An improved procedure for the enantioselective synthesis of (+)- and (-)-cis-4-hydroxyprolines and bulgecinines

Article abstract of DOI:10.1016/0957-4166(96)00150-4

An efficient enantioselective synthesis of both the enantiomers of cis-4-hydroxy-proline and bulgecinine was accomplished starting from synthons 1 or 1'. The improved synthetic route to the aforesaid enantiomerically pure proline derivatives was established via a stereocontrolled double iodocyclization of 3(a,b) or 3'(a,b).