Stereoselective total synthesis method of (2R, 4 'R, 8' R)-alpha-tocopherol

The invention discloses a stereoselective total synthesis method of (2R, 4 'R, 8' R)-alpha-tocopherol. The method comprises the following steps: performing iodination on trimethylhydroquinone serving as a raw material to generate aromatic halide, and performing Heck reaction and Pd/C hydrogenation on the aromatic halide and diester containing a terminal olefinic bond to form saturated aromatic diester; then diester is selectively hydrolyzed to generate monoester with high optical activity, and a chiral three-dimensional center is constructed; then carrying out methylsulfonyl chlorination and lithium aluminum hydride reduction to form a methyl-containing chiral compound; carrying out oxidation ring closing and hydrogenation reduction to construct a chiral chroman mother nucleus; then carrying out benzyl protection and Wittig reaction, and realizing carbon-carbon bond connection with C15 * fat long-chain phosphine salt; finally, double bonds are reduced to obtain (2R, 4 'R, 8' R)-alpha-tocopherol I. The method