A NEW ROUTE TO alpha-TOCOPHEROL, alpha-TOCOPHERYL ALKANOATES AND PRECURSORS THEREOF

摘要

The present invention is concerned with a novel process for the manufacture of (E/Z)-4-alkanoyloxy-3,5,6-trimethyl-2-phytylphenyI esters and silyl ethers, precursors of alpha- tocopherol and alpha-tocopheryl alkanoates, by cross-metathesis reaction of 2-alkenyl-3,5,6-trimethylhydroquinone dialkanoates or 4-alkanoyloxy-2-alkenyl-3,5,6-trimethylphenyI silylethers with 2,6,10,14-tetramethylpentadecene or a phytol derivative, e.g. phytyl acetate, in the presence of a cross-metathesis catalyst. As the cross-metathesis catalyst especially ruthenium metal carbene complexes are suitable which possess (a) ruthenium metal center(s), have an electron count of 16 or 18 and are penta- or hexa- coordinated. A further object of the invention is a process for the manufacture of alpha-tocopherol and alpha-tocopheryl alkanoates comprising this reaction.