Acid-catalyzed reactions of aromatic aldehydes with ethyl diazoacetate: an investigation on the synthesis of 3-hydroxy-2-arylacrylic acid ethyl esters.
Several commercial Lewis acids, including those of the Bronsted type, specifically HBF(4).OEt(2), are able to catalyze the reaction between aromatic aldehydes and ethyl diazoacetate to produce 3-hydroxy-2-arylacrylic acid ethyl esters and 3-oxo-3-arylpropanoic acid ethyl esters. Reactions catalyzed by the iron Lewis acid [(eta(5)-C(5)H(5))Fe(+)(CO)(2)(THF)]BF(4)(-) (i.e., 1) have the best yields and greatest ratio of 3-hydroxy-2-arylacrylic acid ethyl ester. The product distribution of 1 is not affected in the presence of Proton Sponge, but is dependent on temperature and the nature of the substrate aldehyde, whereas the activity of HBF(4).OEt(2) is affected by the presence of Proton Sponge and is reactive at temperatures as low as -78 degrees C. Consequently, both 1 and HBF(4).OEt(2) are valuable catalysts in producing important 3-hydroxy-2-arylacrylic acid ethyl esters as precursors to biologically active compounds.
Dudley
Matthew E
ME
Department of Chemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, USA.
Morshed
Md Monzur
MM
Brennan
Courtney L
CL
Islam
M Shahidul
MS
Ahmad
M Syarhabil
MS
Atuu
Mary-Rose
MR
Branstetter
Bryan
B
Hossain
M Mahmun
MM