Trichothecene macrolides

A mechanistically related and mild fragmentation is that of 2-trimethylsilylethyl esters (Tmse esters). The Tmse residue is a selectively cleavable carboxy-protecting group (see Volume 6, Chapter 3.2) Examples are known for the synthesis, via these esters, of peptides, macrolides such as curvularin and macrocyclic trichothecenes like verrucinol (Scheme 54). °... 

The oxygenation pattern of the trichothecene nucleus in the fungal macrolides is similar to that of the simple trichothecenes, but roritoxin C is a 9yS,10/3-epoxide and four of the five known products of an unidentified Cylindrocarpon sp. have a 7/3,8/3-epoxide. A 7/ ,8/ -epoxide is also found in the simple trichothecene crotocin. 

Figure 3.129 Trichothecene biosynthesis in other genera than Fusarium proposed pathway for type B trichothecene trichothecin 372, type C trichothecene crotocin 373, and type D macrolide trichothecenes roridin A 374 and verrucarin A 375.

The most obvious difference between myrotoxins and the other trichothecenes previously reported is that the myrotoxins lack the conjugated diene system at C7, C8, C9, CIO. Instead, the double bond at C7, C8 has migrated to the C6, C7 position and is now part of an enol ether system. In addition, the myrotoxins, like the satratoxins, possess a tetraphyranyl ring within the macrolide side chain. 

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