Preparation method for medical intermediate N-Boc-cis-4-hydroxy-L-proline

The invention provides a preparation method for a medical intermediate N-Boc-cis-4-hydroxy-L-proline. The preparation method comprises the following steps: with L-hydroxyproline as a raw material, subjecting the raw material to Boc protection; then carrying out hydroxyl radical oxidation so as to obtain N-Boc-4-oxo-L-proline; dissolving N-Boc-4-oxo-L-proline in a solvent and successively carrying out reduction with a reducing agent and purification at a certain temperature so as to obtain the product N-Boc-cis-4-hydroxy-L-proline. The method has the advantages of good reaction selectivity, high product ee value and low preparation cost.