Preparation of (R)-(+)-3-phenyl-2,3,5,6,7,8-hexahydro-oxazolo[3,2-a]pyridin-4-ylium bromide: synthesis of (S)-(+)-coniine, (R)-(-)-coniceine and (R)-(+)-anabasine
作者:A CASTRO、J RAMIREZ、J JUAREZ、J TERAN、L OREA、A GALINDO、D GNECCO
DOI:10.1016/s0385-5414(07)81205-6
日期:2007.12.1
We describe the transformation of (R)-(-)-1-(2'-hydroxy-1'-phenylethyl)piperidin-2-one 1 into (R)-(-)-3-phenyl-2,3,5,6,7,8-hexahydro-oxazolo[3,2-a]pyridin-4-ylium bromide 2 using POBr3, Reduction of 2 with Red-Al at -78 degrees C gave (3R,8aR)-(-)-3-phenylbexahydro-2H-oxazolo[3,8-a]-pyridine 3 as a single diastereoisomer. The synthetic potential of these transformation is illustrated by the enantiopure synthesis of (S)-(+)-coniine, (R)-(-)-coniceine and (R)-(+)-anabasine.