Preparation method of NK-1 receptor antagonist and intermediate thereof

The invention relates to a preparation method of an NK-1 receptor antagonist and an intermediate thereof. The invention provides a preparation method of (5S, 8s)-8-{[1-(3, 5-bis-(trifluoromethyl)phenyl)-ethoxy]methyl}-8-phenyl-1, 7-diaza-spiro[4, 5]dec-2-one (formula I compound), which is prepared from a formula II compound, and also provides the formula II compound and a preparation method thereof. The method provided by the invention has the advantages of simple operation, mild reaction condition, high safety factor, little side reaction, high yield and high purity, lowers the production cost and operation risk, and is very suitable for large-scale industrial production. (formula II as shown in the specification).