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 effect of a range of O-alkyl ester hydrochloride surfactants derived from L-phenylalanine and L-tyrosine as catalysts on the Diels-Alder reaction between cyclopentadiene and methyl acrylate was studied. Both chain lengths (C8-C14) and head groups of the surfactants were found to influence the yield and selectivity of the Diels-Alder product. The C10 derivatives of both phenylalanine and tyrosine surfactants gave the highest yields and selectivity. Phenylalanine ester hydrochlorides showed better catalytic activity than the tyrosine derivatives. Adduct optimum yield was obtained at a concentration relating to their critical micelle concentration (CMC) values. The Diels-Alder reaction was also found to be favored in acidic condition (pH 3) as well as in the presence of lithium chloride (LiCl) as salting out agent.
KEY WORDS: Diels-Alder, Chiral catalysts, Phenylalanine, Tyrosine, Micelle, CMC
Bull. Chem. Soc. Ethiop. 2017, 31(3), 509-518.