A new access to enantiopure β-hydroxylated piperidines from N-Boc-2- acyloxazolidines. Application to the synthesis of (-)-desoxoprosopinine and (+)-pseudoconhydrine

Article abstract of DOI:10.1016/S0040-4020(98)00508-0

The synthesis of (-)-desoxoprosopinine and (+)-pseudoconhydrine were achieved from a common oxazolidine precursor. The three stereocenters present in (-)-desoxoprosopinine as well as the two stereocenters of (+)- pseudoconhydrine were created in highly stereoselective ways. The stereoselectivity observed during the reduction of the ketone moiety in the starting oxazolidine was dependent on the occurrence of a chelated intermediate. The others stereocenters arose from stereoselective reductions or alkylations of intermediate iminium ions.