Developing an Asymmetric Transfer Hydrogenation Process for (<i>S</i>)-5-Fluoro-3-methylisobenzofuran-1(3<i>H</i>)-one, a Key Intermediate to Lorlatinib
Synthesis of (S)-5-fluoro-3-methylisobenzofuran-1(3H)-one (6), a key intermediate to lorlatinib, is described. A few synthetic methodologies, that is, boron reduction, enzymaticreduction, asymmetric hydrogenation, and asymmetric transfer hydrogenation, were evaluated for the chiral reduction of the substituted acetophenone intermediate (8). A manufacturing process, on the basis of the asymmetric transfer