PhI(OAc)<sub>2</sub>-mediated one-pot oxidative decarboxylation and aromatization of tetrahydro-β-carbolines: synthesis of norharmane, harmane, eudistomin U and eudistomin I
DBN has been identified as an efficient reagent for promoting the dehydrogenative/decarboxylative aromatization of tetrahydro-β-carbolines under air atmosphere, to access the corresponding β-carbolines in moderate to good yields. The utility of this protocol for the gram-scale synthesis of β-carboline alkaloids eudistomin U (7) and harmane (10) has also been demonstrated.
A convenient synthesis for the conversion of various substituted tetrahydro-β-carbolines has been developed by iron-catalyzed decarboxylative/dehydrogenative aromatization to construct aromatic β-carbolines under air atmosphere. In the presence of a FeCl3 catalyst, this reaction exhibited a good functional group tolerance to produce corresponding β-carbolines in good yields in the absence of any additive