Practical Asymmetric Synthesis of the Herbicide (S)-Indanofan via Lipase-Catalyzed Kinetic Resolution of a Diol and Stereoselective Acid-Catalyzed Hydrolysis of a Chiral Epoxide

Racemic indanofan [(+/-)-1] was efficiently converted to enantiopure (S)-indanofan [(S)-1] by a combination of enzymatic resolution and chemical inversion techniques. An additional important technique is the use of an o-xylene complex of a hemiketal (S)-3c as a precursor, which can be quantitatively converted to (S)-indanofan and easily purified by recrystallization from o-xylene.