Biomimetic approaches to aflatoxins and aflatoxin model systems: Synthesis of tetrahydrofuro(2,3-b)benzofurans and formal synthesis of aflatoxin B(2).

摘要

An investigation of biomimetic rearrangement reactions in connection with the side chain branching step in the aflatoxin biosynthesis was undertaken. These results were applied to the synthesis of aflatoxins and aflatoxin bis-furan ring system models. The applicability of a cationic model of the chain-branching step in aflatoxin biosynthesis toward the synthesis of aflatoxin bis-furan systems was investigated. We successfully extended the scope of this biomimetic rearrangement by converting 6-methoxymethoxy-4;The investigation of biomimetic rearrangements was also extended to a postulated mechanism based on the rearrangement of the nidurufin side chain in an open chain form. To this end a tosylate analog, 1-(2,6-bis(methoxymethoxy)phenyl-4-;In conjunction with this investigation, a study of the reactivity of allyltriphenylarsonium ylide was conducted. It was observed that when the arsonium ylide was generated employing potassium hexamethyldisilazide, then reacted with an aldehyde, only trans-diene products were obtained. When the ylide was generated using lithium hexamethyldisiazide as the base for deprotonation, then reacted with an aldehyde, only epoxide products were formed in a 2:1 trans/cis ratio. This reactivity was found to be general for a variety of aldehydes (i.e., benzaldehyde, cyclohexanecarboxaldehyde, ;The biomimetic synthesis of the aflatoxin B