Natural bridged biaryls

NATURAL BRIDGED BIARYLS WITH AXIAL CHIRALITY AND ANTIMITOTIC PROPERTIES... 

ABSTRACT Numerous molecules containing a biaryl unit have been found in Nature. Many of them exhibit a variety of biological actions. In this review, we will focus only on natural bridged biaryls that possess axial chirality and exhibit antimitotic activities. Thus, we will first present the occurrence and structure of three families of natural compounds that display these particular structural and biological features the allocolchicinoids, steganes and rhazinilam-type compounds. We will then describe the semi-synthetic and synthetic approaches to biaryls belonging to these three series. Their interaction with tubulin, a heterodimeric protein that is critical for the formation of microtubules and consequently of the mitotic spindle, will be discussed. 

Natural Bridged Biaryls with Axial Chirality and Antimitotic Properties... 

The bis-carbazole alkaloids typically contain previously known monomeric carbazoles as structural subunits. To date, bis-carbazole alkaloids have been isolated from plants of two genera of the family Rutaceae, Murraya and Clausena, and are linked either by a methylene unit, a bisbenzylic ether bridge, a bond joining one aromatic portion directly to an annotated dihydropyran unit, or by a biaryl bond. Many reviews have appeared on the monomeric carbazole alkaloids. However, in these articles only a few bis-carbazole alkaloids were listed (3,5-7). For the first time, in 1992, Furukawa et al. compiled all of the bis-carbazole alkaloids that were known to the end of 1992 (158). Taster and Bringmann summarized to the end of 2001, the occurrence, stereochemistry, synthesis, and biological activity of the bis-carbazoles linked through a biaryl bond (159). We compiled to the mid of 2002, the occurrence, stereochemistry, synthesis, and the biological activity of all classes of bis-carbazoles (8). In this section, we cover the total syntheses of the natural bis-carbazole alkaloids reported since 1990. 

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