23-1. Carbonyl Condensations：The Aldol Reaction

　今回は 23-1.カルボニル縮合反応：アルドール反応 を要約します。

 This theme is 23-1. Carbonyl Condensations：The Aldol Reaction.

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23-1. Carbonyl Condensations：The Aldol Reaction
 Carbonyl condensations proceed by a nucleophilic addition and an α-substitution step with pairs of carbonyl compounds.  In the reaction, a carbonyl compound is converted into an enolate ion nucleophile by base.  And, it adds to the electrophilic carbonyl group of the other to a β-hydroxy carbonyl compound.  Then the base catalyst is regenerated.  The general mechanism is shown as below.

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 One carbonyl condensation reaction in which aldehydes and ketones with an α hydrogen atom are used under a base catalyst is called aldol reaction.  An aldol is an organic compound with both an aldehyde group and an alcohol group.

 The aldol reaction is equilibrium that depends on both reaction conditions and substrate structure.  When aldehydes have no α substituent (RCH2CHO), the equilibrium generally progresses to the condensation product side.  When starting materials are disubstituted aldehydes (R2CHCHO) or ketones, the equilibrium favors the reactants.

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　以上、23-1. アルドール反応 でした。
　次回は 23-2. カルボニル縮合反応とα置換反応の比較 です。

 23-1. The Aldol Reaction has finished.
 I'm going to summarize 23-2. Carbonyl Condensations versus Alpha Substitutions for next entry.