You will prepare and submit a term paper on Total Synthesis of Any Natural Product. Your paper should be a minimum of 1250 words in length. The report focuses on the total synthesis of aflatoxin B2. The target molecule for this library report is Aflatoxin B2 which was selected from a publication entitled “Studies in Mycological Chemistry. Part XXII. Total Synthesis of (±)-Aflatoxin-B2” from the Journal of the Chemical Society C: Organic of the year 1968 on page 22. The authors of this publication are Robert, Sheppard, Roffey and Knight.
The total synthesis of aflatoxin B2 is a multistep process and sequence that was reported first by Robert et al (22). In this initial synthesis, they began with a tricyclic compound in which. The compound was taken through condensation with diethyl beta-oxoadipate which resulted in the formation of lactone. The ethyl ester formed was hydrolyzed followed by the formation of the acid chloride with oxalyl chloride. This was then taken through acylation process without further purification to yield racemic aflatoxin B2. The second total synthesis was published in 1990 by a group of scientists (Trost and Dean, 3090). They began with the intermediate by first regioselectively de-iodinating the intermediate compound to give free alcohol. The free alcohol was then protected using benzyl ether followed by the exchange of a metal halogen with n-BuLi. The products were then followed by transmetalation with lithium 2-thienylcyno curate. The final addition of cuprate unto the cyclopentanone resulted in benzyl ether. Five ringed species was then produced by cleavage of the benzyl ether through a hydrolysis process. This product was then taken through the oxidation process to produce aflatoxin B2.
The first enantioselective total synthesis of aflatoxin B2 was first presented by Zhou and Corey in 2005. They began by tricyclic compound addition between 2,3-Dihydrofuran and a Quinone in the presence of a Corey-Bakshi-Shibata (CBS) catalyst.