Syntheses of Aflatoxin Building Blocks

There exist many references describing the syntheses of aflatoxin Bj and Gj building blocks. Since aflatoxin Bi (1) can be converted via hydrogenolysis into aflatoxins Bj (2) and Gj (3) into G2 (4), the building blocks described in this chapter can also be precursors for aflatoxins B2 (2) and G2 (4). 

In 1988, Sloan et al. presented a building-block synthesis via radical-induced ring closure (55). The aromatic alcohol 78 was first substituted on 5-bromofuran-2(5//)-one, then an intramolecular, radical 1,4-addilion formed 79. Removal of the MOM-protecting group then gave 80. The synthesis is shown in Scheme 2.12. From this intermediate, Biichi et al. described the synthesis of aflatoxin Bi (1) (55). Other syntheses of building block 80 have been described by Hc fmann et al. and Bujons et al. (54,55). 

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