Total Synthesis of a PPAP, Nemorosonol, Using a Tandem Michael Addition-Intramolecular Aldol Reaction

Keisuke Mitsugi1, Toru Takabayashi1, Takayuki Ohyoshi1

  • 1Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan.

Organic Letters
|June 15, 2022
PubMed

Related Concept Videos

Conjugate Addition of Enolates: Michael Addition01:08

Conjugate Addition of Enolates: Michael Addition

The attack of a nucleophile at the β carbon of an α,β-unsaturated carbonyl compound is called conjugate addition. Conjugate addition reactions of active methylene compounds, such as β-diketones, β-keto esters, β-keto nitriles, and α-nitro ketones, are called Michael addition reactions.
2.8K
Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation01:27

Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation

Robinson annulation is a base-catalyzed reaction for the synthesis of 2-cyclohexenone derivatives from 1,3-dicarbonyl donors (such as cyclic diketones, β-ketoesters, or β-diketones) and α,β-unsaturated carbonyl acceptors. Named after Sir Robert Robinson, who discovered it, this reaction yields a six-membered ring with three new C–C bonds (two σ bonds and one π bond).
2.3K
C–C Bond Formation: Aldol Condensation Overview01:10

C–C Bond Formation: Aldol Condensation Overview

Aldol condensation is an important route in synthetic organic chemistry used to generate a new carbon–carbon bond under basic or acidic conditions. The aldol condensation reaction presented in Figure 1 constitutes an aldol addition reaction followed by the dehydration process.
14.0K
Base-Catalyzed Aldol Addition Reaction01:08

Base-Catalyzed Aldol Addition Reaction

As depicted in Figure 1, base-catalyzed aldol addition involves adding two carbonyl compounds in aqueous sodium hydroxide to form a β-hydroxy carbonyl compound.
3.7K
Acid-Catalyzed Aldol Addition Reaction01:15

Acid-Catalyzed Aldol Addition Reaction

The aldol reaction of a ketone under acidic conditions successfully forms an unsaturated carbonyl as the final product instead of an aldol. The acid-catalyzed aldol reaction is depicted in Figure 1.
2.7K
Intramolecular Aldol Reaction01:18

Intramolecular Aldol Reaction

Intramolecular aldol reaction occurs in dicarbonyl compounds such as dialdehydes, diketones, and keto-aldehydes. The dicarbonyl compounds possess more than one nucleophilic ⍺ carbon for the base to deprotonate and form the enolates. For example, in symmetrical diketones, there are four ⍺ carbons. Hence, four types of enolates are possible when treated with a base. However, since the molecule is symmetrical, the enolates formed on either side of one carbonyl group are equivalent to those...
2.4K