Fe(HSO₄)₃(FHS) was used as an efficient catalyst for the heterogeneous addition of a series of benzylic and allylic alcohols to various 𝛽-dicarbonyl compounds, which afforded moderate to excellent yields of 𝐶-alkylated products in 1,2-dichloroethane. In comparison with the previous methods, the present research surprisingly exhibited higher reaction yields without formation of any by-products which could be formed by self-condensation of alcohols. Moreover, the catalyst can be readily recovered and reused up to five times with almost maintained reactivity and yields.

We intended to convert proline as a homogeneous catalyst to a heterogeneous catalyst by prolination of MWCNTs to improve proline efficiency as a catalyst by the ease of separating, catalytic economy, reusability, etc. To reach these goals, we sketched Pro-MWCNT catalyst and characterized it by different analyses such as FT-IR, SEM, EDX, CHNS. The efficiency of this heterogeneous catalyst was investigated and compared with proline homogeneous catalyst in Mannich reaction. The results hold out improvements in stereoselectivity, ease of separating and reusability.