Process for preparing tetralin compounds

A process:

• comprising contacting a compound of Formula (IIa)
• with a chiral ruthenium (II) catalyst and a hydrogen reagent;
• thereby preparing a compound of Formula (Ia):
• wherein
• the chiral ruthenium (II) catalyst is RuCl(p-cymene)[(R,R)-Ts-DPEN];
• R1 and R2 are independently selected from —H, —F, —Cl, and —CN;
• R3 is —H, —F or —Cl;
• R4 is selected from —H, —F, —Cl, —C1-C3 alkyl, and —S(O)2(C1-C3 alkyl), wherein the —C1-C3 alkyl or the —S(O)2(C1-C3 alkyl) is optionally substituted with 1-3 halogen atoms;
• R5 is an alcohol protecting group;
• and
• the compound of Formula (Ia) has at least 90% diastereomeric purity.