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The Lactone Concept: An Efficient Pathway to Axially Chiral Natural Products and Useful Reagents

“…Figure 1). 10,11 This naphthylisoquinoline alkaloid is a most rewarding target molecule, structurally because it is constitutionally unsymmetric, with a stereogenic biaryl axis and two additional stereocenters; biosynthetically because it is different from all the 'usual' isoquinoline alkaloids, an apparently acetogenic 98,2,9 natural product from a botanically remarkable tropical liana, 7ULSK\RSK\OOXP SHOWDWXP (Dioncophyllaceae), [99][100][101] and it has promising bioactivities, 9 among them insect antifeedant, 102,103 molluscicidal, 18,104 and antimalarial 105,106 properties.…”

“…An instructive example of this is dioncophylline C (3-), 113 the naphthylisoquinoline alkaloid with the as yet highest antimalarial activity, 14 actually, one can heal malaria-infected mice with dioncophylline C. 130 But there is no oxygen function next to the axis that might serve as a 'bridge head'. Nontheless, dioncophylline C (3-) was synthesized through the lactone methodology (Scheme 36), 114,9 the first and only synthesis of this bioactive natural product: This was achieved by intramolecular coupling of to the highly strained, slowly helimerizing biaryl lactone , again with the option of pushing virtually the whole synthetic material into one atropisomeric form, 0-, by using an 1TFA substituent, followed by ring cleavage to 0-, and then elimination of its oxygen function, which was not required any more now. This ef- .…”

Quantum chemical CD calculations of dioncophylline A in the solid state

“…Furthermore, to measure solid-state CD spectra, great care is needed to avoid or/and eliminate the inevitably expected artifacts. 13,14,15 In this paper, we describe the first theoretical and experimental solid-state CD investigations on the well-known natural product dioncophylline A (1) 16,17,18,19 as a model compound, which consists of two substantially different chromophoric units, viz. a naphthalene part and an isoquinoline portion, linked through a rotationally flexible, but still configurationally stable biaryl axis.…”

Biomimetic Total Synthesis of Mbandakamine A and Further Antiplasmodial Naphthylisoquinoline Dimers

“…Depending on their individual structures, they have pronounced anti‐infective or antitumoral activities ,. More than 200 representatives of this unique class of natural products have so far been isolated, among them more than 20 dimers, which possess even three biaryl axes ,. A structurally most fascinating dimer is mbandakamine A ( 1 a ) (see Figure ), which has recently been isolated, along with its M ‐configured atropo‐diastereomer mbandakamine B ( 1 b ), from the leaves of a botanically as yet undescribed Ancistrocladus species growing in the proximity of the town of Mbandaka in the Democratic Republic of the Congo .…”

“…Naphthylisoquinoline alkaloids are structurally, biosynthetically, and pharmacologically unique secondary metabolites, isolated from lianas belonging to the paleotropic plant families Ancistrocladaceae and Dioncophyllaceae . They consist of a naphthalene and an isoquinoline portion, both derived from polyketide precursors,, linked together by a biaryl axis that is, in most cases, rotationally hindered and, thus, stereogenic.…”