* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
Reference Example 1: Synthesis of 2-amino-3,3-diphenyl propionic acid; Reaction was carried out in a similar manner to Example 26, except that 2.5 g of N-Boc-glycine methyl ester was used in place of 1-dimethylethyl-(2R)-(2,6-dichlorophenyl)-5-oxo-3-((1'R)-phenylethyl) tetrahydro-1H-1-imidazolecarboxylate to obtain 640 mg of 2-(N-Boc-amino)-3,3-diphenylpropionic acid methyl ester as a colorless oily material (yield: 14%). Further, 354 mg of 2- (N-Boc-amino) -3,3-diphenylpropionic acid methyl ester was mixed with a 6 M solution of aqueous hydrochloric acid, and the mixture was refluxed for 5 hours. Thereafter, the mixture was washed with toluene, and neutralized with a 30% aqueous solution of sodium hydroxide to obtain a white solid of 2-amino-3,3-diphenylpropionic acid. The retention time of the respective isomers was confirmed by using the product.