Absolute stereochemistry of ancistrocladine and ancistrocladinine

Enantioselective synthesis of axially chiral 1-(1-naphthyl)isoquinolines and 2-(1-naphthyl)pyridines through sulfoxide ligand coupling reactions

“…The magnitude (SD3) of the bisignate Cotton effect couplet should be significant (R50) and the dihedral angle between the planes of the two chromophores should be !1108. The exciton chirality method was applied to the assignment of the absolute configuration of a number of naphthylisoquinoline alkaloid derivatives, namely O-methyldidehydroancistrocladine, 29 dideydroancistrocladisine and didehydroancistrocladidine. 30 The correctness of the assignments has been vindicated by X-ray and degradative studies.…”

The online assignment of the absolute configuration of natural products: HPLC‐CD in combination with quantum chemical CD calculations

“…This is frequently the case, e.g., in axially chiral biaryls with additional stereogenic centers, where usually only the axial, not the central chirality can be assigned, due to the predominance of the biaryl chromophore. 67 Thus atropo-diastereomers will usually give near-opposite CD spectra, irrespective of the absolute configuration at the stereogenic center(s). Thus, only in very few cases even two stereogenic elements, biaryl axes and stereogenic centers, could be independently assigned by CD calculations, usually requiring higher-level calculations.…”

Ancistrolikokines E–H and related 5,8′-coupled naphthylisoquinoline alkaloids from the Congolese lianaAncistrocladus likokowith antiausterity activities against PANC-1 human pancreatic cancer cells

“…5) was easily determined to be M due to its opposite ECD spectrum compared to that of the 5,1 0 -coupled ancistrocladeine (23), 38 a known, likewise fully dehydrogenated, but P-congured alkaloid previously obtained by semi-synthesis from ancistrocladine. 38,39 The new alkaloid thus possesses the structure 12. It was named ancistrolikokine G.…”

“…6A) of these 12), by comparison of its ECD spectrum with that of the known P-configured ancistrocladeine (23). 38,39 compounds hinted at the presence of naphthyltetrahydroisoquinolines, again belonging to the 5,8 0 -coupling type. The NMR data clearly revealed a great structural similarity of these metabolites, which only differed by their OH/OMe substitution patterns and the relative conguration in their tetrahydroisoquinoline portions.…”