Isolation and partial synthesis of 3(R)- and 3(S)-deoxypumiloside; structural revision of the key metabolite from the camptothecin producing plant, Ophiorrhiza pumila

Both the C-3 epimeric pair of 3(R)- and 3(S)-deoxypumiloside were found in Ophiorrhiza pumila (Rubiaceae), a source plant of camptothecinoid metabolites. These structures were confirmed by spectroscopic analysis and partial stereoselective syntheses. The configuration at C-3 of the previously reported “deoxypumiloside” is revised to 3(R) from 3(S).