New chiral proline-based catalysts for silicon and zirconium oxides-promoted asymmetric Biginelli reaction
作者:Yulia A. Titova、Dmitry A. Gruzdev、Olga V. Fedorova、Olga A. Alisienok、Anna N. Murashkevich、Victor P. Krasnov、Gennady L. Rusinov、Valery N. Charushin
DOI:10.1007/s10593-018-2285-z
日期:2018.4
4-Hydroxy-(2S)-prolines bearing 3,4-dihydro-2H-1,4-benzoxazine or 1,2,3,4-tetrahydroquinoline fragments were synthesized and studied as chiral catalysts in the Biginelli reaction. The target product ethyl 6-methyl-2-oxo-4-phenyl-1,2,3,4-tetrahydropyrimidine-5-carboxylate was obtained with 54% enantiomeric excess (ee). An increase in ee values of the reaction product up to 76% was observed in the presence of nanosized oxides SiO2-ZrO2 as heterogeneous promoters.