Versatile approach to enantiopure 2,6-disubstituted piperidin-3-ol framework: application to the total synthesis of (+)-deoxoprosopinine.

An efficient synthesis of enantiopure 2,6-disubstituted piperidin-3-ol 19 is developed featuring two key steps: (a). Julia olefination of (2R)-3-phenylsulfonyl-2-tert-butyloxycarbamoylpropanol benzyl ether 9B and (2R,3S)-2-tert-butyldiphenyl-3,4-O-isopropylidine-2,3,4-trihydroxybutyraldehyde 8 and (b). intramolecular N-alkylation. A straightforward asymmetric synthesis of (+)-deoxoprosopinine(2) from 19 is described demonstrating the versatility of this novel approach.