Abstract: A process for the preparation of (R)-1-(2,3-difluoro-6-nitrophenoxy)-propan-2-ol, which is a useful intermediate in the synthesis of the widely used antibiotic Levofloxacin is provided. A process for the preparation of (R)-1-(2,3-difluoro-6-nitrophenoxy)-2-trimethylsiloxypropane is also described. The process includes the ring opening of (R)-propylene oxide with 2,3-difluoro-6-nitrophenyl trimethylsilyl ether in the presence of an optically active Co(salen) catalyst. The trimethylsilyl group of the reactant is transferred to the product aryloxy alcohol, which serves to protect the secondary alcohol in situ. Upon isolation, the trimethylsilyl group is removed and the resulting regioisomeric mixture purified to yield the desired (R)-1-(2,3-difluoro-6-nitrophenoxy)-propan-2-ol in high purity and yield.

Abstract: The present invention includes a process for enantioselective preparation of a non-racemic compound, which is either usable as a fragrance or flavor component or is convertible to a fragrance or flavor component by one or more additional reaction steps. The process includes the step of contacting either a substrate capable of forming a non-racemic compound by an enantioselective reaction and a co-reactant in the presence of a non-racemic catalyst, or a non-racemic or enantiopure substrate and a co-reactant, optionally in the presence of a racemic or non-racemic catalyst. The contacting is carried out at a temperature and length of time that is sufficient to produce the non-racemic compound with high optical purity. The process is used in stereoselective preparation of enantiomerically enriched intermediates useful in the preparation of non-racemic, chiral flavor and fragrance components.

Abstract: A process for the preparation of (R)-1-(2,3-difluoro-6-nitrophenoxy)-propan-2-ol, which is a useful intermediate in the synthesis of the widely used antibiotic Levofloxacin is provided. A process for the preparation of (R)-1-(2,3-difluoro-6-nitrophenoxy)-2-trimethylsiloxypropane is also described. The process includes the ring opening of (R)-propylene oxide with 2,3-difluoro-6-nitrophenyl trimethylsilyl ether in the presence of an optically active Co(salen) catalyst. The trimethylsilyl group of the reactant is transferred to the product aryloxy alcohol, which serves to protect the secondary alcohol in situ. Upon isolation, the trimethylsilyl group is removed and the resulting regioisomeric mixture purified to yield the desired (R)-1-(2,3-difluoro-6-nitrophenoxy)-propan-2-ol in high purity and yield.