aldol variants or enamine catalysis) but are not the standard intermediates in the classic aldol condensation mechanism, which centers on enolates/enolization rather than iminium pathways.
Option: alpha-hydroxycarbonyl. While related to carbonyl chemistry, an alpha-hydroxycarbonyl is not the typical intermediate in the standard aldol sequence; it does not represent the bond-forming step or the dehydration step’s immediate intermediate in this process.
Option: beta-hydroxycarbonyl. This species directly results from the aldol addition step: after the enolate attacks, a newly formed beta-hydroxy carbonyl is generated and represents the classic intermediate before dehydration to yield the enone (alpha,beta-unsaturated carbonyl).
Option: gamma-hydroxycarbonyl. A gamma-hydroxycarbonyl would imply a different positional relationship than what arises in a canonical aldol reaction; it is not the standard intermediate here.
Option: alpha,beta-unsaturated carbonyl. This product form arises after dehydration of the beta-hydroxycarbonyl, not as an intermediate in the initial aldol addition step itself.
Option: beta,gamma-unsaturated carbonyl. This species is not part of the typical aldol mechanism; it does not correspond to the usual dehydration outcome or the bond-forming step in the standard pathway.
In summary, the two items that align with the established intermediates in an aldol condensation are enolate ion (the nucleophilic starting species) and beta-hydroxycarbonyl (the intermediate after nucleophilic addition but before dehydration). The remaining choices do not fit the canonical sequence or roles of intermediates in this reaction.

CHE 008B A01 SS1 2025 Lecture 9 - Reactions of Enolate Ions

Which of these is an intermediate structure for an aldol condensation? (select all that apply)

查看解析

登录即可查看完整答案

类似问题

Put the mechanism steps in order for an aldol condensation. (Not all steps may be used) 1: First Mechanism Process 2: Second Mechanism Process 3: Third Mechanism Process

Which of these is the final product for an aldol condensation if heated?

In a consumer society, many adults channel creativity into buying things

Economic stress and unpredictable times have resulted in a booming industry for self-help products

People born without creativity never can develop it

A product has a selling price of $20, a contribution margin ratio of 40% and fixed cost of $120,000. To make a profit of $30,000. The number of units that must be sold is: Type the number without $ and a comma. Eg: 20000

更多留学生实用工具

考试浏览器助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单