“Micellar” catalysis in the aqueous intermolecular diels-alder reaction: rate acceleration and enhanced selectivity

The use of optically active O-alkyl ester hydrochlorides of L-phenylalanine and L-tyrosine as chiral micellar media for the catalysis of diels-alder reactions

“…The maximum catalytic efficiency was obtained with an alkyl chain length of C 10 for both surfactants. However, a further increase in the chain length from C 10 to C 14 resulted in a decrease in the yield (Table 1, entries 14,15,27,28) (Figure 3). This can be attributed to the coiling effect of the surfactant of higher chain lengths which can potentially alter the orientation of the substrates resulting in reduced yields [24].…”

“…The idea of micellization for the rate-enhancement of Diels-Alder reactions dates back to the 1980s, where higher yields were obtained when using water as solvent compared to other nonpolar solvents [15][16][17][18]. Hence, surfactants offer the possibility for organic reactions to occur in aqueous media, and from the viewpoint of green chemistry, water is safer, harmless and environmentally benign [19].…”

Diels-Alder Reactions of 12-Hydroxy-9(10®20)-5aH-abeo-abieta-1(10),8(9),12(13)-triene-11,14-dione

“…In contrast, triene diol 39 underwent Diels-Alder reaction with quinone 2 using water as the reaction medium [91,92] in a 20% yield of the Diels-Alder adduct 48 (Scheme 12); an X-ray analysis of adduct 48 confirmed the predicted facial and regiospecificity of this cycloaddition [93]. We speculated that the in situ formation of hemi-ketal intermediate 47 causes an intermolecular cycloaddition to become an intramolecular one which controls the regiospecificity of the Diels-Alder reaction.…”

Stereoselective Synthesis of Functionalized 1,3‐Dienes in Water

“…However, organic reactions carried out in water frequently show a rate-attractive effect in spite of low solubility of the substrates in water. [6][7][8][9] As the sighting of the Diels-Alder reaction substituted 1,3-dienes have played a significant function in organic chemistry. [10][11][12][13] Conjugated dienes represent one group of broadly occurring and important organic compounds.…”