Application of Solid Bases MgO and CaO Covered with Al₂O₃ in Alkylation of Malonates

Abstract

Recently developed solid bases of MgO and CaO covered with Al₂O₃ were applied to the alkylation of malonate with several types of alkyl halides. Diethyl malonate was converted into mono-alkylated and/or di-alkylated malonate by these solid bases without solvent. Prepared solid bases showed higher activity than unmodified MgO and CaO. Al₂O₃/MgO gave mono-alkylated malonates with high selectivity. Al₂O₃/CaO gave di-alkylated malonates selectively. Al₂O₃/CaO also catalyzed alkylation of mono-alkylated malonates. MgO and CaO covered with Al₂O₃ are useful solid bases for the alkylation of activated methylene groups. The difference in product selectivity was attributed to the base strength of uncovered MgO and CaO.