A novel highly stereoselective synthesis of chiral 5- and 4,5-substituted 2-oxazolidinones

A scalable and expedient method of preparing diastereomerically and enantiomerically enriched pseudonorephedrine from norephedrine

“…The ultimate formation of pseudonorephedrine was completed through the hydrolysis of 5a and 5b, which was accomplished in a LiOH/H 2 O solution and heating (Table 2). 17 Attempts at hydrolysis with Cs 2 CO 3 and K 2 CO 3 proved not to be very successful. 18 The stereochemical integrity of the pseudonorephedrine from hydrolysis mixture was determined by 1 H NMR spectroscopy and HPLC.…”

Non‐Racemic Halohydrins via Biocatalytic Hydrogen‐Transfer Reduction of Halo‐Ketones and One‐Pot Cascade Reaction to Enantiopure Epoxides

“…Halohydrin (R)-4b is used for the synthesis of (R)-carnitine [46] or bioactive chiral oxazolidinones. [47] The isopropyl ester of 4a was preferred as substrate to the methyl/ethyl ester, which underwent transesterification with the co-substrate 2-propanol when whole cells were employed as catalyst. To our surprise, substrate 5a was not accepted by R. ruber, however, it was completely re- …”

Direct Catalytic Asymmetric Enolexo Aldolizations

“…This anti-diastereoselective proline-catalyzed enolexo aldolization nicely complements alternative methodologies such as the highly enantio-and syn-diastereoselective baker's yeast reduction of b-keto esters. [19] An advantage of the aldolization methodology is that both enantiomeric products can be accessed simply by using either (S)-or (R)-proline, whereas the biocatalysis route is limited to products of a single absolute configuration. [20] Applications in natural product synthesis and further extensions of proline-catalyzed inter-and intramolecular aldolizations are forthcoming.…”