Fumonisins backbone

The biosynthetic origin of fumonisins has been studied by several groups. C-3 to C-20 of the carbon backbone are derived fi om acetate, and C-1 and C-2, as well as the C-2 amino, are derived fi om alanine (17, 19). The two methyl groups at C-12 and C-16 are derived fi om methionine (20). Therefore, the biosynthesis of the carbon backbone of fumonisins is likely to involve a polyketide mechanism (27). The origin of the hydroxyl on the carbon backbone has also... 

A Wittig reaction of the ylide 294 with the aldehyde 289 formed the backbone 295, which was then treated with trifluoroacetic acid to remove the acetonide, followed by acylation of the diol with the (-)-TCA segment 296 (248). Hydrogenatirai of the alkene and hydrogenolysis of all benzyl protecting groups with H2 (1 atm) and Pearlman s catalyst afforded fumonisin B2 (250) (Scheme 5.6). 

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