Synthesis and Candida rugosa lipase resolution of some halohydrins
The halohydrins, (1) (±)-2-chloro-1-phenylethanol and (2) (±)-2-bromo-1-phenylethanol were synthesized. These alcohols are precursors to epoxides common in the asymmetric synthesis of natural products and the production of a variety of pharmaceuticals. These compounds were synthesized via an addition, ring-opening, and substitution mechanism. NMR spectroscopy was utilized to characterize both halohydrins and HPLC was used to monitor the kinetic enzymatic resolution of (±)-2-bromo-1-phenylethanol. ^ Halohydrin (1) was directly synthesized from starting materials along with (±)-styrene dichloride. Radial chromatography resulted in the isolation of (±)-styrene dichloride which was useless for resolution reactions. Reflux of (±)-styrene dibromide yielded halohydrin (2), a better candidate for kinetic enzymatic resolution via lipase from Candida rugosa. After enzymatic resolution, compound (2) displayed a 36% conversion into the laurate ester. This ester was also characterized by NMR spectroscopy. Both halohydrins were found to be quite labile since NMR data revealed additional chemical shifts and HPLC data revealed many peaks which were determined to be impurities. ^
Lara, Blanca Estela, "Synthesis and Candida rugosa lipase resolution of some halohydrins" (2004). ETD Collection for University of Texas, El Paso. AAIEP10789.