Method for preparing chiral 4-aryl-β-amino acid derivative

A method for preparing a chiral 4-aryl-β-amino acid derivative having a structure as shown in Formula I,

• wherein R-configuration or S-configuration is marked with * in the stereocenter;
• the method comprising hydrogenating an enamine compound having a structure as shown in Formula III in an organic solvent in the presence of a catalyst containing a transition metal and BIBOPs;
• wherein Ar is a phenyl, substituted with 1-5 substituents or a mixture of 1-5 substituents independently selected from halogen, trifluoromethyl, and alkoxy;
• PG is hydrogen, an aldehyde group, acetyl, benzyl, Boc, Cbz, PMB, Fmoc, COOR1, or CONR2;
• Z is OR1, SR1 or NR3R4;
• wherein
• R1 is H or C1-6 alkyl;
• R2 is H, C1-6 alkyl, or a three-membered to six-membered heterocycle containing nitrogen, oxygen, and sulfur;
• R3 and R4 are each independently H, C1-6 alkyl, C4-10 cycloalkyl, aryl, or R3 and R4 bonded to the nitrogen atom form a C4-7 membered heterocycle optionally having an additional heteroatom independently selected from O, S, and N—C1-5 alkyl;
• wherein the transition metal comprises [M(COD)2]X,
• wherein X is selected from an uncoordinated anion of tetrafluoroborate, hexafluoroantimonate, and trifluoromethanesulfonate;
• M is rhodium, iridium, or ruthenium;
• wherein a ligand BIBOPs has a structure as shown in Formula IV:
• wherein R′ is hydrogen, alkyl, halogen, hydroxyl, alkoxy, or aryl.