We report here aconcise,collective,and asymmetric total synthesis of sarpagine alkaloids and biogenetically related koumine alkaloids,w hichs tructurally feature ar igid cage scaffold, with l-tryptophan as the starting material. Tw ok ey bridged skeleton-forming reactions,namely tandem sequential oxidative cyclopropanol ring-opening cyclization and ketone a-allenylation, ensure concurrent assembly of the caged sarpagine scaffold and installation of requisite derivative handles.W ith ac ommon caged intermediate as the branch point, by taking advantage of ketone and allene groups therein, total synthesis of five sarpagine alkaloids (affinisine,n ormacusine B, trinervine,N a -methyl-16-epipericyclivine,a nd vellosimine) with various substituents and three koumine alkaloids (koumine,k oumimine,a nd N-demethylkoumine)w ith more complex cage scaffolds has been accomplished.

A Fe(NO 3 ) 3 -mediated ring-opening arylation of cyclopropanol with the electron-rich pyrrole has been developed, which might proceed through oxidative radical ring opening of cyclopropanol followed by cyclization to the pyrrole motif and then aromatization. This method enables direct arylation of cyclopropanol without prefunctionalization and thus allows rapid access to a diverse array of chiral 5,6,7,8-tetrahydroindolizines from easily available chiral amino acid esters. The synthetic utility has been demonstrated by the asymmetric synthesis of alklaoids (−)-indolizidine 167B, (+)-indolizidine 209D, (+)-monomorine I, and a natural product analogue.

We report here aconcise,collective,and asymmetric total synthesis of sarpagine alkaloids and biogenetically related koumine alkaloids,w hichs tructurally feature ar igid cage scaffold, with l-tryptophan as the starting material. Tw ok ey bridged skeleton-forming reactions,namely tandem sequential oxidative cyclopropanol ring-opening cyclization and ketone a-allenylation, ensure concurrent assembly of the caged sarpagine scaffold and installation of requisite derivative handles.W ith ac ommon caged intermediate as the branch point, by taking advantage of ketone and allene groups therein, total synthesis of five sarpagine alkaloids (affinisine,n ormacusine B, trinervine,N a -methyl-16-epipericyclivine,a nd vellosimine) with various substituents and three koumine alkaloids (koumine,k oumimine,a nd N-demethylkoumine)w ith more complex cage scaffolds has been accomplished.

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