(+)-Cavicularin: A novel optically active cyclic bibenzyl-dihydrophenanthrene derivative from the liverwort Cavicularia densa Steph

Unified Syntheses of Cavicularin and Riccardin C: Addressing the Synthesis of an Arene Adopting a Boat Configuration

“…Thus, treatment of the product mixture with boron tribromide provided synthetic samples of cavicularin (5) and riccardin C (4) in 32 and 63 % yield, respectively, each displaying spectral characteristics identical to those reported for the natural products. [3,4,10,11] It is interesting to note that for riccardin C (4) [3,4,10,11] In CDCl 3 at 25 8C the 1 H NMR spectrum shows significant broadening of all ArCH 2 signals and those of the A ring. Consequently, the Scheme 1.…”

“…From a structural perspective, cavicularin (5), from the Japanese liverwort Cavicularia densa, is unusual in having an additional linkage between arenes C and D. [11] This imparts such strain on the paracyclophane core that it induces a boat conformation in arene A. [12] Moreover, though devoid of any stereogenic carbon centres, natural cavicularin is chiral as a result of restricted conformational freedom.…”

The Biocatalytic Repertoire of Natural Biaryl Formation

“…Such modifications can be found in many natural product families across phylogenetically diverse producing organisms and occur both inter-and intramolecularly. This results in a plethora of natural biaryl compounds (Figure 1), [3] ranging from isocyclic congeners, for example, true dimers such as (À)-gossypol (1) [4] or unsymmetric compounds such as (+)-knipholone (2), [5] over biaryls with fused heterocycles, for example, blumeanine (3), [6] and heterobiaryls, such as streptonigrin (4) [7] or even N,C-fused examples such as murrastifoline F (5), [8] to bridged biaryls, including (+)-schizandrin (6), [9] cavicularin (7), [10] and biphenomycin A (8). [11] As a result of the often rewarding biological activities of such molecules, numerous synthetic methods for their preparation have been developed.…”

The [4 + 2] Cycloaddition of 2‐Pyrone in Total Synthesis

“…Cyclophane natural product cavicularin ( 298 ) was isolated from the liverwort Cavicularia densa . Due to the rigid molecular architecture, the structure of cavicularin ( 298 ) included a phenyl A ring that distorted in a boat shape, thus displaying conformational chirality.…”