Synthesis of vitamin K₁ and K₁-chromanol by friedel-crafts alkylation in heterogeneous catalysis

The partly hydroxylated MgF₂ and AlF₃ materials are efficient and selective catalysts for the preparation of two important members of the vitamin K class: vitamin K₁ and vitamin K₁-chromanol. The high activity in combination with high selectivity in one of the target products is due to both the acidic strength and the synergistic effect of the presence of both, optimized Brønsted and Lewis sites. Therefore, the best catalyst for a target product can be obtained through a very simple tuning of the acidic properties of the material. Moreover, the results obtained in the present study (Y_{vitamin K1}=57.8% and Y_{vitamin K1-chromanol}=71.4%) are also very encouraging from the environmental standpoint as green elements are introduced by using solid catalysts and a biphasic solvent system.