The invention provides a synthesis method of a
suvorexant intermediate (5S)-hexahydro-5-methyl-1H-1,4-
diazepine-1-carboxylic t-butyl ester. The synthesis method of the
suvorexant intermediate (5S)-hexahydro-5-methyl-1H-1,4-
diazepine-1-carboxylic t-butyl ester comprises the following steps: (1) enabling a compound Suvor-1 to react with vitride solution to obtain a compound Suvor-2; enabling the compound Suvor-2 to react with 4,4-dimethoxy-2-
butanone to obtain Suvor-3; (3) enabling the compound Suvor-3 to react with
methanesulfonic acid to obtain a compound Suvor-4; (4) enabling the compound Suvor-4 to react with di-tert-butyl
dicarbonate to obtain a compound Suvor-5; (5) enabling the compound Suvor-5 to react with
hydrogen to obtain the
suvorexant intermediate. The synthesis method of the suvorexant intermediate (5S)-hexahydro-5-methyl-1H-1,4-
diazepine-1-carboxylic t-butyl ester provided by the invention has the advantages that the reaction is simple, starting materials are cheap and easy to obtain, the reaction condition is mild, and the production safety is high; in addition, the reaction steps are less, the reaction yield is high, and the production cost is lower; moreover, by introducing a chiral functional group, the purity of a target product obtained after induced synthesis and ring closure is high, the amount of impurities in
enantiomer is small, the ee% is greater than97%, and the method is suitable for commercial large-scale production.