Stereoconservative synthesis of Ipecac alkaloids from secologanin
Abstract
Methyl 3,4-dihydrosecoxyloganin (2a), readily obtained from secologanin (1), has been converted with retention of chirality at C-2 and C-7 into a piperidone (5) which acts as a general synthetic precursor for Ipecac alkaloids exemplified by deoxytubulosine (8b), cephaeline (9b), and emetine (9c).